i
COMPARATIVE STUDY OF Ischial containment socket AND
Quadrilateral socket for functional Ability
IN PERSONS WITH UNILATERAL TRANSFEMORAL AMPUTATION
Dissertation submitted to the Tamil Nadu Dr. MGR Medical University,
Chennai, in partial fulfillment of requirements for the MD Branch XIX
(Physical Medicine and Rehabilitation) examination in April 2016
ii
D E C L A R A T I O N
I hereby declare that “Comparative study of Ischial containment socket
and Quadrilateral socket for functional ability in persons with unilateral
transfemoral amputation” is my bona fide work in partial fulfillment of the
requirement of the Tamil Nadu Dr. MGR Medical University, Chennai, for
the MD Branch XIX (Physical Medicine and Rehabilitation) examination in
April 2016.
Dr. Nitha. J
Candidate Number 201329052
Department of Physical Medicine and Rehabilitation
Christian Medical College
Vellore
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C E R T I F I C A T E
This is to certify that “Comparative study of Ischial containment socket
and Quadrilateral socket for functional ability in persons with unilateral
transfemoral amputation” is the bona fide work of Dr. Nitha. J, Candidate
Number 201329052 in partial fulfillment of the requirement of the Tamil
Nadu Dr. MGR Medical University, Chennai, for the MD Branch XIX
(Physical Medicine and Rehabilitation) examination in April 2016, done
under my supervision and guidance.
Dr. Henry Prakash
Professor
Department of Physical Medicine and Rehabilitation
Christian Medical College
Vellore
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C E R T I F I C A T E
This is to certify that “Comparative study of Ischial containment socket
and Quadrilateral socket for functional ability in persons with unilateral
transfemoral amputation” is the bona fide work of Dr. Nitha.J, Candidate
Number 201329052, in partial fulfillment of the requirement of the Tamil
Nadu Dr. MGR Medical University, Chennai, for the MD Branch XIX
(Physical Medicine and Rehabilitation) examination in April 2016, done
under my supervision and guidance.
Dr. George Tharion
Professor and Head of the Department
Department of Physical Medicine and Rehabilitation
Christian Medical College
Vellore
v
C E R T I F I C A T E
This is to certify that “Comparative study of Ischial containment socket
and Quadrilateral socket for functional ability in persons with unilateral
transfemoral amputation” is the bona fide work of Dr. Nitha.J, Candidate
Number 201329052, in partial fulfillment of the requirement of The Tamil
Nadu Dr. MGR Medical University, Chennai, for the MD Branch XIX
(Physical Medicine and Rehabilitation) examination in April 2016, done
under my supervision and guidance.
Dr. Alfred Job Daniel
Principal
Christian Medical College
Vellore
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ACKNOWLEDGEMENT
Even though my name appears primarily on the covers of this thesis, a great many
people have contributed to its production. I owe my humble gratitude to all these
people who have made this thesis possible and made this work a cherishable
experience.
I would like to express my deep gratitude to my guide Dr. Henry Prakash whose
advice and guidance have enabled me to successfully complete the study. I am also
thankful to him for reading my reports, helping me understand and enrich my ideas.
I would like to thank Dr. George Tharion, Professor and Head of the Department of
PMR for his support and encouragement for this study. His insightful comments and
constructive criticisms were deeply thought provoking.
I wish to thank various people without whom this study would not have been possible
– All who have been involved with the study from the department of Prosthetics and
Orthotics, for their valuable suggestions, time and efforts. Particularly, I would like
to acknowledge Mr. Vinoth Jacob, from P&O for his unstinted support and
cooperation. Special thanks to Mr. Mansur Ali and Mr. Dinesh from P&O for their
support in the completion of the thesis. The doctors in charge of the Amputee Clinic
who helped me enroll my patients, my teachers and friends in the department who
have played a part, I am grateful.
vii
A special thanks to Mrs. Joyce the neutral assessor and gait analyst, who have helped
me with the data acquisition.
I would like to express my great appreciation to the patients who took part in the
study without whom none of this would have been possible.
Most importantly, none of this would have been possible without the love and
patience of my family. I am deeply thankful to my 2 year old son Aadith, who
without any complaints for the limited time I spent with him, has loved me and made
my life meaningful. Special thanks to my loving husband and my ever caring parents,
who have stood by me always.
Last but not the least the God Almighty, who has given me the strength.
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O R I G I N A L I T Y R E P O R T P D F
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CONTENTS
ORGINALITY REPORT PDF………………………………………………………………………………………………………….ix
CONTENTS ................................................................................................................................................................................... x
LIST OF FIGURES ................................................................................................................................................................... xv
LIST OF TABLES ................................................................................................................................................................... xvii
LIST OF EQUATIONS ........................................................................................................................................................ xviii
ABSTRACT ................................................................................................................................................................................ xx
1 INTRODUCTION .............................................................................................................................................................. 1
2 AIMS & OBJECTIVES ..................................................................................................................................................... 3
2.1 AIM ............................................................................................................................................................................. 3
2.2 OBJECTIVE .............................................................................................................................................................. 3
3 REVIEW OF LITERATURE .......................................................................................................................................... 3
3.1 AMPUTATION ........................................................................................................................................................ 3
3.1.1 STATISTICS ................................................................................................................................................... 4
3.1.2 ETIOLOGY OF AMPUTATION ................................................................................................................. 4
3.2 REHABILITATION OF PERSONS WITH TRANSFEMORAL AMPUTATION .................................... 5
3.2.1 PRE-OPERATIVE PERIOD ........................................................................................................................ 6
3.2.2 TRANSFEMORAL AMPUTATION .......................................................................................................... 6
3.2.3 ACUTE POST SURGICAL MANAGEMENT .......................................................................................... 7
xi
3.2.4 PRE-PROSTHETIC TRAINING ................................................................................................................ 8
3.3 PROSTHESIS ........................................................................................................................................................... 9
3.3.1 HISTORY ......................................................................................................................................................... 9
3.3.2 BIOMECHANICAL PRINCIPLES OF TRANSFEMORAL PROSTHESIS .................................... 10
3.4 COMPONENTS OF TRANSFEMORAL PROSTHESIS .............................................................................. 17
3.5 SUSPENSION SYSTEMS .................................................................................................................................... 18
3.6 SOCKET ................................................................................................................................................................... 19
3.7 QUADRILATERAL SOCKET ............................................................................................................................. 20
3.8 ISCHIAL CONTAINMENT SOCKET ............................................................................................................... 21
3.8.1 EVOLUTION ................................................................................................................................................. 21
3.8.2 DIMENSIONS .............................................................................................................................................. 27
3.8.3 NSNA (NORMAL SHAPE-NORMAL ALIGNMENT TECHNIQUE)............................................. 31
3.8.4 CAT-CAM(CONTOURED ADDUCTED TROCHANTERIC-CONTROLLED ALIGNMENT
METHOD) ........................................................................................................................................................................ 31
3.8.5 NARROW M-L (NARROW MEDIO-LATERAL SOCKET) ............................................................. 32
3.8.6 SCAT-CAM (SKELETAL CONTOURED ADDUCTED TROCHANTERIC CONTROLLED
ALIGNMENT METHOD) ............................................................................................................................................. 32
3.9 OTHER SOCKET DESIGNS FOR TRANSFEMORAL PROSTHESIS ..................................................... 32
3.9.1 FLEXIBLE SOCKETS ................................................................................................................................. 33
3.9.2 MARLO ANATOMICAL SOCKET .......................................................................................................... 34
3.9.3 OSSEOINTEGRATION .............................................................................................................................. 35
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3.10 KNEE JOINTS ........................................................................................................................................................ 36
3.11 FOOT-ANKLE ASSEMBLIES ............................................................................................................................ 39
3.12 FABRICATION AND ALIGNMENT OF TRANSFEMORAL PROSTHESIS ......................................... 41
3.13 PROSTHETIC TRAINING .................................................................................................................................. 45
3.14 NORMAL GAIT ..................................................................................................................................................... 45
3.14.1 GAIT ANALYSIS .......................................................................................................................................... 46
3.15 TRANSFEMORAL PROSTHETIC GAIT ........................................................................................................ 47
3.16 ENERGY EFFICIENCY ........................................................................................................................................ 50
3.17 JUSTIFICATION OF THE STUDY ................................................................................................................... 51
4 METHODOLOGY ........................................................................................................................................................... 53
4.1 STUDY DESIGN .................................................................................................................................................... 53
4.2 INTERVENTION .................................................................................................................................................. 53
4.3 SETTINGS AND LOCATION ............................................................................................................................. 55
4.4 ETHICS COMMITTEE APPROVAL ................................................................................................................ 56
4.5 PARTICIPANTS .................................................................................................................................................... 56
4.6 INCLUSION CRITERIA ...................................................................................................................................... 57
4.7 EXCLUSION CRITERIA ...................................................................................................................................... 57
4.8 SAMPLE SIZE ........................................................................................................................................................ 57
4.9 OUTCOME MEASURES ..................................................................................................................................... 58
4.9.1 PRIMARY OUTCOME MEASURES ....................................................................................................... 58
4.9.1.1 6 MINUTE WALK TEST (6MWT) ................................................................................................... 59
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4.9.1.2 TIMED UP AND GO TEST (TUG)..................................................................................................... 59
4.9.1.3 SOCKET COMFORT SCORE (SCS) .................................................................................................. 60
4.9.1.4 SOCKET PREFERENCE ....................................................................................................................... 61
4.9.2 SECONDARY OUTCOME MEASURES ................................................................................................ 61
4.9.2.1 PHYSIOLOGICAL COST INDEX (PCI) ............................................................................................ 61
4.9.2.2 GAIT ANALYSIS ..................................................................................................................................... 62
4.10 STATISTICAL ANALYSIS .................................................................................................................................. 64
4.11 FLOW DIAGRAM ................................................................................................................................................. 65
5 RESULTS .......................................................................................................................................................................... 66
5.1 DEMOGRAPHIC DATA ...................................................................................................................................... 66
5.1.1 AMBULATION STATUS ........................................................................................................................... 67
5.1.2 AGE ................................................................................................................................................................. 67
5.1.3 SIDE OF AMPUTATION ........................................................................................................................... 67
5.1.4 ETIOLOGY .................................................................................................................................................... 68
5.1.5 GENDER ........................................................................................................................................................ 68
5.1.6 BODY MASS INDEX................................................................................................................................... 68
5.1.7 DURATION OF PROSTHETIC USE ...................................................................................................... 69
5.1.8 RESIDUAL LIMB LENGTH INDEX ....................................................................................................... 69
5.2 PRIMARY OUTCOME MEASURE ................................................................................................................... 70
5.2.1 6 MINUTE WALK TEST ........................................................................................................................... 70
5.2.2 TIMED UP AND GO ................................................................................................................................... 72
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5.2.3 SOCKET COMFORT SCORE ................................................................................................................... 75
5.2.4 SOCKET PREFERENCE ............................................................................................................................ 77
5.3 SECONDARY OUTCOME MEASURES .......................................................................................................... 78
5.3.1 ENERGY EFFICIENCY .............................................................................................................................. 78
5.3.2 GAIT VELOCITY ......................................................................................................................................... 79
5.3.3 GAIT CADENCE .......................................................................................................................................... 82
5.3.4 STRIDE LENGTH ....................................................................................................................................... 83
5.3.5 SINGLE LIMB SUPPORT ......................................................................................................................... 85
5.3.6 STANCE SWING RATIO ........................................................................................................................... 86
6 DISCUSSION.................................................................................................................................................................... 87
7 CONCLUSION ................................................................................................................................................................. 94
8 LIMITATIONS................................................................................................................................................................. 95
9 SCOPE OF FUTURE RESEARCH .............................................................................................................................. 96
10 BIBLIOGRAPHY ........................................................................................................................................................ 97
11 ANNEXURE ............................................................................................................................................................. 105
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LIST OF FIGURES
Figure 3-1 - FORCE VECTORS ACTING ON SINGLE LIMB SUPPORT ................................................................ 11
Figure 3-2 – PELVIS ACTING AS LEVER ....................................................................................................................... 12
Figure 3-3 - ALIGNMENT STABILITY ............................................................................................................................ 15
Figure 3-4 HIP ABDUCTOR INSUFFICIENCY .............................................................................................................. 22
Figure 3-5 QUADRILATERAL SOCKET .......................................................................................................................... 22
Figure 3-6 LATERAL TRUNK LEAN ................................................................................................................................ 23
Figure 3-7 PROTO ISCHIAL CONTAINMENT SOCKET ALIGNMENT ................................................................ 25
Figure 3-8 ISCHIAL CONTAINMENT SOCKET ............................................................................................................ 26
Figure 3-9 – COMPONENTS IN TRANSFEMORAL KIT OF ICRC .......................................................................... 41
Figure 4-1 ISCHIAL CONTAINMENT FABRICATION PROCEDURE ................................................................... 55
Figure 4-2 – TIMED UP & GO TEST ................................................................................................................................ 60
Figure 4-3- GAIT ANALYSIS............................................................................................................................................... 63
Figure 5-1 ETIOLOGY OF AMPUTATION ..................................................................................................................... 68
Figure 5-2-6MWT TEST IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET ................................ 71
Figure 5-3 – RELATION OF 6MWT VS AGE ................................................................................................................. 71
Figure 5-4- 6MWT VS ETIOLOGY .................................................................................................................................... 72
Figure 5-5- 6MWT VS DURATION OF PROSTETIC USE ......................................................................................... 72
Figure 5-6- TUG TEST IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET .................................... 74
Figure 5-7- TUG VS ETIOLOGY ......................................................................................................................................... 74
Figure 5-8- TUG VS AGE ...................................................................................................................................................... 75
Figure 5-9- TUG VS DURATION OF PROSTHETIC USE ........................................................................................... 75
Figure 5-10- SCS IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET ............................................... 77
Figure 5-11 – SOCKET PREFERENCE IN TRANSFEMORAL AMPUTEE PERSONS ...................................... 77
Figure 5-12- PCI IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET ............................................... 78
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Figure 5-13- GAIT VELOCITY IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET ..................... 81
Figure 5-14 – GAIT VELOCITY VS ETIOLOGY ............................................................................................................ 81
Figure 5-15- GAIT VELOCITY VS AGE ........................................................................................................................... 81
Figure 5-16- GAIT CADENCE IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET ...................... 83
Figure 5-17 – STRIDE LENGTH IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET .................. 83
Figure 5-18 – STRIDE LENGTH VS AGE ........................................................................................................................ 84
Figure 5-19 – SINGLE LIMB SUPPORT IN AMPUTATED & NORMAL SIDE .................................................... 85
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LIST OF TABLES
Table 3-1PHASES OF AMPUTEE REHABILITATION ................................................................................................. 5
Table 3-2 COMPARISON OF QUAD & IC SOCKET ..................................................................................................... 30
Table 5-1 DEMOGRAPHIC DATA OF PATIENTS........................................................................................................ 66
Table 5-2 AGE DISTRUBUTION OF PATIENTS .......................................................................................................... 67
Table 5-3 DURATION OF PROSTHETIC USE ............................................................................................................... 69
Table 5-4 CORRELATION OF THE 6 MINUTE WALK TEST WITH AGE, ETIOLOGY AND
DURATION OF PROSTHETIC USE IN QUAD AND IC GROUPS .................................................................. 70
Table 5-5 CORRELATION OF THE TIMED UP AND GO TEST WITH AGE, ETIOLOGY AND
DURATION OF PROSTHETIC USE IN QUAD AND IC GROUPS .................................................................. 73
Table 5-6 CORRELATION OF THE SOCKET COMFORT SCORE WITH AGE, ETIOLOGY AND
DURATION OF PROSTHETIC USE .............................................................................................................................. 76
Table 5-7 CORRELATION OF THE PHYSIOLOGICAL COST INDEX WITH AGE, ETIOLOGY
AND DURATION OF PROSTHETIC USE .................................................................................................................. 79
Table 5-8 CORRELATION OF THE GAIT VELOCITY WITH AGE, ETIOLOGY AND DURATION
OF PROSTHETIC USE ........................................................................................................................................................ 80
Table 5-9 CORRELATION OF THE GAIT CADENCE WITH AGE, ETIOLOGY AND DURATION
OF PROSTHETIC USE IN THE QUAD AND IC GROUPS. ................................................................................. 82
Table 5-10 CORRELATION OF THE STRIDE LENGTH WITH AGE, ETIOLOGY AND DURATION
OF PROSTHETIC USE IN THE QUAD AND IC GROUPS .................................................................................. 84
Table 5-11 SINGLE LIMB SUPPORT OF AMPUTATED AND NORMAL SIDE LIMBS WITH QUAD
AND IC SOCKET .................................................................................................................................................................. 85
Table 5-12 STANCE SWING RATIO OF THE AMPUTATED AND NORMAL SIDES WITH QUAD
AND IC SOCKET .................................................................................................................................................................. 86
xviii
LIST OF EQUATIONS
Equation 1 SAMPLE SIZE CALCULATION .................................................................................................................... 58
Equation 2 PHYSIOLOGICAL COST INDEX .................................................................................................................. 62
Equation 3 RESIDUAL LIMB LENGTH INDEX ............................................................................................................ 69
xix
TITLE OF THE STUDY
Comparative study of ischial containment socket and
quadrilateral socket for functional ability in persons with
unilateral transfemoral amputation
PLACE OF STUDY
Dept. of Physical Medicine and Rehabilitation
Christian Medical College, Vellore
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ABSTRACT
TITLE
Comparative study of ischial containment socket and quadrilateral socket for
functional ability in persons with unilateral transfemoral amputation.
OBJECTIVE
To compare ischial containment socket with quadrilateral socket in transfemoral
amputee persons in terms of functional ability and socket preference.
METHODOLOGY
This is an interventional study where transfemoral amputee persons ambulant with
prosthetic limb fitted with quadrilateral socket were enrolled after informed consent.
First assessment was done with the quadrilateral socket during the initial visit. Then
they were provided with ischial containment socket. The knee component, pylon and
the foot piece were retained without alteration. Each patient was given two weeks’
time to acclimatize to the new socket. At the end of two weeks all the assessments
were repeated with the ischial containment socket.
OUTCOME MEASURES
Functional ability was measured with the 6-minute walk test (6MWT) and Timed Up
& Go (TUG) test. Subjective preference was tested with socket comfort score and
xxi
final socket preference. The secondary outcome measures were energy efficiency
with Physiological Cost Index and gait parameters. The outcome measures were
statistically analyzed with the paired T test.
RESULTS
The ischial containment socket (IC) was preferred by 87 % of patients who were
already community ambulant with quadrilateral socket (QUAD). The socket comfort
score significantly improved with the ischial containment socket. The ischial
containment socket is superior to quadrilateral socket in terms of comfort. The
comfortable walking speed of transfemoral amputee persons improved with the
ischial containment socket. The gait velocity and stride length showed statistically
significant improvement with ischial containment socket. The 6MWT, TUG and PCI
showed better results with ischial containment socket even though the improvement
was not statistically significant. Observable variations in gait deviations were not
seen with the socket change.
CONCLUSION
The ischial containment socket is an evolutionary transfemoral socket design, which
provides better comfort for transfemoral amputee persons. The ischial containment
socket might potentially improve walking ability and endurance in unilateral
transfemoral amputee persons.
1
1 INTRODUCTION
Amputation is a lifesaving as well as a life changing event. Once the decision for
elective amputation is made, the primary focus should be preparing the individual
physically and mentally for the surgical procedure. Such amputations should be
followed by a goal oriented extensive rehabilitation phase. Functional rehabilitation
of amputee person’s, especially ones with higher levels of amputation like
transfemoral levels is a challenge. To restore all the functional activities at their near
normal physiological level should be the ultimate goal.
The residual limb is fitted with prosthesis. The expected role of prosthesis is
substituting the functions of normal limb, which is independent ambulation in lower
limb amputee persons. The prosthesis should provide comfort as well as cosmesis.
Prosthetic rehabilitation should make the person capable of leading a normal and
successful life as far as possible.
Understanding of the complex biomechanics of human locomotion as well as
developments in material science has contributed in the advancement in field of
prosthetic design and fabrication. The prosthetic technology has evolved from the
plug fit wooden sockets to osseo-integrated prosthesis, microprocessor knee and
dynamic response feet. Whether these technological advancements are really
reflected in the functional abilities of the amputee persons is not known very
well.
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A socket is a part of the prosthesis which attaches to the residual limb. For
transfemoral residual limb a few socket designs have been developed over the last
few decades. The Quadrilateral socket has been the socket design of choice for
transfemoral prosthesis from its inception in 1950’s till last two decades. The Ischial
containment socket emerged in 1980’s with sound biomechanical concepts while
addressing the short comings of quadrilateral socket. Even though the biomechanical
principles of the ischial containment socket is better; the quadrilateral socket
continued to be the preference in most of the nations.(1) The skill needed to fabricate
an ischial containment socket is more than the conventional quadrilateral socket.
This study aims at comparing the ischial containment socket with quadrilateral socket
in terms of functional abilities and socket preference. Does the theoretical advantage
of ischial containment socket, correlate with the functional outcome of transfemoral
amputee persons?
In this study transfemoral amputee persons who have been ambulant with
quadrilateral socket were recruited and were given prosthesis, where the quadrilateral
socket was replaced with an ischial containment socket. Outcome measures were
assessed with quadrilateral as well as ischial containment socket, followed by
statistical analysis. The outcome measures used in this study were 6 minute walk test,
timed up and go test, socket comfort score, socket preference, gait parameters and
physiological cost index. At the end of the study patients were given an option to
choose whichever socket they like.
3
2 AIMS & OBJECTIVES
2.1 AIM
To evaluate the theoretical advantage of ischial containment socket over quadrilateral
socket in rehabilitation of transfemoral amputee persons.
2.2 OBJECTIVE
To compare ischial containment socket with quadrilateral socket in transfemoral
amputee persons in terms of functional ability and socket preference.
3 REVIEW OF LITERATURE
3.1 AMPUTATION
Amputation is the removal of a limb or a part of the limb by trauma, medical illness,
or surgery. History of amputation dates back to Hippocrates era. Then the surgical
principle was lost in Dark Ages and reintroduced in 1529 by Ambroise Pare, when he
first used ligatures to control bleeding. The introduction of tourniquet by Morel and
antiseptic technique by Lord Lister contributed in the further development of
amputation techniques. The discovery of chloroform as an anesthetic agent made the
surgery more reasonable. The surgical technique of amputation advanced rapidly
after world war. Amputation was done mainly as a lifesaving procedure.(2)
4
3.1.1 STATISTICS
Global burden of disease refers disability as “loss of health where health is
conceptualized in terms of functioning capacity in a set of health domains such as
mobility, cognition, hearing and vision”.(3) According to WHO statistics the global
disability prevalence is 15 % that is about one in seven of world population is
disabled.(4) As per the Census of India 2011, 2.1 percent of Indian population is
estimated to have disability.(5) Even though amputation being a major contributor to
disability, its exact burden on disability or its global incidence is unknown. The
available data shows considerable variations among countries and within countries.
3.1.2 ETIOLOGY OF AMPUTATION
Globally the main three causes for amputation are trauma, diseases and congenital
malformation. Trauma is the major cause of amputation globally.(6) Diabetes
contributes 30-90 percent of lower extremity amputations.(7) In India the major
cause for amputation is trauma.(8,9) The next important cause is diseases. Chronic
diabetes and peripheral vascular disease is the most common non traumatic cause for
lower limb amputations.(10) The study conducted by Pooja et.al from Kolkata
observed that 70 percent of amputation was due to trauma and 27 percent due to
vascular disease. Traumatic amputations are more with young and active individuals,
with male predominance.(8) Lower limb amputations constitute about 95% of all
major amputations. The most common level of amputation is transtibial level.
Amputations due to malignancy, the commonest level is transfemoral.(6)
5
3.2 REHABILITATION OF PERSONS WITH TRANSFEMORAL AMPUTATION
Rehabilitation of an amputee person includes a multidisciplinary approach, involving
surgeon, physiatrist, psychologist, physiotherapist, occupational therapist and
prosthetic technicians. Adequate rehabilitation should aim at restoring the acceptable
functional capacities allowing individuals to achieve their goals, allow participation
in society and to improve quality of life with or without prosthesis.(11) The
rehabilitation process should start when the decision for amputation is made,
covering pre and post-surgical period. The patient should be informed about the
anticipated functional outcomes according to the level of amputation and medical
conditions.(12)The phases of amputee rehabilitation are as follows(6,13,14)
TABLE 3-1PHASES OF AMPUTEE REHABILITATION
PHASES GOALS
1. Preoperative
Preparing psychologically and physically for amputation,
determining the level of amputation, discussing the expected
functional outcomes, alleviating anxiety and stress,
sensitizing about phantom pain and phantom sensation.
2.Amputation
surgery
Myoplasty techniques for better femur adduction, Nerve
handling, Rigid dressing application
3. Acute post-
surgical
Optimization of analgesics. Emotional support, mobilization
of proximal body, wound healing
6
4.Preprosthetic Residual limb shaping, restoring sense of control, improving
muscle power and maintaining full range of motion
5.Prosthetic
Fabrication
Consensus on prosthetic prescription, prosthetic measurement
and fabrication
6.Prosthetic
Training
Functional use of prosthesis
7. Community
integration
Resuming social roles, developing healthy coping strategies,
recreational activities
8.Vocational
Rehabilitation
Job modifications and training
9.Follow up Lifelong medical, functional and prosthetic assessment and
emotional support
3.2.1 PRE-OPERATIVE PERIOD
The functional rehabilitation in the preoperative period includes maintaining ROM,
stretching out the contracted muscles, conditioning the normal side, increasing the
endurance, practicing the single limb gait. This preoperative initiation of
rehabilitation can reduce the time spent in postoperative rehabilitation.(12)
3.2.2 TRANSFEMORAL AMPUTATION
Trans femoral amputations forms about 30% of total major amputations.(6) Trans
femoral amputations can be classified as supracondylar, long, medium and short
depending on the length of the femur segment preserved.(15)
7
Gottschalk modification - Gottschalk found that the prosthetic shape or alignment is
not sufficient to keep hip in adduction. Hence he modified the transfemoral
amputation surgical principle by preserving the adductor magnus if possible and
attaching it to distal end of femur with drill holes, while femur is maintained in
adduction.(16) Even though the biomechanical principle was good, it didn’t evolve as
a standard surgical practice.
3.2.3 ACUTE POST SURGICAL MANAGEMENT
In the acute post-surgical period pain management and wound care is most important.
The residual limb can be fitted with immediate post-operative prosthesis or
prefabricated prosthesis.
IMMEDIATE POST OPERATIVE PROSTHESIS (IPOP) – It is applied in the
operation room itself. It consists of a rigid dressing made of POP or fiberglass, a
connector, pylon and a foot piece. Early ambulation in the second or third post-
operative day is the most important advantage of this technique. The other
advantages are reduction of edema, protection from trauma, lower rate of
complications, early definitive prosthesis fitting and shorter rehabilitation time. IPOP
is an emotional enhancer since the presence of prosthetic limb aids with better body
image. The disadvantages are mechanical stress, tissue necrosis and wound
dehiscence along with reduced access to wound inspection. To apply an IPOP skilled
prosthetic team is required.(17,18)
8
PREFABRICATED POSTOPERATIVE PROSTHETIC SYSTEMS (PFPS)
Prefabricated prosthesis are designed for early gait re-education following surgery.
They provide a psychological boost and decrease the time interval for definitive
prosthesis. They are similar to IPOP methods but use pneumatic technology for
socket holding. The residual limb with soft dressing will be lined by air cell, or air
bags which can be inflated and serves as the socket residual limb interface. This can
be inflated up to 20-40 mm of Hg, thus providing excellent external compression.
The advantages are early weight bearing, easy removal and replacement for wound
inspection. It reduces the limb swelling by pneumatic compression. The
disadvantages are expensive, bulky along with difficult donning and doffing.(18–20)
3.2.4 PRE-PROSTHETIC TRAINING
The goal of early post-operative period is functional rehabilitation.
PHYSICAL TRAINING -Individualized exercise schedule should be instructed to
improve or maintain the range of motion of all the limbs, to improve the strength of
the limbs and to improve endurance for daily activities.(6)
TRANSFERS AND MOBILITY- In the early phase amputee persons are taught
bed mobility, transfers, and mobilization to a chair or wheelchair. Subsequently gait
training is initiated inside the parallel bar and progressed to elbow crutches. The
pre-prosthetic training provides the patient a safe return home with the temporary
assistance of crutches, walker or wheelchair or with an early fitted prosthesis.
9
The residual limb will continue to shrink and hence definitive prosthesis fitting will
require 6- 8 months post amputation.(12)
3.3 PROSTHESIS
Prosthesis is a device which substitutes for a missing body part.
3.3.1 HISTORY
Humans for centuries have discovered ingenious ways to replace the lost body part.
The history of prosthesis dates back to Greek and Roman times, with little
advancement in the Dark Ages. In the year 2000, researchers in Cairo, Egypt,
unearthed the oldest documented prosthesis – 3000 year old toe made of wood and
leather. In 1500’s German’s made prosthetic limbs utilizing iron, springs and leather.
French surgeon Ambrose Paré invented transfemoral prosthesis with peg leg and foot
piece, adjustable harness, knee lock control and other engineering features that are
used in today's devices. Lorrain, a French locksmith used leather, paper and glue in
place of heavy iron in making prosthesis, which later became a major contribution in
prosthetic technology. In 1863, Dubois Parmlee invented an advanced prosthesis with
a suction socket, polycentric knee and multi-articulated foot. Following the U.S Civil
War and World War 2 the number of amputations increased astronomically. This
eventually led to the formation of the American Orthotic & Prosthetic Association
(AOPA) for better prosthetic design and technology.(21) Prosthetic devices which
are much lighter made of plastic, aluminum and composite materials were produced
10
with new technologies and advancement of prosthetic design. In the last century new
sophisticated prosthesis were developed, with microprocessors and computerized
technologies. The socket fitting also got revolutionized with the introduction of
osseo-integrated prosthesis. (2,21)
3.3.2 BIOMECHANICAL PRINCIPLES OF TRANSFEMORAL PROSTHESIS
The requirements for a good transfemoral prosthesis is basically three in number—
comfort, function, and appearance. The user of the prostheses will not be able to wear
it unless it is comfortable. It should enable the wearer to perform functions with ease.
In addition to the above the prosthesis should be cosmetically acceptable and natural
to the wearer as well. The prosthesis should provide adequate support and a naturally
appearing gait. Hence to ensure that all the 3 functionalities are suitably met, the
correct bio mechanical principles are to be used.
MEDIO-LATERAL STABILITY
Two specific deviations of gait observed in transfemoral amputee persons were.
a) Exaggerated lateral movement of the torso from side to side.
b) Increased step width.
Hence achieving a narrow based gait and adequate medio-lateral stability is crucial
for a transfemoral prosthesis.(22) A normal person walks with a step width
measuring about 2-4 inches whereas in the case of an amputee person’s step width is
in the range of 6-12 inch.(22) The greater step width provides stability and comfort.
11
FIGURE 3-1 - FORCE VECTORS ACTING ON SINGLE LIMB SUPPORT
DEFINITIONS (22, 23)
The center of gravity of the body can be defined as a point within the body at
which the effect of all body weight can be assumed to be concentrated. As per the
laws of physics the body weight must be assumed as acting vertically down from this
center of gravity. “The weight line of the body is a line through the center of gravity
along which the body weight can be assumed to
act vertically downward at all times.” The total
force exerted on the sole of the foot is known as
the floor reaction force which is the load which
the leg transmits upwards. The load line can be
defined as the line along which the force
between the foot and the floor acts. The
support line is defined as a vertical or plumb
line, passing through the support point, along
which the effective supporting force between the
socket rim and the residual limb can be assumed
to act.(Figure 3.1)
ROLE OF HIP ABDUCTORS
During midstance the pelvis drops 5 degree in the unsupported side. Further pelvic
drop is prevented by the eccentric contraction of hip abductors. In normal persons
weight bearing occurs through the bones of the leg, and gluteus is effective in
12
FIGURE 3-2 – PELVIS ACTING AS LEVER
controlling the pelvic drop. In case of the transfemoral amputee persons, the residual
femur during weight bearing shift’s laterally since the femur floats in soft tissue mass
without any bony attachment distally.(24) There occurs increase in pressure in the
perineal area due to drop of pelvis towards the normal side, which is uncomfortable,
hence the amputee persons compensates by leaning over the prosthesis which results
in amputee persons’ list or walking with wide base. The gluteus medius has to be
maintained in functional position for providing comfortable and normal gait for the
amputee persons.(25)
THE PELVIC LEVER
As illustrated by the Figure 3.2, while the amputee
person is bearing weight on the prosthesis during
stance phase, the pelvis acts as a lever. The body
weight is supported by the pelvic lever by
balancing action of the hip abductors, using the
ischium as fulcrum. The body weight is balanced
by the tension in the hip abductors whereas the
lever action of the pelvis prevents the dropping of
the pelvis towards the unsupported side.(23)
However this is possible only if the residual limb
abduction is stopped by contact against socket lateral wall.
13
DISTRIBUTION OF LATERAL PRESSURE
Distribution of counter pressure uniformly over the lateral side of the socket ensures
stabilisation of the residual limb. If the length of the residual limb is average, then
stabilisation can be achieved by fitting the residual limb over the entire lateral wall.
However if the hip abductors are used for pelvic stabilisation with residual limb not
properly supported against lateral wall, then end of residual limb may get subjected
to intense compressive forces causing pain.
The lateral stabilisation of the pelvis by the hip abductors is influenced by
predominately two factors (22)
a) Lever arm between the abductor and support point – The tension in
abductors has greater advantage when the lever arm is at the lengthiest. If the
ischial seat and gluteal musculature support the body weight substantially then
amputee persons is at ease to balance the body weight.
b) Degree of residual limb adduction in socket - Efficiency of muscles is at
the peak when they are at normal rest length. If the movement of femur is
anticipated and pelvic femoral angle maintained, then the hip abductors are
most efficient.
KNEE CONTROL
Knee stability refers to maintain the knee in extension during the stance phase. Knee
instability happens when the prosthetic knee buckles under load. Excessive knee
stability will lead to difficult swing phase initiation and increased energy
expenditure. The knee stability can be imparted by involuntary control or voluntary
14
control. Depending on the age and residual limb condition of amputee persons, a
fine balance needs to be maintained between the degree of involuntary and voluntary
control.
Involuntary Control
If the weight line is anterior to the knee axis, the weight bearing tends to extend the
knee and locks it against the extension stop. Prosthesis can be said to be in a state of
high alignment stability when the socket is placed well forward on knee block or
aligned in hyper extension and knee joint posterior to angle.(22) This is
predominantly required for eliminating the fear of falling. However the limitation is
that the prosthesis being hard, flexibility is limited and normal gait gets
compromised.
Voluntary Control
In order to enable amputee persons to have near normal gait, the use of involuntary
control has to be minimised and voluntary control by residual limb action needs to
be emphasised. The key to voluntary control is effective utilisation of the hip
extensor musculature. For voluntary control, the hip extensors – gluteus maximus
and hamstrings should be able to exert enough force to maintain the knee in
extension. However voluntary control is exercised such that the residual limb should
not exceed the limits of hip range of motion.(24)
15
FIGURE 3-3 - ALIGNMENT STABILITY
INITIAL FLEXION
The hip extensors should be at an optimum resting length for exerting extension force
in the knee. For this the glutei has to be kept stretched. The socket is aligned in initial
flexion to increase the resting length.(Figure 3.3) Hence the amputee persons will
have greater knee stability during walking, as the length of the hip extensors is
increased by hip flexion. This enables the residual limb to exert sufficient force
without any conscious effort by the amputee persons, to keep the knee back against
the extension stop.(24) The transfemoral amputee persons walk with increased pelvic
lordosis if the hip extensors are weak, this can be decreased by keeping the socket in
initial flexion.(22,26) The hamstring muscles in the case of amputee persons with a
well-developed musculature tend to force the ischium off the ischial seat. This causes
tremendous pressure on the muscles and
the anterior brim of the socket. This is
reduced to a great extent by the initial
flexion, by allowing the body weight to be
borne by the hamstring musculature. The
flexibility of the prosthetic knee is
enhanced to a great extent by positioning
the socket anterior to the knee axis as this
allows easy transmission of weight from
the prosthesis to normal leg.
16
FOOT POSITION
The feet of the amputee persons should be in medial position alignment to ensure
that weight is borne primarily by the ischial seat and the torso list is minimal.
Normally the center line of feet will be aligned below the ischium for an amputee
person. However this may not apply always, as it is dependent on the ability of
amputee persons to use hip abduction. If an amputee person has a very short
residual limb, then excessive dependence on the abductors may result in pain and
will force him to lean over the prosthesis and walk with wider base. (23)
DYNAMIC ALIGNMENT
The forces acting on the prosthesis in the case of an amputee person varies with the
different phases of gait. The dynamic forces will greatly influence the behaviour of
the prosthesis during the swing phase as well as stance to swing and swing to stance
phase. The pre requisite towards achieving a smooth swing phase is good transition
from the stance to swing phase.(27) When the alignment stability of the prosthesis
is high the initiation of the swing phase will be delayed and the energy required is
high. Swing phase vaulting happens when the prosthesis is too long. The lateral
knee movement along with medial foot movement of the prosthesis caused by poor
dynamic alignment is known as the whip of the prosthesis.(26)
17
ROTATION OF KNEE AXIS
Extensive studies on human locomotion have indicated that during motion, when
the knee is brought forward by hip flexion the femur rotates by 40 on an average.
This medial rotation of the femur will result in lateral displacement of the feet. In
order to overcome this medial rotation of the femur on hip flexion, the knee axis is
also rotated laterally.(22)
ANKLE – FOOT - DYNAMICS
The most unstable phase of an amputee persons’ gait is ‘heel strike’. When the heel
of an amputee person contacts the ground, knee flexor moment is produced causing
the knee to buckle. In normal gait the controlled plantar flexion will stabilize the
knee. In transfemoral prosthesis the stiffness of plantar flexion is the most
significant factor affecting the knee stability. If the ankle is too stiff then, the feet is
not allowed to rotate forward to a flat stable position. This will cause the knee to
buckle on the transfer of weight to prosthesis. On the other hand if the plantar
flexion stiffness is not sufficient then the feet will have a tendency to slap at the
heel contact. Hence the key is to have a proper balance for each amputee
person.(26)
3.4 COMPONENTS OF TRANSFEMORAL PROSTHESIS
Transfemoral prosthesis is constituted by suspension systems, socket, knee joint,
shank, and ankle-foot complex.
18
3.5 SUSPENSION SYSTEMS
A prosthesis can be suspended using many methods like belts, liners, suction and
vacuum suspension.
Belt Suspension - Three different types of belt suspensions are used for a
transfemoral prosthesis i.e. total elastic suspension belt, silesian belt and pelvic band
with hip joint.(12)
Elastomeric Liner Suspension - Liner suspension can be used either with pins /
lanyards. The liner suspension with either pin / lanyard type has advantages like
increased shear control, cushioning, and greater suspension and comfort.(28)
However these liners require frequent replacement, add bulk and pose hygiene
challenges.
Suction Suspension– In this mode of suspension, air is only allowed to exit & not
enter by placing a single side valve near the distal region. On placing the limb in the
socket, the sock is pulled out thereby sliding the limb in the socket. This can be
achieved by use of special nylon socks, elastic bandage or wet fit method. While the
suction suspension is the most secure of all suspensions, it has certain disadvantages
like it is difficult to don.(29) Moreover any weight gain may result in adductor roll,
and erythema whereas volume loss will result in loss of suspension.
19
Vacuum Suspension system - Vacuum systems are new and advanced version of the
suspension systems which use an active mechanism to expel air from inner socket.
These systems require both gel liner and sealing sleeve and the air is removed and
vacuum achieved through a mechanical / electric pump. This provides for better
suspension, maintains the limb volume and increased tissue oxygenation in the
residual limb.(30) However the disadvantage of the system is that the vacuum seal is
lost if a hole is formed on the sleeve. Moreover the cost as well as the weight of the
device is increased on account of this.
3.6 SOCKET
Introduction
Socket is the human prosthesis interface. Earlier design of the transfemoral socket
was wooden socket with a conical interior shape – plug fit. The weight of the
amputee person was transferred through the thigh muscles. The quadrilateral socket
design which provided ischial-gluteal weight bearing was introduced in 1950s. In
1980s a second generation of transfemoral sockets – the ischial containment socket
emerged due to the work of Long, Mayfield and Sabolich. The socket evolution
continued and newer socket design like Marlo Anatomical System developed. By the
end of 19th century direct bony anchoring of the prosthesis – Osseo-integrated
percutaneous prosthetic system emerged. (31,32)
20
3.7 QUADRILATERAL SOCKET
“The quadrilateral socket is truly more than a cross sectional shape at the ischial
level, is a three dimensional receptacle for the residual limb with contour at every
level which are justifiable on a sound biomechanical basis” -RADCLIFFE
Quadrilateral (QUAD) socket was introduced in 1950, by University of California at
Berkeley. It has been the standard socket design for transfemoral prosthesis for about
four decades. Quadrilateral socket has four distinct walls, hence the name. The
medio-lateral diameter is increased and the antero-posterior diameter is shortened. It
has posterior shelf on which ischium rests. The primary weight-bearing surface is the
ischial tuberosity and the gluteal muscles. Hence it’s an ischial gluteal weight bearing
prosthesis in which 83 % of the weight is borne by ischium and gluteal
musculatures.(23,33)
The lateral wall is higher than the posterior wall. The lateral wall primarily stabilizes
the femoral shaft and encloses the gluteus maximus, vastus lateralis and tensor fascia
lata. The lateral wall is kept in adduction and this stretches the hip abductors. The
medial wall is perpendicular to provide counter pressure. It stabilizes the residual
limb by compressing the abductor muscles against the lateral wall. The posterior
wall contains hamstring medially. The hip is kept in flexion by anterior slant of about
7 -10 degrees. This will stretch the gluteus and hamstrings for maximum power
generation. The anterior wall is higher than the posterior wall. It stabilizes the
ischium against the posterior shelf. The anterior wall has reliefs for hip flexors
21
and it presses against the Scarpa’s triangle.(22,23,33) Distally the socket provides
the total contact. Quadrilateral socket provides good stability in the sagittal
plane.(34) The medio-lateral and rotational stability is minimal. The quadrilateral
socket has a better fit with firm, long residual limbs with good adductor
musculature.(24)
3.8 ISCHIAL CONTAINMENT SOCKET
3.8.1 EVOLUTION
The Quadrilateral socket was the socket design of choice till 1980’s.(25) Ivan Long
and Mayfield investigated the performance of the quadrilateral socket in regard to
coronal-plane residual limb-socket biomechanics. They radiologically evaluated 100
transfemoral amputee persons standing erect in quadrilateral socket and found that
majority of them; the femur in residual limb was in abduction. There were gait
deviations like lateral bending of trunk and wide based gait.(35,36)
THE PROBLEM
Considering pelvis as a lever, the ischium as the fulcrum, the hip abductor tension
should be able to balance the weight of the body, preventing the pelvic drop during
stance phase of prosthetic limb. For the maximum physiological efficiency of the
abductors, the normal rest length should be maintained. (Figure 3.4) If not it will lead
to abductor insufficiency. (22) In quadrilateral socket when gluteus medius contracts,
the residual femur abducts, as the lateral stabilization forces are insufficient to
22
FIGURE 3-4 HIP ABDUCTOR INSUFFICIENCY
maintain femur in adduction. The abduction of femur is mainly due to the wider
medio-lateral dimension of quadrilateral
socket. The abduction of the femur causes
more pressure on the distal aspect of the
residual limb.(Figure 3.5) When the
prosthetic side is bearing weight the residual
limb exerts force on the lateral wall which
shifts laterally since the ischium cannot check this displacement. When gluteus
contracts and abducts the femur the pelvis shift medially which makes the lateral
shift worse and cause high shearing force in the soft tissue around the ischial seat and
medial brim.(37) The lateral wall of the socket
is away from the lateral surface of thigh
except in the distal part. This lateral shift of
the socket results in a gap in the proximal
socket – limb interface. The lateral shift of the
socket resulted in compressive forces in the
medial proximal tissues of the limb. This
creates a shearing force in the soft tissue structures between medial brim and medial
structures of pelvis. Thus the quadrilateral socket exerts high pressures in proximal
medial and posterior brim.(37) This in turn results in pain and discomfort in the
perineal area.(22,23,35,36,38) Hence the amputee persons assume a typical lateral
FIGURE 3-5 QUADRILATERAL SOCKET
23
trunk leaning gait.(Figure 3.6)(39) The biomechanical disadvantage of the
quadrilateral socket is more pronounced with shorter residual limb.
Goals of new socket technology were
1. The hip abductor to be maintained in its normal length.
2. The femur to be maintained in physiological position of
adduction.
3. The pressure in the distal lateral aspect of the residual
limb to be distributed for a painless and comfortable gait.
4. The lateral shift of the socket to be controlled
5. Pain and discomfort in the perineal area to be alleviated
6. The gait deviations to be minimized
7. The energy efficiency of the gait to be improved
EMERGENCE OF ISCHIAL CONTAINMENT SOCKET
Initially the alignment modification was tried. The newer alignment techniques were
focused on maintaining the femur in adduction. The head of the femur was aligned to
the center of the medio-lateral dimension of the socket. Ivan Long proposed Long’s
Line-”a straight line from the head of the femur (located approximately at the center
of a narrow socket), through the distal femur, and down to the center of the heel”.
The distal end of the femur and foot has to be under the femur head according to new
FIGURE 3-6 LATERAL TRUNK LEAN
24
alignment. The ischial seat, knee joint and foot should be perpendicular to the Long’s
line. The knee joint was placed laterally in order to avoid the knocking of knees.
Alignment modifications were followed by socket design alterations. To maintain hip
adduction the lateral wall was contoured with sloping medially from sub trochanteric
region to distal end of the socket. To achieve this alignment the medio-lateral
dimension was reduced. This lead to the emergence of the narrow medio-lateral
socket concept. The newer socket alignment method came to be known as Proto
ischial containment limb (Figure 3.7).(40) Femoral alignment, balance and gait
improved with new alignment method.(35,38,40)
Even though the alignment modifications were made, during weight bearing the
ischial tuberosity migrated medially. This resulted in the lateral gap in the proximal
brim of the socket along with medial wall digging inside and lateral leaning of pylon.
Hence amputee persons had pain and discomfort in the perineal area.(39) To maintain
the hip in adduction and for better comfort in the perineal region alignment
modification alone was not sufficient. Hence alterations in socket design were tried.
This lead to the emergence of the ischial containment socket with newer socket
design and alignment technology. It is an evolutionary design rather than a
revolutionary design.(23, 24) The ischial containment socket refers to postero-medial
extension of the proximal brim of the socket, so that the weight is borne against the
pelvis, mainly the ischial tuberosity and the ramus.
25
FIGURE 3-7 PROTO ISCHIAL CONTAINMENT SOCKET ALIGNMENT
Original Source – King. C, 2009 (40)
The postero-medial brim is oblique and sloping and the ischium is contained in it and
hence the name. Along with this there is contouring beneath the ischial tuberosity
resulting in the same amount of ischial weight bearing as quadrilateral socket.(39)
Radcliffe named this newer socket design as Ischial Ramal containment.(24) The
word Ischial containment was first used in print by John Sabolich.(40)
26
The femur is kept in adduction in the ischial containment socket by two methods.
1. The ischial tuberosity and ramus is held inside the socket. That will bear the forces
which are directed laterally. The lateral surface of the socket proximal to the
trochanter is snugly fit into the soft tissue. The ischium and ramus is held in position
by the medially directed forces borne by the proximal femur in the trochanteric and
sub-trochanteric region. The medially directed forces in the mid and distal femur help
in maintaining proper adduction angle. The ischial containment is like a locking
system in which ischium sits inside the socket and the opposing force is given from
the lateral aspect pushing the femur into adduction. The three point pressure system(
Figure 3.8) - laterally directed forces in the ischial tuberosity, the medially directed
forces in the supra-trochanteric region and the medially directed forces in the lateral
aspect of femur along with the bony lock maintains femur in adduction. The
increased adduction angle in ischial containment socket results in considerable
weight bearing by the femur. (24, 39)
2. The narrow medio-lateral dimension will lock
the femur, maintain the hip in adduction. Since the
medio-lateral dimension is narrow the weight is
borne directly by the skeletal structures, reducing
the motion lost through soft tissue interface. A
wide medio-lateral dimension cannot provide this
locking phenomenon since the femur can fall away
FIGURE 3-8 ISCHIAL CONTAINMENT SOCKET
27
from the supporting surfaces. The antero-posterior dimension is widened to
compensate the narrow medio-lateral. Increasing the antero-posterior diameter allows
flexors and extensors which form the major muscle bulk around the hip to function
naturally.(23,39)
The rotational stability of the quadrilateral socket depends mostly on muscle
channels. In ischial containment socket the containment of the ischium and narrow
diameter between the greater trochanter and medial ischial surface provides sufficient
rotational stability.(24) Ischial containment is contoured throughout for total contact
socket. Since more area of the residual limb is contained inside and due to the
contour, it provides greater distribution of weight bearing and stabilization forces.
(34) The weight bearing in ischial containment socket is by ischial tuberosity, gluteal
musculature, femur and hydrostatic compression.(23)
The ischial containment is the socket design of choice for short, fleshy and unstable
residual limb. For functionally active amputee persons and high activity sports ischial
containment is the preferred socket design. For elderly debilitated patients walking
with walking aids quadrilateral socket will be sufficient.(24)
3.8.2 DIMENSIONS
MEDIAL-LATERAL DIMENSION
The ischium sits inside the postero-medial socket wall. To prevent the ischial ramus
from migrating laterally and downward counter pressure is given from the lateral
28
side. This is achieved by reduction in the medio-lateral dimension of subtrochanteric
region. The proximal region is wide enough to accommodate the ischial ramus as
well as greater trochanter. Hence the medio-lateral dimension of ischial containment
at the ischial level is similar to quadrilateral socket. The decrease in the medio-lateral
dimension is mainly 4 cm distal to ischial tuberosity in the subtrochanteric
region.(23). The lateral wall is well above the greater trochanter for medio –lateral
stability. The lateral wall is slanted medially for better adduction.
ANTERIOR-POSTERIOR DIMENSION
The medio-lateral dimension is narrow, in order to accommodate the residual limb
volume the antero-posterior dimension is greater compared to quadrilateral socket.
The major muscle bulk acting in the hip joint is in the sagittal plane. Hence wider
antero-posterior dimension allows the flexors and extensors to function more
effectively (36, 37). Wider the antero-posterior dimension lesser will be the pressure
on Scarpa’s triangle.(39)
MEDIALBRIM
The postero-medial socket wall provides lateral pressure to the ischium in order to
prevent it from slipping medially. Hence the medial wall has to be loaded, while
providing pressure relief for the less pressure tolerant areas like adductor tendon and
pubic ramus. The medial brim extends posterior to enclose ischial ramus and dips
anteriorly to clear adductor longus and pubic ramus. Medial brim parallels the
29
ischium from posterior to anterior direction, hence in the transverse plane it looks
internally rotated.(23)
ANTERIOR BRIM
The anterior trim line of ischial containment and quadrilateral socket is similar, up to
or just proximal to the inguinal crease. While sitting the socket should clear the
superior iliac spine. (23)
LATERAL BRIM
The lateral wall is extended proximally snugly fitting to provide counter pressure for
the ischium in the sloping medial wall. The contouring helps to distribute the
pressure over the entire area. In transverse plane posterior to greater trochanter, there
is extreme obliquity compared to quadrilateral socket. This is termed as wallet
hollow. The postero-lateral brim compresses gluteal muscles and helps in gluteal
weight bearing. Lateral brim locks around the greater trochanter & provides rotatory
stability.(23)
POSTERIOR BRIM
The posterior trim line of the ischial containment socket is 4 cm proximal to the
ischial tuberosity, higher than the quadrilateral socket in order to contain the
ischium.(39)
30
TABLE 3-2 COMPARISON OF QUAD & IC SOCKET
QUAD IC
Ischial containment Ischium is outside the
socket resting in the
ischial seat
Ischium is contained
inside the socket in the
postero-medial wall
Weight bearing Ischial – Gluteal weight
bearing
Ischial tuberosity,
ramus, femur and
hydrostatic compression
Medio – lateral stability No bony lock, less
medio-lateral stability
Hip maintained in
adduction with bony
lock and contoured
lateral wall, greater
medio-lateral stability
Rotational control Lesser rotational control
since ischium slips
from the posterior shelf
Increased rotational
control due to skeletal
lock inside the socket
Socket Shape Wider medio-lateral,
narrow antero-posterior
Narrow ML, Wider
antero-posterior,
subtrochanteric concave
shaped
Alignment Medial wall in line of
progression
Medial wall not in line
of progression. Knee
bolt in 5 -7 degree of
angulation
31
The ischial containment sockets were known in different names. The prosthetic
technique of University of California was named as CAT-CAM. The socket design
followed in Northwestern University was NSNA (Normal Shape-Normal Alignment
technique). In New York University it was known as Narrow Medio-lateral.(25)
3.8.3 NSNA (NORMAL SHAPE-NORMAL ALIGNMENT TECHNIQUE)
Long found that when foot is lined under femur head rather than ischium, the
amputee persons walk with a near normal narrow base. He proposed Long’s Line and
the alignment in NSNA is mainly based on it.
3.8.4 CAT-CAM (CONTOURED ADDUCTED TROCHANTERIC-CONTROLLED ALIGNMENT METHOD)
The Contoured Adducted Trochanteric-Controlled Alignment Method is an ischial
containment socket developed by Sabolich. This design keeps the femur in adducted
position by undercutting of the trochanter. The ischium sits in special fossa in the
posterior wall, with a three dimensional support in the socket, thus forming a bony
lock.(24)
The prosthetic foot is lateral to the plumb line from the ischial tuberosity. In
variation to NSNA the foot is not always under the distal femur or center of hip joint.
In the geriatric population CAT – CAM offers superior comfort due to less pressure
in the Scarpa’s region.(39) The CAT-CAM socket offers more comfort due to
increased space in the perineal region especially in bilateral amputee persons.
32
3.8.5 NARROW M-L (NARROW MEDIO-LATERAL SOCKET)
Narrow Medio-Lateral socket is a type of ischial containment socket. Here the
casting techniques are slightly different. The centralization of femur is achieved by
applying laterally directed forces in the medial distal end of residual limb, while
maintaining femur in adduction with a medially directed force applied on the middle
of the femur shaft. This will provide a distraction force displacing the soft tissue
mass in the distal aspect of residual limb, resulting in centralization of femur and
better contour of the end region of the residual limb.(25)
3.8.6 SCAT-CAM (SKELETAL CONTOURED ADDUCTED TROCHANTERIC CONTROLLED ALIGNMENT METHOD)
Skeletal Contoured Adducted Trochanteric-Controlled Alignment Method is a
modified form of CAT–CAM in which skeletal anatomy is considered more. The
femur is kept in adducted position with Oklahoma fossa and compartment. The
medial brim line is advanced proximally to contain the maximum of the ischium and
the ramus.(39)
3.9 OTHER SOCKET DESIGNS FOR TRANSFEMORAL PROSTHESIS
The prosthetics and orthotics is a developing field of science. The newer sockets are
being developed with advanced technology to meet the variety of needs of the
amputee persons.
33
3.9.1 FLEXIBLE SOCKETS
"To label a socket as flexible I would say that you should be able to deform it by your
hands, and the material should not be elastic enough to stretch under the loads it will
be subjected to." - KRISTINSSON
The flexible socket design concept is introduced by Ossur Kristinsson. The design
was popularly known as Scandinavian Flexible socket or ISNY (Icelandic Swedish
New York) socket. The socket is formed by a flexible thermoplastic which is
supported by a rigid frame. The flexible socket materials are made of laminating
resins like polyurethane, polyester, acrylic, silicone, lynadure, surlyn along with
nylon stockinet with fiberglass stockinet in between. The rigid frame or socket
retainer should be of enough strength to support the residual limb and to resist
deforming forces. The socket retainer is mainly made of carbon fiber. The
suspension system for flexible sockets is mainly vacuum suspension. If needed other
suspension methods can be incorporated.(41–43) The advantages of flexible socket
design is maximal comfort, better proprioception and ability to accommodate minor
changes in limb volume.(26)
34
3.9.2 MARLO ANATOMICAL SOCKET
Marlo Ortiz Vasquez a Mexican prosthetist developed the Marlo Anatomical Socket
(MAS). Marlo Anatomical socket is an ischial ramal containment socket. It deviates
from ischial containment socket by lowering the posterior and anterior timelines. The
ischial ramus is contained inside the socket which provides the skeletal stability. The
medial and anterior portion of ischial tuberosity and ramus is captured inside the
socket with less of posterior aspect of ischial tuberosity. The posterior trim lines are
lowered so that the gluteus maximus is not included in the socket. The anterior trim
lines are also correspondingly lowered. The lateral trim line above the trochanter is
snugly fit and is lower compared to ischial containment socket. MAS is a total
contact socket and the vertical forces are mainly borne by the ischial ramus along
with quasi hydrostatic suspension. Its mainly designed like a flexible socket with
socket retainer made of carbon. The advantages are better cosmesis, easy donning
and doffing, improved proprioception along with more natural sensation of sitting
since there is no socket material beneath the gluteus maximus.(44) The amputee
persons gait is better with MAS socket due to superior containment of bony structure,
and improved range of motion of the hip.(45) The femur is kept in adduction and the
pelvis stability is improved with MAS socket. In comparison to the ischial
containment socket the energy efficiency is better with MAS socket.(46)
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3.9.3 OSSEOINTEGRATION
The osseointegration is a newer and alternative method of attaching prosthesis to
human body. The concept of osseointegration dates back to 1960s when it was found
that titanium is bone friendly. Further research by Swedish Professor Branemark lead
to the use of osseointegrated implants in the dental surgery. The concept was
expanded in 1990s and the transfemoral amputee persons were fitted with
osseointegrated system. In this the prosthesis is directly anchored to the bone. This
requires two stage surgical procedures. In the first stage implant which is a threaded
titanium material is inserted into the marrow cavity of residual femur. This is known
as fixture. This fixture will get integrated to the bone with time. The second surgery
is conducted after six months. The abutment which is a titanium extension is inserted
into the fixture and secured with abutment screw. The abutment penetrates the skin
and protrudes out. The rest of the prosthetic components can be directly fixed to the
abutment in the following phase of comprehensive rehabilitation. This leads to a
gradual and progressive weight bearing of the prosthesis. The entire rehabilitation
will take 6 months for proper weight bearing and gait training. So from amputation to
independent walking with the osseointegrated prosthesis will require a minimum of
one year. The osseointegrated prosthesis the hip range of motion is not restricted
unlike the other sockets.(45) The cumulative survival rate, prosthetic use and
mobility is better with osseointegrated prosthesis.(47) Two years follow up of
transfemoral amputee persons with osseointegrated prosthesis showed better quality
of life and prosthetic function.(48) Hendril et. al compared the walking ability and
36
energy consumption with osseointegrated and conventional transemoral prosthesis.
They found that amputee persons with osseointegrated prosthesis walk with higher
speed and lesser energy expenditure.(49)
The advantages of the osseointegrated prosthesis are. 1. Since there is no socket, the
discomfort, skin irritation, sweating, concentrated pressure and pain occurring in the
human- socket interface can be avoided. 2. The prosthesis can be easily detached
from the abutment. Hence donning and doffing is easy. 3. The suspension is good,
since it is directly anchored to the bone. 4. The hip movements are not restricted
since there is no socket wrapped around the residual limb. 5. The more natural
perception of the prosthetic limb, which is known as osseoperception.(50)
The disadvantages are 1. Need for extensive rehabilitation and longtime interval
between amputation and prosthetic walking. 2. Risk of implant related complications
like infection, implant loosening and failure. 3. Risk of fractures. 4. Permanent
abutment can lead to poor cosmesis. 5. High impact activities like running and
jumping are restricted. 6. Regular skin care for the abutment area is required.
3.10 KNEE JOINTS
Prosthetic knee joint is a complex structure which forms the integral part of the
transfemoral prosthesis. The prosthetic knee can be endoskeltal or exoskeltal. The
knee joint provides adequate support during the stance phase, preventing the failing
of prosthesis under load along with controlled swing phase.
37
SINGLE-AXIS KNEE JOINT(12) - This is the basic or simplest knee joint which works
on a simple hinge mechanism. The stance phase stability is dependent on involuntary as
well as voluntary stability. The advantages are being simple, low cost and easy
maintenance. The disadvantage is compromised mechanical stability.
POLYCENTRIC-AXIS KNEE JOINT(26) – In Polycentric knee the instantaneous center
of rotation changes with respect to flexion and extension of thigh and shank component.
The polycentric knee mainly consists of four bar linkage. The advantage is varying
mechanical stability through the entire gait cycle. During flexion of the knee, there is
inherent shortening which aids in better foot clearance. The polycentric knees are
beneficial for amputee persons with weak hip extensors, short residual limbs and knee
disarticulation.
WEIGHT-ACTIVATED STANCE-CONTROL KNEE(26,27) – It consists of a braking
mechanism which prevents knee from buckling. This brake is activated by applying
weight. The weight required to activate this mechanism can be modified according to
each individual.
MANUAL LOCKING KNEE JOINT(12,26) – This has an automatic locking mechanism
which is activated in extension. This can be unlocked manually. This is the most stable
knee during stance phase. The disadvantage is maximal gait deviations and increased
energy expenditure since amputee persons walk with extended knee in swing phase.
38
FRICTION CONTROL KNEE JOINT(12,27) - A constant mechanical friction is applied
to the knee joint. The friction is adjusted to the normal cadence of the amputee persons.
Alteration in cadence by the amputee persons can result out of phase flexion and
extension of knee joint. The advantages are simple design, dependability and easy to
maintain. The disadvantage is amputee persons have to walk with single cadence.
EXTENSION ASSIST KNEE JOINT(26)– It helps in extending the shank in swing phase
by recoil of a spring mechanism which is being compressed while flexing the knee. It
provides initial stance support since full knee extension is ensured at the end of terminal
swing itself.
PNEUMATIC CONTROL KNEE JOINT (12,26)– Pneumatic knee contains a piston,
which is compressed during the knee flexion. This forces the air in the cylinder to travel
upwards through bottom valve and then back to the central cylinder through another
valve in the top. The resistance offered by the pneumatic control can be adjusted by the
port size. Pneumatic control provides advance swing control and suited for varying
walking speeds. The disadvantages are increased maintenance, heavy and expensive.
HYDRAULIC CONTROL KNEE JOINT (12,26)– The hydraulic control also works with
same principle like pneumatic; the difference is in the medium. The liquid medium
commonly used is silicone oil, since its viscosity variations with temperature is minimal.
The hydraulic units provide better swing control for varying cadence. It’s heavy,
expensive and the maintenance cost is high.
39
THE MICROPROCESSOR KNEE JOINT – Microprocessor-controlled prosthetic knees
has sensors which continuously detect the position of the knee throughout the stance and
swing phases of gait. Microprocessor knee has various software’s that controls and
modifies the function of the prosthetic knee. Using the input from the sensors the knee
adapt to different terrain and walking speeds. It adds stability to the stance phase.
Disadvantages of this system are expensive and high maintenance cost.(51)
3.11 FOOT-ANKLE ASSEMBLIES
The different types of feet has been broadly classified in to following four categories
SOLID-ANKLE, CUSHION-HEEL FEET (SACH FEET) – The SACH feet was introduced by
Foort and Radcliffe in 1956 and is one of the most basic and widely used feet in
prosthetics. SACH feet have solid ankles and attach themselves to the distal aspect of
shank. The SACH feet restrict all motion including dorsiflexion, plantar flexion,
eversion, inversion and transverse plane motions. The cushion heel characteristic of the
feet provides for plantar flexion, which is achieved by means of compression under
loading. The compression helps to absorb shock in loading response and also ground
reaction force to be anterior.(12) The main limitation of the SACH feet is the non-
flexibility or non-responsiveness of the keel. However the low cost and durability of
these feet make them popular.
SINGLE AXIS FEET - As the name suggests, in the single axis feet a mechanical axis
runs from medial to lateral. The feet support plantar flexion in the sagittal plane and in
some cases dorsiflexion as well. The ankle plantar flexion imparts stability in individuals
40
with lower limb amputation. The plantar flexion of the foot provides for an external knee
extension moment, which greatly supports amputee persons with inadequate voluntary
control of knee. (52)
MULTI AXIAL FEET– The multi axial feet is designed to replicate the anatomical feet
and the mult-iaxial motion is achieved either by flexible keel or true mechanical joint
axis. During walking on uneven terrain, the motion happens within the keel in the
multi-axial feet as the ground forces causes’ foot deformation. This foot deformation
enables the feet to maintain ground contact and there by provide stability. The use of
adjustable bumpers enables plantar flexion and dorsiflexion, transverse plane motion,
inversion and eversion.(12)
DYNAMIC RESPONSE FEET– The Dynamic Response feet are energy storing feet.
The keel of the feet deflects and comes back to original shape on loading and unloading
respectively. This lessens the energy expended by the users. The keel stores the energy
during midstance and terminal stance and then releases it in the preswing and intial
swing. The lighter-weight materials like flexible rubber, graphite composite,
polyurethane elastomer, delrin and kevlar are used. The dynamic response feet produce a
more normal gait.(52)
41
3.12 FABRICATION AND ALIGNMENT OF TRANSFEMORAL PROSTHESIS
FIGURE 3-9 – COMPONENTS IN TRANSFEMORAL KIT OF ICRC
Original Source – ICRC Manufacturing Guidelines (53)
1 .Foot Piece, 2. Hexagonal-head bolt and lock washer, 3. Convex ankle, 4. Concave
cylinder and pin 5. Set of washers, nut and bolt, 6.Convex disc 7. Conical cup, 8. Trans-
femoral cup, 9. Knee shell (53)
STEPS OF MANUFACTURE (53)
1. Patient assessment – Prescription of appropriate prosthesis and selection of
individual components is done according to the condition of the residual limb and the
general condition and the affordably of the patient
2. Measurements and casting – The first step in socket manufacture is getting an
impression of the residual limb. The impression can be taken by manual casting or by
using computer technology. For casting, a lubricant which acts like a cast separator is
applied to the residual limb. Then a cotton sock is pulled on which is suspended with
shoulder straps. Plaster of Paris is rolled and molded onto the limb. Once the plaster
42
sets and hardens the cast is removed by sliding it off. Then the mold is filled with
liquid plaster. The mandrel is inserted before the plaster hardens. The built up and
relief is given in the positive mold by adding more to bony prominences and
removing the plaster from weight bearing regions. The prosthetist makes uses of their
knowledge in anatomy, kinesiology and biomechanics to modify the mold. After the
mold is modified, test socket is fabricated. The test socket is made to evaluate the
fitting and comfort of the socket. The test socket can be easily modified with heat,
since it is made up of clear plastic. Once the test socket is finally modified, it can be
filled with liquid plaster. After the plaster hardens the test socket can be removed.
The actual socket fabrication begins with that mold.
3. Transfemoral cup alignment – The transfemoral cup is aligned at the tip of the
positive mold which is fixed with plaster of paris.
4. Socket manufacturing – Polypropylene sheet is heated in the oven at 180 degree
for 20 minutes. Then the sheet is draped over the positive mold and vacuum suction
is switched on. Vacuum suction is on, till the polypropylene cools down. The trim
lines are drawn and cut open the polypropylene through that. The distal part as well
as the trim lines is grinded and smoothened.
5. Suction valve -A hole is made in the medial aspect for the suction valve. After
smoothening the edges suction valve is attached. Suction valve is checked with
pouring water in the socket.
6. Conical cup – it is attached according to the length of the socket.
43
BUILDING UP AND BENCH ALIGNMENT
Ankle-foot alignment- The foot piece is attached to the pylon with the help of
concave and convex ankle discs. This ankle alignment system allows some degree of
movement in sagittal and coronal plane, to adjust to the heel height of the individual
shoes. The foot piece is maintained in external rotation of 5 degree. The alignment
has to be checked wearing the shoe also.
Knee alignment – The length of the normal side from medial tibial plateau till the
foot with added 1.5 -2cm is taken and translated to the prosthesis, from the foot up to
the mechanical knee joint axis.
Socket alignment– The knee joint is connected to the socket through conical disc
and conical cup. The conical disc provides abduction, adduction, flexion and
extension.
Adjustment of length - If length has to be increased two conical cups can be
attached.
Alignment of finished prosthesis –The socket can be kept in flexion, extension or
abduction, adduction depending on individual needs by tilting and sliding the convex
disc and conical cup interface, medially-laterally or antero-posteriorly.
Static alignment - The amputee persons is made to stand with the prosthesis, the
height, fit, comfort and alignment of the socket is checked.
44
Dynamic alignment –The amputee persons is observed for any gait deviations and
alignment problems while walking.
Cosmetic finishing – The final finishing of the prosthesis is done with EVA .The
socket is roughened with sandpaper. Then the socket is covered with EVA which is
secured by adhesive. The shank is covered with a polypropylene sleeve, to provide
the contour of the opposite leg.. EVA is heated to 120 degrees in a hot oven and
rolled over the shank cover along with vacuum suction. The EVA covering is grinded
for finishing.
CAD – CAM
In Computer Aided Design (CAD) the information about the residual limb is fed in
the computer which designs socket shape. This is modifiable at any cross section.
Hence it aids in optimal socket shape. CAD is followed by the CAM (Computer
assisted manufacture). The manufacturing machines are numerically connected to the
computer, which give precise manufacturing instructions to the machines.
Reproducibility, time saving and less manual effort are the advantages of CAD-CAM
method. The CAD – CAM method takes only 40 minutes to make an entire
prosthesis.(54)
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3.13 PROSTHETIC TRAINING
For amputee persons with new prosthesis, gait training is necessary to achieve a
smooth and safe gait. Prosthetic training involves (55):
1. Weight bearing and balance training –It starts with partial weight bearing and
progressing to full weight bearing.
2. Specific gait training- Normal gait pattern with alternate step forward of artificial
leg and sound leg is trained. Walking is initiated within the parallel bars with or
without support.
3. Advanced exercises – It includes walking on uneven surface, negotiating slopes
and ramps and progressed to running.
4. Functional exercises – Amputee persons are trained for negotiating stairs as well
as independent transfers from bed, chair and floor
3.14 NORMAL GAIT
Gait is described as a translatory progression of the body as a whole, produced by
coordinated, rotatory movements of body segments.(56) A gait cycle spans two
successive events of the same limb. During one gait cycle, each extremity passes
through two major phases - stance phase and swing phase. The stance phase
constitutes about 60% of the gait cycle and swing phase forms the rest 40%.(57) The
Rancho Los Amigos classification subdivides gait cycles into initial contact, loading
response, midstance, terminal stance, preswing, initial swing, mid swing and late
swing.(56)
46
3.14.1 GAIT ANALYSIS
The following are the components of gait analysis (56–58)
1. Video gait analysis–Slow motion frame to frame analysis will yield good
descriptive data on gait pattern. It is a qualitative method to develop the initial
assessment of the gait of the patient. The limitations are being a subjective analysis
the possibility of human error is more.
2. Kinematics– It is a quantitative description of the spatial movement of the
segments along with temporal parameters. Data is collected from infrared LEDs
which are placed over the joints of a patient’s body.
3. Kinetics–Kinetic analysis refers to the forces which are produced during walking.
It follows Newton’s third law where “every reaction has an equal and opposite
reaction”. The ground reaction force (GRF) is a reaction of the body weight and
acceleration. The kinetic data is obtained when the patient steps on a force plate
which measures the force of the foot exerted on it.
4. Dynamic electromyography - It describe which muscle is in action at certain
point of gait cycle. It is a more discriminating technique and is measured through
surface EMGs which are attached superficially over the skin. They detect the
electrical signals produced by the active muscle fibers.
5. Energy consumption – Human walking is an energy consuming process. The
concentric muscle contraction generates energy and during eccentric muscle
47
contraction energy is absorbed.(59) Energy consumption measures how much energy
is spent on a certain activity. The energy consumption will be increased in gait
abnormalities due to variation in the determinants of gait responsible for energy
conservation.
3.15 TRANSFEMORAL PROSTHETIC GAIT
Gait is dependent on complex dynamic interaction between sensory afferents and
central motor programme for locomotion. Since amputation leads to loss of sensory
motor functions, locomotion is also affected. Persons with amputation learn to
compensate for the ambulation difficulties by adaptation strategies.
In terms of temporal parameters, transfemoral amputee persons, as compared to able-
bodied individuals, have a decreased cadence, slower gait speed, decreased stride
length, increased cycle time, and decreased stance phase on the prosthetic side.(60)
The plantar flexor force for the push off, which is the major power generator phase is
less in the amputated side.(59)
LATERAL TRUNK BENDING
The transfemoral amputee persons bend the torso towards the prosthetic side during
amputated side stance phase. The causes are weak hip abductors, abducted socket,
inadequate lateral stabilization by the socket wall, increased pressure or pain in the
distal lateral aspect of the residual limb or short prosthesis. When the hip abductors
are weak the pelvic drop is prevented by lateral bending of the trunk.(61) Abducted
48
socket and insufficient lateral support will result in decreased biomechanical
efficiency of the gluteus medius.
HIP HIKING
This can be explained as either as a weakness of the hip abductors or a compensatory
technique to clear the prosthetic limb during swing phase. The swing phase hip is
raised above the stand phase hip either by active use of stance side hip abductors or
by lateral flexion of the trunk.(61)
WIDE WALKING BASE (ABDUCTED GAIT)
The transfemoral amputee persons walk with a wider step width.(22) The causes can
be hip abductor contracture, pain or discomfort in the in the proximal-medial thigh,
too long prosthesis, shank in external rotation and instability feeling by the amputee
persons. Increased pressure by the medial wall of socket can cause perineal area pain
and the amputee persons tries to move the medial brim away by keeping the leg
abducted. Excessive prosthetic length causes difficulty in floor clearance during
swing phase. Widening the walking base gives more stability feel to the amputee
persons.(23)
CIRCUMDUCTION
During the swing phase the prosthetic limb follows a laterally curved line. The most
common cause is increased length of prosthesis. The other reasons are amputee
persons walking with locked knee, inadequate suspension and pistoning effect, foot
piece in excessive plantar flexion and small socket. When the prosthesis is too long
49
the amputee persons swing it to the side to achieve foot clearance during swing
phase.(62)
VAULTING
During unaffected limb stance the entire body is raised with excessive plantar flexion
of the normal foot. It is due to either insufficient friction in the prosthetic knee or due
to longer prosthesis. When the friction is less, heel rise will be excessive and the
shank will take longer time to swing forward. Hence when the prosthetic foot is at
lowest point, the stance limb is not in maximum elevation resulting in excessive
plantar flexion of the normal foot to clear the ground.(62)
SWING-PHASE WHIPS
The medial and lateral whip occurs at toe – off. It is due to improper alignment of the
knee or due to inadequate suspension. In suction socket without auxiliary suspension
it is seen frequently.(62)
FOOT ROTATION AT HEEL STRIKE
If the heel cushion is hard, during initial contact the foot rotates.(62)
FOOT SLAP
When the plantar flexion bumper is too soft, the loading response is rapid and foot
strikes the floor with a slap.
TERMINAL IMPACT
At the terminal swing the prosthetic shank stops in extension with a visible/audible
impact. This is due to inadequate friction at the prosthetic knee.(62)
50
EXAGGERATED LORDOSIS
During prosthetic stance phase the lumbar lordosis is exaggerated. This is due to hip
flexion contracture, weak hip extensors, insufficient socket flexion and weak
abdominal muscles. This results in anterior tilt of the pelvis. This will bring the
center of gravity forward and in order to compensate, the amputee persons attains a
lordotic posture. (41)
3.16 ENERGY EFFICIENCY
The energy cost of walking for the transfemoral amputee persons is higher than the
lower level amputee persons or normal subjects.(46) Hence prosthetic fitting is
aimed at providing most energy efficient gait. Transfemoral amputee persons
walking with prosthetic limb consumes 40% - 65 % more oxygen.(46,63–65) Trans
femoral amputee persons walk with slower speed 50 – 20% of normal walking speed.
Vascular amputee persons walk with lesser speed without much difference in energy
efficiency compared to traumatic amputee persons.(46,63,66,67) In view of
biomechanical advantages of ischial containment socket, it’s proposed to improve
gait deviations and energy efficiency. The energy efficiency of the amputee persons
can be evaluated by different methods. The oxygen uptake per meter walked is the
true net energy cost and is the best way to compare the gait efficiency in lower limb
amputee persons.(63) To assess the oxygen utilization per minute specialized
equipments are needed. Physiological cost index (PCI) is a proxy method to analyze
energy cost in lower limb amputee persons walking with prosthesis.(64)
51
3.17 JUSTIFICATION OF THE STUDY
As stated earlier this study aims at comparing the ischial containment socket with
quadrilateral socket in terms of functional ability and socket preference. Prior
researches in this field are concentrated on gait deviations, energy cost of walking,
pressure distribution and comfort.(37,66,68–70)
In three studies with less than 7 persons with ischial containment socket, in terms of
socket comfort ischial containment is preferred to quadrilateral socket.(68–70) In
terms of gait deviation and femoral shaft adduction angle Flandry et. al (n = 4) found
improvement with ischial containment in comparison to quadrilateral socket.(70). In
two independent studies by Hall et. al and Hachisuka et.al, even though the gait
deviations improved with ischial containment socket, they were not statistically
significant.(68,69) The pressure distribution in ischial containment socket is more
even compared to high localized pressure in quadrilateral socket.(37,68)
Gailey et.al compared the energy cost of walking in transfemoral amputee persons
with quadrilateral and ischial containment socket using heart rate and oxygen
consumption. The transfemoral amputee persons with ischial containment socket use
20% less energy than quadrilateral socket. The walking speed with ischial
containment socket was higher than the quadrilateral group.(66) In contrary to this
Hachisuka et.al study revealed no significant difference in PCI with ischial
containment socket in comparison to quadrilateral socket.(69)
52
These studies were limited with small sample size ≤ 10 patients with ischial
containment socket. There is evidence to say that the comfort and patient preference
is more with ischial socket. The improvement in gait deviations and physiological
cost index is inconclusive with these studies. To our knowledge ours is the first study
comparing the quadrilateral socket and ischial containment socket in terms of
functional abilities.
The current practice in our institution for transfemoral amputee persons is
quadrilateral socket design. Even though the ischial containment is theoretically
better, the skill needed to fabricate it is more. Through this study we intend to look
whether changing the current practice will provide better results as theoretically
expected.
53
4 METHODOLOGY
4.1 STUDY DESIGN
This is an interventional study, with before and after design. The transfemoral
amputee persons ambulant with prosthetic limb fitted with quadrilateral socket were
enrolled after informed consent. First assessment was done with the quadrilateral
socket during the initial visit. Then they were provided with ischial containment
socket. The knee component, pylon and the foot piece were retained without
alteration. Each patient was given a two weeks’ time to acclimatize to the new
socket. At the end of two weeks all the assessments were repeated with the ischial
containment socket.
4.2 INTERVENTION
The ischial containment socket being the intervention was compared with the
quadrilateral socket in persons ambulant with transfemoral prosthesis.
ISCHIAL CONTAINMENT SOCKET FABRICATION PROCEDURE
The first step is patient assessment which includes history taking, muscle power
testing, assessing joint range of motion especially hip flexion contracture. The second
stage involves taking measurements from the normal side like ischium to floor
length, medial tibial condyle to floor length, foot length, maximum and minimum
calf circumference. Followed by amputated side measurement including ischium to
residual limb end length, medio-lateral width measurement, antero-posterior width
54
measurement, femoral adduction angle measurement, circumference at greater
trochanter level and 5 cm interval residual limb circumference. The trim-lines for
ischial containment socket are marked in the stockinet. The markings are anterior
3cm below the ASIS, adductor tendon, and lateral 5 to 8cm above the greater
trochanter, posterior 3cm above the ischium, posterior gluteal muscle fold and medial
1cm below the groin area. The residual limb is casted with four layers of plaster of
paris the containing the ischium and maintaining femur in 5 degree adduction and
flexion. The negative cast is thus obtained. Internal modifications are made and are
used for trials, like a check socket. Negative cast is filled with plaster of paris. This is
the positive mold, which is anchored with the mantle. The positive mold is rectified
and smoothened. The trim-lines are marked. The adaptor is fixed to the socket with
alignment jig. Socket is molded with polypropylene 5mm sheet with vacuum suction
on. Socket grinding is done with grinding machine.(Figure 4-1) The other
components of the transfemoral prosthesis are fitted and bench alignment is done
with respect to anterior, posterior, lateral and medial planes. This is followed by
static alignment. When the amputee persons are standing with the prosthesis and the
height of the prosthesis, foot length, socket fitting, socket trim lines, suspension
system, height of the knee joint, ischium placement and weight bearing is checked.
The dynamic alignment of the prosthesis is done while walking, to observe for any
gait deviations and alignment problems. Once the alignment and socket fit is verified,
amputee persons undergo structured prosthetic training.
55
FIGURE 4-1 ISCHIAL CONTAINMENT FABRICATION PROCEDURE
4.3 SETTINGS AND LOCATION
The study was conducted in the Department of Physical Medicine and Rehabilitation,
Christian Medical College, Vellore. Patients were recruited from the Amputee
person’s clinic held weekly in the outpatient section department. Those who satisfied
the inclusion criteria were explained about the study and informed consent in their
own language was obtained from those who were willing to participate. The
prosthesis was made in the Artificial Limb Centre of CMC, Vellore. The evaluations
56
were done in the Motion Analysis Lab at the Rehabilitation Institute. The outcome
measures such as 6 minute Walk Test, Timed Up and Go test, Physiological Cost
Index and analysis for the temporal gait parameters were completed in the lab.
Socket Comfort Score and Socket Preference were asked by primary investigator.
4.4 ETHICS COMMITTEE APPROVAL
Approval for the study was obtained from the Institutional Review Board
(Annexure1). The consent format was submitted in two different languages as
expected in the population group
4.5 PARTICIPANTS
The transfemoral amputee persons walking independently without any walking aids,
who visited the Amputee person’s clinic and Prosthetics and Orthotics (P&O) lab,
Dept. of Physical Medicine and Rehabilitation (PMR), CMC Vellore from April
2014 till August 2015 were screened. 48 transfemoral amputee persons visited the
P&O lab. The new amputee persons were 20 in number. 28 amputee persons were
ambulant with the transfemoral prosthesis. Applying the inclusion and exclusion
criteria 13 patients were eliminated (8 patients not willing for follow up, 5 patients
walking with aids). Fifteen transfemoral amputee persons walking with quadrilateral
socket were recruited in the study.
57
4.6 INCLUSION CRITERIA
Transfemoral amputee persons
Independent ambulation with quadrilateral socket
12 – 70 years of age
4.7 EXCLUSION CRITERIA
Bilateral transfemoral amputation
Ambulant with walking aids
Residual limb with deformities and ulcers
Functional impairments of the sound limb
Mental/cognitive or other significant disorders
Not willing for follow up
4.8 SAMPLE SIZE
21 unilateral transfemoral amputee persons patients between the ages of 12-70 years
were targeted for selection from the Amputee persons Clinic held in the PMR
department.
58
CALCULATION
The significant clinical improvement was fixed as 10 % increase in 6 minute walk
test, which is the primary outcome. With the expected standard deviation of 30
meters, the sample size was calculated. The paired t-test was used to compare the
outcome measures with 90 % power, assuming an error of 5 %( two-sided). The
sample size needed to detect a significant difference was 21.
Expected Difference (δ)=30m
SD for quadrilateral socket (σ) = 30
α (two-sided) = 0.05; β=0.80
EQUATION 1 SAMPLE SIZE CALCULATION
n = 2 (1.96 + 1.28)2 × 30 2 = 21
4.9 OUTCOME MEASURES
Outcome measures assessed the walking endurance, energy efficiency and subjective
preference.
4.9.1 PRIMARY OUTCOME MEASURES
Functional ability is measured with the 6-minute walk test and Timed Up and Go
(TUG) test. Subjective preference is tested with socket comfort score and final socket
preference.
59
4.9.1.1 6 MINUTE WALK TEST (6MWT)
6MWT challenges an amputee person’s functional capacity, balance, and postural
control abilities, which is required in community ambulation.(71,72) The 6MWT
was initially applied in patients with cardiac or respiratory problems then later to
patients with fibromyalgia, renal failure, and cerebral palsy. In lower limb amputee
persons the interclass correlation coefficient of 6MWT is high suggesting this is a
reliable assessment tool.(71–73) Mean scores of 6MWT in lower limb amputation
was 332 ± 115 m.(73) In transfemoral amputee persons the mean score of 6MWT
was 314±109 m.(72) The patients were asked to walk in a self-selected speed in a
walkway inside the movement analysis lab.
4.9.1.2 TIMED UP AND GO TEST (TUG)
Timed walking tests measure one of the most basic functions of day-to-day life. The
TUG test is used for assessment of postural control, physical mobility, level walking,
transfers, and turns in amputee persons.(72) To measure the physical mobility in
people with amputation of the lower extremity the TUG test is a reliable tool with
adequate concurrent validity and intraclass reliability.(72–74) It measures the time
duration needed to get up from a chair, walk 3m, turn back and get seated. After one
practice trial which was not timed, the patient’s level of functional mobility was
assessed by the time he took to stand up from a chair (44-47cm seating height), walk
3meters (10ft), walk back and sit down on the same chair. The assessment was done
by the gait analyst who was blinded to the intervention. It was done at the Motion
analysis lab at the Rehabilitation Institute. Dite et al found that the cut off for
60
increased risk of fall in unilateral lower extremity amputations was 19 sec (sensitivity
85%; specificity 74%).(75) Mean values for TUG in lower limb amputee persons is
12.3 ± 4.5s.(73) In unilateral transfemoral amputee persons the mean values for TUG
test is 13.3 ± 4.7s.(74)
FIGURE 4-2 – TIMED UP & GO TEST
4.9.1.3 SOCKET COMFORT SCORE (SCS)
Socket comfort score quantifies the subjective experience of socket discomfort and
pain. It is based on the numerical rating scale commonly used in assessment of pain.
However, because the scale assesses comfort rather than pain, the numerical values
are reversed with higher SCS values assigned to a more comfortable socket fit. The
SCS is administered by asking the patient the following question: “If 0 represents the
most uncomfortable socket fit you can imagine and 10 represents the most
comfortable socket fit, how would you score the comfort of the socket fit of your
Return
Gait Initiation Path of Walk Turnaround
3 meters = 10ft
Slow, Stop, Turn and Sit
Sit to Stand
1 Full Lap = 6m (20ft)
61
artificial limb at the moment?” The SCS has shown correlations between clinical
findings and patient reports. The measure has also demonstrated sensitivity to change
as socket adjustments and socket replacements.(76)
4.9.1.4 SOCKET PREFERENCE
At the end of the study patients were given an option to choose whichever socket
they prefer. Hall et. al conducted a field study in 4 transfemoral amputee persons and
found that they preferred ischial containment socket.(68)
4.9.2 SECONDARY OUTCOME MEASURES
4.9.2.1 PHYSIOLOGICAL COST INDEX (PCI)
Physiological cost index reflects the energy efficiency due to the linear relation of
oxygen consumption and heart rate. The Physiological Cost Index (PCI) was
introduced by Macgregor.(77) The lower limb amputee persons modify their walking
speed for an energy efficient gait. PCI has been shown to be effective in reflecting
efficiency of gait in stroke, cerebral palsy, spinal cord injury, head injury and lower
limb amputee persons as well as normal individuals.(78) The test retest variability of
PCI in lower limb amputations is excellent in terms of intra class correlation.(48) PCI
is easy to calculate and it require simple inexpensive equipments.
62
Physiological cost index measures the number of extra heartbeats required per meter
walked. PCI is calculated by the formulae
EQUATION 2 PHYSIOLOGICAL COST INDEX
PCI (Beats/m) = (Exercise heart rate – Resting heart rate)
Walking speed
The mean PCI values for healthy adults range from 0.23 to 0.42.(79,80). The
comfortable walking speed for healthy adults varies from 60 to 100 m/min(81,82)
According to Vllasolli et. al in transfemoral amputee persons the mean value of PCI
found was 0.57 (SD=0.085).(64) The comfortable walking speed in transfemoral
amputee persons ranges from 50 to 75 m/min.(64,81)
PCI was assessed by 25 m of indoor walking in a hallway with a regular floor surface
inside the Movement analysis lab. The amputee persons were walking with a self-
selected speed. The resting heart rate and exercise heart rate was recorded with the
hardware -MA 100 Interface unit, Motion lab.
4.9.2.2 GAIT ANALYSIS
Transfemoral amputee persons who fulfilled the inclusion criteria were made to
ambulate at a self-selected speed on a 25 feet walk way in the motion analysis lab.
Data was collected using optical motion capture system. Videos from anterior,
posterior and both lateral views were taken. They were seen with software Video
NAS which was written in Visual Basic. This software could slow down the videos
allowing a frame by frame observation and comparison of frames
63
FIGURE 4-3- GAIT ANALYSIS
KINEMATICS
Light emitting diodes
(LEDs) were attached to
the bony prominences of
the normal side limb and
the corresponding regions
of the prosthetic limb. The
Phase Space apparatus,
automatically recorded the
movement with the help of
eight infrared cameras which displayed the output as 3D moving stick figures on a
monitor. Using the Position Reference Structure (PRS), the position of the cameras in
the room was defined from a fixed point in the room. The following temporal gait
parameters were measured.
1. Gait velocity (m/min) – It measures the speed of amputee persons gait.
2. Gait cadence (steps/min) – Measured as the number of steps taken in a minute.
3. Stride length (cm) –Measured as the distance between heel strike of one foot to heel strike of the same foot.
4. Stance swing ratio (%) – The ratio of time spent in of stance and swing phase in one gait cycle.
5. Single limb support – It is the percentage of gait cycle for which the weight is borne by single lower limb.
64
4.10 STATISTICAL ANALYSIS
Continuous variables were represented with mean and standard deviation.
Descriptive for categorical variables were represented in frequency and percentage.
Association of the continuous variable with the outcome was assessed using paired
T test. The 5 percent level of significance was considered as statistically significant.
Statistical analysis was done with SPSS version 18.
65
4.11 FLOW DIAGRAM
Total No of patients
Screened [n=48]
No of patients Excluded [n=33]
New Patients
[n =20] Not willing for follow up [n=8]
Uses Walking Aids [n=5]
No of patients Recruited
[n=15]
Assessment with Existing QUAD Socket
New IC Socket Fabrication
IC Socket Acclimitization 2
Weeks
Assessement with IC Socket
Statistical Analysis done
[n=15]
66
5 RESULTS
All the transfemoral amputee persons (n=48) who visited the Artificial Limb Centre,
CMC, Vellore from April 2014 to August 2015 were screened. 33 patients were
excluded and 15 patients were recruited. 20 new patients, 8 patients who did not
consent and 5 who were walking with walking aids were excluded. There were no
drop outs.
5.1 DEMOGRAPHIC DATA
TABLE 5-1 DEMOGRAPHIC DATA OF PATIENTS
Mean age in years.( SD)
Side of amputation. No :(%)
Right
Left
Cause of amputation. No :(%)
RTA
Vascular
Others
Gender. No: (%)
Male
Females
Body Mass Index in kg/m2.
Mean(SD)
Duration of prosthetic use in years.
Mean(SD)
Stump length index. Mean(SD)
30(12.5)
9(60)
6(40)
11(73.3)
2(13.3)
2(13.3)
14(93.3)
1(6.67)
21.5(4.4)
5.8(8.0)
52(4.02)
67
5.1.1 AMBULATION STATUS
All the 15 transfemoral amputated persons participated in the study was ambulant in
the community. All the adults except one were employed after their amputation. The
young amputee persons were continuing their education.
5.1.2 AGE
The mean age of the 15 patients who participated in this study was 30 years. The age
range of the patients who were involved in the study was 12 -56 years. There were 6
patients below 25 years of age and 9 patients above 25 years.
TABLE 5-2 AGE DISTRUBUTION OF PATIENTS
Age Range (years)
Mean Age in years (SD)
≤ 25 years (No :)
>25 years (No :)
12 -56
30(12.5)
6
9
5.1.3 SIDE OF AMPUTATION
60 % of the patients had right lower limb amputated and 40% had amputation of the
left lower limb.
68
5.1.4 ETIOLOGY
The major cause of amputation was road traffic accident accounting for 73 %. In two
patients amputation was done due to vascular cause. Diabetes was not the cause of
amputation in any of these patients. Others included one person with congenital limb
deficiency and one where the cause of amputation was osteosarcoma.
FIGURE 5-1 ETIOLOGY OF AMPUTATION
5.1.5 GENDER
In this study all the participants were male except one female patient.
5.1.6 BODY MASS INDEX
The mean height and mean weight of the participants in the study was 175 cm and
60kg respectively. The mean body mass index was 21.5 ± 4.4.
73%
14%
13%
ETIOLOGY
RTA
VASCULAR
OTHERS
69
5.1.7 DURATION OF PROSTHETIC USE
The study recruited 15 transfemoral amputee persons who were already using a
transfemoral prosthesis with quadrilateral socket. Of these 6 patients had been using
it for less than 1 year. The shortest duration of quadrilateral socket used by an
amputee person in this study was 1 month. Four people were using the prosthesis
between 1-5 years. 5 patients were ambulant with the prosthesis for > 5 years. The
female person with congenital limb deficiency were using it for 30 years.
TABLE 5-3 DURATION OF PROSTHETIC USE
Duration of Prosthetic Use Mean(SD)
≤ 1 year. No:
≥1 year ≤ 5 year. No:
>5 year. No
5.8(8.0)
6
4
5
5.1.8 RESIDUAL LIMB LENGTH INDEX
Length of the residual limb is the distance measured from the greater trochanter to
distal aspect of the residual limb. The sound limb upper segment length is measured
from greater trochanter to the lateral femoral condyle.
EQUATION 3 RESIDUAL LIMB LENGTH INDEX
Residual limb length index is calculated by the formulae
(Length of the residual limb) ×100
(Length of the sound side upper segment)
The index ranged from 46 to 62. All the amputated persons had medium length
residual limb.
70
5.2 PRIMARY OUTCOME MEASURE
5.2.1 6 MINUTE WALK TEST
The amputee persons with the quadrilateral socket walked 322.8 ± 102.9 m in 6
MWT. With the ischial containment socket the same was 332 ± 91.7 m. The walking
speed improved with IC socket but the improvement was not statistically significant.
(p value = 0.43). The correlation of 6MWT with Age, Etiology and Duration of
prosthetic use is shown in table 5.4 and figures 5.3-5.
TABLE 5-4 CORRELATION OF THE 6 MINUTE WALK TEST WITH AGE, ETIOLOGY AND DURATION OF PROSTHETIC USE IN QUAD AND IC GROUPS
p
MEAN ± SD , MEAN ± SD , value
Overall Average 322.82 ± 102.91 [ 270.75 , 374.90 ] 332.06 ± 91.75 [ 285.63 , 378.49 ] 0.439
Etiology
RTA 347.25 ± 91.78 [ 293.02 , 401.48 ] 346.40 ± 96.75 [ 289.23 , 403.58 ] 0.928
Vascular 160.31 ± 2.98 [ 156.18 , 164.43 ] 251.50 ± 44.55 [ 189.76 , 313.24 ] 0.225
Others 351.00 ± 55.15 [ 274.56 , 427.44 ] 333.75 ± 83.79 [ 217.62 , 449.88 ] 0.551
Age
< 25 Years 393.33 ± 106.37 [ 308.22 , 478.45 ] 391.50 ± 98.44 [ 312.74 , 470.26 ] 0.836
> 25 Years 275.82 ± 72.43 [ 228.50 , 323.14 ] 292.44 ± 65.27 [ 249.80 , 335.08 ] 0.398
Duration of Prosthesis
< 1 Year 284.87 ± 123.24 [ 186.26 , 383.48 ] 311.22 ± 134.30 [ 203.76 , 418.68 ] 0.245
>1 Year & < 5 Years 290.85 ± 101.48 [ 191.40 , 390.31 ] 301.75 ± 109.96 [ 193.99 , 409.51 ] 0.726
> 5 Years 393.95 ± 100.17 [ 306.15 , 481.75 ] 381.33 ± 99.21 [ 294.37 , 468.29 ] 0.316
6 MINUTE WALK TEST (METRE)
95% CI 95% CI
QUAD SOCKET IC SOCKET
71
FIGURE 5-2-6MWT TEST IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET
FIGURE 5-3 – RELATION OF 6MWT VS AGE
AVERAGE
QUAD SOCKET 322.82
IC SOCKET 332.06
250.00
270.00
290.00
310.00
330.00
350.00M
ete
rs
6MWT
0.00
50.00
100.00
150.00
200.00
250.00
300.00
350.00
400.00
450.00
< 25 YEARS > 25 YEARS AVERAGE
Me
ters
6MWT Vs Age
QUAD SOCKET
IC SOCKET
p value = 0.44
72
FIGURE 5-4- 6MWT VS ETIOLOGY
FIGURE 5-5- 6MWT VS DURATION OF PROSTETIC USE
5.2.2 TIMED UP AND GO
Transfemoral amputee persons walking with ischial containment completed the TUG
test at an average time of 10.26 seconds and those with the quadrilateral socket completed
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
ROADTRAFFIC
ACCIDENT
VASCULAR OTHERS AVERAGE
Me
ters
6MWT Vs Etiology
QUAD SOCKET
IC SOCKET
0.00
50.00
100.00
150.00
200.00
250.00
300.00
350.00
400.00
450.00
<=1 YEAR >1 & <5YEARS
>5 YEARS AVERAGE
Me
ters
6MWT Vs Duration of Prosthetic Use
QUAD SOCKET
IC SOCKET
73
it in an average time of 10.72 seconds. This difference was not statistically significant
(p value 0.41). The correlation of TUG with Age, Etiology and Duration of
prosthetic use is shown in table 5.5 and figures 5.7-9.
TABLE 5-5 CORRELATION OF THE TIMED UP AND GO TEST WITH AGE, ETIOLOGY AND DURATION OF PROSTHETIC USE IN QUAD AND IC GROUPS
p
MEAN ± SD , MEAN ± SD , value
Overall Average 10.72 ± 4.25 [ 8.57 , 12.87 ] 10.26 ± 3.21 [ 8.64 , 11.88 ] 0.411
Etiology
RTA 9.69 ± 3.23 [ 7.78 , 11.60 ] 9.88 ± 3.06 [ 8.07 , 11.69 ] 0.678
Vascular 18.48 ± 1.29 [ 16.70 , 20.26 ] 13.97 ± 2.96 [ 9.87 , 18.07 ] 0.163
Others 8.63 ± 2.33 [ 5.40 , 11.85 ] 8.65 ± 2.68 [ 4.93 , 12.36 ] 0.949
Age
< 25 Years 8.72 ± 4.03 [ 5.49 , 11.95 ] 8.53 ± 3.68 [ 5.59 , 11.48 ] 0.683
> 25 Years 12.06 ± 4.04 [ 9.41 , 14.70 ] 11.41 ± 2.41 [ 9.84 , 12.99 ] 0.486
Duration of Prosthesis
< 1 Year 12.15 ± 5.15 [ 8.03 , 16.26 ] 11.42 ± 5.29 [ 7.19 , 15.64 ] 0.564
>1 Year & < 5 Years 12.60 ± 5.40 [ 7.31 , 17.89 ] 11.28 ± 3.89 [ 7.46 , 15.09 ] 0.208
> 5 Years 7.51 ± 2.21 [ 5.58 , 9.44 ] 8.06 ± 2.31 [ 6.03 , 10.09 ] 0.246
TIMED UP AND GO TEST (SECS)
95% CI 95% CI
IC SOCKETQUAD SOCKET
74
FIGURE 5-6- TUG TEST IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET
FIGURE 5-7- TUG VS ETIOLOGY
AVERAGE
QUAD SOCKET 10.72
IC SOCKET 10.26
0.00
2.00
4.00
6.00
8.00
10.00
12.00Se
con
ds
TUG
0.0
4.0
8.0
12.0
16.0
20.0
ROADTRAFFIC
ACCIDENT
VASCULAR OTHERS AVERAGE
Seco
nd
s
TUG Vs Etiology
QUAD SOCKET
IC SOCKET
p value – 0.41
75
FIGURE 5-8- TUG VS AGE
FIGURE 5-9- TUG VS DURATION OF PROSTHETIC USE
5.2.3 SOCKET COMFORT SCORE
The mean socket comfort score (SCS) with ischial containment is 8.47, which is
higher than with the quadrilateral socket of 7.13. The difference is statistically
significant with a p value of 0.0031. The correlation of SCS with Age, Etiology and
Duration of prosthetic use is shown in table 5.6.
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
< 25 YEARS > 25 YEARS AVERAGE
Seco
nd
s
TUG Vs Age
QUAD SOCKET
IC SOCKET
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
<=1 YEAR >1 & <5 YEARS >5 YEARS AVERAGE
Seco
nd
s
TUG Vs Duration of Prosthetic Use
QUAD SOCKET
IC SOCKET
76
TABLE 5-6 CORRELATION OF THE SOCKET COMFORT SCORE WITH AGE, ETIOLOGY AND DURATION OF PROSTHETIC USE
QUAD SOCKET p
MEAN ± SD , MEAN ± SD , value
Overall Average 7.13 ± 1.64 [ 6.30 , 7.96 ] 8.47 ± 0.92 [ 8.00 , 8.93 ] 0.003
Etiology
RTA 7.09 ± 1.76 [ 6.05 , 8.13 ] 8.45 ± 0.93 [ 7.90 , 9.01 ] 0.000
Vascular 6.50 ± 2.12 [ 3.56 , 9.44 ] 8.00 ± 1.41 [ 6.04 , 9.96 ] 0.205
Others 8.00 ± 0.00 9.00 ± 0.00 0.000
Age
< 25 Years 7.00 ± 1.67 [ 5.66 , 8.34 ] 8.50 ± 0.84 [ 7.83 , 9.17 ] 0.007
> 25 Years 7.22 ± 1.72 [ 6.10 , 8.34 ] 8.44 ± 1.01 [ 7.78 , 9.11 ] 0.074
Duration of Prosthesis
< 1 Year 7.17 ± 3.28 [ 4.54 , 9.79 ] 8.33 ± 4.19 [ 4.98 , 11.69 ] 0.084
>1 Year & < 5 Years 7.50 ± 1.73 [ 5.80 , 9.20 ] 8.25 ± 0.96 [ 7.31 , 9.19 ] 0.319
> 5 Years 6.80 ± 1.64 [ 5.36 , 8.24 ] 8.80 ± 1.10 [ 7.84 , 9.76 ] 0.061
SOCKET COMFORT SCORE
95% CI 95% CI
IC SOCKET
77
FIGURE 5-10- SCS IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET
5.2.4 SOCKET PREFERENCE
Among the 15 transfemoral amputee persons, 13 preferred ischial containment
socket. 87 % of the transfemoral amputee persons choose to walk with ischial
containment socket rather than quadrilateral socket.
FIGURE 5-11 – SOCKET PREFERENCE IN TRANSFEMORAL AMPUTEE PERSONS
AVERAGE
QUAD SOCKET 7.13
IC SOCKET 8.47
0.00
2.00
4.00
6.00
8.00
10.00Sc
ore
SCS
2
13
Socket Preference
QUAD SOCKET IC SOCKET
p value = 0.003
78
5.3 SECONDARY OUTCOME MEASURES
5.3.1 ENERGY EFFICIENCY
The Physiological Cost Index (PCI) is used as an index of energy efficiency. The
transfemoral amputee persons walked with a PCI of 0.71 with the ischial containment
socket which was lesser than with the quadrilateral socket of 0.87. Paired T test
showed no significant difference in PCI between the two groups with p value of
0.19. The correlation of PCI with Age, Etiology and Duration of prosthetic use is
shown in Table 5.7.
FIGURE 5-12- PCI IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET
AVERAGE
QUAD SOCKET 0.87
IC SOCKET 0.71
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
He
art
Be
ats
/ M
ete
rs
PCI
p value = 0.19
79
TABLE 5-7 CORRELATION OF THE PHYSIOLOGICAL COST INDEX WITH AGE, ETIOLOGY AND DURATION OF PROSTHETIC USE
5.3.2 GAIT VELOCITY
The average gait velocity for patients with the quadrilateral socket was 45 m/min
which improved to 52.6 m/min with the ischial containment.
QUAD SOCKET p
MEAN ± SD , MEAN ± SD , value
Overall Average 0.87 ± 0.39 [ 0.67 , 1.07 ] 0.71 ± 0.37 [ 0.53 , 0.90 ] 0.187
Etiology
RTA 0.90 ± 0.40 [ 0.67 , 1.14 ] 0.75 ± 0.43 [ 0.50 , 1.01 ] 0.320
Vascular 0.52 ± 0.45 [ -0.10 , 1.14 ] 0.50 ± 0.05 [ 0.43 , 0.57 ] 0.977
Others 1.03 ± 0.25 [ 0.69 , 1.37 ] 0.70 ± 0.04 [ 0.64 , 0.76 ] 0.263
Age
< 25 Years 0.82 ± 0.37 [ 0.53 , 1.11 ] 0.92 ± 0.52 [ 0.50 , 1.33 ] 0.388
> 25 Years 0.90 ± 0.43 [ 0.62 , 1.18 ] 0.58 ± 0.14 [ 0.49 , 0.67 ] 0.064
Duration of Prosthesis
< 1 Year 0.92 ± 0.36 [ 0.63 , 1.21 ] 0.78 ± 0.26 [ 0.57 , 0.99 ] 0.510
>1 Year & < 5 Years 0.58 ± 0.33 [ 0.26 , 0.91 ] 0.60 ± 0.11 [ 0.49 , 0.71 ] 0.872
> 5 Years 1.03 ± 0.39 [ 0.69 , 1.37 ] 0.72 ± 0.12 [ 0.62 , 0.83 ] 0.227
PCI
95% CI 95% CI
IC SOCKET
80
The difference in average velocities between the two groups was statistically
significant with a (p value 0.017). Gait velocity in relation to Age, Etiology and
Duration of prosthetic use is given in Table 5.8 and Figure 5.14-15.
TABLE 5-8 CORRELATION OF THE GAIT VELOCITY WITH AGE, ETIOLOGY AND DURATION OF PROSTHETIC USE
QUAD SOCKET p
MEAN ± SD , MEAN ± SD , value
Overall Average 45.00 ± 16.85 [ 36.47 , 53.53 ] 52.62 ± 16.92 [ 44.06 , 61.18 ] 0.017
Etiology
RTA 47.09 ± 18.36 [ 36.24 , 57.94 ] 55.94 ± 17.65 [ 45.51 , 66.37 ] 0.058
Vascular 26.50 ± 0.71 [ 25.52 , 27.48 ] 42.00 ± 7.07 [ 32.20 , 51.80 ] 0.217
Others 37.50 ± 17.68 [ 13.00 , 62.00 ] 44.50 ± 19.09 [ 18.04 , 70.96 ] 0.090
Age
< 25 Years 50.25 ± 23.65 [ 31.33 , 69.17 ] 58.61 ± 16.94 [ 45.05 , 72.17 ] 0.112
> 25 Years 38.28 ± 12.04 [ 30.41 , 46.14 ] 48.52 ± 16.61 [ 37.66 , 59.37 ] 0.052
Duration of Prosthesis
< 1 Year 41.42 ± 16.55 [ 28.18 , 54.66 ] 55.94 ± 20.64 [ 39.43 , 72.46 ] 0.047
>1 Year & < 5 Years 43.38 ± 13.78 [ 29.87 , 56.88 ] 48.17 ± 16.92 [ 31.59 , 64.74 ] 0.313
> 5 Years 44.80 ± 25.38 [ 22.55 , 67.05 ] 52.00 ± 19.46 [ 34.95 , 69.05 ] 0.278
GAIT VELOCITY (m/min)
95% CI 95% CI
IC SOCKET
81
FIGURE 5-13- GAIT VELOCITY IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET
FIGURE 5-14 – GAIT VELOCITY VS ETIOLOGY
FIGURE 5-15- GAIT VELOCITY VS AGE
AVERAGE
QUAD SOCKET 45.00
IC SOCKET 52.62
0.00
10.00
20.00
30.00
40.00
50.00
60.00
Me
ter
/ M
in
Gait Velocity
0.0
10.0
20.0
30.0
40.0
50.0
60.0
ROADTRAFFIC
ACCIDENT
VASCULAR OTHERS AVERAGE
Me
ter
/ M
in
Gait Velocity Vs Etiology
QUAD SOCKET
IC SOCKET
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
< 25 YEARS > 25 YEARS AVERAGE
Me
ter
/ M
in
Gait Velocity Vs Age
QUAD SOCKET
IC SOCKET
p value = 0.02
82
5.3.3 GAIT CADENCE
The average cadence was 85.8 steps/min in the quadrilateral group and 87.13
steps/min in the ischial containment group. This difference was not found to be
statistically significant, (p value = 0.69)
TABLE 5-9 CORRELATION OF THE GAIT CADENCE WITH AGE, ETIOLOGY AND DURATION OF PROSTHETIC USE IN THE QUAD AND IC GROUPS.
p
MEAN ± SD , MEAN ± SD , value
Overall Average 85.80 ± 9.75 [ 80.87 , 90.73 ] 87.13 ± 15.03 [ 79.53 , 94.74 ] 0.697
Etiology
RTA 88.64 ± 8.85 [ 83.41 , 93.86 ] 88.82 ± 16.74 [ 78.93 , 98.71 ] 0.967
Vascular 72.00 ± 0.00 84.00 ± 8.49 [ 72.24 , 95.76 ] 0.295
Others 84.00 ± 8.49 [ 72.24 , 95.76 ] 81.00 ± 12.73 [ 63.36 , 98.64 ] 0.500
Age
< 25 Years 87.67 ± 8.21 [ 81.09 , 94.24 ] 89.00 ± 22.93 [ 70.65 , 107.35 ] 0.859
> 25 Years 84.56 ± 10.94 [ 77.41 , 91.71 ] 85.89 ± 7.88 [ 80.74 , 91.04 ] 0.705
Duration of Prosthesis
< 1 Year 84.50 ± 41.69 [ 51.14 , 117.86 ] 85.00 ± 43.64 [ 50.08 , 119.92 ] 0.941
>1 Year & < 5 Years 87.75 ± 13.72 [ 74.30 , 101.20 ] 85.25 ± 7.37 [ 78.03 , 92.47 ] 0.555
> 5 Years 85.80 ± 5.02 [ 81.40 , 90.20 ] 91.20 ± 17.70 [ 75.69 , 106.71 ] 0.441
GAIT CADENCE
95% CI 95% CI
QUAD SOCKET IC SOCKET
83
FIGURE 5-16- GAIT CADENCE IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET
5.3.4 STRIDE LENGTH
The stride length was greater in the IC group with a mean of 120.8 as compared to
the QUAD group of 3.53 with statistically significant p value of 0.024.
FIGURE 5-17 – STRIDE LENGTH IN QUADRILATERAL & ISCHIAL CONTAINMENT SOCKET
AVERAGE
QUAD SOCKET 85.80
IC SOCKET 87.13
0.00
20.00
40.00
60.00
80.00
100.00
No
of
Ste
ps
Gait Cadence
AVERAGE
QUAD SOCKET 103.53
IC SOCKET 120.80
0.00
20.00
40.00
60.00
80.00
100.00
120.00
140.00
Ce
nti
me
ters
Stride Length
p value -0.02
p value 0.70
84
TABLE 5-10 CORRELATION OF THE STRIDE LENGTH WITH AGE, ETIOLOGY AND DURATION OF PROSTHETIC USE IN THE QUAD AND IC GROUPS
FIGURE 5-18 – STRIDE LENGTH VS AGE
p
MEAN ± SD , MEAN ± SD , value
Overall Average 103.53 ± 25.03 [ 90.87 , 116.20 ] 120.80 ± 24.06 [ 108.63 , 132.97 ] 0.024
Etiology
RTA 104.91 ± 27.81 [ 88.48 , 121.34 ] 125.55 ± 19.19 [ 114.21 , 136.88 ] 0.013
Vascular 85.00 ± 1.41 [ 83.04 , 86.96 ] 115.00 ± 12.73 [ 97.36 , 132.64 ] 0.166
Others 114.50 ± 9.19 [ 101.76 , 127.24 ] 100.50 ± 55.86 [ 23.08 , 177.92 ] 0.745
Age
< 25 Years 107.33 ± 34.07 [ 80.07 , 134.59 ] 137.50 ± 17.07 [ 123.84 , 151.16 ] 0.015
> 25 Years 101.00 ± 18.77 [ 88.73 , 113.27 ] 109.67 ± 21.95 [ 95.32 , 124.01 ] 0.375
Duration of Prosthesis
< 1 Year 104.00 ± 47.67 [ 65.86 , 142.14 ] 129.50 ± 51.21 [ 88.52 , 170.48 ] 0.029
>1 Year & < 5 Years 110.75 ± 22.62 [ 88.58 , 132.92 ] 117.75 ± 21.98 [ 96.21 , 139.29 ] 0.440
> 5 Years 97.20 ± 24.36 [ 75.85 , 118.55 ] 112.80 ± 30.22 [ 86.31 , 139.29 ] 0.423
STRIDE LENGTH (cm)
95% CI 95% CI
QUAD SOCKET IC SOCKET
0.00
20.00
40.00
60.00
80.00
100.00
120.00
140.00
160.00
< 25 YEARS > 25 YEARS AVERAGE
Ce
nti
me
ters
Stride Length Vs Age
QUAD SOCKET
IC SOCKET
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5.3.5 SINGLE LIMB SUPPORT
The single limb support (SLS) of amputated side with ischial containment was
32.07% and of sound side was 42.5%. SLS with quadrilateral socket of amputated
side was 31.27% and normal limb was 38.8%. The improvement in the single limb
support with IC socket was not statistically significant in both sides.
TABLE 5-11 SINGLE LIMB SUPPORT OF AMPUTATED AND NORMAL SIDE LIMBS WITH QUAD AND IC SOCKET
FIGURE 5-19 – SINGLE LIMB SUPPORT IN AMPUTATED & NORMAL SIDE
P VALUE
MEAN ± SD , MEAN ± SD ,
AMPUTATED SIDE 31.27 ± 7.10 [ 27.68 , 34.86 ] 32.07 ± 6.47 [ 28.79 , 35.34 ] 0.59
NORMAL SIDE 38.80 ± 7.02 [ 35.25 , 42.35 ] 42.53 ± 6.28 [ 39.36 , 45.71 ] 0.1
SINGLE LIMB SUPPORT
QUAD SOCKET IC SOCKET
95% CI 95% CI
QUAD IC
AMPUTATED 31 32
NORMAL 39 43
0
10
20
30
40
50
Pe
rce
nta
ge
SINGLE LIMB SUPPORT
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5.3.6 STANCE SWING RATIO
The stance swing ratio in a normal gait cycle is 60/40. The ratio of stance to swing in
the above knee amputee persons is mentioned in the table below.
TABLE 5-12 STANCE SWING RATIO OF THE AMPUTATED AND NORMAL SIDES WITH QUAD AND IC SOCKET
STANCE SWING RATIO
QUAD
SOCKET IC
SOCKET
AMPUTATED SIDE 61/38 58/41
NORMAL SIDE 69/30 69/31
87
6 DISCUSSION
The aim of the study was to compare the effectiveness of ischial containment socket
with quadrilateral socket in terms of walking abilities and subjective preference. 48
patients were screened, 33 patients were excluded and 15 participated in the study.
There were no drop outs in this study. There were no adverse events in this study.
The mean age of the patients recruited for this study was 30 years. The age of the
youngest participant was 12yrs and the oldest was 55yrs. The most common cause
for transfemoral amputation was road traffic accident. In two patients the amputation
was due to vascular etiology. Diabetes was not the reason for amputation in any of
these participants. The other causes were one person with osteosarcoma being the
cause of amputation and another person has a congenital limb deficiency. This
correlated with previous studies which reported increasing number of amputations
due to road traffic accidents resulting in young amputee persons.(6) All the
participants were male except one. The lower extremity amputations are common in
men.(7)
All the transfemoral amputee persons were walking with prosthetic limb fitted with
quadrilateral socket. The minimum duration of prosthetic use was 1month. The mean
duration of prosthetic use was 5.82 years. There were 6 patients who were using the
prosthesis for less than 1 year. Five amputee persons had been using artificial limb
88
for more than 5 years. The maximum duration of prosthetic use was 30 years in the
person with congenital limb deficiency. Since the amputee persons were accustomed
to their prosthesis for a significant period of time, the less will be their acceptance to
change the socket. The ideal design for such a study would have been a cross over
study. Due to difficulty in obtaining sample size and follow up; we choose to conduct
this research as before and after design study. The duration of use of the two
prosthesis was unequal in distribution, with the ischial containment socket being used
for two weeks and quadrilateral socket being used for longer time periods. There is
no literature defining the time period for acclimatization for a new prosthesis. In a
similar study comparing the energy cost of walking with two different sockets one
month follow up was used.(69) In this study, we kept the acclimatization period as 2
weeks. Further prosthetic training was not given in this time period. All the amputee
persons were wearing the artificial limb with ischial containment socket for 2 weeks
and doing their routine activities. The transfemoral amputee persons recruited in this
study were all community ambulant. The elderly person > 55 years old was not
gainfully employed, even though he was ambulant for > 2km/day in the community.
Excluding him, all the adult transfemoral amputee persons were the earning members
of the family. There were 3 amputee persons below 18 years, who were attending
school.
The primary outcome measure for ambulation is the six minute walk test (6MWT).
For 6MWT the amputee persons with IC socket walked more distance in comparison
89
to quadrilateral socket. The improvement was not statistically significant. The
subgroup analysis showed that the amputee persons using the quadrilateral socket for
more than five years walked with slow speed when converted to ischial containment
socket. The reason could be that since they were used to the quadrilateral socket for
many years, they may have required more time period for acclimatization with the
new socket. The walking endurance of the young amputee persons (age < 25 years) is
more compared to the persons with amputation > 25 years. The mean for 6MWT in
younger age group was 390m and the elder group was 280m. The amputee persons
with vascular etiology the endurance was less. They showed a considerable
improvement with the ischial containment socket. This correlates with previous
studies which reports decreased comfortable walking speed in vascular amputee
persons.(60, 63)
Another primary outcome measure was Timed Up and Go test (TUG). The
transfemoral amputee persons with both sockets completed the TUG test with a mean
of around 10 seconds. The mean TUG for lower limb amputee persons is between
12-13 seconds.(72, 73) In our study the time period to complete TUG was lesser
compared to the literature. This is because the young amputee persons finished this
test with shorter duration of about 8.5 seconds. Since the mean age of the participants
were less, the time taken to complete the TUG test was lesser compared to the other
studies. The patients walking with the prosthetic limb for more than 5 years
completed the TUG test in considerably shorter time period. The more the duration of
90
prosthetic use lesser the time taken for functional abilities like getting up from chair
and taking turns. The two patients with vascular etiology required more time (18.5
seconds) to complete TUG test with quadrilateral socket. They showed marked
improvement (14 seconds) with the ischial containment socket. The ischial
containment socket is better than quadrilateral socket in terms of walking
endurance for transfemoral amputee persons.
The subjective evaluation of the socket was done with socket comfort score (SCS).
The SCS in the ischial containment group improved significantly with a mean
difference of 1.4. The above knee amputee persons find ischial containment socket
more comfortable when compared to the quadrilateral socket. The comfort which the
amputee persons stated were in terms of decreased perineal pain decreased pistoning
effect and improved socket fit. Certain patients expressed relief from the discomforts
of posterior shelf for ischial seat in quadrilateral sockets. The discomfort in the distal
aspect of the femur is decreased with Ischial containment socket. The improvement
in socket comfort score correlates with other studies.(65–67) The ischial containment
socket offers better comfort for unilateral transfemoral amputee persons.
At the final assessment all the above knee amputee persons were given an option to
choose whichever socket they like. Eighty five percent of the patients preferred
ischial containment socket over the quadrilateral socket. The persons with longer
duration of quadrilateral socket use for >10 years also preferred to convert
themselves to ischial containment socket due to improved comfort which is reflected
91
in the increased score of SCS. We conclude that the ischial containment socket is
superior to quadrilateral socket in terms of comfort and preference.
The energy efficiency is calculated by the physiological cost index (PCI). The PCI
improved with ischial containment socket with a mean of 0.71 in comparison to
quadrilateral socket (0.87). Even though the PCI improved, it was not statistically
significant. The PCI for transfemoral amputee persons according to the previous
studies is 0.48-0.55.(65,70,80) The difference in PCI in the younger amputee persons
were less. The younger patients were already walking with good self-selected
walking speed. Hence the conversion of socket didn’t alter the walking speed as well
as PCI. In the age group > 25 years, the PCI showed a mean improvement of 0.32
with the ischial containment socket. The improvement in terms of energy
efficiency with ischial containment socket in unilateral above knee amputee
persons as expected by its biomechanical principles is inconclusive.
The mean gait velocity with the quadrilateral socket was 45 m/min which improved
to 52.6 m/min with the IC socket. The improvement in gait velocity with the ischial
containment is statistically significant. This correlates with previous studies in which
the walking speed increases with IC socket. The normal healthy person the walking
speed is 60 -100 m/min. (81,82) The transfemoral amputee persons walks with a
lower speed of 50 -75 m/min.(64,81). The walking speed of the study group is
matching the previous studies. The comfortable walking speed significantly
92
improved with the ischial containment socket even though it is not reflected in the
walking endurance measured by 6MWT. The vascular amputee persons are walking
with lesser speed with a mean of 26.5m/min with quadrilateral socket and 42 m/min
with ischial containment socket. The young amputee persons walk with increased
gait velocity compared to the above 25 age group. The gait cadence increased with
the ischial containment socket by 1.3 steps/min, which is not statistically significant.
The ischial containment is beneficial in the vascular group where the cadence
improved by 12 steps/min. There was not much variation in cadence with age. There
was a significant increase in stride length with ischial containment socket. The stride
length improved about 17.3 cm with the ischial containment socket. The increase in
velocity is due to increase in the stride length rather than the cadence. The vascular
amputee persons showed maximum improvement in stride length with 30 cm
improvement in ischial containment socket group. The amputee persons using the
prosthesis for lesser duration showed maximum variation with the IC socket. The gait
parameters like stance swing ratio and single limb support did not show any
significant improvement. The single limb support in the amputated side was lesser
when compared to the normal limb. The ischial containment socket is a better
option when compared to quadrilateral socket in terms of gait velocity and
stride length.
All of the participants had completed 2 weeks of structured outpatient rehabilitation
in CMC, when they were given the initial prosthesis. The transfemoral amputee
93
persons were walking with considerable gait deviations which were evident in the
observational gait analysis. Four amputee persons were walking with knee joint
locked. They were walking with circumductory gait. They felt speed and stability
increased when the knee was locked. They had good power in hip extensors. The
other gait deviations that were observed in the video gait analysis were lateral trunk
lean, wide based gait, vaulting gait, whips and terminal impacts. There were no
observable differences on video gait analysis with socket change. This may be due
to shorter time period of ischial containment socket usage as well as chronic use of
quadrilateral socket. Reduction in gait deviations were inconclusive in previous
studies.(68)
94
7 CONCLUSION
The ischial containment socket is superior to quadrilateral socket in terms of comfort.
This is reflected in the socket comfort scores as well as the patient preference for
ischial containment socket. The comfortable walking speed of transfemoral amputee
persons significantly improved with the ischial containment socket. The ischial
containment socket might potentially improve walking ability, endurance and enable
independent community ambulation for unilateral transfemoral amputee persons. The
ischial containment socket provides better energy efficiency when compared to
quadrilateral socket even though the improvement was not statistically significant.
All the persons recruited were already using a quadrilateral socket (mean duration of
use: 6 years). There were no observable changes in the gait pattern once the socket
was changed to ischial containment. This could probably be due to the fact that they
were already accustomed to walking with transfemoral prosthesis.
95
8 LIMITATIONS
The acclimatization period for ischial containment socket was short. There is no data
in literature regarding optimum acclimatization period for socket change in
transfemoral amputee persons. The disproportionate time period in using both
sockets is a limitation in this study.
The amputee persons who use quadrilateral socket for prolonged time period may be
more accustomed to it.(30) Hence, their acceptance to change into a ischial
containment socket may be less. Majority of the amputated persons were using
quadrilateral socket for more than couple of years. This could have weakened their
gluteus medius and abductor mechanism.(69) Hence it is difficult to attain reduction
in gait deviations as well as to achieve the entire benefits of the ischial containment
socket.
An attempt was made to radiologically evaluate the hip adduction angle while weight
bearing. The data was not analyzed due to technical errors in data acquisition.
96
9 SCOPE OF FUTURE RESEARCH
The effect of femur adduction on functional outcome in patients with transfemoral
amputation remains an area for future investigation. The research findings are
inconclusive and limited in sample size with respect to femur alignment in ischial
containment socket. The effect of ischial containment socket on reduction in amputee
persons gait deviations is another area to be explored in future research. The majority
of the research in the field of prosthetics is limited due to a smaller sample size. A
randomized control / cross over trial with a larger sample size might be able to reveal
the biomechanical advantages of the ischial containment socket.
97
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11 ANNEXURE
1. Institutional Review Board Acceptance letter
2. Patient Information sheet
3. Consent form
3. Information brochure
4. Patient Database
106
107
108
PATIENT INFORMATION SHEET
COMPARISON OF TWO TYPES OF SOCKET (ISCHIAL CONTAINMENT SOCKET AND QUADRILATERAL SOCKET) FOR FUNCTIONAL ABILITIES INTRANSFEMORAL AMPUTEE PERSONS
Principle Investigator- Dr. Nitha.J Department of PMR Christian Medical College, Vellore
Introduction I am Dr. Nitha.J, working for The Department of Physical Medicine and Rehabilitation, Christian Medical College, Vellore. We are doing comparative study on above knee amputee persons using two different prosthetic sockets. You are being requested to be the part of this research. Before you decide, you can discuss about the research with whoever you want to.
What is the purpose of the research
Patients who have undergone above knee amputation and are walking with conventional type of prosthesis will be provided with another new socket which is theoretically better. The assessments will be done before and after the socket change. We have two different socket options; this research will try to find out which one is better among two sockets.
If you take part what will you have to do?
You will be given one new socket which is made according to your measurements. You will be taught how to walk with it . Some walking tests will be conducted at first visit and at the end of 2 weeks. Participant selection
We are inviting all above knee amputee persons patients within the age of 15-70 years, who will be attending the amputee persons clinic at PMR who are ambulant with quadrilateral socket, to participate in the research .
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Can you withdraw from this study after it starts?
Your participation in this research is entirely voluntary. It is your choice whether to participate or not. After the study has started, you still have the liberty to withdraw out of it. Whether you choose to participate or not, all the services you receive at this clinic will continue and nothing will change. If you choose not to participate in this research project, you will be offered the treatment that is routinely offered in hospital.
What will happen if you develop any study related injury?
We do not expect any injury to happen, but if any unexpected problems occur due to the study, these will be treated at no cost for you. We will however not be able to provide any monetary support.
What will you have to pay for the study?
You will be given one socket free of cost. You will not need to pay for any tests which will be done for you at the starting and at the end of the study. Paying for the rest of prosthesis (if needed) however will be according to the usual protocol and concession will be given in case you are unable to pay the full amount.
What happens after the study is over?
You will be getting one more custom made socket free of cost. At the end of study you can use whichever socket you are more comfortable with and can keep the other with you.
Will your personal details be kept confidential?
The results of this study will be published in a medical journal but you will not be identified by name in any publication or presentation of results. However, your medical notes may be reviewed by people associated with the study, without your additional permission.
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If you have any further questions, please ask Dr. Nitha or Dr. Henry Prakash tel: 0416-2282158/ 9488232242 or email: [email protected]
Informed Consent form to participate in a research study
Study Title: Comparative study of ischial containment socket and quadrilateral socket for functional ability in persons with unilateral transfemoral amputation
Study Number: ____________ Subject’s Initials: __________________ Subject’s Name: _________________________________________ Date of Birth / Age: ___________________________
(Subject) (i) I confirm that I have read and understood the information sheet dated ____________ for the above study and have had the opportunity to ask questions.
(ii) I understand that my participation in the study is voluntary and that I am free to withdraw at any time, without giving any reason, without my medical care or legal rights being affected.
(iii) I understand that the Sponsor of the clinical trial, others working on the Sponsor’s behalf, the Ethics Committee and the regulatory authorities will not need my permission to look at my health records both in respect of the current study and any further research that may be conducted in relation to it, even if I withdraw from the trial. I agree to this access. However, I understand that my identity will not be revealed in any information released to third parties or published.
(iv) I agree not to restrict the use of any data or results that arise from this study provided such a use is only for scientific purpose(s).
(v) I agree to take part in the above study.
Signature (or Thumb impression) of the Subject/Legally Acceptable Date: _____/_____/______ Signatory’s Name: _________________________________ Signature:
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INVESTIGATOR”S BROCHURE
COMPARISON OF IC AND QUAD
Name SL. No
Hospital No: Date IA FA
Age
Address
Contact no:
Premorbid occupation
Present occupation
D. O. Injury
Mode of injury
D.O.Amputation
Side (L / R)
Prosthesis use (months)
Any complication
Any difficulty in ambulation
Stump length
Stump length index
Outcome measures –
Pre Post
6 MWT
TUG
SCS
PCI Final Socket
XRAY Gait
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Patient Database:
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