total hip arthroplasty

Total Hip

Arthroplasty

HISTORY OF HIP

REPLACEMENT SURGERY

Deformed and ankylosed joints surfaces were

contoured with Biological material e.g. Fascia latagrafts as interpositional layer to resurface the joint

and allow movement in UK an Europe in early 20th

century.

1912- Jones used gold foil as inter-

positional layer

1923- Smith-Petrson introduced

“mould arthroplasy”

Later- Backelite and Celluloid

derivatives

1937- Vitallium implants

Professor John Charnley

(1911-1982)

A British Orthopedician, Pioneer of modern hip replacement

Arthroplasty.

Developed the techniques of THR in 1960s.

APPLIED BIOMECHANICS

STRESS TRANSFER TO BONE

IMPORTANCE OF QUALITY OF BONE-

APPROPIATE IMPLANT

OPTIMAL METHOD OF FIXATION

RESPONSE OF BONE TO IMPLANT

ULTIMATE SUCCESS OF ARTHROPLASTY

RADIOGRAPHIC CATEGORISATION

BY DORR ET ALTYPE A

THICK CORTEX AND CANAL

DIMENSION

LARGE POSTERIOR CORTEX-LAT

VIEW

CHAMPAGNE FLUTE

APPEARANCE

MEN AND YOUNGER PATIENTS

GOOD FIXATION IN BOTH

CEMENTED AND CEMENTLESS

SOME BONE LOSS

SHAPE IS MAINTAINED

IMPLANT FIXATION IS NOT

A PROBLEM

TYPE B

TYPE C

MUCH OF THE CORTEX

LOST FROM MEDIAL AND

POSTERIOR CORTX

IM CANAL IS WIDE

LESS FAVORABLE FOR

IMPLANT FIXATION

COMPARISON

STRESS TRANSFER IS DESIRABLE

LESS MODULUS OF ELASTICITY = MORE ELASTIC

=LESS DIAMETER

MORE STRESS TRANSFER TO BONE

PROXIMAL MEDIAL CORTEX-MOST BONE LOSS

COLLAR-PREVENTS BONE LOSS

CEMENTLESS IMPLANTS ARE MORE

PHYSIOLOGICAL

INDICATIONS OF THR

1. Arthritis : RheumatoidJuvenile rheumatoid (Still disease)Ankylosing spondylitis

2. Degenerative joint disease :: Primary: Secondary : Slipped capital femoral epiphysis

Congenital dislocation or dysplasia of hipCoxa plana (Legg-Calvé-Perthes disease)Paget diseaseTraumatic (Fracture/ dislocations)

Hemophilia

INDICATIONS OF THR

Osteonecrosis : Post fracture or Post dislocationIdiopathic

Slipped capital femoral epiphysis

Hemoglobinopathies

Renal diseaseSteroid induced

AlcoholismCaisson disease

LupusGaucher disease

4. Nonunion following # NOF

5. Femoral neck fractures and trochanteric fractures with head involvement

INDICATIONS OF THR

6. Pyogenic arthritis or osteomyelitis : HematogenousPostoperative

7. Tuberculosis8. Congenital subluxation or dislocation9. Hip fusion and pseudarthrosis10. Failed reconstruction following: Osteotomy

Cup arthroplastyFemoral head

prosthesisGirdlestone

procedureTotal hip replacementResurfacing

arthroplasty

11. Bone tumor involving proximal femur or acetabulum

12. Hereditary disorders (e.g., achondroplasia)

TOTAL HIP

COMPONENTS AND

DESIGNS

Total Hip

Components

1.Femoral Components

(Head+ Neck+ Stem)

2.Acetabular Components

Goal of THR

Biomechanically

sound, stable hip joint

by restoration of

normal center of

rotation of femoral

head

The location of

center of rotation of

femoral head is

determined by

1. Vertical offset

2. Horizontal(medial) offset

3. Anterior offset

(Anteversion)

WHAT WILL HAPPEN IF THERE IS INADEQUATE

RESTORATION OF MEDIAL OFFSET?

WHAT WILL HAPPEN IF THERE IS INADEQUATE RESTORATION OF VERTICAL OFFSET

MEDIAL RESTORATION IS SIMPLY CORRECTED BY

MAKING NECK ADJUSTMENT BUT……

LIMB LENGTH INCREASES

VERSION

NORMAL FEMUR IS 10 TO 15 DEGREE ANTEVERTED.

USUALLY ACCOMPLISHED BY ROTATING THE

COMPONENT IN FEMORAL CANAL.

IN PRESS FIT FIXATION IS USED –MODULAR FEMORAL

COMPONENT IS USED.

HEAD NECK RATIO AFFECTS ROM ,IMPINGEMENT,STABILITY OF ARTICULATION.

TYPES OF FEMORAL

COMPONENTS

Cemented stems Cementless stems

porous surface

nonporous surface Specialized custom-made

CEMENTED STEMS

Most designers favour- cobalt chrome alloy

PMMA cement is the standard for

femoral component fixation

Pitfalls- Debonding, Mechanical loosening,

Extensive bone loss with fragmented cement

2. Cementless stems with porous

surface Fixation is more biological.

Material- titanium alloy/ Cobalt-Chromium alloy

Bone ingrowth into porous metal surface

Requires: a)immediate mechanical stability at

the time of surgery

b) intimate contact between porous

surface and viable host bone

So, surgical technique and instrumentation

need to be more precise than cemented

counterpart

Specialized custom-made

Specialized femoral components for replacement of variable lengthth of proximal femur. Stem can

be combined with TKR to replace entire femur

ACETABULAR

COMPONENTS

Cemented

Cementless

Constrained type

Specialized custom made

Cemented acetabular

component

PMMA spacers (3 mm)

are incorporated into

polymerizing cement,

yeilding uninterrupted

cement mantle

Satisfactory in elderly,

low demand patient,

Tumour reconstruction,

and in revision

arthroplasty.

Cementless acetabular

components

1. Porous coated for

bone-ingrowth

2. Fixation with

trans acetabular screw

Constrained acetabular

components Mechanism to lock the

prosthetic femoral head into the

polythene liner

Indications-

-Insufficient soft tissue,

-Deficient hip abductors,

-Neuromuscular disease,

-Hip with recurrent

dislocation despite well-

positioned implants.

Alternative bearings

Highly cross linked polyethylene

Metal on metal bearings

Ceramic on ceramic bearings

Metal on metal bearings

Low wear rate

High carbon cobalt chromium alloy

Diametral clearance-gap between the two

implants at the equator of articulation.

Smaller clearance produce films for lubrication

and reduced wear.

Elevated metal ions in blood that excreted

through urine.

So contraindicated in impending renal failure.

Placental transfer occur of these metal ions.

Delayed type hypersensitivity (aseptic lymphocytic vasculitis associated lesions)

Pseudotumour

Recommendation for symptomatic patients is measurement

of blood cobalt and chromium ion level and/MRI or USG.

CERAMIC ON CERAMIC

BEARINGS

ALUMINA CERAMIC IS USED.

HIGH DENSITY, HYDROPHILLIC, SMOOTHER THAN

METAL.

CERAMIC IS HARDER THAN METAL AND MORE

RESISTANT TO SCRATCHING.

LINEAR WEAR RATE IS 4000 TIME LESS THAN COBALT

CHROME ALLOY ON POLYETHYLENE.

DISADVANTAGE

IMPINGEMENT BETWEEN THE FEMORAL NECK AND

RIM OF THE CERAMIC ACETABULAR COMPONENT.

IMPLANT MALPOSITION

STRIPE WEAR

SQUEAKING

OSTEOLYSIS

OXIDIZED ZIRCONIUM

CERAMIC METAL ALLOY.

NOT SUSCEPTIBLE TO CHIPPING,FLAKING,OR

FRACTURES.

Templating of radiograph

for pre-operative planning

1. Determination

of the amount

of limb

shortening

2. Acetabular

over-lay

templating and

center marking

3. Femoral overlay

templating and

measurement of

precise size of

proximal canal

4. Selection of

appropriate

neck-length to

restore limb

length and

femoral offset

5. If no shortening present, we match the center head with previously marked center of the acetabulum

6. If a discrepancy exists, the distance between the femoral head center and acetabular center should be equal to the measured limb length discrepancy

SURGICAL

APPROACHES

POSITION OF THE

PATIENT FOR

POSTERIOR

APPROACH

POSTERIOR

APPROACH

Reaming of acetabulum

Femur is retracted anteriorly to allow clear access to acetabulum

REAMING OF

ACETABULUM

SOCKET POSITIONING

Safe and unsafe

quadrants of

acetabulum

POSTEROSUPERIOR

QUADRANT- SAFEST

FIXATION HOLES FOR

CEMENT IN ACTABULUM

ACETABULAR CEMENT

PRESSURIZER

PRECAUTIONS

FIXATION MUST BE AUGMENTED BY SCREWS OR

SPIKES.

PERIPHERAL PART OF POSTEROSUPERIOR SEGMENT ARE SAFEST.

PALPATION OF GREATER SCIATIC NOTCH IS MUST.

INTRAOPERATIVE CHANGE IN THE POSITION.

PREPARATION

OF THE FEMUR

POSITIONING OF FEMUR

FOR REAMING

Neck is cut

planned at

appropriate level

and angle by

using trial

components of

templeted size

Removal of

remining lateral

edge of femoral

neck and medial

portion of GT with

box osteotome

Reaming of

femoral canal

Hand or power

reamer must be

lateralized into

GT to maintain

neutral

alignment of

femoral canal

Femoral

broaching

Progressively larger

broaches are inserted,

lateralizing each one

to maintain neutral alignment

Femoral

component

anteversion

Calcar

planning

with

prcision

reamer

Assembly of trial

head and neck

segments

determined

from pre-

operative

templating

Canal

blocking

Retrograde

injection of

cement with

gun in early

dough phase

Cement

pressurization

Manual

cement

packing

(PALACOS cement)

HIP SHOULD BE STABLE IN

IN FULL EXTENSION WITH 40 DEGREE OF EXTERNAL

ROTATION.

IN FLEXION TO 90 DEGREE WITH ATLEAST 45 DEGREE OF INTERNAL ROTATION

WITH THE HIP FLEXED 40 DEGREE WITH ADDUCTION

AND AXIAL LOADING-

IF HIP DISLOCATE OR SUBLUXATE –USE LONGER

NECK.

WHAT IF FRACTURE

OCCUR

STOP THE INSERTION

EXPOSE THE FRACTURE

IF AN INCOMPLETE FRACTURE OCCUR WITH

EXTENSION ONLT AT THE LEVEL OF LT-ENCIRCLAGE

,REINSERT AND REASSESS THE STABILITY.

BELOW LT –LONGER STEM

GT IS # AND UNSTABLE-FIX THE GT WITH WIRES.

TROCHANTERIC

OSTEOTOMY

SURGICALS PROBLEMS

RELATIVE TO SPECIFIC HIP

DISORDER

OSTEOARTHRITIS

MC INDICATION

REMOVAL OF OSTEOPHYTES MAY BE NECESSARY.

Difficulty in delivering femoral head.

RHEUMATOID ARTHRITIS

THEY GENERALLY RECEIVES IMMUNOSUPPRESSIVE DRUGS.

IF BOTH HIP AND KNEE IS INVOLVED EQUALLY, HIP ARTHROPLASTY

SHOULD BE DONE FIRST .

OSTRONECROSIS

STAGE 1 AND 2-CORE DECOMPRESSION

,VASCULARISED GRAFT OR BY VALGUS

OSTEOTOMY

RESURFACING ARTHROPLASTY IF < 50 % OF HEAD

MOSTLY AGE GROUP IS 25 TO 45 YEARS-THR IS NOT

VERY SUCCESSFUL.

IMPROVED RESULT WITH ALUMINA CERAMIC HEAD

HIGHLY CROSSLINKED POLYETHYLENE.

DWARFISM/DYSPLASIA

NARROW CANAL

BOWING

ALTERD FEMORAL ANATOMY

PREVIOUS FEMORAL OSTEOTOMY

SHORT FEMORAL COMPONENT IS USED .

ACUTE FEMORAL NECK

FRACTURE

THR > HRA>INTERNAL FIXATION

THOSE WHO ARE LESS HEALTHY,COGNITIVELY

IMPAIRED OR REQUIRE ASSISTIVE DEVICE FOR AMBULATION ARE BETTER SUITED FOR HRA.

Post operative hip

re-dislocation can be avoided by:

Maintaining abduction using pillows

Avoiding crossing legs

Avoiding squating

Using chairs with armrest

Not bending forward past 90 degrees

Using a high-rise toilet seat if necessary

Avoiding pronation the legs

Avoiding stairs

Exercise PrescriptionEarly Stage

Exercise Prescription

- Later Stages -

COMPLICATIONS OF THR

1. Hematoma formation

2. Heterotropic ossification

3. Thromboembolism

4. Nerve injuries (sciatic, femoral, obturator or sup gluteal

nerve)

5. Vascular injuries

COMPLICATIONS OF THR

6. Limb length Discrepency

7. Dislocation and subluxation

8. Fractures of acetabulum and femur

9.Trochenteric nonunion and migration

10. Infection

11. Loosening ( Femoral and acetabular

component)

12. Osteolysis

POST OPERATIVE

X-RAY

THANK YOU