Functional assessment of knee joint position sensefollowing anterior cruciate ligament reconstruction

S M Mir, M-R Hadian, S Talebian, N Nasseri

Rehabilitation Faculty, TehranUniversity of Medical Sciencesand Health Services (TUMS),Pich-Shemiran, Tehran, Iran

Correspondence to:Associate Professor M R Hadian,Rehabilitation Faculty, TehranUniversity of Medical Sciences,Tehran, Iran; hadianrs@sina.tums.ac.ir; hadian_ras@yahoo.com

ABSTRACTContext: The anterior cruciate ligament (ACL) has bothmechanical and proprioceptive (sensory) functions. Knee-joint proprioception has been assessed using eitherreproduction of position or threshold to detect passivemotion in non-weight-bearing positions. It has beensuggested that a more functional and dynamic/activeassessment of proprioception might clarify the effects ofinjury and reconstruction on the proprioceptive function ofACL at the knee joint.Objective: To assess knee joint position sense (JPS)following ACL reconstruction in functional positions.Subjects: Twelve male patients who had undergone ACLreconstruction and 12 male healthy control subjectsparticipated in the study.Methods and main outcome measures: JPS wasevaluated by reproduction of the angles in weight-bearingposition with limb movement into flexion and extension.The dominant knee of healthy subjects and both(reconstructed and uninjured) knees of the patients weretested. Absolute angular error was used as a dependentvariable.Results: There was no significant difference between theoperated and uninjured knees of patients or betweenpatients and healthy controls (p>0.05). These resultswere measured during two tasks of limb movement intoflexion and extension.Conclusion: We found no evidence of impaired JPS inweight-bearing positions in subjects with ACL recon-struction at a mean follow-up of 11 months after surgerycompared with subjects with healthy knees.

Proprioception is a sensory system that encom-passes the sensations of joint position and motion.The afferent signals of proprioception are sensedby peripheral receptors within joints and by thesurrounding musculature and cutaneous struc-tures. Histological studies show that mechano-receptors such as Ruffini endings, Paciniancorpuscles and Golgi tendon organs are present inthe anterior cruciate ligament (ACL).1–4

In recent years, the focus of ACL reconstructionhas been on determining how to reconstruct amechanically strong ligament. However, the suc-cess of ACL reconstruction may depend not onlyon the strength, range of motion and integrity ofthe graft, but also on the recovery of propriocep-tion after ACL injury. Recently, much attentionhas been devoted to the role of proprioception as acontributing factor to functional stability of theknee joint.5

The ACL may have two complementary func-tions: proprioceptive (sensory) and mechanical.6 Ithas been suggested that sensory information fromthe ACL assists in providing functional stability to

the knee joint by contributing to neuromuscularcontrol.5 In recent years, interest in assessment,prevention and treatment of proprioceptive deficitshas increased. This appears to be related to theincreased incidence and socioeconomic importanceof joint injuries in sports. In addition, increasingnumbers of authors have recommended weight-bearing (WB) tests of joint position or movementsense. These author suggest that WB tests are morefunctional and involve all of the cutaneous,articular and muscular proprioceptors that act inconcert during normal everyday activities, and thatstanding WB assessments have more clinicalrelevance in evaluating proprioception in relationto WB-specific conditions.7–9

Therefore, the aim of this study was (1) tomeasure knee joint position sense (JPS) in patientsafter reconstruction of ACL by comparing theinjured leg with the uninjured and (2) to comparethe JPS of the patients separately with age-matched reference controls. The test procedureincluded active reproduction of the angles in WBpositions with limb movement into flexion andextension.

METHODSThe study was approved by the ethics committeeof Tehran University of Medical Sciences, and allsubjects gave written informed consent to partici-pate in this study.

SubjectsIn total, 12 male patients who had undergone ACLreconstruction (mean age 23 (SD 4.75) years) andTwelve male healthy control subjects (22 (SD4.35) years) participated in the study. Mean timeafter surgery was 11 months. All patients weregiven a neuromuscular rehabilitation programmefocusing on regaining range of motion, strength,endurance and coordinated limb movements,mainly using closed-chain exercises.

Study exclusion criteria for patient and controlsubjects included: (1) a history of hip, ankle, or footinjuries with either leg within the previous6 months that had resulted in total inability tobear weight or in limping; (2) injury, surgery,significant pain or loss of function in the contral-ateral limb in the previous 6 months; (3) complica-tions after ACL surgery; (4) major balance deficitsor inner ear disturbances; (5) any musculoskeletalconditions; and (6) any neurological abnormalities.

ProceduresAll of the subjects were familiarised with theprocedure by explanation, demonstration and onepractice repetition. Before the tests, each subject

Original article

300 Br J Sports Med 2008;42:300–303. doi:10.1136/bjsm.2007.044875

group.bmj.com on November 11, 2014 - Published by http://bjsm.bmj.com/Downloaded from

also watched a videotape showing the squatting movementdemonstrated by a trained person performing the movement ata controlled velocity of 10u/s, and the subjects were asked tosquat as shown in the film.

Testing procedures were completed in an isolated room; thesubjects wore loose-fitting shorts. The dominant knee of healthysubjects and both (reconstructed and uninjured) knees of thepatients were tested. Each subject was asked to lie down on theirback on the treatment couch. Four circular markers, each 4 cm indiameter, were attached to their leg at three locations while thesubject was in this position: (1) proximal to a quarter of thedistance along a line joining the greater trochanter to the lateralknee joint line, (2) over the neck of the fibula, (3) over theproximal part of the lateral malleolus. A fourth marker wasattached over the iliotibial tract adjacent to the superior border ofthe patella when the subject was in a sitting position. The choiceof marker locations was based on previous studies.10–12

The subject then stood with the feet shoulder-width apart.The foot in the untested limb was lifted from the floor. Theipsilateral hand was placed over the chest, and the subject wasallowed to use minimum contact of the fingertips in thecontralateral hand for balance. Two goniometers were stuckonto the wall, out of sight of the subject, at angles of 30u and60u as indicators.

To measure JPS in the knee, subjects moved their limbs at acontrolled velocity of 10u/s into flexion and extension.

Flexion to extensionThe starting position was a semi-squat (,60u). The subjectstood with eyes closed, and was instructed to: (1) lift theunexamined foot from the floor; (2) slowly extend the WB limbuntil told to stop (,30u); (3) identify (sense) the knee positionwhile isometrically holding the test position for approximately5 seconds; (4) return to the erect bilateral WB stance (for7 seconds); and (5) reproduce the previous unilateral flexedposition, concentrating on the knee.

Extension to flexionThe starting position was straightening of the knee (0u). Thesubject stood with eyes closed, and was instructed to: (1) lift the

unexamined foot from the floor; (2) slowly flex the WB limbuntil told to stop (,30u); (3) identify (sense) the knee positionwhile isometrically holding the test position for approximately5 seconds; (4) return to the erect bilateral WB stance (for7 seconds); and (5) reproduce the previous unilateral flexedposition, concentrating on the knee.

The holding times used in this study were the same as thoseused in previous studies.13–15 Measurement of knee JPS wererepeated three times and the average was taken for the limb.

EquipmentA system comprised of a digital camera (Canon 8MP MV750i;Canon, Tokyo, Japan), nonreflective markers and automaticcomputer-aided design (AutoCAD) software was used formeasuring joint angles. The test and replicated angles weremeasured by taking a digital photograph of the subject with adigital camera positioned 185 cm from the subject and 65 cmfrom the ground. After completing the procedure for allsubjects, the test and replicated angles were measured using theAutoCAD software and determining the centre of the markers(fig 1).The test–retest reliability of the measuring method(AutoCAD analysis) had already been tested before analysis andfound to be high (r = 0.99).

Data analysisThe Kolmogorov–Smirnov test was used for determination ofthe normal distribution of the data. An average was taken fromthree trials for each test. By subtracting the test angle (TA) fromthe reproduced angle (RA), the absolute angular error (AAE)was calculated as a dependent variable. This variable repre-sented the accuracy of the replication. The Wilcoxon signedrank test was used for comparisons within groups and fordirection of movement (flexion to extension, extension toflexion), and the Mann–Whitney U test was used forcomparison between groups.

All the collected data were analysed using SPSS V.11.5).Descriptive statistics were used to calculate the means (SD).Significance was set at p(0.05.

RESULTSThe Kolmogorov–Smirnov test showed that there was a normaldistribution for age, weight and height in the two groups. Mean(SD) values of AA for direction of movement of both(reconstructed and uninjured) knees in patients and thedominant knee in healthy subjects are presented in table 1,and those of the reconstructed and uninjured knees in patientsin table 2. Mean (SD) values of AAE for the comparison

Figure 1 The test angles and the replicated ones were measured usingthe AutoCAD software.

Table 1 The values of absolute angular error for direction ofmovements of reconstructed and uninjured knees in patients and thedominant knee in healthy subjects

GroupsTestposition

AAE (degrees),mean (SD) p Value

Reconstructed knee, patients A* 3.65 (2.39) 0.87

B{ 3.77 (2.04)

Uninjured knee, patients A 4.28 (2.08) 0.53

B 4.13 (2.51)

Dominant knee, healthy subjects A 3.90 (1.77) 0.27

B 5.49 (3.31)

AAE, absolute angular error.*Flexion to extension.{Extension to flexion.

Original article

Br J Sports Med 2008;42:300–303. doi:10.1136/bjsm.2007.044875 301

group.bmj.com on November 11, 2014 - Published by http://bjsm.bmj.com/Downloaded from

between the reconstructed knee in patients and the dominantknee in healthy subjects are presented in table 3, and those forthe comparison between the uninjured knee in patients and thedominant knee in healthy subjects in table 4. No significantdifference was found in direction of movement within orbetween groups (p>0.05).

DISCUSSIONNumerous studies over the past decade have attempted toevaluate changes in proprioception after ACL injury andreconstruction. These studies have mainly investigated theknee position sense in seated, supine and side-lying positions,which are therefore non-weight-bearing (NWB) positions. Thus,results of studies using NWB positions may not correspondwith those from studies using WB functional positions.

In the current study, JPS of the knee in WB positions wascompared between patients with ACL reconstruction andhealthy subjects. Assessment of JPS in WB positions potentiallyprovides clinicians with more functional information on thestatus of the reconstructed ACL, thus making possible greaterprecision in structuring suitable rehabilitation programmes.

These results showed no evidence of impaired JPS in WBpositions in subjects with ACL reconstructions compared withsubjects with healthy knees. Furthermore, we found that therewas no significant difference between the operated anduninjured knee in patients. These results are in accordancewith those of Hopper et al, Ochi et al and Feremery et al.15–17

Several studies have suggested that the re-innervation (neuralingrowth) of the reconstructed ACL and/or the recovery of thesurrounding capsular and ligamentous receptors could bepossible mechanisms for greater accuracy in JPS. In addition,

active tasks could improve the repositioning results of knee JPSvia co-contraction of muscles during the WB tests.15–17 Previousstudies have also suggested that the afferent information fromthe intra-articular and periarticular receptors in one limb couldaffect muscle spindle signalling in the contralateral limb.18

However, some other studies are not consistent with ourresults. Lephart et al19 and MacDonald et al20 studied subjectswho underwent ACL reconstruction and found impairedthresholds for detection of passive movement (TDPM) in theACL reconstruction group compared with the contralateraluninvolved knee. These discrepancies may be due to the testpositions (WB or NWB) and testing methods (active or passive).Variability in the pattern of innervation of the ACL,1 variabilityin the number of mechanoreceptors in different knees,2 anddifferences in subject population, surgical techniques andrehabilitation protocols15 are other possible explanations forthese discrepant results.

Moreover, it has been suggested that loss of proprioceptionfollowing ACL rupture is not due only to loss of input from thenerve endings in the ACL, but also to altered kinematics causedby disruption of the ligament.21 The changes in knee kinematicsfollowing an ACL tear lead to changes in the tension and forceson uninjured capsular structures, so that their input is‘‘confused.’’ Thus, re-establishing the mechanical function ofthe ACL may produce an immediate improvement in kneekinematics and thus an improvement in proprioception.

CONCLUSIONWe found no evidence of impaired JPS in WB position insubjects with ACL reconstruction at a mean follow-up of11 months after surgery compared with subjects with healthyknees. Furthermore, our study showed no significant differencebetween the operated and uninjured knee of the patients. Theseresults are inconsistent with the results of some researches,thus, further studies are needed to detect the exact mechanismof the inconsistency in the results of studies.

Competing interests: None.

Table 2 The values of absolute angular error of reconstructed anduninjured knees in patients

Testposition

AAE (degrees), mean (SD)

p ValueReconstructedknee

Uninjuredknee

A 3.65 (2.39) 4.28 (2.08) 0.81

B 3.77 (2.04) 4.13 (2.51) 0.81

AAE, absolute angular error.

Table 3 The values of absolute angular error of reconstructed knee inpatients and the dominant knee in healthy subjects

Testposition

AAE (degrees), mean (SD)

p ValueReconstructedknee, patients

Dominant knee,healthy subjects

A 3.65 (2.39) 3.90 (1.77) 0.56

B 3.77 (2.04) 5.49 (3.31) 0.18

AAE, absolute angular error.

Table 4 The values of absolute angular error in the uninjured knee inpatients and the dominant knee in healthy subjects

Testposition

AAE (degrees), mean (SD)

p ValueUninjuredknee, patients

Dominant knee,healthy subjects

A 4.28 (2.08) 3.90 (1.77) 0.64

B 4.13 (2.51) 5.49 (3.31) 0.29

AAE, absolute angular error.

What is already known on this topic

c The ACL has both mechanical and proprioceptive (sensory)functions. Knee joint proprioception has been assessed usingeither reproduction of position or threshold to detect passivemotion in non-weight-bearing positions.

c It has been suggested that a more functional and dynamic/active assessment of proprioception could clarify the effects ofinjury and reconstruction on the proprioceptive function of ACLat the knee joint.

What this study adds

c We found no evidence of impaired joint position sense inweight-bearing positions in subjects with ACL reconstructionsat a mean follow-up of 11 months after surgery comparedwith subjects with healthy knees.

c Furthermore, there was no significant difference between theoperated and uninjured knee in patients.

Original article

302 Br J Sports Med 2008;42:300–303. doi:10.1136/bjsm.2007.044875

group.bmj.com on November 11, 2014 - Published by http://bjsm.bmj.com/Downloaded from

REFERENCES1. Kennedy JC, Alexander IJ, Hayes KC. Nerve supply of the human knee and its

functional importance. Am J Sports Med 1982;10:329–35.2. Schutte MJ, Dabezies EJ, Zinny ML, et al. Neural anatomy of the human anterior

cruciate ligament. J Bone Joint Surg Am 1987;69:243–7.3. Denti M, Monteleone M, Berardi A, et al. Anterior cruciate ligament

mechanoreceptors. Clin Orthop 1994;308:29–32.4. Schultz RA, Miller DC, Kerr CS, et al. Mechanoreceptors in human cruciate

ligaments: A histological study. J Bone Joint Surg 1984;66A:1072–6.5. Riemann BL, Lephart SM. The sensorimotor system. Part II: The role of proprioception

in motor control and functional joint stability. J Athl Train 2002;37:80–4.6. Frank CB, Jackson DW. The science of reconstruction of the anterior cruciate

ligament. J Bone Joint Surg 1997;79A:1556–76.7. Andersen SB, Terwilliger DM, Denegar CR. Comparison of open versus closed kinetic

chain test positions for measuring joint position sense. J Sport Rehabil 1995;4:165–71.8. Kiefer G, Forwell L, Kramer J, et al. Comparison of sitting and standing protocols for

testing knee proprioception. Physiother Can 1998;50:30–4.9. Reider B, Arcand Ma, Diehl Lh, et al. Proprioception of the knee before and after

anterior cruciate ligament reconstruction. Arthroscopy 2003;19:2–12.10. Tully E, Stillman B. A revised model for 2D kinematic analysis of supine hip and knee

motion in the sagital plane. Proceedings of the 128th International Congress of theWorld Confederation for Physical Therapy, Washington: 1995;732.

11. Cappozzo A, Catani F, Leardini A, et al. Position and orientation in space of bonesduring movement: Experiment of artifacts. Clin Biomech 1996;11:90–100.

12. Lamoreux LW. Coping with soft tissue movement in human motion analysis In:Harris GF, Smith PA, eds. Human motion analysis: Current applications and futuredirections. New York: Institute of Electrical and Electronic Engineers. 1996:43–7.

13. Marks R, Quinney HA, Wessel J. Proprioceptive sensibility in women with normaland osteoarthritic knee position. Clin Rheumatol 1993;12:170–5.

14. Marks R. The reliability of knee position sense measurements in healthy women.Physiother Can 1994;46:37–41.

15. Hopper DM, Creagh MJ, Formby PA, et al. Functional measurement of knee jointposition sense after anterior cruciate ligament reconstruction. Arch Phys Med Rehabil2003;84:868–72.

16. Ochi M, Iwasa J, Uchio Y, et al. The regeneration of sensory neurones in thereconstruction of the anterior cruciate ligament. J Bone Joint Surg Br 1999;81:902–6.

17. Fremerey RW, Lobenhoffer P, Zeichen J, et al. Proprioception after rehabilitation andreconstruction in knees with deficiency of the anterior cruciate ligament. J Bone JointSurg Br 2000;82:801–6.

18. Roberts D, Friden T, Stomberg A, et al. Bilateral proprioceptive defects in patientswith a unilateral anterior cruciate ligament reconstruction. J Orthop Res2000;18:565–71.

19. Lephart Sm, Kocher Ms, Fu Fh. Proprioception following anterior cruciate ligamentreconstruction. J Sport Rehab 1992;1:188–96.

20. MacDonald Pb, Hedden D, Pacin O, et al. Proprioception in anterior cruciateligament-deficient and reconstructed knees. Am J Sports Med 1996;24:774–8.

21. Iwasa J, Ochi M, Adachi N, et al. Proprioceptive improvement in knees with anteriorcruciate ligament reconstruction. Clin Orthop 2000;381:168–76.

Original article

Br J Sports Med 2008;42:300–303. doi:10.1136/bjsm.2007.044875 303

group.bmj.com on November 11, 2014 - Published by http://bjsm.bmj.com/Downloaded from

reconstructionsense following anterior cruciate ligament Functional assessment of knee joint position

S M Mir, M-R Hadian, S Talebian and N Nasseri

doi: 10.1136/bjsm.2007.0448752008 42: 300-303 Br J Sports Med 

http://bjsm.bmj.com/content/42/4/300Updated information and services can be found at:

These include:

References #BIBLhttp://bjsm.bmj.com/content/42/4/300

This article cites 19 articles, 2 of which you can access for free at:

serviceEmail alerting

box at the top right corner of the online article. Receive free email alerts when new articles cite this article. Sign up in the

CollectionsTopic Articles on similar topics can be found in the following collections

(43)Procedures

Notes

http://group.bmj.com/group/rights-licensing/permissionsTo request permissions go to:

http://journals.bmj.com/cgi/reprintformTo order reprints go to:

http://group.bmj.com/subscribe/To subscribe to BMJ go to:

group.bmj.com on November 11, 2014 - Published by http://bjsm.bmj.com/Downloaded from