Joint position sense in total knee arthroplasty

Early Postoperative Change in Hip Rotation Angle and Factors Contributing to It for Patients Undergoing Total Hip Arthroplasty

OBJECTIVE

A possible impairment in hip proprioception after total hip arthroplasty (THA) has been an issue of concern. The aims of this study were to investigate the extent of early postoperative change in standing hip rotation angle (HRAng) in patients with osteoarthritis (OA) undergoing THA and to consider a possible mechanism behind this.

MATERIALS AND METHODS

A total of 82 hips (82 patients; 63 women and 19 men) undergoing unilateral primary THA with total capsulectomy were included. We characterized the standing HRAng and internal/external range of motion (ROM) in the prone position before THA and 2 weeks after THA. Acetabular/cup and femoral/stem anteversion, combined anteversion (CA), and leg length discrepancy were also characterized. Correlations were examined postoperatively between the HRAng and the other analyzed variables.

RESULTS

The median standing HRAng showed a significant internal shift from external to more medial position (6.3° to 1.7°) 2 weeks after THA (P<.0001). The postoperative change in standing HRAng was significantly negatively correlated with the difference between the postoperative femoral anteversion and the stem anteversion (rs=-0.429, P<.0001) and with the pre- to postoperative change in CA (rs=-0.3012, P=.0063).

CONCLUSION

This study demonstrated that the extent of the rotational shift of the distal femur toward medial direction was significantly associated with increasing stem anteversion and CA. This phenomenon can be interpreted as a compensatory mechanism for maintaining the relative positional relationship between the pelvis and the proximal femur using proprioception. Therefore, we conclude that the extracapsular/extra-articular components may be prominent determinants of joint position sense. [Orthopedics. 2024;47(3):e114-e118.].

Proprioception and Mechanoreceptors in Osteoarthritis: A Systematic Literature Review

PURPOSE

Osteoarthritis (OA) is one of the most common chronic diseases in the world. It is frequently accompanied by high levels of persistent pain, as well as substantial impairments in function and functional capacity. This review aims to systematically analyze the changes in proprioception and related mechanoreceptors in OA patients.

METHODS

Studies from September 2013 to September 2023 were identified by conducting searches on the PubMed, Web of Science, and Scopus electronic databases following the PRISMA statement. One reviewer independently assessed and screened the literature, extracted the data, and graded the studies. The body of evidence underwent an evaluation and grading process using the ROBINS-I tool, which was specifically designed to assess the risk of bias in non-randomized studies of interventions. Results were summarized using descriptive methods.

RESULTS

A search through 37 studies yielded 14 clinical studies that were ultimately included. The primary focus of the studies was on the knee joint, particularly the posterior cruciate ligament (PCL). The studies found that PCL in OA patients had impaired proprioceptive accuracy, possibly due to changes in mechanoreceptors (Ruffini, Pacini, and Golgi Mazzoni corpuscles). This suggests that dysfunctional articular mechanoreceptors, especially in severe cases of OA, may contribute to reduced proprioception. Dynamic stabilometry also identified significant proprioceptive deficits in patients with knee articular cartilage lesions, underscoring the impact of such lesions on knee proprioception.

CONCLUSIONS

Literature data have shown that proprioceptive accuracy may play an important role in OA, particularly in the knee PCL and cartilage. However, the role of proprioception and related mechanoreceptors needs to be further clarified. Future studies focusing on the relationship between proprioception, OA disease, and symptoms, considering age and gender differences, and exploring OA joints other than the knee should be conducted to improve clinical and surgical outcomes in cases where proprioception and mechanoreceptors are impaired in OA patients.

The effects of total knee arthroplasty on knee proprioception of patients with knee osteoarthritis: a meta-analysis

BACKGROUND

Studies have given some pieces of evidence for the effect of total knee arthroplasty (TKA) on knee proprioception of patients with knee osteoarthritis (KOA), but their results were conflicting. This review was performed to provide an updated evidence-based meta-analysis investigating the influence of TKA on knee proprioception.

METHODS

The electronic databases including PubMed, Google Scholar, and the Cochrane Library were accessed from their inception to March 2020. Two reviewers identified the studies that met the selection criteria for this review. Information on study type, participants, follow-up time, and outcome measures was extracted. Methodological quality was independently assessed by two reviewers using the Cochrane Handbook 5.1.0. Eleven studies with 475 participants were included in the meta-analysis.

RESULTS

The I² index assessed the heterogeneity between studies. The results showed that the pooled standard mean difference of mean angle of error was - 0.58° (95% CI - 1 to - 0.16; P = 0.007; I² = 69%), and the joint position sense of KOA patients was better after TKA surgery than that before surgery. Pooled standard mean difference of displacement of center of pressure (COP) was - 0.39 (95% CI - 0.72 to - 0.06; P = 0.02; I² = 51%), and KOA patients had better static balance after TKA surgery than before surgery.

CONCLUSIONS

To conclude, no standardized comprehensive evaluation protocol presently exists though different assessment tools are available to measure proprioception. Contrasting results were found in the literature since some studies found that TKA improves proprioception in KOA patients, while others found no difference in proprioception. These differences are seen whether the proprioception was assessed by joint position sense (JPS), or it was indirectly assessed by static balance. However, the lack of sufficient data on the threshold to detect passive movement (TTDPM) and dynamic balance made it difficult to draw a conclusion about whether or not the sense of motion improved after surgery. The method for measuring and evaluating knee joint force sense is worth paying attention, which will make progress with knee proprioception on TKA patients.

Characteristics of the joint position sense in children with developmental dyslexia

[Purpose] Developmental dyslexia is a disorder in which reading and writing of characters is difficult. The present study investigated age-dependent joint position sense of the forearm and wrist and whether children with developmental dyslexia have less joint position sense than typically developing children. [Participants and Methods] The participants were comprised of 84 typically developing elementary school students, 12 university students, and 2 children with developmental dyslexia. Joint position sense was evaluated using the reproduction method based on four tasks. The participants were divided into three age groups. The children with developmental dyslexia were compared with the typically developing children in the same age group. [Results] Significant negative correlations were found between the reproduction error of the typically developing children and that of the university students in most tasks. The children with developmental dyslexia showed increased reproduction error relative to the reproduction error of the typically developing children in the same age group in 4 of the 8 tasks. [Conclusion] The accuracy of the joint position sense improved with development. However, the joint position sense of the children with developmental dyslexia was lower than that of the typically developing children in the same age group. The difficulty in writing experienced by children with developmental dyslexia may be related to joint position sensing impairment due to impaired joint position sense.

Comparison of proprioception between osteoarthritic and age-matched unaffected knees: a systematic review and meta-analysis

PURPOSE

Theoretically, proprioceptive acuity could decrease in patients with knee osteoarthritis. However, there have been conflicting results in terms of proprioceptive deficit in osteoarthritic knees. The purpose of this systematic review and meta-analysis was to compare knee proprioception between osteoarthritic and healthy control knees.

METHODS

Studies comparing proprioception in osteoarthritic and healthy knees of age-matched control group using thresholds to detect passive motion (TTDPM) or joint position sense (JPS) tests were identified. JPS was assessed by measuring the reproduction of passive positioning (RPP) or active positioning (RAP) of the knees.

RESULTS

Seventeen studies were finally included in this meta-analysis. The pooled results of the analyses of the TTDPM for both 30° and 45° knee flexion showed that the mean angle of error was 0.83° greater (95% confidence interval: 0.44 to 1.23°; p < 0.001) in the osteoarthritic knees than in control knees. The pooled data of the RAP and RPP also showed that the mean angle of error was 1.89° greater in the osteoarthritic knees than in the control group. The mean difference in the angle of error between the osteoarthritic knees and control group was 1.06° greater in the JPS test than in the TTDPM (p < 0.001).

CONCLUSION

The knee proprioceptive acuity of the patients with knee osteoarthritis was poorer than that of the patients with unaffected knees in the age-matched control group both in terms of the TTDPM and JPS; clinical relevance of these deficits needs to be clarified in further studies.

LEVEL OF EVIDENCE

Meta-analysis, Level II.

Effectiveness of early high-intensity balance training for early home life independence after total knee arthroplasty: a pseudo-randomized controlled trial

OBJECTIVE

In Japan, the number of elderly individuals living alone is increasing, leading to an increase in hospital medical expenses attributed to total knee arthroplasty (TKA). Improvement in balance and functional performance is a priority in the early postoperative stages after TKA. However, there are no reports on the effectiveness of balance training (BT) for inpatients in the early postoperative period. Thus, we aimed to evaluate the effectiveness of early high-intensity BT for early home-life independence after TKA.

METHOD

This pseudo-randomized controlled trial included 49 inpatients who underwent TKA and had osteoarthritis. Inpatients were categorized into the BT or typical training (TT) group. The BT program began on post-TKA day 4, with 12-14 sessions between day 7 and 10 (i.e., 1-2 sessions per day). The effect of the intervention was assessed using balance ability as the main outcome. Sub-outcomes included evaluation of motion function. The differences in each variable before and after intervention were compared, including covariance analysis adjusted for age and sex.

RESULTS

The mean (standard deviation) balance ability indexes in the left and right directions were BT, pre 4.5 (0.8) and post 4.4 (0.8); TT, pre 4.8 (0.9) and post 4.4 (0.8), and those in the forward and backward directions were BT, pre 4.7 (1.7) and post 5.1 (2.1); TT, pre 6.3 (2.6) and post 5.9 (2.0). No significant differences were found between the preoperative and postintervention scores in the two groups for any measured outcome.

CONCLUSION

BT did not appear to improve balance ability or functional performance.

Shoulder proprioception following reverse total shoulder arthroplasty

Joint replacement affects the proprioception, as shown in knees, elbows, and shoulder studies.

AIM

The aim was to evaluate shoulder joint position sense (JPS) following reverse total shoulder arthroplasty (rTSA) for patients with cuff arthropathy.

METHODS

Twenty-nine patients that underwent unilateral rTSA (19 females, 10 males) and 31 healthy volunteers evaluated for JPS of shoulder using a dedicated high accuracy electronic goniometer. Error of active reproduction of joint position (EARJP) was assessed at the following reference positions: 30°, 60°, 90°, and 120° for forward flexion and abduction and 15°, 30°, and 45° for internal and external rotation in rTSA, contralateral non-operated, and control shoulders.

RESULTS

Results of EPRJP for rTSA, contralateral, and control (respectively) are as follows:Forward flexion: 30° = (8.0 ± 5.7, 9.8 ± 6.1, and 4.9 ± 3.0), 60° = (5.0 ± 2.8, 5.9 ± 2.7, and 5.1 ± 3.2), 90° = (3.1 ± 1.6, 5.5 ± 2.6, and 3.2 ± 1.4), and 120° = (3.4 ± 2.1, 5.6 ± 4.0, and 3.5 ± 1.7)Abduction: 30° = (5.2 ± 2.5, 9.1 ± 6.1, and 4.6 ± 2.3), 60° = (5.2 ± 3.6, 6.6 ± 4.1, and 5.3 ± 3.1), 90° = (3.8 ± 2.0; 7.4 ± 5.5, and 4.1 ± 1.9), and 120° = (5.3 ± 2.9, 7.7 ± 5.3, and 4.2 ± 1.9)Internal rotation: 15° = (4.3 ± 3.1, 6.2 ± 4.4, and 2.8 ± 1.2), 30° = (3.2 ± 1.9, 4.5 ± 2.3, and 3.3 ± 1.4), and 45° = (3.5 ± 2.0, 4.1 ± 1.8, and 2.8 ± 1.0)External rotation: 15° = (3.0 ± 1.7, 4.2 ± 2.2, and 3.6 ± 1.4) and 30° = (3.1 ± 1.5, 3.8 ± 2.6, and 3.4 ± 1.6)The results showed significantly better JPS (lower EPRJP) in shoulders following rTSA and normal control shoulders comparing with the patient's contralateral shoulder. The explanation can be that rTSA improves joint kinematics and stability, which allows better muscular performance and proprioception feedback.

CONCLUSION

Shoulders following rTSA show JPS superior to non-operated contralateral shoulders and comparable with healthy population shoulders. It seems that rTSA restores shoulder proprioception.

Total Knee Arthroplasty with a Ti6Al4V/PEEK Prosthesis on an Osteoarthritis Rat Model: Behavioral and Neurophysiological Analysis

Arthroplasty is a surgical procedure to restore the function of the joint of patient suffering from knee osteoarthritis. However, postoperative functional deficits are reported even after a rehabilitation program. In order to determine the origin of functional deficits of patient suffering from knee osteoarthritis and total knee arthroplasty, we developed a rodent model including a chemically-induced-osteoarthritis and designed a knee prosthesis (Ti6Al4V/PEEK) biomechanically and anatomically adapted to rat knee joint. Dynamic Weight-Bearing, gait kinematics, H-reflex from vastus medialis muscle and activities from metabosensitive III and IV afferent fibers in femoral nerve were assessed at 1 and 3 months post-surgery. Results indicate that knee osteoarthritis altered considerably the responses of afferent fibers to their known activators (i.e., lactic acid and potassium chloride) and consequently their ability to modulate the spinal sensorimotor loop, although, paradoxically, motor deficits seemed relatively light. On the contrary, results indicate that, after the total knee arthroplasty, the afferent responses and the sensorimotor function were slightly altered but that motor deficits were more severe. We conclude that neural changes attested by the recovery of the metabosensitive afferent activity and the sensorimotor loop were induced when a total knee replacement was performed and that these changes may disrupt or delay the locomotor recovery.

Comparing single and multi-joint methods to detect knee joint proprioception deficits post primary unilateral total knee arthroplasty

BACKGROUND

The use of various single-joint proprioception measurements has resulted in contradictory findings after knee arthroplasty. The use of balance as a surrogate measure to assess knee proprioception post-operation has resulted in further confusion. The aim of this study was to measure single joint knee proprioception in participants after unilateral knee arthroplasty, and compares it to multi-joint balance.

METHODS

Eleven participants at 1 year after unilateral total knee arthroplasty and twelve age-matched controls were enrolled. The threshold to detect passive motion and the sensory organization test were used to measure single joint knee proprioception and multi-joint balance respectively. Two-way ANOVA and independent t-tests were used to measure differences between and within groups. Regression analysis was used to measure the association between proprioception and balance measurements.

FINDINGS

Surgical knees demonstrated significantly more deficient proprioception compared to the non-surgical knees and both knees of the control groups during flexion (P < 0.01) and extension (P < 0.05). Non-surgical knees showed similar proprioception to both knees of the control group during flexion and extension. Within the knee arthroplasty group, only deficiencies during flexion showed significant correlation with Sensory Organization Test visual ratio. No additional differences between both groups during balance measurements, nor any correlations between local joint proprioception and balance were seen.

INTERPRETATION

These findings indicate deficient surgical knee proprioception in participants one year after unilateral total knee arthroplasty. Limited associations between measurements indicate that balance may be a poor measure of single-joint proprioception.

Proprioceptive deficit after total elbow arthroplasty: an observational study

BACKGROUND

During total elbow arthroplasty (TEA), most of the joint capsule is removed, including many mechanoreceptors important for proprioception, which potentially limits the patient's postoperative functional recovery. We quantified proprioceptive loss by measuring the threshold to detection of passive motion (TTDPM) in patients after unilateral TEA compared with the contralateral side.

METHODS

A continuous passive motion device moving the elbow at 0.5°/s was used to evaluate TTDPM in 8 patients (mean ± standard deviation age, 69.1 ± 9.93 years) at least 1 year after unilateral semiconstricted linked TEA for a range of diagnoses. Elbow function after TEA was assessed using the Mayo Elbow Performance Scale.

RESULTS

Postsurgical Mayo scores revealed 4 excellent results, 2 good, and 2 poor. The TTDPM in the elbows undergoing arthroplasty was still significantly higher compared with the contralateral elbow at 4.2° (15.6  ± 6.9 seconds vs. 7.2  ± 2.6 seconds; D = 3.23, P = .01) equivalent to 8.4 seconds.

CONCLUSIONS

Patients who have had severe joint disease requiring semiconstrained TEA have long-term proprioception deficits. A more conservative technique that maximally preserves insertions and soft tissues, might minimize upper limb proprioceptive deficit.

Bio-Inspired Adaptive Control for Active Knee Exoprosthetics

On the quest to bring function of prosthetic legs closer to their biological counterparts, the intuitive interplay of their control with the user's impedance modulation is key. We present two control features to enable more physiological and more user-adaptive control of prosthetic legs: a neuromusculoskeletal impedance model ( ) including a reflexive component, and a human model reference adaptive controller ( ), which can be combined with the former. In stance-phase simulations, the allowed to control a prosthetic leg with physiological knee joint angle and moment. When perturbations were applied, the reduced the resulting root mean square error (RMSE) between simulated and physiological reference angle by 96%. In a pilot experiment with two unimpaired and one amputee subject, gait with the deviated more from a physiological reference than with a conventional visco-elastic impedance controller. Subjects, however, preferred the . When adding the to either of the two impedance controllers, the RMSE between the actual and the physiological reference angle was reduced by up to 54%. Subjects confirmed this finding and reported an easier stance-to-swing transition. Simulation and pilot experiment suggest that a reflex-based impedance controller combined with an adaptive controller may improve user-cooperative behavior of active knee exoprostheses.

Do Pilates-based exercises following total knee arthroplasty improve postural control and quality of life?

PURPOSE

The aim of this prospective, randomized, controlled study was to investigate the effects of the addition of Pilates-based exercises to standard exercise programs performed after total knee arthroplasty on quality of life and balance.

METHOD

Forty-six volunteers were divided into two groups. The control group (n = 17) was assigned a standard exercise program after discharge; the study group (n = 17) was assigned Pilates-based exercises along with the standard exercise program. We carried out clinical evaluations of all patients on the day of discharge and after the completion of the 6-week exercise program. We also recorded sociodemographic data, Berg Balance test scores, and Short Form-36 (SF-36) health-related quality of life measurements.

RESULTS

When we compared the differences between pre- and post-treatment balance scores of the groups, we found a significant change in favor of the Pilates-based exercise group (13.64 ± 1.45; p < 0.01). The changes in the pre- and post-treatment SF-36 scores of the Pilates-based exercises group were found to be significant in terms of physical function (p = 0.001), physical role restriction (p = 0.01), and physical component score (p = 0.001).

CONCLUSIONS

Pilates-based exercises performed along with standard exercise programs were more effective for improving balance and quality of life than standard exercise programs alone.

Repeatability of position sense measurements in persons with osteoarthritis of the knee: a pilot study

Several reports have described a position sense deficit in persons with osteoarthritis of the knee. For purposes of future comparison, this study determined the agreement between serial measurements of knee position sense conducted over a 10-day period for eight persons of mean age 67.87 ± 7.36 years with stable knee-joint disease. The knee angles used to determine position sense were recorded in the seated position using a potentiometer. The outcome measure was the mean absolute error between five set angles and their matching angles. The intra-class correlation coefficients (ICCS) used to assess reliability of the mean absolute error measurements within and between sessions ranged from 0.57 to 0.52 with an average standard error of measurement of 1.18 degrees. It is concluded that while fairly reliable, clinicians should interpret changes in knee position sense of less than 2.31 degrees carefully in these patients before concluding that a true improvement or deterioration in their knee positioning accuracy has occurred.

Proprioception and Knee Arthroplasty: A Literature Review

Proprioceptive mechanoreceptors provide neural feedback for position in space and are critical for three-dimensional interaction. Proprioception is decreased with osteoarthritis of the knees, which leads to increased risk of falling. As the prevalence of osteoarthritis increases so does the need for total knee arthroplasty (TKA), and knowing the effect of TKA on proprioception is essential. This article reviews the literature regarding proprioception and its relationship to balance, aging, osteoarthritis, and the effect of TKA on proprioception. Knee arthroplasty involving retention of the cruciate ligaments is also reviewed, as well the evidence of proprioception in the posterior cruciate ligament after TKA.

Correlation of knee proprioception with muscle strength and spasticity in stroke patients

[Purpose] The purpose of this study was to investigate the relationship of knee proprioception with muscle strength and spasticity in stroke patients. [Subjects and Methods] The subjects were 31 stroke patients. The subjects received an explanation of the procedures and methods and provided informed consent before the experiment. A measurement board was used to determine the the proprioception deficit of the knee as a proprioception test. The proprioception test consisted of a passive and active angle reproduction test. A manual muscle test and modified Ashworth scale were used to evaluate knee muscle strength and spasticity level. The data were analyzed using an independent t-test and Spearman correlation. [Results] The results of this study revealed a significant difference between the affected side and non-affected side in the passive angle reproduction test and a significant difference in the correlation of the proprioception level with muscle strength and spasticity level. [Conclusion] This study indicates that the knee proprioception level is associated with spasticity and muscle strength in stroke patients.

Articular contact kinematics of the knee before and after a cruciate retaining total knee arthroplasty

Accurate knowledge of tibiofemoral articular contact kinematics of the knee after total knee arthroplasty (TKA) is important for understanding the intrinsic knee biomechanics and improving the longevity of the components. The objective of this study was to compare the in vivo articular contact kinematics of the knees with end-stage medial osteoarthritis (OA) during a weight-bearing, single leg lunge activity before and after a posterior cruciate retaining TKA (CR-TKA) using a dual fluoroscopic imaging technique. We found that the CR-TKA resulted in more posterior contact positions on the tibial surface and a reduced range of motion in the medial and lateral compartments. The distances between medial and lateral contact locations in the CR-TKA knees were statistically larger than the OA knees. The articular contact centers have shifted from medial side of the tibial plateau pre-operatively to the lateral side after operation. This study indicated that the CR-TKA resulted in significant changes in contact kinematics of the knees in both anteroposterior and mediolateral directions. Further studies are needed to determine the influence of the altered in vivo contact kinematics on the longevity of polyethylene liner and long term clinical outcomes of the TKA.

Muscle force steadiness in older adults before and after total knee arthroplasty

The ability to control submaximal muscle forces has been shown to be associated with age-related decreases in physical function, such as increased tendency to fall. This study compared quadriceps muscle force steadiness (MFS) in individuals with knee OA before and after total knee arthroplasty (TKA) to an age-matched group of controls. Lower extremity MFS was measured in 13 subjects with knee OA before and at six months after TKA (TKA-GROUP) and compared to an age-matched control group (CONTROL-GROUP). MFS was significantly more impaired in the TKA-GROUP at the pre-operative, but not post-operative visit, and significantly improved between the pre-operative and post-operative visits. Further research is warranted to evaluate the relation between this MFS measurement and physical functional performance in those at high risk for falling.

Muscle force and movement variability before and after total knee arthroplasty: A review

Variability in muscle force output and movement variability are important aspects of identifying individuals with mobility deficits, central nervous system impairments, and future risk of falling. This has been investigated in elderly healthy and impaired adults, as well as in adults with osteoarthritis (OA), but the question of whether the same correlations also apply to those who have undergone a surgical intervention such as total knee arthroplasty (TKA) is still being investigated. While there is a growing body of literature identifying potential rehabilitation targets for individuals who have undergone TKA, it is important to first understand the underlying post-operative impairments to more efficiently target functional deficits that may lead to improved long-term outcomes. The purpose of this article is to review the potential role of muscle force output and movement variability in TKA recipients. The narrative review relies on existing literature in elderly healthy and impaired individuals, as well as in those with OA before and following TKA. The variables that may predict long-term functional abilities and deficits are discussed in the context of existing literature in healthy older adults and older adults with OA and following TKA, as well as the role future research in this field may play in providing evidence-based data for improved rehabilitation targets.

Bicompartmental knee arthroplasty of the patellofemoral and medial compartments

PURPOSE

Studies have shown that after total knee arthroplasty neither normal biomechanics nor function is obtained. Selective resurfacing of diseased compartments could be a solution. A narrative review of the available literature on bicompartmental arthroplasty is presented.

METHODS

A literature review of all peer reviewed published articles on bicompartmental arthroplasty of the knee was performed. Bicompartmental arthroplasty is by definition the replacement of the tibiofemoral and the patellofemoral joint. It can be performed with a modular unlinked or a monolithic femoral component.

RESULTS

Bicompartmental arthroplasty performed with modular components obtains good to excellent results at ± 10 years follow-up. Function and biomechanics are superior to total knee arthroplasty. Modern monolithic femoral components are reported to give early failure and high revision rates and should be avoided.

CONCLUSION

Modular bicompartmental arthroplasty is an excellent alternative to treat bicompartmental arthritis of the knee leading to good functional results and superior biomechanics in well-selected patients. Caution is needed since only a few peer reviewed articles with small series and old implant designs are available on this type of arthritis treatment. Survivorship in these studies is inferior to total knee arthroplasty.

Proprioceptive accuracy in women with early and established knee osteoarthritis and its relation to functional ability, postural control, and muscle strength

The purpose of this study was to identify differences in knee proprioceptive accuracy between subjects with early knee osteoarthritis (OA), established knee OA, and healthy controls. Furthermore, the relation between proprioceptive accuracy on the one hand and functional ability, postural balance, and muscle strength on the other hand was also explored. New MRI-based classification criteria showing evidence of beginning joint degeneration have been used to identify subjects with early knee OA. A total of 45 women with knee OA (early OA, n = 21; established OA, n = 24) and 20 healthy female control subjects participated in the study. Proprioceptive accuracy was evaluated using the repositioning error of a knee joint position sense test using a three-dimensional motion analysis system. Subjective and objective functional ability was assessed by the knee injury and osteoarthritis outcome score, the timed "Up & Go" test, and the stair climbing test. The sensory organization test measured postural control. Muscle strength was measured by isokinetic dynamometry. Early OA subjects showed no significant differences in proprioceptive accuracy compared to healthy controls. In contrast, established OA subjects showed a higher repositioning error compared to early OA subjects (+29 %, P = 0.033) and healthy controls (+25 %, P = 0.068). Proprioceptive accuracy was not significantly associated with functional ability, postural balance, and muscle strength. Knee joint proprioceptive deficits were observed in established OA but not in early OA, suggesting that impaired proprioception is most likely a consequence of structural degeneration, rather than a risk factor in the pathogenesis of knee OA. Impaired proprioceptive accuracy was not associated with disease-related functionality in knee OA patients. Treatment strategies designed to address proprioceptive deficits may be not effective in prevention of knee OA progression and may have no impact on patients' functionality. However, this should be confirmed further in well-designed clinical trials.

Difference in knee joint position sense in athletes with and without patellofemoral pain syndrome

PURPOSE

The purpose of this study was to evaluate knee joint position sense (JPS) in athletes with patellofemoral pain syndrome (PFPS) and compare it with healthy participants under non-weight bearing (sitting) and weight bearing (standing) conditions.

METHODS

Twenty patients and 20 healthy athletes participated in this study. JPS was evaluated by active replication of knee angles with visual cues eliminated. Two target angles in sitting and one in standing were tested. Each test and replication was repeated three times. By subtracting the test angle from the replicated angle, the absolute error was calculated as a dependent variable.

RESULTS

No significant difference in knee JPS was found between groups either in the sitting or in the standing tests.

CONCLUSION

It seems that PFPS does not affect the knee JPS in athletes. The lack of deficiency in patients could possibly be attributed to their severity of knee pathology, pain intensity and their physical activity level.

LEVEL OF EVIDENCE

Case-control study, Level III.

Validation of spinal motion with the spine reposition sense device

Background

A sagittal plane spine reposition sense device (SRSD) has been developed. Two questions were addressed with this study concerning the new SRSD: 1) whether spine movement was occurring with the methodology, and 2) where movement was taking place.

Methods

Sixty-five subjects performed seven trials of repositioning to a two-thirds full flexion position in sitting with X and Y displacement measurements taken at the T4 and L3 levels. The thoracolumbar angle between the T4 and the L3 level was computed and compared between the positions tested. A two (vertebral level of thoracic and lumbar) by seven (trials) mixed model repeated measures ANOVA indicated whether significant differences were present between the thoracic (T4) and lumbar (L3) angular measurements.

Results

Calculated thoracolumbar angles between T4 and L3 were significantly different for all positions tested indicating spinal movement was occurring with testing. No interactions were found between the seven trials and the two vertebral levels. No significant findings were found between the seven trials but significant differences were found between the two vertebral levels.

Conclusion

This study indicated spine motion was taking place with the SRSD methodology and movement was found specific to the lumbar spine. These findings support utilizing the SRSD to evaluate changes in spine reposition sense during future intervention studies dealing with low back pain.

Muscle and exercise in the prevention and management of knee osteoarthritis: an internal medicine specialist's guide

This article outlines the influence of muscle activity on knee-joint loading, describes the deficits in muscle function observed in people with knee osteoarthritis, and summarizes available evidence pertaining to the role of muscle in the development and progression of knee osteoarthritis. The article focuses on whether muscle deficits can be modified in knee osteoarthritis and whether improvements in muscle function lead to improved symptoms and joint structure. This article concludes with a discussion of exercise prescription for muscle rehabilitation in knee osteoarthritis.

Cruciate ligaments in arthritic knees: a histologic study with radiologic correlation

Anterior cruciate ligaments (ACLs) and posterior cruciate ligaments (PCLs) from 45 osteoarthritic knees were histologically examined to evaluate the frequency and grade the severity of degenerative changes, which were correlated with radiologic grade of arthritis and severity of deformity at the knee. Immunohistochemical staining was used to identify neurofilaments in 10 knees. A histologic score was generated for both cruciates based on changes found on light microscopy. The ACL was severely degenerated, absent, or disrupted in knees with radiologic arthritis higher than grade 3 and varus deformity exceeding 15 degrees . The PCL was moderately degenerated in most knees irrespective of the grade of arthritis and severity of deformity. Neurofilaments were present in all 10 PCLs and absent in 4 ACLs.

Local subcutaneous and muscle pain impairs detection of passive movements at the human thumb

Activity in both muscle spindle endings and cutaneous stretch receptors contributes to the sensation of joint movement. The present experiments assessed whether muscle pain and subcutaneous pain distort proprioception in humans. The ability to detect the direction of passive movements at the interphalangeal joint of the thumb was measured when pain was induced experimentally in four sites: the flexor pollicis longus (FPL), the subcutaneous tissue overlying this muscle, the flexor carpi radialis (FCR) muscle and the subcutaneous tissue distal to the metacarpophalangeal joint of thumb. Tests were conducted when pain was at a similar subjective intensity. There was no significant difference in the ability to detect flexion or extension under any painful or non-painful condition. The detection of movement was significantly impaired when pain was induced in the FPL muscle, but pain in the FCR, a nearby muscle that does not act on the thumb, had no effect. Subcutaneous pain also significantly impaired movement detection when initiated in skin overlying the thumb, but not in skin overlying the FPL muscle in the forearm. These findings suggest that while both muscle and skin pain can disturb the detection of the direction of movement, the impairment is site-specific and involves regions and tissues that have a proprioceptive role at the joint. Also, pain induced in FPL did not significantly increase the perceived size of the thumb. Proprioceptive mechanisms signalling perceived body size are less disturbed by a relevant muscle nociceptive input than those subserving movement detection. The results highlight the complex relationship between nociceptive inputs and their influence on proprioception and motor control.

Postural responses following a rotational support surface perturbation, following knee joint replacement: frontal plane rotations

Total knee arthroplasty (TKA) is associated with altered sensory and motor functions of the knee which may impair balance control when standing and walking. This study examined the organization of electromyographic and kinematic postural responses to frontal plane support surface rotations, after TKA. Eight TKA patients and nine control participants volunteered. Patients demonstrated changes in onset latency of rectus femoris and gluteus medius, and in amplitude of muscle activity in tibialis anterior, gastrocnemius, rectus femoris, and gluteus medius, for both perturbation directions, and for both the surgical and sound limbs. Peak knee joint angular velocity was reduced among the patients for both perturbation directions and both the surgical and sound limbs, and patients demonstrated greater peak center of mass displacement. The CNS appears to alter the response to postural perturbation of both lower limbs, based on the reduced capacities of the surgical limb. Impaired detection of the valgus-varus loading of the knee joints may lead to the changes in muscle activity and resultant kinematics. Clinically, these findings are relevant in understanding that fully recovered TKA patients may continue to demonstrate balance impairments, and that balance training during physical rehabilitation may be advantageous to these patients.

Does arthroplasty type influence knee joint proprioception? A longitudinal prospective study comparing total and unicompartmental arthroplasty

Proprioception was assessed after knee replacement to compare total (TKA) to unicompartmental (UKA) knee arthroplasty. Thirty-four patients were recruited; seventeen patients underwent TKA and seventeen patients underwent UKA. The patient's age was similar in both groups. Two measures of proprioception, joint position sense (JPS) and postural sway (PS) were measured. Function was assessed using the Oxford Knee Score (OKS). Measurements were taken pre-operatively and 6 months post-operatively on both the operated and contralateral leg. Pre-operatively, no differences in JPS or PS were found between groups or between limbs in either group. Post-operatively, both groups had significant improvement of JPS in the operated limb only (20% increase). The improvement in JPS was similar in both groups. PS also improved significantly in both groups although the improvement of PS in the UKA group was twice that for the TKA group. The OKS improved by a similar amount in both groups. Both UKA and TKA result in a significant improvement in proprioception. Dynamic aspects of proprioception improve more after UKA than TKA, which may explain, in part, why UKA patients have superior functional outcome to that of TKA patients.

A prospective study of 3-day versus 2-week immobilization period after anterior cruciate ligament reconstruction

BACKGROUND

Aggressive early rehabilitation is recommended after reconstruction of the anterior cruciate ligament (ACL) using a patellar tendon-bone graft. However, rehabilitation after reconstruction of ACL using the multistranded hamstring is controversial. In this study, we compared the clinical results of 3-day immobilization after reconstruction of ACL using the multistranded hamstring, with those of 2-week immobilization prospectively.

METHODS

A total of 30 consecutive patients with ruptured ACL underwent single-socket ACL reconstruction. 10 male and 5 female patients (mean age of 29.2+/-10.0 years) were prospectively randomized for a 3-day immobilization period, and 6 male and 9 female patients (mean age of 27.3+/-10.9 years) were randomized for a 2-week immobilization period. We measured the anterior laxity with a KT-2000 arthrometer, joint position sense, and thigh muscle strength at 3, 6 and 12 months after surgery.

RESULTS AND CONCLUSIONS

There were no statistically significant differences between the two groups. We concluded that the post-operative 3-day immobilization period is preferable to the longer 2-week period in our rehabilitation program from the viewpoint of psychological load to the patients and the duration of hospitalization after ACL reconstruction using multistranded hamstring tendons.

Decrease in anterior knee laxity by electrical stimulation of normal and reconstructed anterior cruciate ligaments

We have investigated the changes in anterior laxity of the knee in response to direct electrical stimulation of eight normal and 45 reconstructed anterior cruciate ligaments (ACLs). In the latter, the mean time from reconstruction was 26.7 months (24 to 32). The ACL was stimulated electrically using a bipolar electrode probe during arthroscopy. Anterior laxity was examined with the knee flexed at 20 degrees under a force of 134 N applied anteriorly to the tibia using the KT-2000 knee arthrometer before, during and after electrical stimulation. Anterior tibial translation in eight normal and 17 ACL-reconstructed knees was significantly decreased during stimulation, compared with that before stimulation. In 28 knees with reconstruction of the ACL, in 22 of which the grafts were found to have detectable somatosensory evoked potentials during stimulation, anterior tibial translation was not decreased. These findings suggest that the ACL-hamstring reflex arc in normal knees may contribute to the functional stability and that this may not be fully restored after some reconstructions of the ACL.

Balance Confidence and Function after Knee-Replacement Surgery

This study examined the relationship between balance confidence and function in older adults after knee-replacement surgery. Thirty-six adults (20 men and 16 women age 58–84 years) completed measures of balance confidence, general self-efficacy, and function. Results showed that participants with greater balance confidence had better functional performance and reported fewer difficulties with activities of daily living. General self-efficacy and age were not related to any of the functional measures. Women scored lower than men for all balance-confidence and function measures. These findings highlight the potential value of studying balance-related self-efficacy beliefs in people with knee replacements. Longitudinal studies are now needed to determine whether a change in balance confidence is associated with a change in function and to further explore gender differences.

Knee joint position sense in compressive myelopathy

STUDY DESIGN

The knee joint position sense (JPS) and kinesthesia were measured in patients with compressive myelopathy.

OBJECTIVES

To find out how the knee JPS and kinesthesia are useful to evaluate lower limb function in patients with compressive myelopathy.

SUMMARY OF BACKGROUND DATA

No previous reports have been written on the quantitative analysis of knee joint proprioception in myelopathy patients.

METHODS

Twenty-one compressive myelopathy patients with a mean age of 64 years were studied. The measured values of JPS and kinesthesia were examined in relation to the following: lower limb function and central motor conduction time (CMCT).

RESULTS

Inaccurate angles of the knee JPS in patients with severe walking disability were significantly larger than those in patients with mild disability. Inaccurate angles of the knee JPS in patients with severe sensory disturbance were significantly larger than those in patients with mild disturbance. CMCT showed a significant correlation to the knee JPS.

CONCLUSIONS

The knee JPS was useful to evaluate lower limb function in patients with compressive myelopathy.

[Electromyographic study of stretch reflexes in the normal and prosthetic hip]

PURPOSE OF THE STUDY

Several studies have been devoted to the effect of proprioception on joint function. Modifications in feedback control from the cord have been observed in unstable joints due to capsule and ligament laxity. A few studies have examined the effect of knee and hip arthroplasty on proprioception, but none have established whether stretch reflexes affect function of a prosthetic joint. The purpose of the present study was to demonstrate the electromyographic characteristics of stretch reflexes of the normal hip joint and to compare them with those observed in the prosthetic hip.

MATERIAL AND METHODS

Two groups of patients were studied. The first included eleven subjects free of neurological disorders whose studied limb was healthy. The second group included ten subjects with a total hip prosthesis who had undergone extensive capsulectomy during the arthroplasty. Voluntary muscle contraction was noted in each subject. In addition, electromyographic recordings were made to note response of the ipsilateral and contralateral quadriceps crural and tensor of the fascia lata during changes in joint position. Recordings were made with the subject in the supine position, the limb suspended, hip flexed at 45 degrees and knee extended. Three series of ten recordings were made in random order to measure the latency of muscle response to free fall of the limb, accelerated fall of the relaxed limb, and accelerated fall associated with calibrated contraction of the quadriceps. Mean latency of muscle response was calculated for each trial.

RESULTS

In the conditions of this study, there was no statistically significant difference (p = 0.05) in the reflex time course between natural and prosthetic hips.

DISCUSSION

Changes due to joint replacement and capsulectomy do not appear to affect the stretch reflexes of the hip joint.

Effects of Kinesthesia and Balance Exercises in Knee Osteoarthritis

BACKGROUND

In patients with knee osteoarthritis (OA), there is a prominent loss in proprioception and kinesthesia sensation compared with control subjects of the same age and gender.

OBJECTIVES

The aim of this study is the investigation of short-term clinical effects of kinesthesia and balance exercises in patients with knee OA.

METHODS

This 8-week study was conducted on 66 female patients with knee OA who were randomized into 2 groups. The first group received kinesthesia and balance exercises (such as retrowalking, walking on their toes, leaning to the sides, balance board exercises, minitrampoline exercises, plyometric exercises, and so on) in addition to strengthening exercises. The second group received only strengthening exercises.

RESULTS

: Statistically significant improvements were observed postexercise for both groups with respect to baseline for WOMAC, SF-36 Form, times for performing activities of daily living, isokinetic quadriceps muscle strength, and proprioceptive sensation levels. In the first group with kinesthesia training, compared with the second group, significantly greater improvements were obtained in all the subparameters that measure functional status (WOMAC-physical function value, SF-36 Form [physical function, role limitations-physical and vitality-energy or fatigue variables], 10 stairs climbing, and 10-m walking times) and in isokinetic muscle strength at high angular velocities (P < 0.05). The absolute angular error percentage (to assess proprioceptive accuracy) was significantly improved postexercise in both groups. There were no differences between the groups.

CONCLUSIONS

Additive positive effects of kinesthesia and balance exercises in knee OA have been demonstrated. Used in clinical applications, they should be able to increase the functional capacities of patients. Long-term studies about efficacy and cost-effectivity of these exercises are needed.

Improvements in balance after total hip replacement

We have investigated whether control of balance is improved during stance and gait and sit-to-stand tasks after unilateral total hip replacement undertaken for osteoarthritis of the hip.

We examined 25 patients with a mean age of 67 years (sd 6.2) before and at four and 12 months after surgery and compared the findings with those of 50 healthy age-matched control subjects. For all tasks, balance was quantified using angular measurements of movement of the trunk.

Before surgery, control of balance during gait and sit-to-stand tasks was abnormal in patients with severe osteoarthritis of the hip, while balance during stance was similar to that of the healthy control group. After total hip replacement, there was a progressive improvement at four and 12 months for most gait and sit-to-stand tasks and in the time needed to complete them. By 12 months, the values approached those of the control group. However, trunk pitch (forwards-backwards) and roll (side-to-side) velocities were less stable (greater than the control) when walking over barriers as was roll for the sit-to-stand task, indicative of a residual deficit of balance.

Our data suggest that patients with symptomatic osteoarthritis of the hip have marked deficits of balance in gait tasks, which may explain the increased risk of falling which has been reported in some epidemiological studies. However, total hip replacement may help these patients to regain almost normal control of balance for some gait tasks, as we found in this study. Despite the improvement in most components of balance, however, the deficit in the control of trunk velocity during gait suggests that a cautious follow-up is required after total hip replacement regarding the risk of a fall, especially in the elderly.

Clinical and functional comparison of uni- and bicondylar sledge prostheses

The aim of the present study was the evaluation of differences in clinical results, proprioceptive performance and gait in patients with unicondylar and bicondylar sledge prostheses of the knee. In a retrospective study, 17 patients with unicondylar sledge prostheses were compared with 15 patients with bicondylar sledge prostheses. Clinical examination was rated using HSS, Knee Society, and patellar scores and a visual analogue scale for pain. Proprioceptive performance was examined using sway measurements during single leg stance on a force platform. In addition, the patients underwent 3-D gait analysis including measurements of ground reaction forces and surface electromyographic (EMG) investigation of the lower extremity. Comparing both patient groups in clinical scores, gait, EMG and proprioception, no significant differences were found. Implantation of bicondylar sledge prostheses retaining both cruciate ligaments achieves functional results as good as unicompartmental arthroplasty. The presented results might encourage future research on new models of total joint replacement with preservation of both cruciate ligaments.

Proprioception and performance after anterior cruciate ligament rupture

The aim of this study was to investigate the characteristics of proprioception in patients with an anaterior-cruciate-ligament (ACL)-injured knee and to determine whether there is a correlation between proprioception and performance. We studied 32 patients with unilateral isolated ACL ruptures. Proprioception of the knee was evaluated by examining the joint position sense. Functional performance was evaluated with the one-leg hop (OLH) and one-leg vertical jump (OLV) tests. The mean error angle of the joint position sense was 3.6+/-1.5 degrees on the intact side and 5.2+/-1.9 degrees on the injured side. The joint position sense was thus clearly reduced on the injured side (p<0.05). The distance of jumping in the OLH test and the height of jumping in the OLV test was also clearly reduced on the injured side compared with that on the intact side (p<0.01) both with and without visual control. Moreover, we found a significant correlation between proprioception and performance in the ACL-injured knees, and this correlation was more distinct with visual deprivation. In conclusion, decreased proprioception in patients with ACL deficiency reduced their functional ability.

Association of sensorimotor function with knee joint kinematics during locomotion in knee osteoarthritis

OBJECTIVE

To evaluate the relationship between quadriceps sensorimotor function (knee joint-position sense, quadriceps strength, and quadriceps onset of activity) and knee joint kinematics (knee flexion at initial contact and loading) during level walking and stair descent in a large cohort of 220 people with knee osteoarthritis.

DESIGN

Cross-sectional correlational study.

RESULTS

Joint-position sense correlated with knee flexion at initial contact during both tasks (r = -0.20 and -0.14, P <0.05). Strength correlated with peak loading response knee flexion during both tasks (r = 0.17 and 0.20, P < 0.05). Quadriceps onset correlated with knee flexion at initial contact during stair descent (r = 0.14, P < 0.05). Furthermore, differences in kinematic variables were observed when participants were divided into those with best and worst sensorimotor function.

CONCLUSION

Impaired sensorimotor function as measured in this study is not strongly associated with altered knee joint kinematics observed in knee osteoarthritis patients during locomotion.

Proprioceptive deficits are comparable before unicondylar and total knee arthroplasties, but greater in the more symptomatic knee of the patient

The clinical importance of the known proprioceptive deficit in patients with osteoarthritis of the knee is unclear. Attention to the factors that influence proprioception is needed to better understand the role that proprioception plays in the disease process and to assess how these deficits influence clinical outcomes of various treatment options for osteoarthritis. We hypothesized that preoperative proprioception would be poorer in knees with greater symptoms and that knees considered candidates for unicompartmental arthroplasty would have superior proprioception to those in which a total knee arthroplasty was indicated because of the less extensive disease process in the former group. Proprioceptive thresholds were measured in 119 patients with osteoarthritis and no prior knee arthroplasties who were scheduled for unicondylar or total knee arthroplasty. Proprioception examinations consisted of passively flexing and extending each of the bilateral knees in patients independently, from 45 degrees flexion until the blinded patient identified motion. Proprioceptive thresholds for flexion and extension were computed from the angular delays that elapsed before the patient recognized the stimulus. Multiple regression analysis was done to assess the association that these proprioceptive thresholds had with patient factors (age, gender, body mass index, activity level, functional capacity) and knee factors (surgical history, osteoarthritis severity, angular deformity, instability, range of motion). Patient age was the strongest predictor of proprioceptive thresholds, with older patients tending to respond slower to stimulus. Comparison of the right and left knees of each patient showed that proprioception was significantly poorer in the more symptomatic of the two knees. Preoperative thresholds did not differ between knees that received a total knee arthroplasty and those that received a unicondylar arthroplasty.

Physical functioning over three years in knee osteoarthritis: Role of psychosocial, local mechanical, and neuromuscular factors

OBJECTIVE

To identify factors that predict a poor physical function outcome over 3 years in individuals with knee osteoarthritis (OA), in an effort to aid in the development of strategies to prevent such functional limitations and consequential disability.

METHODS

Community-recruited individuals with knee OA underwent baseline, 18-month, and 3-year assessments of candidate risk factors and physical function. Risk factors were age, body mass index (BMI), knee pain intensity (on a visual analog scale [VAS]), local mechanical and neuromuscular factors (varus-valgus laxity, malalignment, proprioceptive inaccuracy, quadriceps strength, hamstring strength), activity level (Physical Activity Scale for the Elderly, amount of aerobic exercise), and psychosocial factors (Short-Form 36 [SF-36] mental health and role-functioning emotional subscales, self-efficacy using the Arthritis Self-Efficacy Scale physical function subscale, and social support using the Medical Outcomes Study Social Support Survey). Outcome was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function scale and rate of chair-stand performance. Participants were grouped by quintile of baseline WOMAC score. The baseline to 3-year outcome was considered "good" when function improved by 1 or more quintiles or remained within the 2 highest function groups, and was considered "poor" when function declined by 1 or more quintiles or remained within the 3 lowest function groups. The same approach was taken for chair-stand outcome. Logistic regression was used to evaluate both the baseline level and the baseline to 18-month change in each factor as a predictor of physical function outcome over 3 years, adjusting for age, BMI, knee pain intensity, disease severity, and additional potential confounders.

RESULTS

Factors that significantly increased the likelihood of a poor WOMAC outcome were baseline laxity (crude odds ratio [OR] 1.48/3 degrees, 95% confidence interval [95% CI] 1.02-2.14), BMI (OR 1.26/5 units, 95% CI 1.01-1.57), knee pain intensity (OR 1.21/20 mm on VAS, 95% CI 1.00-1.47), and baseline to 18-month increase in knee pain (OR 1.32/20 mm on VAS, 95% CI 1.06-1.65). Factors that significantly protected against a poor WOMAC outcome were better baseline mental health (OR 0.62/5 points, 95% CI 0.44-0.87), self-efficacy (OR 0.79/5 points, 95% CI 0.67-0.93), and social support (OR 0.86/10 points, 95% CI 0.75-0.98), and greater amount of aerobic exercise (OR 0.75/60 minutes each week, 95% CI 0.63-0.89). Factors that increased the likelihood for a poor function outcome by the chair-stand performance rate were age and proprioceptive inaccuracy, and factors that reduced the likelihood for poor chair-stand outcome were strength (attenuated after adjusting for pain intensity or self-efficacy), self-efficacy, and aerobic exercise. Individuals who sustained high function and those who sustained low function over the 3 years were described.

CONCLUSION

Factors placing individuals with knee OA at greater risk of a poor function outcome by at least 1 of the 2 function measures included the local factors laxity and proprioceptive inaccuracy, as well as age, BMI, and knee pain intensity. Factors protecting against a poor function outcome included strength, the psychosocial factors mental health, self-efficacy, and social support, and the activity level measured by the amount of aerobic exercise per week. The identification of these factors provides possible targets for rehabilitative and self-management strategies to prevent disability.

Relationship of knee joint proprioception to pain and disability in individuals with knee osteoarthritis

Proprioception plays an integral role in neuromotor control of the knee joint and deficits in knee joint proprioception are well documented in individuals with knee osteoarthritis (OA). However, the functional relevance of these deficits is not clear. This cross-sectional study evaluated the relationship between knee joint proprioception and pain and disability in a large cohort of individuals with knee OA. Two hundred and twenty participants (145 F, 75 M) with symptomatic knee OA were recruited from the community. Five non-weight bearing active tests with ipsilateral limb matching responses were performed at 20 degrees and 40 degrees flexion to measure knee joint position sense. Pain and disability were assessed by self-reported questionnaires and objective measures of balance and gait. Results showed little association between knee joint position sense variables and measures of pain and disability (r values <0.24, most p>0.05). When comparing participants with the worst and best joint position sense, no significant differences in pain and disability could be found (p>0.05). While our study design does not allow causality to be established, these results suggest that deficits in joint position sense may be due to factors other than pain and that deficits are not large enough to impact upon disability.

Balance and gait in total hip replacement: a pilot study

OBJECTIVE

Evaluation of balance, gait changes, sexual functions, and activities of daily living in patients with total hip replacement in comparison with healthy subjects.

DESIGN

A total of 30 patients were included in the study after total hip replacement. Balance was examined using dynamic posturography, and gait evaluation was done clinically. Sexual functions and activities of daily living were also assessed. A total of 30 healthy subjects of comparable age and sex served as a control group.

RESULTS

Dynamic balance and gait differed significantly in both the groups. Despite capsulectomy, no significant difference was observed on testing proprioception. In the sensory organization tests with difficult tasks, patients needed more sensory input from vision and vestibular sense, despite normal proprioceptive sense. Significant difference was observed for limits of stability, rhythmic weight shifts, and for gait variables other than walking base. Some of the patients had major difficulties with sexual functions and activities of daily living.

CONCLUSIONS

Compared with the healthy age- and sex-matched controls, patients with total hip replacement did not have any proprioceptive deficit. Patients required extrasensory input, and there was a delayed motor response. Gait and dynamic balance results also indicated the motor deficit and required a compensatory strategy. Restoration of the postural control in these patients is thus essential. Necessary training is required for balance, gait, and activities of daily living, and proper sexual counseling is necessary in postoperative care.

Is there a difference in hip joint position sense between young and older groups?

BACKGROUND

Joint position sense (JPS) in the knee has been shown by many authors to decline with age. It has been speculated that this decrease contributes to abnormal joint mechanics during load-bearing activities and putatively results in joint degeneration. Surprisingly little research has been conducted on the human hip to determine benchmarks for normal JPS.

METHOD

Fifty-nine community dwelling subjects, 30 young (mean age 21.7 years) and 29 older (mean age 75 years), were recruited to determine normal reference ranges for the effect of age on hip JPS. Active and passive repositioning tasks were performed in inner and outer ranges of the hip abduction plane of movement. An electromagnetic tracking system was used to obtain accurate error measurements of the angular displacement.

RESULTS

Results indicated no difference in hip JPS between the young and older subjects (F(1,57) = 0.011, p = .917). However, it was found that for both age groups, accurate reproduction of position at the hip joint occurred in the inner range (F(1,57) = 13.760, p < .001). For both groups, active repositioning was more accurate than passive (F(1,57) = 9.265, p = .004).

CONCLUSIONS

In this study, no difference in hip JPS was found between young and older subjects. Accuracy was greater in the inner range, with active repositioning demonstrating higher precision compared to passive repositioning of the limb.

Effects of localization and intensity of experimental muscle pain on ankle joint proprioception

Accurate proprioceptive input is a prerequisite for balance control and coordination of movement. The present study investigated whether experimental muscle pain induced in healthy human subjects disturbed movement sense (detection of movement) or position sense (recognition of a reference position). Muscle pain was produced by infusion of 6% hypertonic saline simultaneously in m. tibialis anterior (TA) and m. soleus (experiment 1), by infusion of 6% hypertonic saline in TA (experiment 2) and by infusion of 9% hypertonic saline in TA (experiment 3). Control measurements were done with infusions of 0.9% isotonic saline. All infusions of 6% and 9% saline produced pain intensities significantly higher than the corresponding control infusions. Only infusion of 6% saline in two muscles (visual analogue scale=4-5) produced an elevation in movement detection thresholds which was significantly higher, compared with before infusion. No other significant changes in movement and position sense were found during the painful or control infusions. Pain of relatively high intensity in two antagonist muscles is necessary to disturb the movement detection threshold. The ability to recognize a reference position is not disturbed by experimentally induced muscle pain. Whether the disturbed movement sense is caused by sensitivity changes in muscle spindle afferents or altered processing of proprioceptive input cannot be answered. The present findings indicate that human ankle proprioception is rather robust to muscle pain.