Trevor B. Birmingham

A Randomized Trial of Arthroscopic Surgery for Osteoarthritis of the Knee

BACKGROUND The efficacy of arthroscopic surgery for the treatment of osteoarthritis of the knee is unknown. METHODS We conducted a single-center, randomized, controlled trial of arthroscopic surgery in patients with moderate-to-severe osteoarthritis of the knee. Patients were randomly assigned to surgical lavage and arthroscopic débridement together with optimized physical and medical therapy or to treatment with physical and medical therapy alone. The primary outcome was the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (range, 0 to 2400; higher scores indicate more severe symptoms) at 2 years of follow-up. Secondary outcomes included the Short Form-36 (SF-36) Physical Component Summary score (range, 0 to 100; higher scores indicate better quality of life). RESULTS Of the 92 patients assigned to surgery, 6 did not undergo surgery. Of the 86 patients assigned to control treatment, all received only physical and medical therapy. After 2 years, the mean (+/-SD) WOMAC score for the surgery group was 874+/-624, as compared with 897+/-583 for the control group (absolute difference [surgery-group score minus control-group score], -23+/-605; 95% confidence interval [CI], -208 to 161; P=0.22 after adjustment for baseline score and grade of severity). The SF-36 Physical Component Summary scores were 37.0+/-11.4 and 37.2+/-10.6, respectively (absolute difference, -0.2+/-11.1; 95% CI, -3.6 to 3.2; P=0.93). Analyses of WOMAC scores at interim visits and other secondary outcomes also failed to show superiority of surgery. CONCLUSIONS Arthroscopic surgery for osteoarthritis of the knee provides no additional benefit to optimized physical and medical therapy. (ClinicalTrials.gov number, NCT00158431.)

Hop Testing Provides a Reliable and Valid Outcome Measure During Rehabilitation After Anterior Cruciate Ligament Reconstruction

Background and Purpose Although various hop tests have been proposed as performance-based outcome measures following anterior cruciate ligament (ACL) reconstruction, limited reports of their measurement properties exist. The purpose of this study was to investigate the reliability and longitudinal validity of data obtained from hop tests during rehabilitation after ACL reconstruction. Subjects Forty-two patients, 15 to 45 years of age, who had undergone ACL reconstruction participated in the study. Methods and Measures The study design was prospective and observational with repeated measures. The subjects performed a series of 4 hop tests on 3 separate occasions within the 16th week following surgery and on a fourth occasion 6 weeks later. The tests were a single hop for distance, a 6-m timed hop, a triple hop for distance, and crossover hops for distance. Performance on the ACL-reconstructed limb was expressed as a percentage of the performance on the nonoperative limb, termed the “limb symmetry index.” Subjects also completed the Lower Extremity Functional Scale and a global rating of change questionnaire. Results Intraclass correlation coefficients for limb symmetry index values ranged from .82 to .93. Standard errors of measurement were 3.04% to 5.59%. Minimal detectable changes, at the 90% confidence level, were 7.05% to 12.96%. Changes in hop test scores on the operative limb were statistically greater than changes on the nonoperative limb. Pearson correlations (r) between change in hop performances and self-reported measures ranged from .26 to .58. Discussion and Conclusion The results show that the described series of hop tests provide a reliable and valid performance-based outcome measure for patients undergoing rehabilitation following ACL reconstruction. These findings support the use and facilitate the interpretation of hop tests for research and clinical practice.

Lateral trunk lean explains variation in dynamic knee joint load in patients with medial compartment knee osteoarthritis

OBJECTIVE To test the hypothesis that selected gait kinematics, particularly lateral trunk lean, observed in patients with medial compartment knee osteoarthritis explain variation in dynamic knee joint load. METHOD In this cross-sectional observational study, 120 patients with radiographically confirmed varus gonarthrosis underwent three-dimensional gait analysis at their typical walking speed. We used sequential (hierarchical) linear regression to examine the amount of variance in dynamic knee joint load (external knee adduction moment) explained by static lower limb alignment (mechanical axis angle) and gait kinematics determined a priori based on their proposed effect on knee load (walking speed, toe-out angle, and lateral trunk lean angle). RESULTS Approximately 50% of the variation in the first peak external knee adduction moment was explained by mechanical axis angle (25%), Western Ontario and McMaster Universities Osteoarthritis Index pain score (1%), gait speed (1%), toe-out angle (12%), and lateral trunk lean angle (13%). There was no confounding or interaction with Kellgren and Lawrence grade of severity. CONCLUSIONS Gait kinematics, particularly lateral trunk lean, explain substantial variation in dynamic knee joint load in patients with medial compartment knee osteoarthritis. While largely ignored in previous gait studies, the effect of lateral trunk lean should be considered in future research evaluating risk factors and interventions for progression of knee osteoarthritis.

The Familial Predisposition toward Tearing the Anterior Cruciate Ligament: A Case Control Study

Purpose A study of 171 surgical cases and 171 matched controls was conducted to investigate whether a familial predisposition toward tearing the anterior cruciate ligament of the knee exists. Study Design Case control study; Level of evidence, 3. Methods Patients who were diagnosed with an anterior cruciate ligament tear were matched by age (within 5 years), gender, and primary sport to subjects without an anterior cruciate ligament tear. All 342 subjects completed a questionnaire detailing their family history of anterior cruciate ligament tears. Results When controlling for subject age and number of relatives, participants with an anterior cruciate ligament tear were twice as likely to have a relative (first, second, or third degree) with an anterior cruciate ligament tear compared to participants without an anterior cruciate ligament tear (adjusted odds ratio = 2.00; 95% confidence interval, 1.19-3.33). When the analysis was limited to include only first-degree relatives, participants with an anterior cruciate ligament tear were slightly greater than twice as likely to have a first-degree relative with an anterior cruciate ligament tear compared to participants without an anterior cruciate ligament tear (adjusted odds ratio = 2.24; 95% confidence interval, 1.24-4.00). Conclusions Findings are consistent with a familial predisposition toward tearing the anterior cruciate ligament. Clinical Relevance Future research should concentrate on identifying the potentially modifiable risk factors that may be passed through families and developing strategies for the prevention of anterior cruciate ligament injuries.

Radiographic Measures of Knee Alignment in Patients With Varus Gonarthrosis Effect of Weightbearing Status and Associations With Dynamic Joint Load

Background Radiographic measures of lower limb malalignment are used to indicate abnormal loading of the knee and to plan corrective procedures. Hypotheses Weightbearing status during hip-to-ankle radiographs will significantly affect malalignment measures; malalignment in single-limb standing will be most highly correlated to the external knee adduction moment during gait, a proposed dynamic measure of functional knee joint load. Study Design Controlled laboratory study. Methods Mechanical axis angle was measured in 40 patients with varus gonarthrosis from hip-to-ankle radiographs taken with patients in single-limb standing, double-limb standing, and supine positions. Kinematic and kinetic data were collected during walking and used to calculate the peak adduction moment about the knee. Results Repeated-measures analysis of variance and Scheffé post hoc tests indicated that mechanical axis angle measured on single-limb standing radiographs (-8.7°± 4.0°) was significantly greater than on double-limb standing radiographs (-7.1°± 3.8°), which was significantly greater than on supine radiographs (-5.5°± 2.8°). The peak knee adduction moment (2.8 ± 0.8 percentage body weight × height) was only moderately correlated with mechanical axis angle on single-limb standing (r = -0.46), double-limb standing (r = -0.45), and supine (r = -0.43) radiographs. Conclusion Patient position significantly affects frontal plane knee alignment. However, the peak knee adduction moment is only moderately correlated to mechanical axis angle, regardless of weightbearing status. Clinical Relevance These findings are inconsistent with the hypothesis that mechanical axis angle measured in single-limb standing is more representative of dynamic joint load and further highlight the differences between static and dynamic measures. Results also underscore the importance of reporting patient position during radiographs and keeping positions consistent when evaluating patients over time.

Medial opening wedge high tibial osteotomy: A prospective cohort study of gait, radiographic, and patient-reported outcomes

OBJECTIVE To evaluate the effect of medial opening wedge high tibial osteotomy on gait, radiographic, and patient-reported outcomes over a 2-year postoperative period in patients with varus alignment and medial compartment knee osteoarthritis, and to identify significant predictors of outcome. METHODS We used an observational cohort study design and prospectively administered 3-dimensional quantitative gait analysis, hip to ankle weight-bearing radiographs, and patient-reported outcomes preoperatively and 6, 12, 18, and 24 months postoperatively. Observed changes with 95% confidence intervals (95% CIs) were calculated. Multivariate linear regression and cluster analysis were used to evaluate associations between patient characteristics and 2-year outcomes in dynamic knee joint load (external knee adduction moment during gait) and Knee Injury and Osteoarthritis Outcome Scores (KOOS). RESULTS A total of 126 patients (mean age 47.48 years) were included in the study. Mean changes suggested clinically important improvements in malalignment (change in mechanical axis angle 8.04 degrees [95% CI 7.16 degrees , 8.93 degrees ]), medial compartment load during gait (change in knee adduction moment -1.38 [95% CI -1.53, -1.22] percentage body weight x height), and all KOOS domain scores (change in pain 23.19 [95% CI 19.49, 26.89] KOOS points). A small (13%) increase in knee adduction moment was observed from 6 to 24 months postoperatively. Few preoperative clinical and/or gait characteristics assessed at baseline were significantly associated with 2-year outcomes. CONCLUSION A medial opening wedge high tibial osteotomy with correction to approximately neutral alignment produces substantial and clinically important changes in dynamic knee joint load and patient-reported measures of pain, function, and quality of life 2 years postoperatively. Changes in knee adduction moment observed in the first 2 years postoperatively should be explored as potential predictors of longer-term success and subgroups of patients with poor outcomes.

Knee bracing after ACL reconstruction : effects on postural control and proprioception

PURPOSE To evaluate the effects an anterior cruciate ligament (ACL) brace has on various measures of knee proprioception and postural control. METHODS Thirty subjects (mean age 27 +/- 11 yr) having undergone unilateral ACL reconstruction were tested with and without wearing their own custom-fit brace on their involved limb. Proprioception was assessed using joint angle replication tests completed on an isokinetic dynamometer. Postural control was assessed using a series of single-limb standing balance tests completed on a force platform. The balance tests included: 1) standing on the stable platform with eyes open, 2) standing on a foam mat placed over the platform with eyes open, 3) standing on the platform with eyes closed, and 4) standing on the platform after landing from a maximal single-limb forward hop. RESULTS The brace provided a small but statistically significant improvement in proprioception (mean reduction in error scores between target and reproduced angles = 0.64 +/- 1.4 degrees, P = 0.02). For the postural control tests, there was a significant brace condition by test situation interaction (P = 0.02), with the brace providing a small but statistically significant improvement during the test completed on the stable platform with eyes open (mean reduction in center of pressure path length = 4.2 +/- 8.4 cm, P = 0.02) but not during the other more challenging test situations. Additional post hoc analyses indicated that the relationship between knee proprioception and postural control measures were low and not significant (r = 0.003 to 0.19, P > 0.32), consistent with the suggestion that changes in knee proprioception can occur in the absence of substantial changes in postural control. Also, standing balance tests that challenged the somatosensory contribution to postural control (i.e., those completed on foam, or with eyes closed) were significantly related to single-limb forward hop distances (r = -0.4, P < 0.05), whereas performance during the proprioception test was not (r = 0.1, P > 0.50). CONCLUSIONS In general, bracing appears to improve performance during tasks characterized by relatively limited somatosensory input but not during tasks characterized by increased somatosenory input. The small magnitude of the improvements, coupled with their apparent lack of carry over to more difficult and functionally relevant tasks, questions the clinical benefit of the present effects of bracing.

A Randomized Controlled Trial Comparing the Effectiveness of Functional Knee Brace and Neoprene Sleeve Use After Anterior Cruciate Ligament Reconstruction

Background Despite a lack of evidence for their effectiveness, functional knee braces are commonly prescribed to patients after anterior cruciate ligament (ACL) reconstruction. Purpose This trial was conducted to compare postoperative outcomes in patients using an ACL functional knee brace and patients using a neoprene knee sleeve. Hypothesis Patients using a brace will have superior outcomes than those using a sleeve. Study Design Randomized controlled clinical trial; Level of evidence, 1. Methods One hundred fifty patients were randomized to receive a brace (n = 76) or neoprene sleeve (n = 74) at their 6-week postoperative visit after primary ACL reconstruction with hamstring autograft. Patients were assessed preoperatively, then 6 weeks and 6, 12, and 24 months postoperatively. Outcome measures included disease-specific quality of life (Anterior Cruciate Ligament–Quality of Life [ACL-QOL] Questionnaire), anterior tibial translation (KT-1000 arthrometer side-to-side difference), the single-limb forward hop test (limb symmetry index), and Tegner Activity Scale. Outcomes at 1 and 2 years were compared after adjusting for baseline scores. Subjective ratings of how patients felt while using the brace/sleeve were also collected for descriptive purposes using a questionnaire. Four a priori directional subgroup hypotheses were evaluated using tests for interactions. Results There were no significant differences between brace (n = 62) and sleeve (n = 65) groups for any of the outcomes at 1- and 2-year follow-ups. Adjusted mean differences at 2 years were as follows: −0.94 (95% confidence interval [CI], −7.52 to 5.64) for the ACL-QOL Questionnaire, −0.10 mm (95% CI, −0.99 to 0.81) for KT-1000 arthrometer side-to-side difference, −0.87% (95% CI, −8.89 to 7.12) for hop limb symmetry index, and −0.05 (95% CI, −0.72 to 0.62) for the Tegner Activity Scale. Subjective ratings of confidence in the knee provided by the brace/sleeve were higher for the brace group than the sleeve group. Subgroup findings were minimal. Adverse events were few and similar between groups. Conclusions A functional knee brace does not result in superior outcomes compared with a neoprene sleeve after ACL reconstruction. Current evidence does not support the recommendation of using an ACL functional knee brace after ACL reconstruction.

Minimal Detectable Change in Quadriceps Strength and Voluntary Muscle Activation in Patients With Knee Osteoarthritis

OBJECTIVE To examine the test-retest reliability and quantify the minimal detectable change (MDC) in quadriceps strength and voluntary activation in patients with knee osteoarthritis (OA). DESIGN Repeated measures over a 1-week interval. SETTING Tertiary care center. PARTICIPANTS A convenience sample of patients (N=20) diagnosed with knee OA. INTERVENTION Isokinetic and isometric quadriceps strength testing and voluntary quadriceps activation testing using interpolated twitch technique. MAIN OUTCOME MEASURES Peak isokinetic and isometric knee extension torque (Nm) and percentage of voluntary quadriceps activation (%). RESULTS The mean differences with 95% confidence intervals between the 2 test sessions for quadriceps isokinetic strength, isometric strength, and percent of voluntary activation were -4.34Nm (-14.01 to 5.34Nm), 1.56Nm (-5.56 to 8.68Nm), and 1.34% (-.53 to 3.22%), respectively. The intraclass correlation coefficients for all measures ranged from .93 to .98. The standard errors of measurement (SEMs) for quadriceps isokinetic and isometric strength were 14.57Nm and 10.76Nm, respectively. The SEM for percentage of voluntary activation was 2.84%. Based on these values, the MDCs were 33.90Nm, 25.02Nm, and 6.60% for quadriceps isokinetic strength, isometric strength, and percentage of voluntary activation, respectively. CONCLUSIONS Maximal quadriceps isokinetic strength, isometric strength, and percentage of voluntary activation measures demonstrate excellent test-retest reliability in patients with knee OA. In addition to research applications, the present findings suggest these measures are appropriate for use when evaluating change in neuromuscular function of the quadriceps in individual patients.

Effect of a neoprene sleeve on knee joint kinesthesis: influence of different testing procedures.

PURPOSE Objectives of this study were to examine the perceived sense of knee joint position during selected test situations, and to evaluate the proposed kinesthetic effect of a neoprene knee sleeve during these test situations. METHODS Fifty-nine young healthy subjects (39 females and 20 males) attempted to replicate target knee joint angles using active and passive knee extension movements completed in sitting (nonaxially loaded) situations, and during active knee extension movements completed in supine while applying a load of 15% body weight through the long axis of the tibia (axially loaded). The criterion measure used was the absolute difference between target and reproduced angles, averaged over five attempts (Average absolute difference: AAD). RESULTS A three-way ANOVA (two genders by three test situations by two sleeve conditions), with repeated measures on the last two factors, indicated a significant main effect for test situation and sleeve condition (P < 0.05), but not for gender. There was also a significant test situation by sleeve condition interaction (P < 0.05). Post-hoc analysis indicated that the AAD score during the active nonaxially loaded test situation without the sleeve was significantly greater than AAD scores for all other tests (P < 0.01). CONCLUSIONS Pre-existing differences in knee joint kinesthesis observed during different contexts of limb movement must be recognized before various interventions, including the effect of knee supports, can be adequately interpreted. Because knee joint position sense was attenuated during voluntary active movement, and because this attenuation was ameliorated by the use of a sleeve, future studies evaluating the kinesthetic effects of knee bracing may benefit from using active movements. However, since the sleeve did not affect performance during the axially loaded test situation, future studies should also evaluate the relationship between tests of knee joint kinesthesis and other more functional tests of neuromuscular performance.