Reduction In External Knee Adduction Moment Research Articles

Do non-responders to lateral wedge insoles remain non-responders after an eight week intervention?

Purpose: One common conservative treatment in medial knee osteoarthritis (OA) are lateral wedge insoles which can be worn long-term and have been shown to reduce the medial knee loading. Studies assessing the external knee adduction moment (EKAM) have demonstrated reductions of around 5–6%. However, it has been shown that there are inconsistent reductions in EKAM in individuals with medial knee OA whereby around 30% of individuals have an increase in their moment. These are classed as non-responders to the biomechanical treatment. To date, there have been no reports on what happens to the individual over time and if an individual who is classed as a non-responder at a baseline visit still remains a non-responder at a follow-up visit. We hypothesized that individuals who are biomechanical non-responders remain biomechanical non-responders after an eight-week intervention period. Methods: This ancillary study is part of a larger randomised controlled cross-over trial of persons with painful medial knee OA (In-Respond trial). The inclusion criteria were global knee pain in last week >=4 [0–10 scale]) age 40–85 years who had knee x-rays showing Kellgren and Lawrence grade 2–4 OA and definite medial without lateral narrowing. On examination by an experienced physiotherapist, they had to have medial tenderness but were excluded if they had pain at the lateral patellar facet or a positive patellar compression test. Subjects underwent three-dimensional motion analysis screening in both their own shoes and an off-the-shelf lateral wedge insole (Salford Lateral Wedge, 5 degree and 70 Shore A density). The individuals were classified into biomechanical responders (ones who's EKAM was reduced over 2% compared to their own shoe and a neutral insole) and biomechanical non-responders (those who's EKAM did not reach those reductions). The biomechanical non-responders were given a lateral wedge insole and were followed for eight weeks to determine any changes in EKAM. The analysis tested whether individuals who were biomechanical non-responders were still classified as this after 8 weeks. We calculated the percentage difference in EKAM when the lateral wedge was worn in the patients' compared to no insole, and also against a neutral insole. Percentage differences were calculated at both the baseline and 8 weeks visits. Excluding patients who had reductions in EKAM naturally leads to a non-normally distributed sample, hence we summarized the data at both time points using a five number summary (median, minimum, maximum, and interquartile range). In addition, we used Wilcoxon signed-rank tests for to test formally whether distributions of percentage changes differed between visits. Results: 192 potential subjects were screened for the study, where 109 were excluded who didn't meet inclusion criteria (60 did not meet x-ray criteria; 28 were ineligible based mostly on patellofemoral findings on physical examination, the remainder for other reasons). Out of these 83 remaining individuals 21 were classed as non-responders (mean increase 1.5%; range 18% increase –1% decrease in EKAM). Of these 21, 16 returned for the second gait analysis with 5 withdrawing from the study (3 due to problems with increased pain and 2 were not contactable). There was no difference when comparing the median reduction in EKAM between the baseline and the follow-up visit (Table 1). However, 12 of the individuals still remained as a biomechanical non-responder but 4 individuals demonstrated a change into a biomechanical responder which would have resulted in them being eligible for this trial.Table 1Percentage Differences in EKAM in Lateral Wedge Condition, Relative to Control ConditionsGait conditionStudy visitPercentage differencesWilcoxon signed-rank test for equality of distributions between visitsMedianLower quartileUpper quartileMinimumMaximumz, POwn shoe vs Lateral wedge insoleBaseline0.61−1.222.34−1.7017.561.75, 0.088 week follow-up−0.62−6.071.82−10.2314.24Neutral insole vs Lateral wedge insoleBaseline0.43−0.752.99−4.2716.591.34, 0.188 week follow-up−0.63−3.952.07−6.827.70 Open table in a new tab Conclusions: As in previous studies, there were individuals who did not biomechanically respond to the lateral wedge insoles. When using this as stratification for inclusion in a trial, it showed that the majority of these individuals remained classed as this non-responder. However, four individuals did change. Understanding why these individuals changed classification is a future research direction.

Progressive Changes in Walking Kinematics and Kinetics After Anterior Cruciate Ligament Injury and Reconstruction: A Review and Meta-Analysis.

Anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) result in persistent alterations in lower extremity movement patterns. The progression of lower extremity biomechanics from the time of injury has not been described. To compare the 3-dimensional (3D) lower extremity kinematics and kinetics of walking among individuals with ACL deficiency (ACLD), individuals with ACLR, and healthy control participants from 3 to 64 months after ACLR. We searched PubMed and Web of Science from 1970 through 2013. We selected only articles that provided peak kinematic and kinetic values during walking in individuals with ACLD or ACLR and comparison with a healthy control group or the contralateral uninjured limb. A total of 27 of 511 identified studies were included. Weighted means, pooled standard deviations, and 95% confidence intervals were calculated for the healthy control, ACLD, and ACLR groups at each reported time since surgery. The magnitude of between-groups (ACLR versus ACLD, control, or contralateral limb) differences at each time point was evaluated using Cohen d effect sizes and associated 95% confidence intervals. Peak knee-flexion angle (Cohen d = -0.41) and external knee-extensor moment (Cohen d = -0.68) were smaller in the ACLD than in the healthy control group. Peak knee-flexion angle (Cohen d range = -0.78 to -1.23) and external knee-extensor moment (Cohen d range = -1.39 to -2.16) were smaller in the ACLR group from 10 to 40 months after ACLR. Reductions in external knee-adduction moment (Cohen d range = -0.50 to -1.23) were present from 9 to 42 months after ACLR. Reductions in peak knee-flexion angle, external knee-flexion moment, and external knee-adduction moment were present in the ACLD and ACLR groups. This movement profile during the loading phase of gait has been linked to knee-cartilage degeneration and may contribute to the development of osteoarthritis after ACLR.

Lateral Wedge Insoles for Reducing Biomechanical Risk Factors for Medial Knee Osteoarthritis Progression: A Systematic Review and Meta-Analysis.

Lateral wedge insoles are intended to reduce biomechanical risk factors of medial knee osteoarthritis (OA) progression, such as increased knee joint load; however, there has been no definitive consensus on this topic. The aim of this systematic review and meta-analysis was to establish the within-subject effects of lateral wedge insoles on knee joint load in people with medial knee OA during walking. Six databases were searched from inception until February 13, 2015. Included studies reported on the immediate biomechanical effects of lateral wedge insoles during walking in people with medial knee OA. Primary outcomes of interest relating to the biomechanical risk of disease progression were the first and second peak external knee adduction moment (EKAM) and knee adduction angular impulse (KAAI). Eligible studies were pooled using random-effects meta-analysis. Eighteen studies were included with a total of 534 participants. Lateral wedge insoles resulted in a small but statistically significant reduction in the first peak EKAM (standardized mean difference [SMD] -0.19; 95% confidence interval [95% CI] -0.23, -0.15) and second peak EKAM (SMD -0.25; 95% CI -0.32, -0.19) with a low level of heterogeneity (I(2) = 5% and 30%, respectively). There was a favorable but small reduction in the KAAI with lateral wedge insoles (SMD -0.14; 95% CI -0.21, -0.07, I(2) = 31%). Risk of methodologic bias scores (quality index) ranged from 8 to 13 out of 16. Lateral wedge insoles cause small reductions in the EKAM and KAAI during walking in people with medial knee OA. Current evidence demonstrates that lateral wedge insoles appear ineffective at attenuating structural changes in people with medial knee OA as a whole and may be better suited to targeted use in biomechanical phenotypes associated with larger reductions in knee load.

An analysis of the mechanisms for reducing the knee adduction moment during walking using a variable stiffness shoe in subjects with knee osteoarthritis

Variable stiffness shoes that have a stiffer lateral than medial sole may reduce the external knee adduction moment (EKAM) and pain during walking in patients with medial compartment knee osteoarthritis (OA). However, the mechanism by which EKAM may be reduced in the OA knee with this intervention remains unclear. Three hypotheses were tested in this study: (1) The reduction in EKAM during walking with the variable stiffness shoe is associated with a reduction in GRF magnitude and/or (2) frontal plane lever arm. (3) A reduction in frontal plane lever arm occurs either by moving the center of pressure laterally under the shoe and/or by dynamically reducing the medial component of GRF. Thirty-two subjects (20 male, 12 female; age: 58.7±9.3 years; height: 1.62±0.08 m; mass: 81.3±14.6 kg) with medial compartment knee osteoarthritis were studied walking in a gait laboratory. The frontal plane lever arm was significantly reduced (1.62%, 0.07%ht, p=0.02) on the affected side while the magnitude of the GRF was not significantly changed. The reduction in the lever arm was weakly correlated with a medial shift in the COP. However, the combined medial shift in the COP and reduction in the medial GRF explained 50% of the change of the frontal plane lever arm. These results suggest that the medial shift in the COP at the foot produced by the intervention shoe stimulates an adaptive dynamic response during gait that reduces the frontal plane lever arm.