Reduction In Knee Adduction Moment Research Articles

Toe-In during Sit-To-Stand Reduces Knee Adduction Moment in People with Moderate Knee Osteoarthritis

Toe-In during Sit-To-Stand Reduces Knee Adduction Moment in People with Moderate Knee Osteoarthritis

Can exercise interventions reduce external knee adduction moment during gait? A systematic review and meta-analysis

BackgroundAn increased external knee adduction moment has been identified as a factor contributing to the progression of medial knee osteoarthritis. Interventions that reduce knee adduction moment may help prevent knee osteoarthritis onset and progression. While exercise interventions have been commonly used to treat knee osteoarthritis, whether exercises can modulate knee adduction moment in knee osteoarthritis patients remains unknown. This systematic review and meta-analysis aimed to determine if exercise interventions are effective in reducing knee adduction moment during gait. MethodsStudy reports published through May 2023 were screened for pre-specified inclusion/exclusion criteria. Nine studies met the eligibility criteria and yielded 24 effect sizes comparing the reduction in knee adduction moment of the exercise intervention groups to the control groups. Moderator/experimental variables concerning characteristics of the exercise interventions and included subjects (e.g., sex, BMI, type of exercise, muscle group targeted, training volume, physical therapist supervision) that may contribute to variation among studies were explored through subgroup analysis and meta-regression. FindingsThe effect of exercise intervention on modulating knee adduction moment during gait was no better than control (ES = -0.004, P = 0.946). Sub-group analysis revealed that the effect sizes of studies containing only females (positive exercise effect) were significantly greater than studies containing both males and females. InterpretationExercise may not be effective in reducing knee adduction moment during gait. Clinicians aiming to decrease knee adduction moment in patients with medial knee osteoarthritis should consider alternative treatment options. Exploring the underlying mechanism(s) regarding a more positive response to exercises in females may help design more effective exercise interventions.

Comparing the Immediate Effect of Pneumatic and Conventional Knee Braces on Gait, Satisfaction and Pain in Patients With Knee Medial Osteoarthritis

Background/Aims Knee braces can change loading direction on knees in people with osteoarthritis, thereby reducing symptoms and progression of the disease. The aims of this study were to explore the immediate effect of two types of braces, a pneumatic knee brace with air pressure embedded in a sandal cuff (sandal cuff pressure) and a conventional knee brace on gait, pain and satisfaction during walking in patients with knee medial osteoarthritis. Methods A total of 28 patients with knee medial osteoarthritis were assigned to two groups, 14 patients used a conventional brace and 14 used a prototype brace with a pneumatic system, which was designed and fabricated by the authors, and followed the mechanism of variable pressures in the stance and swing phases of a gait cycle in a patient’s knee. The gait parameters (walking self-selected speed, cadence, stride length, knee range of motion, and maximum knee adduction moment) were measured with a Kistler force plate and Vicon motion analysis under two conditions: with and without brace for the conventional brace group, and under three conditions of no brace, brace with sandal cuff pressure, and brace without sandal cuff pressure for the pneumatic brace group. Patients’ pain and satisfaction were also measured using a visual analogue scale and Likert scale respectively. Results Both groups showed a significant reduction in maximum knee adduction moment and pain wearing braces in comparison to no brace during walking (P<0.05). The knee range of motion was significantly decreased in the pneumatic brace group with and without sandal cuff pressure compared with no brace (P<0.001). No significant difference was found for any of the variables when using the pneumatic brace with and without sandal cuff pressure (P>0.05). In the between-group comparison, only patients’ satisfaction was significantly reduced when using the pneumatic brace in both walking with (P=0.041) and without (P=0.02) sandal cuff pressure compared to those using the conventional brace. Conclusions Both conventional and pneumatic braces led to reduced knee adduction moment and pain in patients with knee osteoarthritis. However, using a pneumatic brace reduced the knee range of motion and satisfaction of patients, which could be because the brace was a prototype.

Placebo gait retraining for use in knee osteoarthritis clinical trials does not change surrogate knee load measures: A randomized pilot study

Introduction: Gait retraining is a novel management strategy which has shown ability to reduce pain and the peak knee adduction moment (KAM) (a surrogate measure of medial knee load) in people with medial knee osteoarthritis. However, no published study has compared gait retraining to placebo gait retraining (a gait change which does not affect KAM). Therefore, it is unknown whether pain improvement with gait retraining is due to KAM reduction. Our primary aim was to determine knee joint loading outcomes during placebo, toe-in, and toe-out gait retraining compared to baseline.

Predicting knee adduction moment response to gait retraining with minimal clinical data.

Knee osteoarthritis is a progressive disease mediated by high joint loads. Foot progression angle modifications that reduce the knee adduction moment (KAM), a surrogate of knee loading, have demonstrated efficacy in alleviating pain and improving function. Although changes to the foot progression angle are overall beneficial, KAM reductions are not consistent across patients. Moreover, customized interventions are time-consuming and require instrumentation not commonly available in the clinic. We present a regression model that uses minimal clinical data-a set of six features easily obtained in the clinic-to predict the extent of first peak KAM reduction after toe-in gait retraining. For such a model to generalize, the training data must be large and variable. Given the lack of large public datasets that contain different gaits for the same patient, we generated this dataset synthetically. Insights learned from a ground-truth dataset with both baseline and toe-in gait trials (N = 12) enabled the creation of a large (N = 138) synthetic dataset for training the predictive model. On a test set of data collected by a separate research group (N = 15), the first peak KAM reduction was predicted with a mean absolute error of 0.134% body weight * height (%BW*HT). This error is smaller than the standard deviation of the first peak KAM during baseline walking averaged across test subjects (0.306%BW*HT). This work demonstrates the feasibility of training predictive models with synthetic data and provides clinicians with a new tool to predict the outcome of patient-specific gait retraining without requiring gait lab instrumentation.

The dynamic characteristics of the center of pressure for toe-out gait: implications for footwear design

BackgroundToe-out gait is often used as a conservative technique to reduce knee adduction moment, which has been targeted to modify knee osteoarthritis progression. The center of pressure (COP) can not only be used to evaluate gait stability, but is also more reliable and practical than local plantar pressures as it does not depend on accurate foot zone divisions. However, to the authors’ knowledge, few study has reported the influence of the foot progression angle on the dynamic characteristics of the COP.Research questionThe aim of the study was to investigate the effects of the deliberately toe-out gait on the COP trajectory and stability during walking in healthy individuals.MethodsThirty healthy young adults were asked to walk along an 8-m walkway. A Footscan 1 m pressure plate was used to measure the center of pressure during walking.ResultsCompared to the normal gait, the COP of the toe-out gait shifted laterally during the initial contact phase, and shifted laterally and anteriorly during the forefoot contact phase. The mean anterior–posterior velocity of COP reduced by 0.109 m/s during the foot flat phase and the duration of the foot flat phase and forefoot push off phase increased by 4.5% and reduced by 7.0%, respectively.SignificanceCompared to the normal gait, the findings of this study suggest that biomechanical alteration of foot under our experimental conditions may decrease gait stability and increase forefoot load during toe-out walking. The situation may be improved by well-designed footwear or custom-made insole and the biomechanics analysis method can be used to test the efficacy of therapeutic footwear or insole for individuals with deliberately toe-out walking.Graphical

Hindfoot Flexibility Influences the Biomechanical Effects of Laterally Wedged Insoles and Ankle-Foot Orthoses in Medial Knee Osteoarthritis

ObjectiveTo investigate the relationship of frontal plane ankle mobility with the effects of an ankle-foot orthosis (AFO) and a laterally wedged insole (LWI) on knee adduction moment (KAM) in the treatment of medial knee osteoarthritis. DesignRandomized, nonblinded crossover trial. SettingOutpatient clinic of university hospital. ParticipantsReferred sample of 20 patients (N=20) with medial knee osteoarthritis stage 1-3 (Kellgren and Lawrence), aged 56.4±6.5 years; 58 patients were assessed, 21 were included, and 1 was a dropout. There were 14 healthy reference participants without knee osteoarthritis (convenience sample) who were matched by age. InterventionsPatients received AFO and LWI for 6 weeks each with gait analysis after each 6-week intervention. Patients underwent additional barefoot gait analysis, walking on even ground and on a cross slope of 5° lateral elevation and standing on inclinations of 0°, 5°, 10°, and 20°. Main Outcome MeasuresSpearman correlation between the immediate change in first peak of KAM with each aid and the change in hindfoot varus on the cross slope relative to level ground. ResultsThe KAM reduction with AFO correlated significantly with hindfoot varus reaction to the cross slope during walking: the greater the hindfoot valgization on the cross slope, the greater the KAM reduction with AFO (Spearman ρ=0.53, P=.02).The KAM reduction with LWI correlated moderately negatively with the change in hindfoot varus: the greater the hindfoot valgization on the cross slope, the smaller the KAM reduction with LWI (r=−0.31 P=.18). ConclusionsLWI may be suitable for patients with limited to normal frontal plane ankle mobility. Patients with greater frontal plane ankle mobility benefit most from frontal plane ankle bridging with AFO. Studies with larger samples are necessary.

A shoe-insole to improve ankle joint mechanics for injury prevention among older adults

Technologies to assist senior individuals with active walking are important. This experiment aimed to investigate whether a customised insole geometry would reduce the risk of falls and locomotive injuries. The tested insole incorporated a built-in inclination to assist ankle dorsiflexion (2.2°) and eversion (4.5°). Twenty-six older adults and 30 younger counterparts undertook gait assessment with and without the experimental insole while 3 D motion capture and force plates recorded gait. The insole increased swing foot-ground clearance, with.43 cm for the older adults' dominant foot. The insole also prevented excessive lateral centre of pressure movement. The main insole effects on foot contact mechanics were (i) prolonged time to foot-flat (.015 s) and (ii) improved energy efficiency (2%). Reduced knee adduction moment (>15%) was observed in the older group. Shoe insoles to provide dorsiflexion and eversion support may have the potential to reduce the risk of falls and locomotion-related injuries for older adults. Practitioner Summary: Using 3 D gait assessment techniques this research investigated shoe-insoles incorporating ankle dorsiflexion and eversion support features. It was shown that falls risk and locomotive injuries could be reduced by the application of orthotics to support ankle dorsiflexion and eversion. Shoe-orthotics may provide practical low-cost solutions to correcting gait impairments. Abbreviations: MFC: minimum foot clearance; CoP: centre of pressure; OA: osteoarthritis; GRF: ground reaction forces; IREDS: infra-red light emitting diodes; PE: potential energy; KE: kinetic energy; IQR: interquartile range; ANOVA: analysis of variance

Effects of an Exercise Therapy Targeting Knee Kinetics on Pain, Function, and Gait Kinetics in Patients With Knee Osteoarthritis: A Randomized Clinical Trial.

In this study, the effects of an exercise therapy comprising yoga exercises and medial-thrust gait (YogaMT) on lower-extremity kinetics, pain, and function in patients with medial knee osteoarthritis were investigated. Fifty-nine patients were randomly allocated to three treatment groups: (a)the YogaMT group practiced yoga exercises and medial thrust gait, (b)the knee-strengthening group performed quadriceps- and hamstring-strengthening exercises, and (c)the treadmill walking group practiced normal treadmill walking in 12 supervised sessions. The adduction and flexion moments of the hip, knee, and ankle; pain intensity; and 2-min walking test were assessed before and after treatment and at 1-month follow-up. The YogaMT group experienced a significant reduction in knee adduction moment. All groups showed significant improvement in pain and function. The YogaMT may reduce medial knee load in patients with knee osteoarthritis in the short term. A larger clinical trial is required to investigate the long-term outcomes of this intervention.

A novel walking cane with haptic biofeedback reduces knee adduction moment in the osteoarthritic knee

Knee osteoarthritis is a leading cause of ambulatory disability in adults. The most prescribed mobility aid, the walking cane, is often underloaded and therefore fails to reduce knee joint loading and provide symptomatic relief. For this study, a novel walking cane with haptic biofeedback was designed to improve cane loading and reduce the knee adduction moment (KAM).To determine; 1) the short-term efficacy of a novel walking cane using haptic biofeedback to encourage proper cane loading and 2) the effects of the novel cane on KAM.Cane loading and KAM, peak knee adduction moment (PKAM), and knee adduction angular impulse (KAAI)) while walking were calculated under five conditions: 1) naïve, 2A) after scale training (apply 20%BW to cane while standing, using a beam scale), 2B) scale recall (attempt to load the cane to 20%BW), 3A) after haptic training (vibrotactile biofeedback delivered when target cane load achieved), and 3B) haptic recall (attempt to load the cane to 20%BW with vibrotactile biofeedback delivered). Compared to the naïve condition all interventions significantly increased cane loading and reduced PKAM and KAAI. No differences between haptic recall and scale recall condition were observed.The haptic biofeedback cane was shown to be an effective and simple way to increase cane loading and reduced knee loading. Haptic biofeedback and scale training were equally effective at producing immediate short-term improvements in cane loading and knee loading. Future studies should examine the long-term effects of scale training and canes with haptic biofeedback on knee joint health, pain, and osteoarthritis disease progression.

Unilaterally Implemented Trunk Modification Associated With Asymmetrical Increase In Spinal Load

Trunk modification (TM) is associated with reduced knee adduction moment during gait in both healthy and symptomatic individuals. Reported reductions are dependent on the magnitude of modification implemented. Evidence however suggests that increased trunk motion augments structural loading at the spine. Despite the positive adaptations at the knee, potential unanticipated changes in spinal load are yet to be investigated. PURPOSE: To investigate changes in trunk joint reaction force (JRF) during ipsilateral (IP) and contralateral (CT) stance phases subsequent to implementing unilateral subject-specific TM. METHODS: 19 healthy participants (26.7±4.8 years; 1.69±0.17 m; 72.3±11.8 kg) were recruited. Trunk lean was implemented towards the side of the preferred kicking limb. Participants average trunk angle (TA) was assessed during 10 baseline trials using a motion capture system (200Hz) and force plates (1000Hz). Subject-specific TA range was determined by adding 1-3 standard deviations (small), and 3-5 standard deviations (large) to baseline value. Participants completed 5 trials using both small and large subject-specific TM angles. Real-time TA projected as a line graph which was visible to participants during TM trials reinforced performance. Visual 3D was used to deliver feedback and determine trunk JRF (N/kg). Changes to trunk JRF was assessed using a Friedman test with Wilcoxon signed-ranked test and Bonferroni-adjusted significance level. Analyses were conducted using a significance level of p<0.017. RESULTS: Peak lateral JRF during IP and CT stance were significantly greater during TM trials (χ2 (2) = 32.9, and 30.7, p<0.001 respectively). Participants experienced increased lateral JRF during both IP (d=1.5, and d=1.7, small and large TM respectively), and CT (d=1.6, and d=1.7, small and large TM respectively) compared to baseline. CONCLUSION: Changes in trunk JRFs are indicative of elevated spinal loads. During CT stance, lateral JRF in the direction of the modified side persisted which is indicative of continued asymmetric trunk load. Findings suggest TM could result in detrimental adaptations and may be contraindicated for certain individuals. Further research employing longitudinal design is needed to investigate if observed acute changes are transient in nature.

Eight Week Gait Modification Intervention To Reduce Knee Adduction Moment: Randomized Controlled Trial: Preliminary Analysis

Gait modifications (GM) have successfully reduced knee adduction moment (KAM) which is linked with medial compartment knee osteoarthritis (mKOA). Prior studies have largely relied on single-session designs with healthy participants. Experimental designs with mKOA patients are necessary to confirm these findings. PURPOSE: Measure the effect of an GM intervention compared to normal walking on KAM in a randomized sample of mKOA patients. METHODS: 7 participants with mKOA completed the intervention (61 ± 13 yrs, 1.7 ± 0.1 m, 80 ± 23 kg). After baseline, participants were randomized into GM or control (CTRL) group. The GM group performed trunk lean (TL) - leaning the trunk over the affected limb. During training, the TL group was provided with real-time haptic feedback. No feedback provided for the CTRL group. 8-week training sessions were performed with KAM measured baseline, week 5 (PT1), 8 (PT2), and 1-week post-training (PT3). During posttests, participants performed 5 unprompted trial, and then were prompted to perform TL gait for 5 more (TL group). Two-sample randomization tests were performed to determine if mean change in PKAM and TL angle from baseline to posttests were significantly different between groups (p<0.05). RESULTS: TL angle increased and KAM decreased from baseline to posttest when prompted in the GM group compared to CTRL; however, not all differences reached statistical significance (Table 1). CONCLUSIONS: Preliminary data suggests that an 8-week intervention is sufficient for mKOA patients to learn and replicate a modified gait strategy when prompted to reduce KAM. Yet, it appears that there is minimal change in TL angle without prompting, suggesting continued training and/or feedback may be necessary for internalization of the modification.Table 1.: Difference in mean change in KAM and TL from baseline to posttest (GM-CTRL). Positive difference in mean KAM change corresponds to “reduction” in KAM from baseline to posttest (closer to zero). *p<0.05

Immediate effects of valgus bracing on knee joint moments during walking in knee-healthy individuals: Potential modifying effects of body height

BackgroundThe goal of valgus knee brace treatment is to reduce medial knee joint loading during walking, often indicated by external knee adduction moment (KAM) measures. However, existing healthy-subjects studies have been equivocal in demonstrating KAM reduction with valgus knee bracing. Research questionWhat are the immediate effects of valgus bracing at different tension levels on KAM during walking at a controlled speed and does body height modify the brace-KAM associations? MethodsData from 32 knee-healthy participants were analysed in this randomized crossover trial. Participants performed walking trials at controlled speed (1.3 ± 0.065 m/s) both with and without an Ossür Unloader One® brace. During the bracing condition, valgus tension was incrementally increased, from zero tension to normal tension and to maximum tolerable tension. ResultsValgus bracing minimally increased knee flexion at heel-strike (P < 0.001) in a dose-dependent manner and minimally reduced gait velocity (∼0.015m/s) across all tension levels. Valgus bracing, overall, did not significantly reduce the various KAM measures. However, brace use at maximal tension was associated with a 0.04Nm/kg (9.2 %) increase in first peak KAM amongst participants with a body height of 1.75 m and a 0.03Nm/kg (7.6 %) decrease in first peak KAM amongst participants with a body height of 1.55 m. SignificanceValgus bracing did not reduce the various KAM measures during walking; however, body height may play a moderating role. Given knee brace sizes vary more in circumference than length, this result may be due to the ratio between effective moment arm length relative to limb length. A deeper understanding of the potential neuro-biomechanical effects of valgus knee bracing and how these effects are potentially modified by body height may be critical to the design of effective knee braces.

Changes in knee adduction moment wearing a variable-stiffness shoe correlate with changes in pain and mechanically stimulated cartilage oligomeric matrix levels.

This study aimed to determine if changes in knee adduction moment (KAM) after 6 months of variable-stiffness shoe wear are associated with changes in symptoms or serum levels of cartilage oligomeric matrix protein (COMP) following a mechanical stimulus in subjects with medial knee osteoarthritis (OA). Twenty-five subjects were enrolled in the study and assigned a variable-stiffness shoe, and 19 subjects completed the 6-month follow-up. At baseline and follow-up subjects underwent gait analysis in control and variable-stiffness shoes, completed Western Ontario and McMaster Universities (WOMAC) questionnaires, and serum COMP concentrations were measured immediately before, 3.5 and 5.5 hours after a 30-minute walking activity. Relationships between changes in KAM (first peak and impulse) and changes in (a) COMP levels in response to the 30-minute walking activity and (b) WOMAC scores from baseline to 6-month follow-up were assessed by Pearson correlation coefficients. Changes in first peak KAM were associated with changes in COMP levels 5.5 hours postactivity from baseline to follow-up (R = .564, P = .045). Subjects with greater reductions in KAM had larger decreases in COMP (expressed as a percent of preactivity levels) at follow-up. Subjects with greater reductions in KAM impulse had significantly greater improvements in WOMAC Pain (R = -.56, P = .015) and Function (R = -.52, P = .028) scores at follow-up. The study results demonstrated the magnitude of reduction in the KAM wearing a variable-stiffness shoe is associated with decreases in mechanically stimulated COMP levels and pain/function. This work suggests that interactions between COMP and joint loading during walking should be further investigated in future studies of treatment outcomes in OA.

Modifying Stride Length in Isolation and in Combination With Foot Progression Angle and Step Width Can Improve Knee Kinetics Related to Osteoarthritis; A Preliminary Study in Healthy Subjects.

The purpose of this study was to determine the effects of modifying stride length (SL) on knee adduction and flexion moments, two markers of knee loading associated with medial-compartment knee osteoarthritis (OA) progression. This study also tested if SL modifications, in addition to foot progression angle (FP) and step width (SW) modifications, provide solutions in more subjects for reducing knee adduction moment (KAM) without increasing knee flexion moment (KFM), potentially protecting the joint. Fourteen healthy subjects (six female) were enrolled in this preliminary study. Walking trials were collected first without instructions, and then following foot placement instructions for 50 combinations of SL, FP, and SW modifications. Repeated measures analysis of variance was used to detect group-average effects of footprint modifications on maximum KAM and KFM and on KAM impulse. Subject-specific dose-responses between footprint modifications and kinetics changes were modeled with linear regressions, and the models were used to identify modification solutions, per subject, for various kinetics change conditions. Shorter SL significantly decreased the three kinetics measures (p < 0.01). Potential solutions for 10% reductions in maximum KAM and KAM impulse without increasing maximum KFM were identified for five subjects with FP and SW modifications. A significantly higher proportion of subjects had solutions when adding SL modifications (11 subjects, p = 0.04). In conclusion, SL is a valuable parameter to modify, especially in combination with FP and SW modifications, to reduce markers of medial knee loading. Future work is needed to extend these findings to osteoarthritic knees.

Effect of walking with a modified gait on activation patterns of the knee spanning muscles in people with medial knee osteoarthritis

ObjectiveTo evaluate muscle activation patterns and co-contraction around the knee in response to walking with modified gait patterns in patients with medial compartment knee-osteoarthritis (KOA). Design40 medial KOA patients walked on an instrumented treadmill. Surface EMG activity from seven knee-spanning muscles (gastrocnemius, hamstrings, quadriceps), kinematics, and ground reaction forces were recorded. Patients received real-time visual feedback on target kinematics to modify their gait pattern towards three different gait modifications: Toe-in, Wider steps, Medial Thrust. The individualized feedback aimed to reduce their first peak knee adduction moment (KAM) by ≥10%. Changes in muscle activations and medial/lateral co-contraction index during the loading response phase (10–35% of the gait cycle) were evaluated, for the steps in which ≥10% KAM reduction was achieved. ResultsData from 30 patients were included in the analyses; i.e. all who could successfully reduce their KAM in a sufficient number of steps by ≥10%. When walking with ≥10% KAM reduction, Medial Thrust gait (KAM −31%) showed increased flexor activation (24%), co-contraction (17%) and knee flexion moment (35%). Isolated wider-step gait also reduced the KAM (−26%), but to a smaller extent, but without increasing muscle activation amplitudes and co-contraction. Toe-in gait showed the greatest reduction in the KAM (−35%), but was accompanied by an increased flexor activation of 42% and hence an increased co-contraction index. ConclusionGait modifications that are most effective in reducing the KAM also yield an increase in co-contraction, thereby compromising at least part of the effects on net knee load.

Preliminary Analysis: The Effects of Gait Interventions on Knee Joint Contact forces in Healthy Adults

The effects of gait modifications (GM) are of interest as a non-invasive strategy to slow the progression of knee osteoarthritis. Previous research has found a reduction in knee adduction moment (KAM) as a result of GM. However, there is conflicting research regarding the relationship between KAM and joint contact forces. PURPOSE: To compare the effects of two GMs on the estimated joint contact forces in the medial and lateral knee compartments. METHODS: 5 healthy volunteers (27.8 ± 4.1 years, 1.74 ± 0.10 m, 74.98 ± 13.7 kg) completed 10 trials each of walking with a normal gait (NG) and with 2 different interventions: foot progression (FP) & lateral trunk lean (TL). During each trial GM parameter magnitude (1-5 SD relative to baseline) was estimated using Visual3D and real time visual feedback was provided to participants. Data was collected using a motion capture system (200Hz) while participants walked across a ~6-meter walkway; 4 in-line force plates (1000Hz) captured ground reaction force and speed was controlled for during each trial. Data was imported into OpenSim to estimate the joint contact forces in the knee of the dominant leg. Differences between the 3 GMs were analyzed using an ANOVA (α<0.05). RESULTS: Average peak joint contact force for both the medial and lateral knee compartments are summarized in table 1. A one-way ANOVA found no statistical differences (p>0.05) between gait strategies for all conditions. CONCLUSION: While no significant differences were found it may be due to the small preliminary sample size. It also plausible that the OpenSim model of the knee joint may not be able to accurately reflect the in-vivo biomechanics of the knee in the frontal plane due to the model’s degree of freedom. Further research should be conducted to verify these findings in a larger sample. Table 1: Simulated Knee Joint Contact Forces Normalized by Bodyweight (mean±sd)

The Efficacy of a Lateral Wedge Insole for Painful Medial Knee Osteoarthritis After Prescreening: A Randomized Clinical Trial.

Lateral wedge shoe insoles decrease medial knee loading, but trials have shown no effect on pain in medial knee osteoarthritis (OA). However, loading effects of insoles are inconsistent, and they can increase patellofemoral loading. We undertook this study to investigate the hypothesis that insoles would reduce pain in preselected patients. Among patients with painful medial knee OA, we excluded those with patellofemoral OA and those with a pain rating of <4 of a possible 10. We further excluded participants who, in a gait analysis using lateral wedges, did not show at least a 2% reduction in knee adduction moment (KAM), compared to wearing their shoes and a neutral insole. We then randomized subjects to lateral wedge versus neutral insole for 8-week periods, separated by an 8-week washout. The primary outcome measure was knee pain (0-10 scale) during the past week, and secondary outcome measures included activity pain and pain rated in the Knee Injury and Osteoarthritis Outcome Score questionnaire. We carried out mixed model analyses adjusted for baseline pain. Of 83 participants, 21 (25.3%) were excluded from analysis because of insufficient reduction in KAM. In the 62 patients included in analysis, the mean ± SD age was 64.2 ± 9.1 years, and 37.1% were women. Lateral wedge insoles produced a greater reduction in knee pain than neutral insoles (mean difference of 0.7 on 0-10 scale [95% confidence interval 0.1, 1.2]) (P = 0.02). Findings for secondary outcome measures were mixed. In participants prescreened to eliminate those with patellofemoral OA and biomechanical nonresponders, lateral wedge insoles reduced knee pain, but the effect of treatment was small and is likely of clinical significance in only a minority of patients. Targeting patients may identify those who respond to this treatment.

Can individuals with knee osteoarthritis learn a gait modification after 3 weeks of unsupervised gait retraining

Purpose: The knee adduction moment (KAM) is a surrogate measure of mediolateral loads across the tibiofemoral joint and is associated with radiographic severity and progression of knee osteoarthritis (OA). Recent literature suggests that healthy individuals can reduce KAM using auditory feedback from a lab-based pressure detecting shoe insole to reduce KAM. This clinical trial (NCT02955225) employs a novel, clinically feasible gait retraining protocol for patients with medial knee OA using pressure-based auditory feedback (PBF) generated from a wireless shoe insole (OpenGo, Moticon) and a smartphone. The training goal for following the auditory cues is to medialize foot center-of-pressure. We recently reported that patients with knee OA can respond to such clinically appropriate insole-driven training, subtly altering their walk to reduce KAM after a single baseline training visit. Here we explore how the same patients with medial knee OA kinetically responded after 3 weeks of unsupervised insole-based feedback training. Methods: In this IRB approved study, individuals with mild to moderate clinical and radiographic medial knee OA participated in two study visits over 3 weeks. During the baseline visit, subjects first walked in a standardized, flexible shoe (FlexOA, Dr. Comfort) at their comfortable pace (Week 0-Normal). Next, they trained with PBF from the wireless shoe insole and smartphone. To medialize foot center-of-pressure, they practiced to limit lateral plantar pressure to 85-95% (training parameters that were individualized based on each patient’s capability/tolerance at baseline). After about 30 minutes of in-lab training, subjects walked with the gait modification while receiving auditory feedback (Week 0-Feedback). Only walking trials in which participant successfully responded to the feedback were recorded. Subjects subsequently trained at home with insole-generated feedback for 3 weeks (training program: 5 min, 3x daily, 6 days per week), after which they returned for their Week 3 visit. During this visit, patients first walked with their normal, non-cued gait (Week 3-‘Normal’) and then with the gait modification they had been practicing over the last 3 weeks (Week 3-VerbalCue). It is important to note that no auditory feedback from the smartphone was provided during the Week 3 visit. For each visit, paired t-tests compared KAM, other knee moments, and spatiotemporal variables of the normal and modified conditions. Results: Data from 17 subjects were available and analyzed (14F/3M, 63 ± 10 years, 9 KL-2/8 KL-3). BMI remained unchanged between visits (30.4±5.9 kg/m2 & 30.3±5.9 kg/m2, p = 0.993). Peak knee moments and spatiotemporal variables are summarized in Table 1. At the baseline visit, subjects reduced peak KAM of midstance (KAM1) (p = 0.019, Fig 1) when feedback was provided, along with a reduction in speed (p = 0.035) and cadence (p = 0.032). At the Week 3 visit, after having trained with PBF for 3 weeks, KAM values were unchanged compared to baseline (W3-‘Normal’ vs. W0-Normal, p = 0.331). However, after being instructed to reproduce the gait modification, subjects walked with a significantly lower KAM1 (p = 0.026). This KAM reduction was attained without any significant difference in spatiotemporal variables, but was similar to the reduction obtained with auditory feedback during the baseline visit. Conclusions: After 3 weeks of training, individuals with knee OA had learned a gait modification that reduced peak KAM. No auditory cues were necessary to help in the execution of the modification. This is exciting as it suggests that patients can reproduce learned gait modifications without being reliant on feedback cues. However, their normal gait at the Week-3 time point did not differ from baseline. This suggests that patients achieved “motor performance” but not “motor learning” after 3 weeks of PBF. It is likely that additional training is required, including personal therapy sessions educating patients on the relevance of their achievements. This may allow transfer of their newly learned gait pattern into a normal habit. http://www.abstractsonline.com/admin/Report/abstractProofReport.aspTabled 1Table 1 Peak knee moments and spatiotemporal varialbesW0-BaselineW0-FeedbackPaired t-testW3-'Normal'W3-VerbalCuePaired t-testMean (SD)Mean (SD)p-valueMean (SD)Mean (SD)p-valuePeak knee moments (%BW*HT)Flexion1.845 (1.022)1.701 (1.091)0.5321.792 (1.089)1.588 (1.075)0.083Extension2.660 (0.905)2.510 (1.077)0.1942.869 (0.892)2.680 (0.998)0.195KAM12.877 (0.756)2.665 (0.837)0.0192.955 (0.852)2.774 (0.894)0.026KAM22.191 (0.946)2.245 (0.999)0.3602.321 (0.936)2.313 (0.945)0.898External Rotation0.146 (0.094)0.136 (0.089)0.3960.136 (0.086)0.139 (0.088)0.805Internal Rotation0.953 (0.311)0.946 (0.334)0.8131.025 (0.354)0.994 (0.404)0.311Spatiotemporal VariablesSpeed (m/s)1.210 (0.203)1.143 (0.206)0.0351.235 (0.203)1.174 (0.201)0.116Stride length (m)1.251 (0.175)1.243 (0.188)0.7831.291 (0.154)1.254 (0.170)0.169Cadence (strides/min)56.49 (5.14)54.58 (4.96)0.03257.26 (4.96)55.95 (4.70)0.087 Open table in a new tab

Unsupervised gait retraining using a wireless pressure-detecting shoe insole

BackgroundThe knee adduction moment (KAM) is a surrogate measure of mediolateral distribution of loads across the knee joint and is correlated with progression and severity of knee osteoarthritis (OA). Existing biomechanical approaches for unloading the arthritic medial knee compartment vary in their effectiveness in reducing KAM. This study employed a completely wireless, pressure-detecting shoe insole capable of generating auditory feedback via a smartphone. Research question: To investigate whether auditory cues from a smartphone can prompt subjects to adjust their gait pattern and reduce KAM. Methods: Nineteen healthy subjects underwent gait training inside the lab (Phase 1) and received auditory cues during mid- and terminal stance to medialize their foot COP (center-of-pressure). This initial training period was continued unsupervised while walking around campus (Phase 2). ResultsAfter Phase 1, subjects reduced their KAM by 20.6% (p = 0. 001), a finding similar to a previous study that used a wired, lab-based insole system. After further unsupervised training outside the lab during Phase 2, subjects were able to execute the newly learned gait pattern without auditory feedback still showing a KAM reduction of 17.2% (p < 0.001). Although, speed at Phase 2 was lower than at baseline (p = 0.013), this reduction had little effect on KAM (r = 0.297, p = 0.216). In addition, the adduction angular impulse was reduced (p = 0.001), despite the slower speed. SignificanceTogether, these results suggest that the wireless insole is a promising tool for gait retraining to lower the KAM and will be implemented in a home-based clinical trial of gait retraining for subjects with knee OA.