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

Abstract

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.

Physical therapy and orthopaedic equipment-induced reduction in the biomechanical risk factors related to knee osteoarthritis: a systematic review and Bayesian network meta-analysis of randomised controlled trials

“…Despite a majority of therapies displaying a null statistical KAM and KAAI reduction, the clinical usage of these treatment modalities could significantly improve the presenting symptoms and physical activity level without increasing the biomechanical magnitude; thus, improving the quality of life of patients with KOA. Although the results of this study suggested that wearing variable-stiffness shoes is not preferable for long-term KAM reduction, our current study explained that variable-stiffness shoes displayed a major advantage in reducing KAM for patients with increasing walking speed 68. At the same time, variable-stiffness shoes had relatively less discomfort than equipment such as LWI.…”

“…Although the results of this study suggested that wearing variable-stiffness shoes is not preferable for long-term KAM reduction, our current study explained that variable-stiffness shoes displayed a major advantage in reducing KAM for patients with increasing walking speed. 68 At the same time, variable-stiffness shoes had relatively less discomfort than equipment such as LWI. Since the studies included in this NMA mainly involves patients with medial KOA, the consolidated results would be more useful for such patients.…”

Visualizing pre‐osteoarthritis: Integrating MRI UTE‐T2* with mechanics and biology to combat osteoarthritis—The 2019 Elizabeth Winston Lanier Kappa Delta Award

“…These data showed that early changes in gait mechanics following ACLR are associated with longer‐term clinical changes and that higher KAM may be an important mechanical marker of OA risk. Because elevated KAM can be reduced through interventions such as knee braces, footwear, 37 and gait modifications, 38,39 pathological elevations are also potentially reversible, and thus, we consider KAM to be a mechanical marker of “pre‐OA.” 3 …”

“…Erhart‐Hledik et al 42 demonstrated the utility of such a “stimulus–response” approach where measuring the within‐person change in serum biomarkers after walking for 30 minutes was shown to result in changes to serum levels of cartilage oligomeric matrix protein (COMP), a marker of cartilage turnover, that predicted cartilage thinning 5 years later. Furthermore, observations that the change in KAM wearing a load‐altering shoe correlated with changes to pain and mechanically stimulated serum COMP in patients with medial knee OA highlight a potential role for the stimulus–response approach in monitoring disease‐modifying therapies 37 …”

Clinically-available and laboratory-derived predictors of biomechanical response to standalone and supported lateral wedge insoles in people with knee osteoarthritis

“…This lack of established superiority has resulted in clinical guidelines not recommending the use of LWIs in the clinical management of knee OA (7,8). Despite some evidence supporting an association between the cross-sectional magnitudes of KAM and knee pain (9,10), as well as associations in changes in between these outcomes after an intervention (11,12), a major limitation of the clinical trials used to inform these guidelines is the likely inclusion of biomechanical non-responders to LWIs, who would subsequently be less likely to improve pain under a biomechanically-driven framework.…”