Correlation between body composition and efficacy of lateral wedged insoles for medial compartment osteoarthritis of the knee.

Objective: To investigate anthropometric measures that closely correlate with symptomatic relief of osteoarthritis (OA) of the knee in response to lateral wedged insole use.

Methods: Seventy-one patients with medial compartment knee OA were treated with insoles with subtalar strapping or insoles with talonavicular strapping. Randomization was performed according to birth date. The following variables were evaluated: age, disease duration, Kellgren-Lawrence radiographic stage, body mass index, percent body fat, waist to hip ratio, lower extremity lean body mass (L-LBM) per body weight, and radiographic femorotibial angle at baseline. The trial lasted 8 weeks. The correlation between each variable and the remission score (delta score) using the Lequesne index of severity was analyzed.

Results: In the subtalar strapping group (n = 34), delta score of knee OA was more strongly associated with age (p = 0.004, r = 0.48) than other variables. A significant correlation was also observed between L-LBM per body weight and delta score (p = 0.041, r = -0.36) in the subtalar strapping group. No other variables significantly correlated with the delta score in the subtalar strapping groups. No variable significantly correlated with the ? score in the talonavicular strapping group (n = 37).

Conclusion: We previously reported that use of insoles with subtalar strapping leads to valgus realignment of the femorotibial angle in patients with knee OA with varus deformity, and it may have a similar therapeutic effect to that of high tibial osteotomy. These data suggest that the insole with subtalar strapping is more efficacious for younger patients and those with a higher L-LBM per body weight, and less efficacious for older patients with sarcopenia.