Predictors of walking capacity in obese adults with knee osteoarthritis

Knee osteoarthritis(KOA) has a considerable prevalence in obese individuals and recommendations of weight loss for KOA management are gaining greater importance. Exercise is recommended to interrupt the cycle obesity-KOA-pain-inactivity, where walking is the most common exercise pattern recommended for obese individuals who initiate a weight loss exercise program. Thus this study aimed to analyse the factors which can affect the walking capacity in obese adults with symptomatic KOA.

48 obese adults (age=55±7years; BMI=35±5 Kg/m2) with clinical and radiological KOA completed self-reported questionnaires (Knee Injury and Osteoarthritis Outcome Score, Brief Pain Inventory and Beck Depression Inventory), physical function tests (Six Minutes Walking Test-6MWT, chair sit and reach-CSRT, five repetition sit-to-stand test-FRSTST, handgrip strength-HST, isokinetic knee strength) and body composition was determined.

The best model (F= 41.485; p<.001) explained 73% of the 6MWT's variance, where fat mass of the most painful limb, knee pain severity and lower limb strength were the strongest predictors of the 6MWT.

Despite the importance of lower limb fat mass and strength, pain was the only variable that appeared as a predictor of 6MWT in the three tested models. The existence of knee pain affects the capacity to walk or to perform weight bearing exercises and consequently the exercise's adherence, compromising the objective of body composition improvement. Thus, authors suggest that, additionally to the lower limb strengthening, knee pain should be screened, controlled and acknowledged for exercise prescription. This study is inserted in the PICO Project (Clinical trial: NCT01832545).