Longitudinal Associations Between Baseline Sarcopenia and Knee Osteoarthritis Progression and Risk of Knee Replacement.

Objective: Sarcopenia and knee osteoarthritis (KOA) are common conditions in older adults, but their relationship is controversial. We aimed to examine the potential role of sarcopenia in KOA progression and subsequent knee replacement (KR).

Methods: Using data from the Osteoarthritis Initiative, baseline sarcopenia was first screened according to the EWGSOP2 algorithm using the SARC-F (Strength, Assistance with walking, Rise from a chair, Climb stairs, and Falls) questionnaire (screened sarcopenia [Scre-S]), then further assessed combined with the five times chair-stand-test (probable sarcopenia [Prob-S]). Radiographic KOA progression was evaluated by changes in Kellgren-Lawrence Grade and Osteoarthritis Research Society International atlas scores from baseline to the 24- and 48-month follow-ups. Symptomatic progression was evaluated similarly using the Western Ontario McMaster Osteoarthritis Index. The associations of sarcopenia with radiographic or symptomatic progression and subsequent KR were analyzed before and after adjusting for potential confounders and propensity score (PS) matching.

Results: A total of 4,316 participants were included; 27.2% were Scre-S and 16.8% were Prob-S. Baseline Scre-S and Prob-S were positively associated with both radiographic and symptomatic progression in KOA over 24 and 48 months. Both Scre-S and Prob-S were associated with a higher risk of subsequent KR (Scre-S: hazard ratio [HR] 3.84, 95% confidence interval [CI] 3.18 to 4.62; Prob-S: HR 2.29, 95% CI 1.87 to 2.81). These results remained significant in the PS-matched cohort.

Conclusion: Scre-S and Prob-S were significantly and longitudinally associated with both radiographic and symptomatic progression in KOA and subsequent KR. Our findings indicated a potential causal role of sarcopenia in KOA progression and highlighted its potentially therapeutic effect in KOA management.