Predictors of successful viscosupplementation in osteoarthritis of the knee.

Abstract

Knee osteoarthritis (OA) is a common cause of disability among older adults. Common treatments include intra-articular corticosteroids (IACS) and viscosupplementation (VS). However, many insurance carriers either decline to cover VS or require prior IACS failure. Limited data exist on whether IACS response can guide VS use. To determine whether response to IACS predicts subsequent response to VS, and whether age, gender, body mass index (BMI), and OA severity are associated with VS outcomes. Retrospective cohort study. Outpatient physical medicine and rehabilitation clinics at a tertiary-care academic medical center. Four hundred sixty three adult patients (≥18 years) with primary knee OA who received both IACS and VS injections. Primary independent variable was response to IACS. Additional variables were age, gender, BMI, and OA severity. Primary outcome was pain relief following VS, categorized as favorable (>33% relief) or unfavorable (≤ 33% relief ). The favorable response rate to VS among IACS nonresponders was 55% (95% confidence interval [CI]: 48%-62%) compared to 72% (95% CI: 67%-76%) in IACS responders (p < .001). IACS response was associated with higher odds of VS response (odds ratio [OR] = 2.10, 95% CI: 1.41-3.12, p < .001), which remained significant after adjusting for age, gender, BMI, and OA severity (OR = 2.25, 95% CI: 1.54-3.28, p <.001). BMI and age were not independently associated with VS response; however, both demonstrated a nonsignificant trend toward lower odds of response (BMI: OR = 0.88 per 5 kg/m², 95% CI: 0.77-1.01, p = .08; age: OR = 0.95 per 5 years, 95% CI: 0.87-1.04, p = .24). No significant associations were observed for gender or OA severity. Response to IACS predicts subsequent response to VS in patients with knee OA. These findings may help guide treatment selection, though prospective studies are needed.