Physical Activity Intervention Within Outpatient Physical Therapy For Knee Replacement

Abstract

PURPOSE: To examine the feasibility and acceptability of a physical activity intervention delivered within outpatient physical therapy for adults after knee replacement. METHODS: As part of a cluster randomized trial, adults with knee replacement starting outpatient physical therapy were recruited across four physical therapy sites. Sites were randomized and physical therapists delivered either an Enhanced Physical Activity Intervention or served as a Control condition. The Intervention consisted of physical therapists providing standard physical therapy plus goal setting, problem-solving, and use of some of the principles of motivational interviewing to promote 150 mins per week of aerobic moderate intensity physical activity. Physical therapists at sites serving as the Control provided only the standard physical therapy. Feasibility and acceptability were determined based on recruitment and retention rates at 12 weeks after surgery. Outcomes including objectively measured physical activity, pain, and self-reported function were examined between groups from baseline to 12 weeks. RESULTS: Thirty-three percent of candidates screened were randomized (n = 45) and retention at 12 weeks after surgery was 91% (no difference by condition). Moderate-vigorous activity increased at 12 weeks by 18.4 minutes (95% CI -4.7, 41.4) in Intervention and 40.7 minutes (95% CI 8.2, 47.6) in Control (no difference by condition). Pain decreased (-7.0 vs. -5.2) and self-reported function improved (-12.1 vs. -12.7) by Intervention and Control respectively, but there were no between group differences between baseline and 12 weeks. CONCLUSIONS: Implementing a minimal physical activity intervention within outpatient physical therapy for adults after knee replacement is feasible, however, it was not sufficient to increase moderate intensity physical activity relative to standard physical therapy. Future studies are needed to explore additional low cost strategies and the optimal time to promote physical activity after knee replacement.