Association of Psychosocial Factors With Physical Activity and Function After Total Knee Replacement: An Exploratory Study.

Objectives: To examine the association between self-efficacy, social support, and fear of movement with physical activity and function at baseline and after 12 weeks of physical therapy.

Design: Nonrandomized cohort study, repeated-measures design.

Setting: Outpatient rehabilitation clinic within the general community.

Participants: Adults (N=49) undergoing outpatient physical therapy for total knee replacement (TKR).

Interventions: Not applicable.

Main Outcome Measures: Self-efficacy for exercise (SEE), fear of movement, leisure-time physical activity (LTPA), 6-minute walk test (6MWT), and Knee Outcome Survey-Activities of Daily Living Scale (KOS-ADLS) were assessed at baseline and 12 weeks.

Results: Mean functional change scores significantly increased at 12 weeks for the 6MWT (95% confidence interval [CI], 42.3-106.2), KOS-ADLS (95% CI, 12.7-23.3), and LTPA (95% CI, 6.5-26.1). Self-efficacy and fear of movement were not significantly associated with function at baseline or 12 weeks. Participants with lower SEE had 6 fewer metabolic equivalents per week of improvement in LTPA than those with high self-efficacy (95% CI, -27.9 to 14.8), and those with high fear of movement had 26.1m less improvement in the 6MWT than those with low fear of movement (95% CI, -42.2 to 94.5). Most participants reported having no family or peer support for exercise.

Conclusions: Physical therapy for TKR improves physical function and self-reported physical activity. High fear of movement and low SEE may be associated with less improvement in physical activity and function over time.