Effects of Pre-habilitation on Self-Efficacy for Exercise and Outcome Expectations for Exercise Among Patients Before and After Total Knee Arthroplasty

Osteoarthritis (OA) is a clinical condition affecting over 27 million Americans. There is no known cure for OA other than replacing the diseased joint with a partial or total joint prosthesis, total knee arthroplasty (TKA). PURPOSE: The purpose of this research is to compare pre and post-surgical exercise self-efficacy and outcome expectations for exercise among TKA patients who do and do not receive prehabilitation (exercise intervention before surgery). METHODS: 31 participants (22 female, 9 male) scheduled for a TKA from a single orthopedic practice were randomly assigned to a Control (CON) or a prehabilitation (PRE) group following baseline testing. Outcome variables at baseline testing included the Self-Efficacy for Exercise (SEE) scale and the Outcome Expectations for Exercise (OEE) scale. In addition to baseline (T1), participants completed the outcome data collection protocols just prior to surgery (T2) and at 1 (T3) and 2 (T4) weeks following surgery. RESULTS: Repeated measures ANOVA were conducted examining the effect of group (PRE vs. CON) over the four data collection points (Baseline, T2, T3 & T4). Significant main or interaction effects were explored further by calculating Fischer’s least significant difference post hoc comparisons. Conducting a RM-ANOVA with time (T1, T2, T3, T4) [F (1, 18) = .42, p = .53] and group (PRE vs CON) [F (1, 18) = .03, p = .86] and interaction of group and time [F (1, 18) = .69, p = .419] as the sources of variability indicated no significant effect of the time, group or group x time on SEE. The SEE, of the PRE appeared to be consistently maintained over the study, and actually trended upward after their TKA at T3 and T4, but did not significantly increase. Differences in OEE within the sample over the duration of the study indicated a significant time effect [F (1, 18) = 4.57, p = .04]. Post hoc analysis indicated that the CON group significantly declined between T2 and T4; however the PRE group did not significantly change. CONCLUSIONS: These findings indicate self-efficacy for exercise was unaffected by the preoperative exercise intervention (prehabilitation), while the outcome expectations for exercise improved in the PRE group. This improvement in outcome expectations for exercise may contribute to improve compliance with post operative rehabilitation exercises among TKA patients