The effect of a prehabilitation exercise program on quadriceps strength for patients undergoing total knee arthroplasty: a randomized controlled pilot study.

OBJECTIVE To examine the effect of a 6-week prehabilitation exercise training program on presurgical quadriceps strength for patients undergoing total knee arthroplasty (TKA). DESIGN Two-arm, parallel, randomized, controlled pilot trial. SETTING Private exercise space in a research facility. PARTICIPANTS Twenty-two patients scheduled for primary TKA. METHODS Participants completed a series of baseline questionnaires (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], Short Form 36, and Arthritis Self-efficacy Scale) and functional testing (isometric quadriceps strength assessment, flat-surface walk test, and stair ascent-descent test). The participants were randomized to a lower-body strength training program or to a nonspecific upper-body strength training program. The participants exercised 3 times per week for 6 weeks before TKA. Postintervention assessment occurred immediately before TKA, with follow-up assessments at 6 and 12 weeks after surgery. OUTCOMES The primary outcome was isometric quadriceps strength. Secondary outcomes were mobility, pain, self-reported function, health-related quality of life, and arthritis self-efficacy. RESULTS There was no significant treatment condition-by-time effect on quadriceps strength, but the effect size was large (F(3,18) = 0.89, P = .47, η(2) = 0.13). Similar findings were shown for walking speed (F(3,18) = 1.47, P = .26, η(2) = 0.20). There was a significant treatment-by-time effect for the Short Form 36 mental component score (F(3,18) = 0.41, P = .02, η(2) = 0.41), with differences emerging before surgery but not at either postoperative assessment. For all other secondary outcome measures, the treatment-by-time effect was nonsignificant and small. CONCLUSION The intervention elicited clinically meaningful increases in quadriceps strength, walking speed, and mental health immediately before TKA. It did not impart lasting benefits to patients in the 12 weeks after surgery. Analysis of the results suggests that quadriceps strength may not drive functional improvements after surgery. These findings need to be replicated in larger trials before clinical recommendations are made about including strength training prehabilitation in everyday practice.