Optimal Duration of Physical Therapy Following Total Knee Arthroplasty

The purpose of this study was to identify patient characteristics associated with engagement and completion of physical therapy (PT) following total knee arthroplasty (TKA) and examine the relationship between number of PT sessions attended and outcomes during the first 12 weeks after surgery.

Patients underwent unilateral primary TKA by a single surgeon and were advised to complete 17 PT sessions over 6 weeks at a hospital-affiliated facility. Analyses examined predictors of PT engagement (attendance of ≥2 sessions) and completion (attendance of 17 ± 1 sessions) within 6 weeks and associations between number of PT sessions attended and changes in range of motion (ROM) and Knee Injury and Osteoarthritis Outcome Score (KOOS) values.

Patients living <40 km were more likely to be engaged in PT than those living ≥40 km from the clinic (P < .0001). Among patients who completed PT within 6 weeks, 95.0%, 85.1%, and 56.4% achieved flexion of, respectively, ≥90°, ≥100°, and ≥110°. Among engaged patients, the active flexion thresholds of ≥90°, ≥100°, and ≥110° were achieved by, respectively, 94.4%, 82.5%, and 58.1% by 6 weeks and by 96.7%, 92.1%, and 84.2% by 12 weeks. Improvement in KOOS Symptoms (P = .029), Function in daily living (P = .030) and quality of life (P = .031) linearly decreased as number of PT sessions increased.

These results raise the question of whether patients who meet satisfactory outcomes before completing 6 weeks of prescribed PT and those who attend more PT sessions than prescribed may be over-utilizing healthcare resources without additional benefit.