Improved early outcome after TKA through an app-based active muscle training programme-a randomized-controlled trial.

PURPOSE: The purpose of this prospective randomized-controlled trial (RCT) was to evaluate if an app-based feedback-controlled active muscle training programme can be used to improve the outcome in the immediate postoperative period after total knee arthroplasty (TKA).

METHODS: Sixty patients, with a median age of 65.9 years (range 45-84), awaiting primary TKA were randomized into a control and training group. Both groups followed an identical postoperative protocol. In addition, the training group postoperatively performed an app-based feedback-controlled active muscle training programme multiple times daily. Outcome measures were active and passive range of motion (ROM), pain at rest and in motion, knee extension strength, the timed "Up and Go", 10-m Walk Test, 30-s Chair Stand Test, Knee Injury and Osteoarthritis Outcome Score (KOOS), Knee Society Score (KSS), and clinical data.

RESULTS: The training group performed an average of 18.4 training sessions, which led to significantly higher ROM, less pain at rest and in motion, higher strength, and significantly higher functional scores. More training correlated with a better outcome.

CONCLUSIONS: The use of an app-based feedback-controlled active muscle training programme can improve the clinical outcome after TKA, especially ROM and reduce pain. Clinically relevant is that the training programme could be considered an alternative to continuous passive motion after total knee arthroplasty.

LEVEL OF EVIDENCE: II.