Clinical prediction rule for early recovery of knee range of motion after total knee arthroplasty: A prospective cohort study.

Objective: To derive a clinical prediction rule for early recovery of knee range of motion after total knee arthroplasty.

Methods: This prospective cohort study evaluated the data of 273 individuals undergoing primary total knee arthroplasty. The individual factors, the physical and motor function data were assessed preoperatively upon admission as a baseline survey. The knee joint extension angle and knee joint flexion angle were re-evaluated on postoperative day 14 as a follow-up. The recovery group comprised individuals with a knee joint extension angle of more than -5 degrees and knee joint flexion angle of more than 110 degrees on postoperative day 14. The other patients constituted the non-recovery group. Multivariate logistic regression analysis was used for deriving a clinical prediction rule.

Results: The results indicated that the use of a cane, knee joint extension and flexion angles, and Timed Up and Go test time were significant factors for predicting early recovery of knee range of motion after total knee arthroplasty. Furthermore, a clinical prediction rule was derived and included the use of a cane, knee joint extension angle ≥ -15 degrees, knee joint flexion angle ≥ 125 degrees, and a Timed Up and Go test time < 11.2 s. A total clinical prediction rule score ≥ 8 indicated a positive likelihood ratio of more than 10 for a successful outcome and the post-test probability was approximately 95%.

Conclusions: The derived clinical prediction rule might be a useful screening tool for proper postoperative goal setting and the establishment of individualized physical therapy programs.