Stratification of Outpatient Physical Therapy Following Total Knee Arthroplasty: Knee Arthroplasty Physical Therapy Pathways (KAPPA) Trial

Background:
Given the existing and predicted future financial burden associated with total knee arthroplasty (TKA) procedures, it is crucial to critically evaluate the efficacy and economic efficiency of perioperative care, including physical therapy, which features in most TKA rehabilitation protocols. Improvements in clinical outcomes and shorter hospital lengths of stay for patients undergoing TKA bring into question the role of continued outpatient physical therapy postdischarge and whether there is an opportunity for startification of service and further cost savings.

Global utilization of outpatient physical therapy following TKA has been reported as high as 85% for supervised physical therapy postdischarge from the acute inpatient hospital setting. However, this widespread use of supervised physical therapy post-TKA contrasts with evidence suggesting noninferior outcomes for a population who undergo unsupervised or self-directed rehabilitation, while also offering greater convenience for patients and potential savings for service providers. Despite the evidence supporting self-directed rehabilitation for individuals post-TKA, there appears to be no established criteria to determine who can successfully self-direct their rehabilitation versus those who would benefit further from outpatient physical therapy.

Purpose:
The aim of the Knee Arthroplasty Physical Therapy Pathways (KAPPA) trial was to determine if early postoperative criteria can be established to stratify TKA patients into a self-directed rehabilitation or supervised physical therapy pathway without compromising clinical outcomes or patient satisfaction.

Methods:
Overall, 60 TKA patients were initially allocated to a self-directed, unsupervised protocol for their postoperative rehabilitation. Baseline demographics, along with functional and self-reported outcomes, were assessed preoperatively and at 2 weeks, 6 weeks, and 4 months following surgery. Patients were referred to supervised outpatient physical therapy if they met any of the following Knee Arthroplasty Physical Therapy Pathways (KAPPA) criteria: (1) knee flexion range of motion <90 degrees; (2) knee extension range of motion lacking >10 degrees; or (3) dissatisfaction with the progress of their rehabilitation. Patients in the study who did not meet any of the KAPPA criteria for referral to supervised physical therapy at 2 weeks or 6 weeks following their TKA continued with self-directed rehabilitation at home.

Results:
At 2 weeks post-TKA, 28 participants met the KAPPA criteria for supervised physical therapy for reasons of knee flexion <90 degrees (61%), a lack of knee extension >10 degrees (36%), or not being satisfied with the progress of their recovery (3%). The remaining 32 participants continued with a self-directed rehabilitation pathway. All outcomes assessed favored the self-directed group at 2 weeks, however, after an average of 4 supervised physical therapy sessions at 4 months there were no longer any differences between the 2 groups.

Conclusion(s):
Approximately half of the included participants in the KAPPA trial could successfully self-direct their rehabilitation following TKA without supervised physical therapy, while also maintaining excellent clinical and self-reported outcomes. A physical assessment of knee ROM corresponded to all other outcomes when assessed at 2 weeks post-TKA.

Implications:
The results of the KAPPA trial support the feasibility of self-directed rehabilitation and have established potential early postoperative criteria to indicate who may benefit from referral to supervised physical therapy at 2 weeks post-surgery.

Keywords:
Total knee arthroplasty
Supervised physical therapy
Rehabilitation

Funding acknowledgements:
This research was supported by Bond University Faculty of Sciences and Medicine Early Career Research Seed Grant.

Primary topic:
Orthopaedics