Examining the use of the pressure modulated knee rehabilitation machine (PMKR) with traditional physical therapy versus traditional physical therapy alone following total knee arthroplasty: a randomized control study

Abstract

Background: Total knee arthroplasty (TKA) is considered a successful operation, however, 8% to 25% of patients are not satisfied with their TKA after surgery, with contracture being a common reason. The purpose of this study was to compare range of motion (ROM), patient-reported outcomes, and patient satisfaction between patients who utilized the X10™ Pressure Modulated Knee Rehabilitation (PMKR) machine (X10 Therapy, Franklin, MI) in addition to physical therapy and patients who only had physical therapy after TKA. Methods: Patients were randomized to either the PMKR plus traditional physical therapy group or the traditional physical therapy only group. Patient-reported outcome scores and ROM were recorded at baseline, 2 wk, 4 wk, and 4 mo postoperatively. Patient satisfaction was also assessed. Results: A total of 107 patients underwent TKA surgery (50 PMKR group, 57 traditional therapy alone group). At 4 wk, the PMKR group exceeded the minimally clinical important difference of 5 degrees after TKA; however, this was not sustained at 4 mo. There were no statistically significant differences in the patient-reported outcome scores, but patients in the PMKR group had statistically significantly higher satisfaction. Conclusions: In summary, our results demonstrate that patients who utilize a PMKR machine in addition to traditional physical therapy may have an initial increase in postoperative knee ROM; however, this clinical relevance was not sustained at the 4-month time point. Even though this difference in ROM was not maintained over the entire study, patients who used the PMKR machine had greater satisfaction with their TKA than those who underwent traditional physical therapy alone. Level of Evidence: Level II.