Prospective, Randomized Clinical Trial Comparing a Novel Motion-Assistive Device to Standard Physical Therapy for Initial Management of Knee Range of Motion after Primary Total Knee Arthroplasty

This prospective randomized clinical trial assessed a novel device for initial management of knee range of motion (ROM), pain, and function after total knee arthroplasty (TKA). Primary TKA patients with preoperative ROM of at least 5 degrees to 115 degrees were randomized to initial knee motion management: Mizzou BioJoint Flex-novel motion-assistive device with prescribed physical therapy or standard physical therapy-prescribed physical therapy. ROM, pain score, and knee injury and osteoarthritis score for joint replacement (KOOSjr) were obtained preoperatively and 2 weeks, 6 weeks, and 3 months postoperatively. Patient satisfaction for both cohorts and subjective assessments of the MBF device were assessed at 3 months. Readmissions, reoperations, and complications were assessed through 1 year. Nineteen patients were randomized to each cohort, with no significant preoperative differences in demographics, pain score, KOOSjr score, or ROM. Six SPT (31.6%) and 3 MBF (15.8%) patients failed to regain preoperative ROM ( p =0.044). One SPT (5.3%) and eight MBF (42%) patients exceeded 125 degrees ROM ( p =0.019) by 3 months. Total ROM ( p =0.039), pain ( p =0.0068), and function ( p =0.0027) were significantly better for MBF at 3 months. MBF patients reported significantly higher satisfaction (mean, 9.4 +/- 1.1 vs. 8.0 +/- 1.8, respectively; p =0.0084). One patient in each group underwent manipulation under anesthesia. No other readmissions, reoperations, or complications were reported. A novel durable medical equipment device can provide a safe and effective patient-controlled method for initial management of knee ROM, pain, and function after primary TKA with potential clinically meaningful advantages over physical therapy alone. In conjunction with physical therapy, management with this novel knee flexion device more effectively restored knee ROM and early patient function when compared with therapy alone and was associated with higher proportions of patients regaining minimum (115 degrees) and desired (125 degrees) levels of knee ROM and clinically meaningful differences in pain scores, knee function, and patient satisfaction. This is a Level 1, prospective trial study.