Utilization and outcomes of neuromuscular electric stimulation in patients with knee osteoarthritis: a retrospective analysis.

Background Knee osteoarthritis (OA) is a chronic debilitating condition that is estimated to affect approximately 12% of the current adult population in the United States, and is associated with severe pain and disability. Among these patients, quadriceps muscle atrophy and concomitant weakness are frequent findings that contribute significantly to the burden of this disease. One emerging method of quadriceps muscle strengthening and rehabilitation in knee OA patients is the use of neuromuscular electrical stimulation therapy (NMES). Among the currently available systems for NMES therapy are the mobile health (mHealth) platforms allowing clinicians to monitor patient compliance and utilization trends in addition to capturing certain clinical outcome points. The aim of this study was to analyze data collected by a commercially available mobile-app controlled NMES platform and to examine: (I) utilization trends, (II) range-of-motion (ROM) changes, (III) pain scores, and (IV) patient reported outcome scores in patients who used this device as part of management of their knee OA. Methods We retrospectively reviewed patients who received mobile-app controlled NMES therapy for knee OA who were enrolled in this multi-center study between April 2017 and July 2018 in a cloud-based provider online portal system. A total of 41 patients met all our inclusion and exclusion criteria and were included in our final analysis. For each patient, the total number of NMES sessions, the duration of NMES therapy, visual analogue pain scores, ROM, and the Knee injury Osteoarthritis Outcome Score (KOOS, JR) were collected and analyzed. Patient's utilization trends were reported through analyzing NMES sessions and therapy durations. Descriptive statistics were utilized to analyze all relevant values. Results Across all patients, NMES therapy was utilized for an average of 3.5 months (range, 2 weeks to 10 months). On average, 90 sessions (range, 6 to 487) of therapy were received by patients for an average of 1,819 minutes (range, 120 to 9,740 minutes). Overall, patients achieved a mean ROM of 99˚±4.3˚ at final follow-up. Pain scores reduced from a mean of 5 points prior to device use (range, 1 to 8 points) to 2.5 points after use (range, 0 to 6 points) (P<0.001). Evaluation of KOOS questionnaires available for 17 patients showed incremental improvement from 52.46 points when therapy was started, to 63 points at 6 months following NMES therapy. No complications or adverse events were reported from any of the participants. Conclusions Although NMES therapy has been reported on by multiple authors, including in knee OA, there are limited have been no studies that have reported on the compliance, feasibility, and patient outcomes of using a mobile-app controlled NMES therapy devices in the setting of knee OA. Furthermore, the incorporation of cloud-based provider online platform may offer an additional advantage by allowing clinicians to monitor the progress and compliance of their patients in real-time. Therefore, patients who are making sub-optimal progress may benefit from an early intervention to modify their therapy protocol to achieve the best outcome.