Comparing Functional Recovery Between Total and Unicompartmental Knee Arthroplasty: A Prospective Health Kit Study

Abstract

Background: Both total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) have demonstrated excellent clinical outcomes for end-stage osteoarthritis. Although UKA has been shown to have lower survivorship, many patients are interested in a partial knee arthroplasty due to the perception of "better" function and a "quicker" recovery. The purpose of this study was to objectively compare and understand functional recovery between TKA and UKA through the utilization of cutting-edge technological health metrics.

Methods: Over a 2-year period, 185 patients undergoing TKA or UKA (152 versus 33, respectively) were prospectively followed for 1 year postoperatively. Smart devices were worn by these patients to track their daily steps, steadiness, standing time, 6-minute walk test, and gait speed, and were averaged weekly at multiple time points ranging from immediately preoperatively to 1 year postoperatively. Propensity matching scores were conducted in a 1:3 UKA to TKA ratio, resulting in a final cohort of 120 patients undergoing TKA or UKA (87 versus 33). Additionally, EuroQol 5 dimension survey and Knee Injury and Osteoarthritis Outcome scores were compared between groups.

Results: At 6 weeks postoperatively, the mean gait speed was quicker for patients who underwent a UKA in comparison to those who underwent a TKA (0.97 versus 0.89 meters/second, P = 0.02). Furthermore, the average steadiness at 6 weeks postoperatively was better in the UKA group when compared to the TKA cohort (0.60 versus 0.40 (0 to 1 scale), P = 0.03). No further differences were demonstrated between groups at the 6-week time point. No data or reported outcomes varied between the UKA and TKA cohorts at both 6-month and 1-year postoperative time points.

Conclusions: This prospective study compared UKA and TKA through the incorporation of real-time objective technological data. Although steadiness and gait speed were better in the UKA group at the 6-week follow-up, no differences existed beyond this time point. This study demonstrates that both UKA and TKA had the same recovery and functionality in regards to gait speed, daily step counts, standing time, steadiness, and the 6-minute walking test at 6-month and 1-year follow-up.

Keywords: recovery following knee replacement; total joint function; total joint recovery; total knee arthroplasty; unicompartmental knee arthroplasty.