Comparison of Short Term Functional Outcomes of Single Radius Vs Multi Radius Total Knee Replacement

OBJECTIVES: The main objective of this study was to compare functional outcome in patients who have undergone a single-radius (SR) or multi-radius (MR) total knee arthroplasty (TKA). The secondary objective was to observe changes in knee range of movement (ROM) and standardized knee scores (KSCs) in these patients. The hypothesis was that there would be a statistically significant difference between the two patient groups in functional outcome. METHODS: Thirty unilateral Total knee replacements were performed by a single surgeon from July 2017 till April 2018 secondary to Osteoarthritis of the knee joint. It was a prospective cohort based study that included patients from the age of 18-90 years. Preoperative and postoperative functional outcomes at 10 days and 90 days were calculated by the Knee society scoring and then analyzed. There were 13 unilateral total knee replacements done with a single radius design and 17 unilateral total knee replacements done with a multi radius design. The single radius designs used in the study were DJO 3DKneeTM system, Zimmer Biomet Vanguard® system and multi radius designs were Smith & Nephew Genesis II system and DePuy P.F.C.®SIGMA® Knee system. Analysis was done via t-test for analysis of continuous data with Normal distribution and Mann-Whitney U test for data with non- Normal distribution with group (SR & MR). Differences were considered significant at p < 0.05. RESULTS: At 10 days postoperatively, there was a statistically significant difference between the SR and MR patient populations in terms of functional knee scoring by the knee society scoring (p < 0.05). No significant difference was noted in the knee society scoring, Knee range of motion, and Visual analog scale for pain at 10 days and 90 days post op. There was a statistically significant difference between the body mass index of women who underwent total knee replacements and men who underwent total knee replacements (p < 0.05). CONCLUSION: While an SR femoral implant design has several theoretical biomechanical advantages, postoperative standardized Knee Society scores in this single-surgeon series do not show a clear advantage of one design over the other