Range of Motion Comparison Following Total Knee Arthroplasty with and without Patella Resurfacing

Background: Despite significant evaluation, no consensus has been reach for best clinical practice for resurfacing the patella during total knee arthroplasty. Further complicating the ability to reach a conclusion is the inclusion of several different implant types used in previous research. Questions/Purpose: The purpose of this study was to compare post-TKA outcomes between two cruciate retaining implants with or without patella resurfacing. Methods: This retrospective review included 289 patients (380 knees) with a minimum six-month follow-up. All patients received a CR implant, with either a symmetric or an asymmetric tibial baseplate. Post-TKA knee flexion was categorized as <120° and ≥120° and knee extension classified as 0° or >0° and required knee manipulations were noted. Descriptive, nonparametric statistics were performed and a multivariate logistic regression was performed to determine risk of poor range of motion and manipulations. Results: Age was significantly lower in the resurfaced group (p=0.001) and the resurfaced group had longer tourniquet time (p=0.003). The symmetric-resurfaced group had ≥120° of flexion and full extension in 72% and 98.7% of patients, respectively. Compared to symmetric-resurfaced, all other groups had a significantly greater risk of not reaching 120° of knee flexion (p<0.05). There were no significant differences in the risk of requiring a MUA between groups (p>0.06). Conclusions: The effect of resurfacing the patella on post-TKA outcomes may be influenced by tibial implant design. Compared to all other combinations, a symmetric tibial baseplate and resurfaced patella resulted in the highest percentage of patients reaching ≥120°, with a low incidence of manipulations.