Are asymmetric tibial baseplates superior in primary total knee arthroplasty? A systematic review of clinical studies

Background: Despite the asymmetric nature of the native tibial condyles, traditional primary total knee arthroplasty (TKA) has overwhelmingly employed the use of symmetric tibial baseplates. However, designs exist utilizing an asymmetric tibial baseplate that mimics normal tibial anatomy. The purpose of this review was to assess the functional and radiographic outcomes of asymmetric tibial base plates. Methods: Embase, MEDLINE, and Web of Science were searched for relevant literature from database inception until September 2019, and after screening by two reviewers, studies investigating the use of asymmetric tibial baseplates in primary TKA were included. Demographic data as well as data on revision rates, functional and radiographic outcomes, and complications were recorded. A risk of bias assessment was performed for all studies. Results: Overall, 24 studies were identified with a total of 4776 patients (4937 knees). Seventeen studies (1895 knees) reported a pooled revision rate of 2.4% (45/1845) at a mean follow-up of 72.9 mo. TKA with an asymmetric baseplate resulted in improvement of range of motion and functional outcome scores postoperatively, as well as radiographic evidence of good tibial component positioning and bone coverage. Lastly, the overall pooled complication rate of reporting studies was 12.7%. Conclusions: The use of an asymmetric tibial baseplate in primary TKA is a safe and effective option, with the potential for improved component alignment and tibial coverage. However, more evidence is needed to determine if there are significant differences in failure rates and postoperative functional outcomes before justifying the implementation of a new and potentially more costly technology. Level of Evidence: Level IV.