Implant survival of 3rd-condyle and post-cam posterior-stabilised total knee arthroplasty are comparable at follow-up > 10 years: a systematic review

Abstract

Purpose: To summarise the literature on 3rd-condyle total knee arthroplasty (TKA) designs and compare their survival rates to those of post-cam TKA designs. The null hypothesis was that 3rd-condyle TKAs would have equivalent survival rates compared to contemporary post-cam TKAs.

Methods: An electronic literature search for Level I-V studies was independently conducted by two researchers using Medline^® and Web of Science for studies published between January 1984 and October 2020 that specifically reported on rates of implant survival and complications, joint kinematics, clinical outcomes, and radiographic outcomes of 3rd-condyle TKA. The methodological quality of clinical studies was assessed according to the Downs and Black Quality Checklist for Health Care Intervention Studies, and for in vitro and in silico studies according to the Joanna Briggs Institute (JBI) tool for assessing analytical cross-sectional studies. Findings extracted for each TKA design were presented as reported and synthesised narratively. Survival rates at 5, 10 and > 10 years of 3rd-condyle TKA designs were graphically compared to rates of post-cam TKA designs published in joint registries.

Results: A total of 38 studies were identified that reported on kinematics, clinical outcomes, radiographic alignment, and rates of complications and survival. Mean survival rates ranged from 96 to 98% at 5 years, 78-100% at 5-10 years, and 86-99% at > 10 years for 3rd-condyle PS TKAs. Mean survival rates ranged from 93 to 98% at 5 years, 89-99% at 5-10 years, and 88-95% at > 10 years for post-cam PS TKAs.

Conclusion: Implant survival rates of 3rd-condyle TKAs are comparable to those of post-cam TKAs at follow-up > 10 years. When compared to post-cam PS TKA, 3rd-condyle designs offer an alternative for younger and more active patients when considering the added benefits of a lowered point-of-contact and larger congruent contact area at the intercondylar tibial sulcus, that reduce risks of loosening and component wear.

Level of evidence: V.

Keywords: 3rd condyle; Posterior stabilised; Survival; Total knee arthroplasty; Total knee replacement.