Outcome of single radius constrained condylar device in primary and revision total knee arthroplasty: a retrospective cohort study

Abstract

Background: Instability is a common cause of failure after total knee arthroplasty (TKA). It can be reduced with constrained condylar knee (CCK) devices. Our aims were to evaluate survivorship and functional outcomes of CCK implants in primary and revision TKA. Methods: We assessed 136 patients (138 knees) who underwent a primary (75) or revision (63) arthroplasty with a CCK TKA between 2008 and 2011. Implant survival was assessed with Kaplan-Meier estimate, and functional outcome was assessed with Knee injury and Osteoarthritis Outcome Score (KOOS). Results: Mean follow-up was 3.8 yr. Three (4%) primary CCK TKA patients and nine (14%) first time revision CCK TKA patients required a second operation. Five-year implant survival rate for primary CCK TKA was 96% (95% CI, 0.88 to 0.99), and for revision CCK TKA 85% (95% CI, 0.66 to 0.94). Mean KOOS pain score was 79 in the primary TKA group, and 61 in the revision TKA group. Conclusions: Implant survival was excellent after primary CCK, and acceptable after revision CCK. Level of Evidence: Level III.