Guided-motion hinged knee replacement prosthesis: early survival rate and postoperative patient function and satisfaction

Literature on the survival rates and function of hinged total knee replacement (HTKR) prostheses is scarce, and to our knowledge there is not yet any published literature on the Legion HK Hinge Knee Replacement prosthesis (Smith & Nephew) with guided-motion articulation. The objective of this study was to establish the early survival rate of this modern HTKR at a single institution and to investigate postoperative patient function and satisfaction. This retrospective study included patients who received the Legion HTKR prosthesis with guided-motion inserts as a primary or revision implant between October 11 and March 2016 at a tertiary care centre in Manitoba, Canada. Preoperative and postoperative functional scores on the 12-item Oxford Knee Score and postoperative patient satisfaction were assessed. Thirty-nine HTKR implantations (38 patients) were included in this study: 12 primary cases and 27 revision cases. Three revision surgeries and 4 perioperative complications were noted at a mean follow-up of 29.1 months. The 2-year survivorship of the HTKR system was 90.7%. Postoperative functional scores improved significantly and the majority of patients were satisfied or very satisfied at all follow-up time points. The early survival rate of a modern guided-motion HTKR prosthesis is similar to the survival rates of other hinged knee prostheses published in the literature. The prosthesis demonstrated substantial postoperative functional improvement when used in the setting of complex primary or revision total knee replacement.