Total knee arthroplasty with rotating-hinge Endo-Model prosthesis: clinical results in complex primary and revision surgery

Rotating-hinge knee implants are highly constrained devices able to provide the stability needed for arthroplasty in case of severe bone loss and complex instability. Notable doubts still exist in using rotating-hinge devices, mainly due to risk of mechanical failure and risk of infection. We retrospectively evaluated the functional and clinical outcomes in a series of patients treated with the rotating-hinge Endo-Model prosthesis either for primary or revision total knee arthroplasty. Between 1997 and 2009 we implanted 123 Endo-Model prosthesis (118 patients) at our institution. At the time of this study we could evaluate 45 prosthesis (25 primary and 20 revision TKAs) from the clinical and radiological site, with average follow-up of 42.2 months. During the follow-up period, three patients reported complications, which in two cases finally led to revision with explantation. Mean survival of the implants attested at 93.3 %. The average post-operative clinical Knee Society score in the evaluated series was 94.2, the functional one 78.7. The average range of motion was 0A degrees-108A degrees. No signs of joint instability or misalignment were noted. Pain was present in a minority of patients, but always at a mild/occasional extent. No evidences of loosening or implant failure have been reported. No substantial divergences in the outcomes have been found across different patient categories after stratification in agreement with the Knee Society. Coherent with previously published works, we confirm the Endo-Model prosthesis to provide excellent pain relief, restoration of walking capacity and intrinsic knee stability both in complex primary and in revision knee arthroplasty, with good or excellent results in the majority of patients and acceptable complication rate.