Implant survival and outcome after rotating-hinge total knee revision arthroplasty: a minimum 6-year follow-up

Data on long-time survival and clinical function of rotating hinge knee prostheses used in revision total knee arthroplasty (TKA) are scarce. We evaluate the outcome of 42 revision TKA in 38 patients using the Endo-model rotating hinge total knee prosthesis after a minimum of 6 years, with 10-year implant survival as our primary outcome measure. Only revision TKAs performed due to aseptic loosening were included, and the Swedish Knee Arthroplasty Register was consulted in order to ensure that patients unavailable for clinical follow-up had not been revised elsewhere. Mean follow-up was after 8.8 (6-18) years, mean age at revision surgery was 72 (55-88) years, and most patients had severe medical comorbidities (n = 31). At follow-up, four knees had been re-revised due to aseptic loosening, and five further knees underwent re-revision due to other reasons. With implant revision due to aseptic loosening as the endpoint, 10-year survival was 89.2%, and with implant revision due to any reason 10-year survival was 65.1%. 11 patients (13 knees) eligible for clinical follow-up were evaluated according to the Hospital for Special Surgery score (HSSS), the Knee Society scores (KSS), and by plain radiography. Mean HSSS was 67 (36-90), mean KSS-knee was 85 (73-96), and mean KSS-function was 29 (0-100). Radiography showed that no implant was in need of revision. Our results indicate that revision arthroplasty of the knee with this rotating hinge prosthesis can be performed with satisfactory or good results in an elderly population with severe comorbidities.