Longer term follow up of outcomes following implantation of a modular rotating hinge knee prosthesis: 53 implants at mean 7.6 year follow up

Abstract

BackgroundRotating hinge knee replacements are becoming more common but have historically had high complication and failure rates. This study is one of the largest to assess the implant survival and patient outcomes of a third-generation rotating hinge knee replacement at a single tertiary orthopaedic centre. MethodsData for consecutive operations at our tertiary unit between 2006 to 2020 were assessed with review of electronic patient and radiology records. The Oxford Knee Score was used to assess outcomes and the Kaplan Meier method used to estimate survivorship. Results53 rotating hinge knees were implanted in 46 patients (13 male, 33 female) at a mean age of 67.8 years. 21 were primary and 32 were revision procedures. Indications for use of this implant included instability, loosening, fracture and infection. Survivorship was 77.8% at the mean follow up of 7.6 years. A total of 29 complications were noted with ongoing pain, stiffness, infection and patellofemoral symptoms being the most common. 8% of unresurfaced patellas required a subsequent secondary resurfacing. The Oxford Knee Score demonstrated a significant improvement from 14.6 preoperatively to 27.5 at one year postoperatively, which was maintained in the longer term. ConclusionThe third-generation rotating hinge knee implant in use at our unit has improved outcomes for patients. The survivorship of the implant is comparable to the published literature, although there is a paucity of data. The complication rates remain relatively high and patients should be counselled appropriately. We advise resurfacing the patella to avoid the need for secondary procedures.