Total knee arthroplasty in patients with varus deformities greater than ten degrees: survival analysis at a mean ten year follow-up

IntroductionTotal knee arthoplasty (TKA) is a secure procedure with more than 90% survival at ten years. The purpose of this study was to report both clinical and radiological outcomes of TKA with a varus >10 degrees. The second objective was to identify risk factors for failure or bad clinical results. Our hypothesis was that results and survey are comparable to TKA with lesser deformities.MethodsEighty-two TKA (69 patients) between January 2004 and December 2008 with a varus >10 degrees were reviewed retrospectively. The endpoints were clinical (range of motion, IKS knee score, Oxford, and SF-12) and radiological (HKA post-operative and the existence of radiolucent lines or loosening at last follow-up).ResultsSixty-three TKA (55 patients) were assessed with a mean follow-up of 10.9years. The global IKS score significantly increased (p=0.04). Seven TKA needed a revision: two for sepsis, four for aseptic loosening, and one for polyethylene wear, with an overall survival of 91.6% at ten years. For aseptic loosening, the survival rate was 94.7% at ten years. Risk factors for failure were age (p=0.001), weight (p=0.04), and a post-operative HKA lesser than 175 degrees (p=0.05) for aseptic loosening.DiscussionThe hypothesis was confirmed: the results showed a significant improvement of function and quality of life with a survival rate comparable to those found in the literature for greater varus but also inferior to 10 degrees. Three risk factors have been identified suggesting increased surveillance in these cases.ConclusionThe results of this survey confirm the work hypothesis. Total knee arthroplasty in patients with important axial deformities is a confirmed, reliable, patient-friendly and predictable good outcome procedure.