IMPLANT POSITIONING WITH MINIMALLY INVASIVE UNICOMPARTMENTAL KNEE ARTHROPLASTY

Introduction: Satisfactory ten-year survival statistics from the Swedish Arthroplasty Register, combined with new minimally-invasive surgical implantation techniques, have seen a resurgence in interest in unicompartmental knee arthroplasty (UKA). Aim: To compare unicompartmental component positioning following minimally invasive and open implantation. Methods: The radiographs of patients with UKAs implanted using a minimally invasive technique were retrospectively compared with a similar number of UKAs implanted using an open technique. Optimal component positioning and methods of determining this from radiographs will be presented. Results: Twenty-three consecutive Ripicci UKAs (21 patients) were implanted using a minimally invasive technique. Radiographs were compared with an equivalent number of Marmor UKAs implanted using an open technique. All patients derived from a single surgeon’s practice. Preliminary results indicated that tibial tray positioning was satisfactory, and that variations in the femoral component positioning were due largely to the design modifications of the Ripicci UKA.