Computer-Assisted Navigation in Total Knee Arthroplasty without Femoral Hardware Removal

PURPOSE OF THE STUDY The use of navigation applied to total knee arthroplasty in knees with femoral hardware retained has not been studied. MATERIAL AND METHODS We use navigation in six patients to implant a total knee arthroplasty while retaining the femoral hardware. The retained materials were screws in two cases, diaphyseal plates in another two, intramedullary nails in one and supracondylar tube/plate in another one. Preoperative knee scores were within the 46-66 range, whereas the functional scores were within 40-68. The coronal deformity varied between 30 degrees varus and 5 degrees valgus. RESULTS The final femoral mechanical axis was between 2 degrees valgus and 3 degrees varus; the axis of the limb was between 4 degrees valgus and 3 degrees varus. Knee scores improved in all cases, with scores between 75 and 90 points (p = 0.028); functional scores were between 64 and 90 points (p = 0.043). The final range of mobility was within the 70 degrees-110 degrees range, with a slight improvement over the preoperative status (p = 0.042). No complications have arisen throughout the follow-up (mean 16 months). CONCLUSIONS The use of navigation constitutes a good option in the treatment with total arthroplasties for patients with femoral hardware retained.