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° varus and 5° valgus. RESULTS: The final femoral mechanical axis was between 2° valgus and 3° varus; the axis of the limb was between 4° valgus and 3° 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°-110° 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.