Computer Navigation-Aided Excision of Proximal Femoral Osteochondroma: Surgical Technique.

Purpose: Symptomatic osteochondroma of the proximal femur necessitates a surgical excision. The purpose of this study was to describe a novel technique of computer navigation-aided excision for osteochondromata of the proximal femur. Outcomes of this technique are also presented. Methods: A total of 13 patients underwent computer navigation-aided excision of osteochondromata of the proximal femur from February 2012 to August 2016 in our institution. They were enrolled in this study. OrthoMap 3D (Stryker Orthopaedics, Mahwah, NJ, USA), a commercially available navigation software system, was used to merge computed tomography images of the proximal femur with an osteochondromata with the image of a normal proximal femur. Using the normal proximal femur as a template, intended resection margins for the proximal femur with osteochondromata were planned and then executed using intraoperative navigation guidance. Patients were followed up clinically and radiographically. The physical and mental health of patients was assessed with the Musculoskeletal Tumor Society (MSTS) score. Results: Eight patients had isolated exostoses. Five patients had tumors associated with multiple hereditary exostoses. For tumors projecting posteriorly or posteromedially, a posterolateral approach was used. For tumors projecting anteriorly or medially, an anterior approach was used. Prophylactic fixation was performed in four patients who required an anterior approach. The mean duration of the surgery was 189 minutes. There were no intraoperative fractures or postoperative complications. A secondary procedure was not needed for any case. The mean MSTS score at a mean follow-up of 17 months was 28.6 (maximum MSTS score: 30). Conclusions: This is the first study to report a novel application of computer navigation for aiding the excision of osteochondromata of the proximal femur. It demonstrated favorable postoperative functional scores with a low rate of complications. The applicability, safety, and efficacy of this technique were demonstrated. It is particularly useful for resections involving large tumors that can obscure anatomical landmarks and for patients with associated proximal femoral deformity.