Clinical and computed tomography evaluation of surgical outcomes in tarsal navicular stress fractures

Background: As clinical suspicion increases and radiographic evaluation improves, navicular stress fractures are becoming a more recognized injury. To date, there is a small volume of literature examining these stress fractures, particularly as it pertains to outcomes of surgical management. Purpose: To evaluate the clinical and computed tomography (CT) outcomes of surgically treated navicular stress fractures. Study Design: Case series; Level of evidence, 4. Methods: Ten navicular stress fractures in 10 patients were available for follow-up at an average of 42.4 months postoperatively (range, 16.8-79.9). These patients underwent a clinical examination and a CT scan of their operatively treated foot. The American Orthopaedic Foot & Ankle Society (AOFAS) and SF-36 scores were completed for each fracture at the time of examination. The CT scans were blindly evaluated for bony union. Results: According to the CT scan evaluation, 8 of 10 navicula (80%) had gone on to union. Clinical outcome scores on all patients were an average AOFAS hindfoot score of 88.5 and an average SF-36 score of 88.3. The feet with united fractures had an average AOFAS score of 92.1 (range, 83-100) and an average SF-36 score of 91.9 (range, 79-98). The 2 patients with nonunions had AOFAS scores of 74 and 74 and SF-36 scores of 70 and 78, respectively. Both nonunions were complete, displaced fractures on preoperative imaging. Conclusion: In our series of operatively treated navicular stress fractures, 80% went on to union, as verified by CT scan. Patients with united fractures had a clinically significant improvement in outcome, with higher AOFAS and SF-36 scores as compared with the 2 patients with nonunions. Patients with complete, displaced navicular stress fractures may be more likely to develop nonunions.