Background: Evaluating postoperative patients with hardware is challenging following surgical intervention for hip maladies such as femoral neck fractures and slipped capital femoral epiphysis (SCFE). These children are at increased risk of developing avascular necrosis, and imaging may be requested to confirm or exclude this diagnosis. Children with Legg-Calvé-Perthes disease can be monitored for restoration of blood flow to the capital femoral epiphysis to guide management and help with prognosis. Although MRI is sensitive for detecting early avascular necrosis, the presence of hardware degrades image quality.
Objective: This report examines the utility of bone scans for evaluating femoral head perfusion in children who have undergone surgery for femoral neck fractures, SCFE or Legg-Calvé-Perthes disease.
Materials and methods: A retrospective review of 20 patients (22 scans) after fixation for femoral neck fracture, SCFE or Legg-Calvé-Perthes disease from 2012 to 2015 was performed. The bone scan findings were correlated with the intraoperative findings or clinical follow-up.
Results: Twenty-one of the 22 (95%) bone scans in 19 of the 20 (95%) patients demonstrated findings consistent with clinical outcomes and/or the intraoperative appearance of the femoral head. Four of 20 patients (20%) had bone scan features of avascular necrosis, defined as "absent" or "moderately diminished" femoral head activity, which were confirmed intraoperatively and resulted in poor outcomes.
Conclusion: Radionuclide imaging of hips in the postoperative setting is a valuable modality for assessing the risk of avascular necrosis, a complication of femoral neck fractures and SCFE and for evaluating the restoration of flow to the capital femoral epiphyses of children with Legg-Calvé-Perthes disease.
Keywords: Avascular necrosis; Bone scintigraphy; Children; Femoral neck fractures; Legg-Calvé-Perthes; Slipped capital femoral epiphysis.