Role of SPECT CT in detection of viable femoral head following surgery for Slipped Upper Femoral Epiphysis

Objectives Avascular necrosis in the region of femoral epiphysis is a disease in which there is ischemic death of the cellular elements of bone and marrow. This condition affects both adults and children and predisposing causes include dislocation of the hip, femoral neck fracture, corticosteroid usage, alcoholism, collagen vascular disease, haemoglobinopathies, Gaucher’s disease, Caisson’s disease and some skeletal dysplasias. In paediatric population the condition is associated with history of fall in adolescent patients (SUFE-slipped upper femoral epiphysis). The purpose of the current study is to evaluate the role of SPECT CT in detection of viability of the femoral heads following surgery for SUFE.

Methods This study included those patients who presented to the accident and emergency department with history of fall, reduced motion and altered weight bearing. Initial radiographic and subsequent MRI examination confirmed slipped upper femoral epiphysis (SUFE). These patients underwent surgical fixation of the SUFE. As these patients could not have post operative MRI due to presence of metal, these underwent 3 phase scintigraphy (Tc99m MDP) and SPECT CT to evaluate the viability of the femoral head following surgery.

Results A total of 12 patients were included in this prospective study. The age range was 8-15 years (average 12.5 years). There were 5 female and 7 male patients. Initial radiological investigations confirmed SUFE (8 on the left side and 4 on the right). The dynamic, blood pool and delayed static images showed reduced flow, reduced blood pool activity and uptake in 4 patients while in 8 patients the appearances of the femoral head was considered satisfactory. These findings were further confirmed with SPECT-CT which showed reduced viability of the femoral head in 4 patients while in 8 patients the femoral head was viable with osteoblastic activity. The position of screws was normal in all 12 patients. The findings correlated with intra-operative Doppler to evaluate the blood flow to the femoral head.

Conclusions Triple phase scintigraphy and SPECT-CT is a valuable tool to detect viability of the femoral head following surgery. Patients with reduced viability are offered calcium supplements (bisphosphonates) to enhance bone healing. Bone Scan coupled with SPECT CT facilitates triage of patients who benefit from medical treatment post surgery for SUFE.