False negative bone scan in a female runner

Abstract

Stress fractures are more prevalent in today's fitness cognizant society. Stress fractures of the femoral neck are common and present with specific symptoms and findings. The diagnosis is based on clinical history, physical exam, radiography, bone scintigraphy, and computed tomography (C.T.) scans. The triple-phase bone scan is the most sensitive test for the diagnosis of stress fractures and is considered the gold standard for the diagnosis of the occult stress fracture. This case presents a 42-yr-old female marathon runner who presented with hip pain and clinical symptoms indicating a stress fracture of the femoral neck. Initial radiographs and a triple-phase bone scan were negative. When symptoms persisted, a repeat x-ray revealed a femoral neck fracture of the superior surface. In spite of a false negative bone scan, clinical suspicion allowed appropriate treatment of this femoral neck stress fracture. Nondiagnosed stress fractures of the femoral neck may lead to severe disability, including avascular necrosis of the femoral head. Therefore, clinical index of suspicion is very important even if ancillary tests are nondiagnostic.