Differential diagnosis of a femoral neck/head stress fracture

Abstract

Study design: Resident's case problem.

Background: Identifying stress fractures of the hip can be a challenging differential diagnosis. Pain presentation is not always predictable and radiographs may not show the fracture, especially during its early stages. Hip stress fractures left untreated can displace and necessitate open reduction internal fixation or total hip arthroplasty.

Diagnosis: A 70-year-old woman presented to the physical therapy clinic with complaints of right hip pain. She had been evaluated by a physician and radiographs of the hip, which revealed some arthritic changes, were otherwise normal. Upon examination, the physical therapist observed an antalgic gait, a noncapsular pattern of limitation of hip motion, an empty painful end feel at the end range of motion (ROM) for hip abduction, external rotation, and flexion, and extreme tenderness to palpation over the anterior hip region. The therapist suspected a more pernicious problem than osteoarthritis and discussed his suspicion with the physician. The physician subsequently requested an MRI that revealed a femoral neck and head stress fracture that was later confirmed with a bone scan. The patient was provided with a walker for ambulation with a non-weight-bearing status for 6 weeks, after which she returned to physical therapy for progressive weight bearing and strengthening. She was discharged with a relatively pain-free hip and was ambulating with a cane. A 2-month follow-up examination revealed a pain-free hip and a return to all premorbid activities, including ambulation without an assistive device.

Discussion: The presence of a normal radiograph of the hip should not be considered conclusive in ruling out a stress fracture in the hip region. The current case demonstrates how careful evaluation can reveal occult pathologies and prevent potentially catastrophic morbidity.