Diagnosis of femoral neck fractures in patients with a femoral shaft fracture. Improvement with a standard protocol.

Background: An ipsilateral fracture of the femoral neck is seen in association with 1% to 9% of femoral shaft fractures, and 20% to 50% of these injuries are missed initially. Recognition of an associated femoral neck fracture prior to stabilization of the femoral shaft fracture is imperative to avoid or minimize complications of displacement and osteonecrosis.

Methods: A protocol to look for a femoral neck fracture in all patients with a femoral shaft fracture was instituted at a single level-I trauma center. This protocol consisted of a dedicated anteroposterior internal rotation plain radiograph, a fine (2-mm) cut computed tomographic scan through the femoral neck, and an intraoperative fluoroscopic lateral radiograph prior to fixation as well as postoperative anteroposterior and lateral radiographs of the hip in the operating room prior to awakening the patient. A chi-square analysis comparing pre-protocol and post-protocol fracture prevalences was used to assess the relative risk of missing an associated femoral neck fracture.

Results: Two hundred and sixty-eight consecutive patients with a femoral shaft fracture formed the basis of the study group. Of 254 who were followed for at least two months, sixteen were identified as having an associated ipsilateral femoral neck fracture with use of the protocol. Thirteen associated femoral neck fractures were identified before the patient entered the operating room for definitive fixation, and twelve of them were identified with the fine-cut computed tomographic scan. One fracture was identified intraoperatively. There was one iatrogenic fracture and one delayed diagnosis of a femoral neck fracture. With this protocol, we reduced the delay in diagnosis by 91% as compared with our experience in the year prior to the initiation of the protocol.

Conclusions: In the presence of a femoral shaft fracture, evaluation of the femoral neck with fine-cut computed tomography and dedicated internal rotation hip radiographs significantly improves the ability to diagnose an associated femoral neck fracture.