Review Question - QID 215582

This patient sustained a high-energy femoral shaft fracture. Imaging of the ipsilateral hip should be obtained to rule out a concomitant femoral neck fracture.

Ipsilateral femoral neck fractures should be considered in all high-energy femoral shaft fractures, as they have a reported incidence of 0-15%. These associated injuries are often basicervical, vertical, and nondisplaced in nature. The lack of displacement is due to the majority of energy being dissipated through femoral shaft. These injuries are missed approximately 19-31% of the time. Imaging of the ipsilateral hip should be obtained.

Cannada et al. retrospectively reviewed the incidence of femoral neck fractures with high-energy shaft fractures to determine whether there was a correlation of neck fractures with antegrade or retrograde intramedullary nailing. They reported a rate of neck-shaft combinations of 3.2%, and that ipsilateral femoral neck fractures were missed in 26% of cases. They concluded that patients with femoral shaft fractures should have good quality radiographs after femoral nailing to minimize the risk of missed femoral neck fractures.

Alho et al. performed a meta-analysis of ipsilateral fractures of the hip and femoral shaft. They reported that that ipsilateral hip fractures were divided into 5 subtypes with the following distributions: subcapital-2%, midcervical-21%, basicervical-39%, pertrochanteric-14% and intertrochanteric-24%. Furthermore, they noted that the diagnosis of the hip fracture was delayed in 30% of the cases. They concluded that early diagnosis of all injuries and operative treatment of all fracture components are the key factors in reducing complications and improving the outcome in ipsilateral hip and shaft fractures.

Rogers et al. reviewed whether the preoperative diagnosis of ipsilateral femoral neck fractures in patients with high-energy femoral shaft fractures can be improved with magnetic resonance imaging (MRI) compared with radiographic and CT imaging. They reported that rapid limited-sequence MRI of the pelvis for patients with femoral shaft fractures identified femoral neck fractures that were not diagnosed on thin-cut high-resolution CT in 12% of patients. They concluded that the frequency of femoral neck fractures may be underrepresented on CT imaging in polytraumatized patients.

Illustration A is an AP radiograph of the femur demonstrating an femoral shaft fracture with an ipsilateral vertical basicervical femoral neck fracture.

Incorrect Answers:
Answer 1: CT imaging of the knee would be indicated in a distal femoral shaft fracture to evaluate for a Hoffa fracture, which is an intra-articular distal femoral fracture in the coronal plane, occurring in 38% of cases.
Answer 2: Bilateral femur fractures should be considered in a polytraumatized patient, as carry a higher mortality than ipsilateral femur shaft fractures, 5.6% vs. 1.5%, respectively. However, these injuries are often evident on initial examination and not routinely missed as are ipsilateral femoral neck fractures
Answer 4: A floating knee, which is a femoral shaft fracture with an ipsilateral tibia fracture, is often evident on initial examination and not routinely missed as are ipsilateral femoral neck fractures
Answer 5: A radiograph of the lumbar spine should be obtained with any concerns for spinal injury.