Clandestine Femoral Neck Fractures with Ipsilateral Diaphyseal Fractures

We present a protocol for diagnosis of all femoral neck fractures associated with ipsilateral femoral diaphyseal fractures. A 30% incidence of delayed diagnosis has been reported by other investigators. Between 1982 and 1990, we have treated 32 patients with ipsilateral femoral neck and shaft fractures due to blunt trauma. Only 22 femoral neck fractures were diagnosed on prediaphyseal fixation radiographs. This left the 10 patients in this study who had normal prediaphyseal fixation radiographs and were subsequently found to have femoral neck fractures. The ipsilateral femoral neck fractures were found through a retrospective chart and radiographic review of all 555 femoral diaphyseal fractures identified through our trauma and fracture registries. The clinical and radiologic techniques for diagnosing the femoral neck fractures were presented. The time to union of the femoral shaft and neck was determined, and a preliminary radiologic assessment of the vascularity of the femoral head was made. Ten femoral neck fractures (31%) with normal preoperative radiographs were diagnosed after femoral diaphyseal fixation. One patient did not have a post-diaphyseal fixation radiograph. An incidental radiograph at 6 weeks showed a mildly displaced femoral neck fracture in an asymptomatic patient. At 16 weeks the patient became symptomatic, and a repeat radiograph showed the fracture. Five fractures were diagnosed in asymptomatic patients on routine post-femoral fixation radiographs. Two patients had normal post-femoral fixation radiographs, became symptomatic, and had their femoral neck fractures diagnosed on repeat radiographs at 3 and 7 days. One patient had normal pre- and postfixation radiographs, and on a 25-day routine femoral radiograph, the femoral neck fracture was diagnosed. In one patient, a femoral neck fracture was diagnosed during insertion of an intramedullary nail. Nine of the femoral diaphyseal fractures were plated because these were blunt polytrauma patients. All fractures were Pauwelʼs classification III. Our study demonstrates that routine preoperative radiographs of the hip are inadequate to diagnose all femoral neck fractures associated with ipsilateral femoral diaphyseal fractures. We suggest (a) routine postoperative radiographs, (b) routine 2- to 4-week postinjury radiographs, and (c) radiographs any time a patient becomes symptomatic. Our incidence of delayed diagnosis of femoral neck fractures is similar to that reported in the literature. I