Figure 1. Magnetic resonance imaging (MRI) of the pelvis.
Figure 2. MRI coronal view of the right hip.
A 42-year-old man presents to the office with 2 months of right hip pain. He fell on the hip after slipping on ice and has had moderate pain in the hip since. The initial radiographs of the hip taken at the time of injury were negative for a fracture. Magnetic resonance imaging (MRI) was conducted, the results of which are shown in Figures 1 and 2.
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The patient has MRI findings of bone edema across the right femoral neck consistent with a femoral neck stress fracture. This is often seen in runners as a result of repetitive stress to the femoral neck. In this case, a traumatic event caused a stress fracture that never healed. Femoral neck stress fractures can be difficult to diagnose as the physical examination is often benign. Initial radiographs are usually negative for fracture. MRI is the next best step if there is suspicion of an occult fracture. MRI is the study of choice to diagnose a femoral neck stress fracture.
Treatment of femoral neck stress fractures is determined by the location of the bone edema on MRI. Edema located on the inferior medial femoral neck (compression side) is often stable and less likely to displace. Edema located on the superior lateral femoral neck (tension side) is more prone to displacement. Compression-sided edema that involves less than 50% of the femoral neck can usually be treated with a period of non-weight bearing and activity modification. Tension-sided edema should be treated with percutaneous screw fixation to prevent the disastrous consequences of a displaced femoral neck fracture.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).