Isolated fractures of the greater trochanter with occult intertrochanteric extension

Isolated fractures of the greater trochanter (GT) are relatively rare. The diagnosis can be done on routine radiographs, but it is difficult to fully define the geographic extent of these injuries. This study examined the pattern and extent of an injury shown by magnetic resonance imaging (MRI) and radionuclide bone scan (RBS) in patients whose plain radiographs revealed fractures limited to the GT.

Between July 2004 and October 2008, 25 patients who displayed an isolated GT fracture on plain radiograph examination were examined by both MRI and RBS due to a suspicion of an extension into the intertrochanteric (ITC) region. The patients were then divided into two groups. Group A patients had an isolated fracture of GT, and group B patients had an occult fracture of ITC.

All 25 cases were caused by a low-energy injury and plain radiographs showed non-displaced or minimally displaced isolated GT fractures. For 22 of the 25 patients, the result agreed with MRI and RBS. However, three patients had focal increased uptake at the GT region only according to RBS and an extension of signal intensity into the ITC region according to MRI. Group A and B comprised 5 and 20 patients, respectively. Of the group B patients, 8 had fractures with MRI evidence of complete extension across the ITC region and 12 had incomplete extension. Eleven of the 12 incomplete types showed an extension more than half way to the medial cortex. Fifteen group B patients underwent an internal fixation using a two-hole dynamic hip screw.

Patients with an isolated fracture of GT can have a broader fracture extending into the ITC region than that diagnosed by standard radiographs. We recommend that all patients presenting with an isolated GT fracture on the plain radiographs should undergo MRI examination.