Further Imaging for Suspected Isolated Greater Trochanteric Fractures: Multiplanar Reformation Computed Tomography or Magnetic Resonance Imaging

Background: Most isolated greater trochanter (IGT) fractures are treated conservatively. However, some require surgical fixation although indications for surgery have not yet been established. Many surgeons perform surgical fixation when the intertrochanteric extension crosses the midline on magnetic resonance (MR) images. Nevertheless, for mechanical strength, cortical bone integrity is more important than that of intramedullary cancellous trabeculae. We retrospectively evaluated the clinical usefulness of multi -planar reformation computed tomography (MPR CT) in determining treatment strategies for IGT fractures. Methods: We evaluated 99 cases of suspected IGT fractures between October 2004 and December 2019. They were 66 women and 33 men with a mean age of 77 years. The mean follow-up period was 34 months. Most patients were evaluated with plain ra-diographs, followed by additional imaging study via MPR CT in 65 cases, magnetic resonance imaging (MRI) in 5 cases, and both in 17 cases. Typically, fractures were fixed surgically when a cortical breakage was detected in the intertrochanteric area on MPR CT, while fractures without evidence of cortical breakage on MPR CT were treated conservatively. Results: In 13 out of 82 cases evaluated by MPR CT, incomplete cortical breakage in the intertrochanteric area was detected, of which 10 were treated surgically. The remaining 3 cases were treated conservatively due to patient's refusal, poor medical condi-tion, and failure to detect breakage. Of 69 cases without cortical breakage, 61 cases were successfully treated conservatively. Among the 17 cases evaluated by both MPR CT and MRI, cortical breakage was detected in 3, of which the intertrochanteric exten-sion crossed the midline on the MR image only in 1 case. Of the remaining 14 cases without breakage, the intertrochanteric exten-sion crossed the midline in 5. Among these 5 cases, 3 were treated conservatively. Conclusions: The results suggest that MPR CT is a useful imaging modality for further evaluation of IGT fractures. It was espe-cially valuable in evaluating cortical bone integrity, which may be more critical for fracture stability.