Purpose: A focused hip MRI (FHMR) for the detection of radiographically occult hip fractures was implemented in our emergency department (ED) in 2013. The goal of this study was to assess the clinical utility of this protocol.
Methods: We retrospectively reviewed radiology reports of 262 unique patients who underwent 263 FHMR (coronal T1, coronal STIR, axial T2 fat saturated) for suspected hip fracture in the ED from October 2013 to March 2020. Electronic medical records were reviewed for the ED course, follow-up imaging, and clinical management within 90 days.
Results: Seventy-one patients had one or more fractures identified by FHMR: one-third had proximal femoral fractures; two-third had pelvic fractures. Of these 71 patients, 53 (74%) had radiographically occult fractures, including 14 (20%) with occult proximal femoral fractures; 4 patients had fractures occult on CT. Nineteen patients with a suspected fracture on radiography were found to have no fracture on FHMR. Four fractures not reported on FHMR were later seen on follow-up imaging: these included 1 isolated greater trochanter, 1 additional ischial tuberosity, 1 additional superior pubic ramus, and 1 additional sacrum. All four fractures were treated non-operatively. Muscle/tendon injury was the most common type of injury, seen in 50% (130/262) patients with the most commonly torn tendons being the hamstring (44%; 15/34) followed by gluteus medius tendon (18%; 6/34). A full-hip or pelvis MRI was done after FHMR in only 5 patients, primarily for the purpose of better characterizing findings already identified on FHMR (2 for fracture, 2 for tendon injury, 1 for soft tissue metastasis). Only one of these five studies provided new information: ruling out a previously questioned fracture. Clinical management of the vast majority of patients was based solely on findings from the FHMR.
Conclusions: FHMR offers reliable identification of radiographically occult hip fractures and muscle/tendon injuries. The protocol is well trusted in guiding patient management in our ED.
Keywords: Abbreviated MRI; Occult hip fracture; Occult proximal femoral fracture.