MRI Compared to CT Scan in the Diagnosis of Occult Hip Fracture

Introduction: MRI is a very sensitive and specific exam for the diagnosis of occult femoral neck fractures. The role of MRI in the evaluation of suspected occult fracture of the hip is increasing worldwide. Conventional radiography is insufficient for diagnosis in small but not unimportant number of hip fractures, and secondary imaging with computed tomography (CT) or magnetic resonance imaging (MRI) is warranted.

Purpose of Study: To evaluate the diagnostic performance and the effect on the operative decision of MRI in the evaluation of occult hip fracture in our institution. To compare MRI to CT diagnosis in the evaluation of occult fracture of the hip

Methods: retrospective study on 58 patients which MRI exam was conducted in the evaluation of occult hip fracture during the period of 1/1/2012 to 1/7/2016. Radiograph was done in all patients and CT exam was done in 53. Aspects including diagnosis of fracture, influence on operative decision making, comparison of the MRI and CT diagnosis where retrospectively evaluated.

Results: 12 patients (21%) were operated as a result of fracture revealed by MRI and missed by CT. In 4 patients (7%) the MRI exam influenced the decision not to operate due to better classification of the fracture compared to CT and x-ray exams. In 48 patients (83%) non-surgical diagnosis was found (pubic rami fracture, hematoma, nonspecific edema, acetabular fracture, osteoarthritis, trochanteric bursitis, infection, and muscle contusion.

Discussion /Conclusion: The study illustrates the high incidence of fractures which are not apparent on plain radiographs and CT. We found that MRI was a superior tool in occult hip fracture diagnosis, helped to operative decision making, and in acute traumatic painful hip diagnosis.