MRI diagnosis of occult hip fractures

Abstract

Background Most fractures of the proximal femur are easily diagnosed by conventional radiography. When the images are judged to be negative or equivocal and a clinical suspicion of fracture persists, another approach is to use magnetic resonance imaging (MRI) to help reach a diagnosis.

Methods In a prospective study running from November 1998 to December 2001, we registered all patients being examined by MRI who had had a negative or equivocal radiograph and where there was continued clinical suspicion of hip fracture.

Results 100 consecutive patients (67 women) were included, with an average age of 80 (37–100) years. The MRI examinations corresponded to 4% of the 2,350 patients admitted with hip trauma during the study period. 46 patients had a femoral neck or intertrochanteric fracture on MRI. 27 patients had other fractures. 18 had other findings on MRI, and 10 were interpreted as being negative, although one of these was a false negative. In a separate interobserver analysis, two experienced radiologists agreed on the diagnoses in 19/23 cases (kappa value 0.78). They agreed with a less experienced radiologist in 17/23 and 19/23 cases, respectively (kappa values 0.66 and 0.76).

Interpretation MRI is a useful tool for demonstration of occult hip fractures. In the absence of a hip fracture, another explanation for the patient’s pain and disability will often be given.