The MRI Findings of Ischiofemoral Impingement Syndrome

Objective: To summarize the MRI findings of ischiofemoral impingement syndrome (IFIS), promote the recognition of this disease. Materials and Methods: The MRI images of 84 hips with IFIS (case group) confirmed in our hospital and 116 normal hips (control group) were retrospectively analyzed. Ischiofemoral space (IFS), quadratus femoris space (QFS), distance between sciatic tuberosity were measured on the axial T1WI MR images, and the morphological and signal of the quadratus femoris muscle were observed on the axial PDWI-FS images. Results: Independent sample t-test analysis indicate the IFS and QFS ((2.36±0.47) cm, (1.58±0.39) cm) of control group were significantly higher than that of case group ((1.56±0.42) cm, (0.89±0.24) cm), and the distance between sciatic tuberosity of control group ((10.51±1.53) cm) was lower than that of case group ((11.39±1.01) cm), and the differences between the two groups were statistically significant (P<0.05). Pearson correlation analysis indicate there was a significant positive correlation between IFS and QFS, r=0.813, P<0.05; There was a negative correlation between distance between sciatic tuberosity and IFS, r=-0.263, P<0.05. In the IFIS patients, the quadratus femoris muscle showed different degrees of deformation and edema. In the whole data, the IFS and QFS in the young and middle-aged group ((2.09±0.55) cm, (1.32±0.47) cm) were all higher than that of the elderly group ((1.90±0.58) cm, (1.19±0.39) cm), P<0.05; and there was no significant difference in the distance between sciatic tuberosity between the two groups. Conclusion: The narrowing of IFS and QFS, and the deformation and edema of quadratus femoris, are the typical MRI findings of ischiofemoral impingement syndrome.