Is there a relationship between femoral neck-shaft angle and ischiofemoral impingement in patients with hip pain?

Ischiofemoral impingement (IFI) is a cause of deep gluteal space syndrome. The prevalence of radiographic findings in patients with hip pain is unknown. To assess if there is a correlation between femoral neck-shaft angle (NSA) and the distance of the ischiofemoral space (IFS) and quadratus femoris space (QFS) and to determine the prevalence of quadratus femoris (QF) edema in patients with hip pain. A retrospective case series was conducted involving 100 consecutive hip or pelvis magnetic resonance imaging scans on patients presenting with hip pain. NSA, IFS and QFS distances were measured and presence of QF edema was noted. Analysis of the groups (QF edema vs no edema) was performed using two-tailed t-test and Pearson correlation. There were 18 hips in the edema group (mean age 51.11 years ± 10.5) and 82 hips in the non-edema group (mean age 40.79 years ± 15.9). Within the edema group, there was a moderate positive correlation between NSA and QFS (r = 0.498, P = 0.036) and a weak positive correlation between NSA and IFI (0.312, P = 0.208). The prevalence of QF edema in this study was 18% with only 28% of those subjects having clinical symptoms of IFI. Patients with QF edema had significantly narrower QFS and IFS distances (P < 0.001). The prevalence of QF edema is 18% in a consecutive sample of adults with hip pain. In patients with QF edema, only 28% have symptoms of IFI. In patients with QF edema, there was a moderate positive correlation between NSA and QFS.