Miriam Antoinette Bredella MD, Presenter: Nothing to Disclose

Debora Cristina Azevedo MD, Abstract Co-Author: Nothing to Disclose

Adriana Maria De Lima Oliveira MD, Abstract Co-Author: Nothing to Disclose

Frank J. Simeone MD, Abstract Co-Author: Nothing to Disclose

Connie Y. Chang MD, Abstract Co-Author: Nothing to Disclose

Ambrose J. Huang MD, Abstract Co-Author: Nothing to Disclose

Martin Torriani MD, Abstract Co-Author: Nothing to Disclose

Ischiofemoral impingement (IFI) is associated with abnormalities of the quadratus femoris muscle and narrowing of the ischiofemoral (IF) and quadratus femoris (QF) spaces. Anatomic variations in pelvic morphology such as a wider inter-ischial distance and femoral neck anteversion may predispose patients to IFI. The purpose of our study was to assess new MRI measures to quantify pelvic morphology which may predispose to IFI. We hypothesized that patients with IFI have a wider inter-ischial distance and increased femoral neck anteversion compared to normal controls.  

The study was IRB approved and complied with HIPAA guidelines. The study group comprised 78 patients with IFI (mean age: 52.2±15.6 y, 68 f, 10 m) and 51 age and gender matched controls. Control subjects underwent MRI of the hip for acute trauma but were otherwise asymptomatic. Two MSK radiologists independently measured IF and QF distance , femoral cross sectional area (CSA) at the level of the lesser trochanter, the ischial angle as a measure of inter-ischial distance, and femoral neck angle as a measure of femoral anteversion. The quadartus femoris was evaluated for edema and atrophy. Groups were compared with ANOVA.

All patients with IFI and none of the controls subjects had abnormalities of the quadratus femoris muscle (p<0.0001). Out of the 78 patients, 14 (18%) had bilateral MRI findings of IFI. Patients with IFI had decreased IF and QF distance (p<0.0001) compared to controls. Patients with IFI had increased ischial angle (p=0.04) and increased femoral neck angle (p=0.03) compared to controls. There was a trend toward decreased femoral CSA (p=0.08) in IFI compared to controls.

Patients with IFI have increased ischial and femoral neck angles compared to controls. These anatomic variations in pelvic morphology may predispose to IFI. MRI is a useful method to not only assesses the osseous and soft tissue abnormalities associated with IFI but also to quantify anatomic variations in pelvic morphology that can predispose to IFI. 

MRI can be used to assess osseous and soft tissue abnormalities associated with IFI and to quantify anatomic variations in pelvic morphology that can predispose to IFI. 

Bredella, M, Azevedo, D, Oliveira, A, Simeone, F, Chang, C, Huang, A, Torriani, M, Pelvic Morphology in Ischiofemoral Impingement .  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045667.html