MRI NEWSLETTER: Ischiofemoral Impingement

Ischiofemoral impingement is a condition that presents with pain in the hip, groin or buttock region. Pain can radiate to the lower extremity due to an irritation of the sciatic nerve. Ischiofemoral impingement is much more common in women than in men, approximately 3:1. Bilateral disease is present in one third of cases. The average patient age is older than most impingements, approximately 52 years of age. Diagnosis is made by MRI.

Patients with ischiofemoral impingement have a reduced ischiofemoral space, which is the distance between ischial tuberosity and the lesser tuberosity. In the syndrome, the space is reduced to less than 18 mm while in normal patients it averages 23 mm. There is also frequently a decrease in the quadriceps femoris space. This is the space from the lateral border of the ischial tuberosity to the hamstring tendons. This averages less than 7mm in patients with ischiofemoral impingement.

Axial T2 image of a normal male showing normal distances of both the ischiofemoral space and quariceps femoris spaces.

Narrowing of the ischiofemoral space to approximately 14 mm and narrowing of the quadriceps femoris space to 12 mm. High signal is noted within the quadriceps femoris muscle consistent with edema. 

Narrowing of the ischiofemoral space and quadriceps femoris space with high signal medial to the quadriceps femoris muscle due to partial tear of the quadriceps femoris.

The eitology of ischiofemoral impingement is thought to be congenital, however acquired forms have been reporting from fracture of the proximal femur, older patients with superior and medial migration of the femur due to osteoarthritis of the hip, or in patients with intertrochanteric osteotomy.

Initial treatment is that of physical therapy and CT-guided injection steroids. Arthroscopic resection of the lesser trochanter with iliopsoas tendon resection has been suggested in some patients.

Read the full article here: Ischiofemoral Impingement
By Dr William Renner

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