Ischiofemoral Impingement: The Other Snapping Hip

Most things that pop, click, and snap around the hip are actually outside the joint, commonly tendons and muscles that flip back and forth. The adage, if you can hear it, it’s the iliopsoas tendon, and if you can see it, it’s the iliotibial band, accounts for 90% of all snapping phenomena. It is the other 10% that can be elusive. Within this group is ischiofemoral impingement.

With ischiofemoral impingement, the quadratus femoris muscle gets entrapped between the ischium, which is the sit bone part of the pelvis, and the lesser trochanter, which is the bony prominence of the femur where the iliopsoas tendon attaches. It is a developmental problem and usually not associated with a specific injury.

The pain that is caused is deeply situated in the hip area and can be hard to localize. The discomfort tends to be more towards the buttock than the groin. Popping can occur, which is often more of a grating sound while walking.

Narrowing of the space between the ischium and the lesser trochanter of the femur is commonly present. X-rays can sometimes detect this. However, the most constant feature is injury to the quadratus femoris muscle with edema, inflammation, and cystic changes which are identified by MRI. This can occur with or without narrowing of the space.

There can be a significant dynamic component to this problem as the space broadens and narrows depending on the position of the pelvis and the gait pattern. Thus, physical therapy with stabilization and proper strengthening exercises can be beneficial in alleviating symptoms in some cases.

The source of pain with this disorder is not always clear. A skilled ultrasonographer can inject this area, which helps to confirm the diagnosis, and can have therapeutic value in reducing symptoms. Alternatively, injection can also be performed under CT guidance. The advantage of ultrasound is that it can be performed conveniently in the office without requiring admission to a radiology department for the CT method, and there is also no radiation exposure.