CASE 44

By: Dr. Mai Mattar, MD and Dr. Nizar Al-Nakshabandi MD, FRCPC

HISTORY: 50-year-old female with severe bilateral hip pain.

What are your findings?

What is the differential diagnosis?

What are the causes?

FINDINGS:

Axial T1 and T2FS images of the pelvis at the level of the ischial tuberosities demonstrate a narrowing of the ischiofemoral and quadratus femoral lines with edema within the quadartus femoris muscles bilaterally.

DIFFERENTIAL DIAGNOSIS:

Bilateral ischiofemoral impingement.

Lumbar disc disease.

Tendionsis/muscle injury.

DIAGNOSIS:

Bilateral ischiofemoral impingement.

PEARLS AND DISCUSSION:

Ischiofemoral impingement refers to impingement of the soft tissue between the ischial tuberosity and lesser trochanter of the femur.

The quadratus femoris muscle is usually involved. The narrowing of the distance between the two osseous marks the ischiofemoral space predisposes for and correlates with ischiofemoral impingement.

Patients present with pain due to pinching of the soft tissues between the bone prominences. Since 2008, ischiofemoral impingement has been known as a source of pain in the hip or groin and posterior thigh. Prior to that any edema in the quadratus femoris muscle was thought to be due to muscle strain.

Grading of the impingement is as follows:

grade 0 – normal muscle signal intensity.

grade 1 – focal edema where IFS and QFS [Quadriceps femoris space] were narrowest.

grade 2 – diffuse edema confined to muscle.

grade 3 – edema extending to surrounding soft tissues.

Initial treatment is with conservative measures and include rest and nonsteroidal anti-inflammatory drugs. CT-guided infiltration of the quadratus femoris muscle with corticosteroid and long acting anesthetic has been reported to provide long-lasting pain relief.

Surgical resection of the lesser trochanter and removal of the reaction or bursal type tissue has been performed.

FURTHER READING:

1. Johnson KA. Impingement of the lesser trochanter on the ischial ramus after total hip arthroplasty. Report of three cases. J Bone Joint Surg Am 1977; 59:268-269.

2. Patti JW, Ouellette H, Bredella MA, Torriani M. Impingement of lesser trochanter on ischium as a potential cause for hip pain. Skeletal Radiol 2008; 37:939-941.

3. Torriani M, Souto SC, Thomas BJ, Ouellette H, Bredella MA: Ischiofemoral impingement syndrome: an entity with hip pain and abnormalities of the quadratus femoris muscle. AJR 2009; 193:186-19