Bilateral acetabular protrusion with pincer type femoro-acetabular impingement

CT Pelvis:

Bilateral protrusio acetabuli results in over-coverage of both femoral heads and a pincer type of femoro-acetabular impingement.

Coronal images best show the medialisation of the medial wall of the acetabulum with the femoral heads entirely covered by acetabulum.

Multiplanar multi-sequence MRA imaging of the right hip performed following intra-articular injection of 0.01% gadolinium solution. Adequate joint distension achieved. Over-coverage of the femoral head by the bony acetabulum with pincer type femoroacetabular impingement. Abnormal contour at posterior and inferior head/neck junction with an inferiorly projecting bony bump/osteophyte.

The superior labrum is blunted with superior labral tear (11-1 o'clock). In addition, there is a tear of the posterior labrum (3 - 5 o'clock).

There is loss of articular cartilage superiorly with small subchondral cysts medially.

Normal appearance of the iliopsoas, gluteal, and hamstring tendons. No muscle abnormality. No evidence of trochanteric bursitis.

Conclusion:

Pincer type FAI with anterosuperior labral tear and posterior labral tear. Early degenerative changes are present.

Post operative films. Since no preoperative films are available this film is included since it best shows the signs of acetabular protrusio. Note how the medial wall of the acetabulum is more medial than the ilio-ischial line.