Femoroacetabular impingement - pincer type

Case contributed by Ammar Haouimi
Diagnosis probable


Bilateral mechanical hip pain.

Patient Data

Age: 50 years
Gender: Male

This radiograph demonstrates an abnormal shape of the acetabuli with an over-coverage of the femoral heads by the acetabulum. There is associated bilateral coxa proufunda. 

Case Discussion

Case of a femoroacetabular impingement - pincer type. Femoroacetabular impingement is considered as a risk factor for the development of osteoarthritis. The abnormal morphology of the acetabulum and/or femoral head result in abnormal contact during hip motion which can cause a damage of the articular cartilage as well as the acetabular cartilage and be the origin of early hip osteoarthritis. 

The differential diagnosis of an over-coverage of the femoral head includes mainly:

  • labral ossification is a rare condition; it considered as an adult acquired form of pincer impingement; there is a predilection for middle-age females; it can be seen as a small punctate calcification at the superolateral acetabular margin or as an entire ossification of the labrum
  • os acetabuli are unfused secondary ossification centers of the acetabulum. Usually rounded with convex medial border and concave lateral border; they may be bilateral and partially fused to the acetabulum.
  • acetabular rim stress fractures: usually have a vertical orientation and the fragment lies near the acetabular margin

Additional contributor: A. Ramdani, MD.

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