What is femoroacetabular impingement?
Femoral acetabular impingement is the formation of bony bumps, either at the head/neck junction of the femoral component of the hip joint or along the acetabulum or the socket of the hip joint. Formation of the small bony bumps around the head/neck concavity of the hip joint are known as cam lesions and formation of the bony bumps around the acetabular component are known as pincer lesions.
What are the symptoms and signs?
The symptoms classically are activity-related groin pain in the young adult hip.
What investigations may be required?
The gold standard investigation is an MR arthrogram which involves the infiltration of a small amount of dye into the hip followed by an MRI scan and this gives unrivalled access to the bony or soft tissue structural derangement which may exist.
Can the problem get worse?
Once the impingement has set in, the problem is unlikely to spontaneously resolve unless significant activity modification is undertaken. There is now also an accruing body of evidence to suggest that these lesions may be pre-arthritic in nature.
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Differential diagnosis
- Rectus femoris tendon inflammation
- Snapping hip
- Rectus femoris avulsion fracture
- Iliopsoas bursitis
- Hip flexor strain
- Inguinal hernia
- Groin strain
- Femoral hernia
- Labral tear
- Osteoarthritis