What is FAI?
FAI describes excess bone at the femoral head (the ball), the acetabulum (the socket), or both. With movement, the bone of the femoral neck contacts the rim of the socket, pinching the labrum and the cartilage between them.
- CAM impingement — excess bone on the femoral neck, so the joint is no longer truly round.
- Pincer impingement — excess bone over the rim of the socket, so the labrum is repeatedly crushed against the femur.
- Mixed — both CAM and pincer features in the same hip (very common).
Labral tears
The labrum is a fibro-cartilaginous ring around the socket that deepens the joint and helps seal it. With FAI, the labrum gradually frays, splits or detaches from the bone. Labral tears can also occur after a single twisting injury.
Symptoms
- Groin pain that worsens with activity
- Pain worse after sitting for long periods, sports involving twisting, or deep flexion
- A catching, clicking or locking sensation
- Reduced range of motion, particularly with hip flexion and internal rotation
Diagnosis
A standing X-ray of the pelvis shows the bony shape of the hip. MRI — often with a contrast injection (MR arthrogram) — confirms labral and cartilage damage. A CT scan can help map the bone in more detail when surgery is planned.
Non-surgical treatment
Around 60% of patients with FAI and labral tears respond well to non-surgical care, particularly when symptoms are mild or recent.
- Activity modification — reducing the movements that aggravate symptoms
- Physiotherapy focused on hip and core stability
- Anti-inflammatory medications
- An intra-articular cortisone injection — both diagnostic and therapeutic
Surgical treatment
If symptoms persist despite non-surgical care, hip arthroscopy can reshape the impinging bone and repair or debride the labrum through keyhole incisions.