Femoroacetabular Impingement (FAI)

Femoroacetabular impingement (FAI) is when the head of the thigh bone (femur) and the socket in the pelvis (acetabulum) do not match in shape and knock against each other, especially when the hip bends and turns inwards. There may be extra bone at the head–neck junction of the femur (cam type), too much cover at the rim of the socket (pincer type), or both (mixed type). Over time it can cause a labral tear and cartilage damage; it is common in young, active people.

Symptoms

Typical complaints:

• Pain in the groin or front of the hip, especially after sitting for a long time
• Pain when squatting, getting into a car or crossing the legs
• Strain during sudden changes of direction and jumping in sport
• Catching or clicking in the hip (when a labral tear is present)
• Limited hip movement, especially turning inwards

Diagnostic Methods

In the examination, the impingement (FADIR) test, which brings on pain as the hip is bent and turned inwards, is a useful guide. X-rays show the shape difference and its type. MRI or MR arthrography assesses the labrum and cartilage, and CT helps plan surgery when needed. A diagnostic injection into the joint can also help show where the pain comes from.

Treatment Approach

Non-Surgical Treatments

The first step is avoiding the movements that trigger pain, physiotherapy to balance the hip and core muscles, and anti-inflammatory medication. If the symptoms do not settle, surgery is considered.

Surgical Treatment

With hip arthroscopy, the extra bone is reshaped to remove the impingement (osteoplasty) and the torn labrum is repaired. In patients with advanced cartilage damage and a narrowed joint space, arthroscopy helps less, and other options are considered.

Surgical Process

Performed under general or spinal anaesthesia through small incisions with a camera, usually taking 1.5–2.5 hours.

Hospital Stay

Usually one night in hospital.

Recovery Process

• Weeks 0–3: Partial weight bearing on crutches, movement restrictions, controlled exercises
• Weeks 3–6: Moving to full weight bearing, physiotherapy
• Weeks 6–12: Strength and endurance
• Months 3–6: Sport-specific exercises and a gradual return to sport

Return to Work

Desk work usually after 2–3 weeks, standing jobs after 6–8 weeks, heavy physical work after 3–4 months.

Potential Complications

Possible problems: temporary numbness from the traction applied to the leg during surgery, adhesions or stiffness in the hip, deep vein thrombosis, infection (rare) and symptoms that persist. Patients with advanced cartilage damage may develop arthritis in later years.