Femoroacetabular Impingement

What is Femoroacetabular Impingement (FAI)?

Femoroacetabular impingement (FAI) is a condition in which there is abnormal contact between the bones of the hip joint during movement. The hip is a ball-and-socket joint, formed by the head of the femur (the ball) and the acetabulum (the socket). In FAI, extra bone develops on the femoral head, the rim of the socket, or both, causing the two to abut abnormally — particularly when the hip is flexed and rotated. Over time this repeated abnormal contact can damage the labrum (the cartilage rim of the socket) and the joint cartilage, and is a recognised contributor to hip pain and early arthritis in younger, active people.

Types of FAI

FAI is generally described in terms of where the extra bone lies:

• Cam type: extra bone on the femoral head/neck, so it is not perfectly round and jams against the socket during movement.
• Pincer type: the socket provides too much coverage over the femoral head, leading to abnormal contact at the rim.
• Mixed type: a combination of both, which is common.

Symptoms

• Groin pain, often brought on by activity or prolonged sitting
• Pain with movements that flex and rotate the hip, such as squatting or getting in and out of a car
• A catching, clicking, or pinching sensation in the hip
• Stiffness and a reduced range of movement
• Symptoms common in active individuals and athletes

Diagnosis

Diagnosis is based on the history and a clinical examination, including specific tests that reproduce the impingement, supported by imaging. X-rays identify the bony shape of the femoral head and socket and any extra bone. MRI — sometimes with contrast injected into the joint — is used to assess the labrum and cartilage in detail. Accurate assessment of both the bony anatomy and the soft tissues guides treatment.

Treatment Options

Treatment depends on the severity of symptoms, the structural findings, the condition of the labrum and cartilage, and your activity goals.

Non-surgical treatment

• Activity modification to reduce provoking movements
• Physiotherapy to optimise hip muscle strength and movement patterns
• Anti-inflammatory and pain-relieving measures
• Injections in selected cases

Surgical treatment

Where symptoms persist despite non-surgical treatment, surgery may be considered to address the abnormal bony shape and treat any associated labral or cartilage damage. This is commonly performed arthroscopically (keyhole surgery) and aims to reshape the bone so the hip can move without impingement and to repair or treat the labrum where needed. The most appropriate approach depends on individual factors and will be discussed with you at your consultation. (See also the Hip Arthroscopy and Labral Tears pages.)

Recovery and Outlook

Treating FAI aims to relieve symptoms and, by correcting the abnormal contact, may help protect the joint over the longer term. Where surgery is undertaken, a structured, staged rehabilitation programme is important to a good outcome. Recovery depends on the specific treatment and will be explained according to your circumstances.

Frequently Asked Questions

Does everyone with FAI on imaging have symptoms?

No. The bony shapes associated with FAI can be present in people without symptoms. Treatment is directed at FAI that is actually causing pain and dysfunction, which is why diagnosis combines your symptoms, examination, and imaging rather than relying on imaging alone.

Can FAI be treated without surgery?

Many people improve with non-surgical treatment focused on activity modification and physiotherapy. Surgery is generally considered when symptoms persist despite these measures, or where there is significant associated labral or cartilage damage.

Is FAI linked to hip arthritis?

FAI is recognised as a contributor to labral and cartilage damage and to early hip arthritis in some people. Addressing significant, symptomatic FAI aims to relieve symptoms and may help protect the joint, though outcomes vary between individuals.

Medical Disclaimer
The information on this page is intended as general patient education and does not constitute medical advice. Every patient is different, and treatment decisions should always be made in consultation with a qualified medical professional based on your individual circumstances, health history, and imaging. Outcomes from treatment vary between patients and cannot be guaranteed. If you have concerns about your hip health, please contact Dr Slattery’s rooms to arrange a consultation.