Hip impingement (FAI) in younger patients

Femoroacetabular impingement — usually shortened to FAI — is a common cause of hip and groin pain in younger, active adults. It is less well known than arthritis, but recognising it matters, because it can both cause significant symptoms and, in some people, contribute to the development of hip arthritis over time.

What is FAI?

The hip is a ball-and-socket joint. In FAI, the bony shapes of the ball (the top of the thigh bone) and the socket do not fit together perfectly, so they pinch or impinge against each other at the extremes of movement. There are two main patterns, which often occur together: a cam shape, where the ball is not perfectly round, and a pincer shape, where the socket covers too much of the ball.

Who gets it?

FAI tends to affect younger, active people, and is common in those who have been involved in sport, particularly during the growing years. The abnormal bone shapes develop over time and then cause symptoms when the hip is loaded and moved repeatedly.

Symptoms

The typical complaint is pain in the groin or front of the hip, often brought on by activity, deep squatting, or prolonged sitting. Some patients notice clicking, catching or a feeling of stiffness, and a reduced range of movement. The pain can build gradually and is sometimes mistaken for a simple muscle strain.

Why it matters

Beyond the pain itself, the repeated impingement can damage the labrum — the rim of cartilage around the socket — and the joint surface. Over years, in some people, this contributes to the early development of hip arthritis. Addressing significant impingement is therefore partly about relieving symptoms and partly about protecting the joint.

Diagnosis

Diagnosis combines the history, a clinical examination that reproduces the impingement, and imaging. X-rays show the bony shapes, and an MRI can assess the labrum and cartilage in more detail. It is important to confirm that the hip is genuinely the source of the pain, as groin pain has several possible causes.

Treatment

Many patients improve with non-surgical management: activity modification, physiotherapy to optimise the muscles around the hip and pelvis, and time. Where symptoms persist despite this, and imaging confirms structural impingement, surgery to reshape the bone and repair the labrum — often performed arthroscopically — may be considered. The right approach depends on the individual, the severity, and whether arthritis has already developed.

The bottom line

Hip impingement is a recognised and treatable cause of hip pain in younger people. If you have persistent groin or hip pain with activity, it is worth assessing properly — both to relieve symptoms and to understand the long-term picture for your hip.