Femoroacetabular impingement (FAI)

There are two types of hip impingement: 'Cam' and 'Pincer'. Cam is when the head is not perfectly round and doesn't fit the joint. 'Pincer' is where the extra bone extends over the joint socket, causing the femur bone to bump into the rim of the socket.

Both conditions wear down the shock absorbing cartilage in the hip joint and the nerve-packed seal around the edge of the joint (labrum). This causes pain and makes it hard to move.

Other symptoms include:

• stiffness in the thigh, hip, or groin
• the inability to flex the hip beyond a right angle
• pain in the groin area
• pain in the hip, groin, or lower back when resting
• clicking of the hip

Your consultant will discuss your symptoms to help make a thorough diagnosis. FAI can affect people of all ages, and is often missed in 30-40-year-olds. Taking a careful history, and carrying out a thorough examination can help identify the likely cause.

Imaging, such as an MRI scan (sometimes with an arthrogram) of the hip, can help confirm the underlying diagnosis (as X-ray cannot rule out FAI). A CT scan can also be very helpful giving a 3D reconstruction of the joint. Consultants skilled in sports injury are often experts at identifying FAI.

FAI may require keyhole surgery (hip arthroscopy) to reshape the joints, but in some cases injection therapy and robust physiotherapy or osteopathy may be enough to get a person back to full activity.

An abnormally shaped femoral head or hip socket can often be sculpted and reshaped. These procedure restore smooth movement in the hip and reduce pain. If there is an associated labral tear, this is often repaired.