Femoro-Acetabular Impingement (FAI) / Labral Tear
What is the hip joint?
The hip joint is a ball and socket joint. The femoral head is the ball at the top of your thigh bone (femur), which sits inside the socket (acetabulum) in the bones of your pelvis. The ball and socket are both covered by a thin layer of articular cartilage. This is the smooth surface which allows your hip to move freely without friction. Around the edge of the socket is another layer of fibrocartilage called the labrum. This cartilage is strong and helps deepen the hip joint and provide stability to your hip. The whole joint is surrounded by a layer of fibrous tissue called the hip capsule. This separates the joint from the surrounding muscles and tendons.
What is femoro-acetabular impingement (FAI)?
In a normal hip joint the ball and socket are both perfectly round. This means that the ball can move freely in all directions without touching the edge of the socket. FAI is a condition in which excess bone forms at the edge of the ball or socket. When the hip joint moves into certain positions such as deep bending (flexion), the ball comes into contact with the edge of the socket. With time this causes damage to the labrum (see above) and results in pain. Over many years this can eventually lead to arthritis.
There are two main types of FAI:
CAM impingement. This occurs when extra bone forms on the femoral head. The bump of bone is called a CAM lesion.
Pincer impingement. This occurs when extra bone forms at the edge of the socket. The spur of bone is called a pincer lesion.
CAM and pincer impingement can also occur together.
What is a labral tear?
A labral tear is when the cartilage rim (labrum) around the socket becomes frayed, torn or detached from the edge of the hip socket (acetabulum). This can happen either acutely as a result of an injury, or gradually as a result of FAI or hip arthritis. Different treatment may be recommended depending on the cause of the tear.
What are the symptoms of a labral tear / FAI?
Patients with a labral tear or FAI typically present with deep groin pain which is made worse by physical activity. The pain may start after an injury, or can come on gradually. Pain is generally less when resting. The pain is often made worse by activities such as sports, running, prolonged sitting or driving.
How is a labral tear /FAI diagnosed?
A labral tear or FAI can usually be identified from your symptoms and clinical examination. The extra bone which forms in FAI can be seen on x-rays. Cartilage is best seen on an MRI scan. A combination of x-rays and an MRI scan are needed to confirm the diagnosis and plan for any surgery. A CT scan may also be required to help your surgeon plan your operation.
Can my hip be treated without surgery?
The signs of FAI are commonly seen on x-rays of patients who do not have any symptoms (up to 1 in 4 people). Most people will not go on to develop pain or arthritis. Even people who develop pain can improve with non-operative treatment. A recent large study showed up to 60% of patients with a labral tear will get better without surgery. Treatment with physiotherapy, activity modification, anti-inflammatory medication and cortisone injection into the hip joint (only in some cases) is often recommended before considering surgical intervention. Physiotherapy should be directed by a physiotherapist trained in sports rehabilitation, and should be targeted to improve the strength of the hip girdle and pelvic stabilising muscles.
Who needs Surgery?
Surgery for FAI or labral tears is indicated if pain and restriction of daily activities persist after an appropriate non-surgical rehabilitation programme. Keyhole hip surgery is most effective for traumatic labral tears, or labral tears caused by FAI. Degenerative labral tearing can occur as a result of hip arthritis and can not be improved with keyhole surgery. Labral tears can also occur in hip dysplasia (a condition in which the hip socket is too shallow). Surgery could be required for this condition, but may involve open surgery to re-align the hip socket.
What is hip arthroscopy?
Please click this link to learn more about hip arthroscopy.