Impingement (FAI)
What is Femoro-Acetabular Impingement?
Femoro-acetabular Impingement (FAI) is a condition where the bony shape of femoral head (ball) or the acetabulum (socket) is abnormal, resulting in progressive injury to the hip joint cartilage. Due to the abnormal shape of the hip joint, the thigh bone abnormally strikes against the rim of the socket, causing damage to the socket lining. FAI is a leading cause for the development of osteoarthritis, particularly in men.
Figure: FAI. Abnormal ridge of bone at upper end of thigh bone marked (arrows)
What is causes FAI?
The abnormality in shape of the hip joint bones may be present at birth or develop in early childhood. Some childhood hip conditions may result in irregularity of the shape of the upper thigh bone. In most cases the condition has been silent and unrecognised for many years.
I've never had a pain from my hip before, why now?
The hip does not become painful until enough damage has accumulated in the joint. The first symptoms are often mild groin discomfort. Once the joint becomes painful, a gradual deterioration can reliably be predicted, however reducing your activity level may reduce the symptoms.
What are the consequences of FAI?
Patients with FAI experience hip discomfort and pain. The symptoms fluctuate according to activity levels and are often made worse by sport and activities which require deep bending of the hip (for example getting out of a car). Some patients report a history of repetitive 'groin sprains' which typically are slow to settle or recur easily. In the long term, FAI causes progressive damage to the cartilage on the rim of the hip socket, leading to osteoarthritis. While osteoarthritis is a slow process to develop, surgical treatment of the abnormality causing FAI may slow or prevent the progression of joint damage and improve symptoms.
What treatment options are available?
Many patients with FAI or early arthritis can improve their symptoms by reducing or modifying their activity levels, together with the use of pain killers and anti-inflammatory medications. Surgical treatment depends on the type of FAI and its cause. In the abscence of significant arthritis, many patients with FAI are suitable for treatment with hip arthroscopy (minimally invasive key-hole surgery). Other surgical treatments for FAI include open debridement, femoral osteotomy and triple pelvic osteotomy. I will recommend a particular treatment based on the assessment of your condition.
What is hip arthroscopy?
Arthroscopy is key-hole surgery of the hip joint using a pencil sized fibre-optic camera. Arthroscopy allows the surgeon to safely and accurately assess damage to the hip joint and to perform corrective procedures. Hip arthroscopy is a minimally invasive procedure which allows a relatively rapid post-operative recovery and is useful in the treatment of FAI. The most common types of FAI can often be treated with an arthroscopic bone reshaping procedure called an osteoplasty.
What is an open hip debridement?
Open debridement is usually used in situations where the shape of the ball or socket is too distorted to allow treatment by arthroscopy, or where the portion of bone that needs to be reshaped is better accessed by an open procedure. Open debridement involves an incision either on the side of the thigh or around the lower bikini line, allowing the bone of the hip joint to be reshaped.
What is a femoral osteotomy?
Femoral osteotomy is a procedure used to realign an abnormally twisted thigh bone. A femoral osteotomy can be used to treat FAI, but can also provide improved range of motion to the hip joint and help correct leg length inequality. A femoral osteotomy involves cutting the thigh bone and placing a metal plate and screws to hold the bone in the corrected position until the bone unites. Femoral osteotomy is sometimes combined with an open hip debridement.
What is a triple pelvic osteotomy?
Triple Pelvic Osteotomy (TPO) is an operation used to correct an abnormally directed hip socket. TPO is performed by making two incisions, one in the buttock region and one around the lower bikini line. The pelvic bone is cut in three places, and the hip socket is rotated into correct alignment. A metal plate and screws are placed to hold the hip socket in the corrected position until the bone re-unites.
This information handout has been written by Dr Patrick Weinrauch for the purposes of patient education. The details provided are of general nature only and do not substitute for professional recommendations based an individual clinical assessment.
