What is Femoroacetabular Impingement (FAI)?
Hip impingement, also known as femoroacetabular impingement (FAI), is a condition in which there is abnormal contact between the femur bone (femoral head) and socket of the hip joint (acetabulum) during certain movement of the hip.
The resulting impaction can damage the cartilage inside the hip joint. There is growing evidence that this may lead to premature arthritis.
FAI was first described by a Professor of Orthopaedic Surgery from Switzerland and is traditionally described as due either to a shape abnormality of the ball of the femur (CAM FAI) or of the acetabular socket (PINCER FAI).
However, recent research by Mr Freedman and Professor Damian Griffin has demonstrated that movement of the hip joint is complex and that the overall 3-dimensional shape and orientation of the hip should be considered to properly evaluate and treat clinical impingement.
Patients with FAI often experience pain in the groin with deep flexion or rotation of the hip during certain activities. If the condition has been present for some time, there may also be inflammation of the tissues surrounding the hip such as on the outer side of the hip (trochanteric bursitis), the groin muscles (adductor tendonitis) or inflammation of tendons in front of the hip. Eventually, as the damage continues, the patient may begin to develop more arthritic symptoms such as a dull ache in the groin and increasing stiffness. Hip-related pain is not always felt directly over the groin. It may also be felt on the outer aspect of the thigh, the buttock or traveling down the leg.
Patients who have symptoms suggestive of hip impingement are usually investigated with x-rays of the hip, a CT scan and special MRI scan called Magnetic Resonance Arthrography (MRA). The CT scan is performed to study the bony detail of the hip and the MRI is used to assess the cartilage, labrum and other soft tissue structures in and around the hip. Mr Freedman will often also organise for a computer-generated 3-D model of your hip to be produced so that the shape of your hip can be accurately studied. This assists in planning for accurate corrective surgery. New motion analysis software adds further sophistication to operative planning.
- Non-surgical Treatment for FAI:
Treatment of femoroacetabular impingement symptoms often begins with conservative, non-surgical methods. Mr Freedman utilises a special hip rehabilitation program developed by specially trained hip physiotherapists to improve the stability and function of the hip. Rest, activity modifications and selective use of non steroidal medication are often helpful in alleviating early symptoms. An injection of the hip joint with anesthetic can provide some relief as well as diagnostic information in patients with symptoms which are unresponsive to treatment.
- Surgical Treatment for FAI:
For definitive treatment, Femoroacetabular Impingement (FAI) can be addressed with surgery to improve the shape of the hip.
The aim is to correct the bony deformity before there is irreversible joint damage. In many cases this can be done by hip arthroscopy (keyhole surgery). Using minimally invasive surgery and specialised instruments, the deformity can be delicately reshaped. Hip arthroscopy is highly specialised and technically difficult surgery but can achieve excellent results if carried out correctly and on the right patient.
Occasionally, the bony deformity may be so large or awkwardly situation that an adequate bony reshaping may not reliably be achieved using key-hole surgical techniques. In those cases the operation may be performed using a “mini-open” or open technique. The advantages and disadvantages of the various treatment options will be discussed at the time of your consultation.