Femoro-acetabular Impingement(FAI) Symptoms & Treatment

The hip is often referred to as a “ball and socket” joint. The ball at the top of the thigh bone (called the femur) fits into the socket (the acetabulum) in the pelvic bone. The hip labrum is a special ring of cartilage, or rubber-like tissue, that attaches to and covers the outer rim of the acetabulum. It helps to secure the ball in the socket and also gives your hip joint additional cushioning and stability. In Femoro-acetabular Impingement (FAI), either as a result of congenital formation of the hip joint or in some cases early joint degeneration, bony overgrowth occurs preventing the bones from moving smoothly during your range of motion. This results in abnormal contact between the femur and the acetabulum which often leads to tearing of the labrum and damage to the joint surfaces.

There are three types of FAI

Pincer – This type occurs when the bony overgrowth occurs on the acetabulum or socket side.

Cam – This type occurs when the bony overgrowth occurs on the femoral side where the femoral head (or ball of the hip joint) is not round and therefore cannot rotate smoothly in the socket.

Combined – This type occurs when there is bony overgrowth on the acetabulum (socket) combined with loss of the normal round shape of the femora head (ball). 

FAI is caused by abnormal development of the hip bones resulting in one of the three types of impingement in association with high intensity repetitive activities especially those that demand flexion (bending) and rotation of the hip such as running, jumping, cutting and pivoting.

 FAI is a common injury in the following sports:

• Soccer
• Tennis
• Lacrosse
• Hockey
• football
• squash
• martial arts
• gymnastics

Typical symptoms of FAI include pain in the groin, but it is not unusual to have pain more diffusely throughout the hip joint.

The most common hip symptoms are:

• Limping
• Pain with activity especially with bending the hip combined with turning inward
• Stiffness and limited range of motion of your hip

Clicking or catching with rotation of the hip

If your symptoms don’t improve or get worse over time, you should see your doctor. Your doctor will ask questions about your symptoms (called a medical history) while also inquiring about your sports activity. Your doctor will then examine your hip. One physical test for a FAI  is called the “impingement test.” This test involves bending your hip to a right angle while bringing it slightly across your midline, and then turning the hip inward to duplicate the position of abnormal contact. If this test causes pain, you may have FAI.

Special x-rays of the hip will assist your doctor in making the diagnosis of FAI by showing the shapes of the bone. CT scans are useful to further demonstrate the bony anatomy.  However, when FAI is suspected by history and physical exam, magnetic resonance imaging (MRI) tests are very useful for showing damage to the labrum, the joint cartilage and other soft tissue

If your physician suspects FAI he/she may suggest:

• Rest
• Applying ice to the affected area
• NSAIA (non-steroidal anti-inflammatory analgesic) pain relief drugs such as ibuprofen or aspirin
• Activity modification
• Physical therapy
• Cortisone injection to relieve pain

Surgical intervention might be necessary if non-operative treatment fails.  Surgical treatment options will depend on the type of FAI identify on the x-rays and CT, the MRI findings and certain patient specific factors (for example, age, weight, athletic interests, and extent of the condition).  The surgical options for FAI include:

• Arthroscopic surgery – arthroscopic surgical techniques are useful to remove the bony overgrowth on the acetabular (socket) and femoral side – to “reshape” the bones so that the impingement is relieved. In addition, certain tears of the labrum associated with FAI can be repaired arthroscopically.  Finally, damage to the joint surfaces, if detected, can be cleaned, trimmed and smoothed arthroscopically.  These procedures are most often performed as “day surgery” in ambulatory surgical centers (ASC).
• Open surgery – in some situations, the bony deformities (pincer, cam or combined) are of such extent that they are too large to be treated arthroscopically. In these cases, your surgeon may recommend a more formal open procedure to remove the impingement.  These may be performed in an ASC or a hospital setting.
• Total hip replacement – if damage to the joint as a result of longstanding FAI is severe and has progressed to the point that areas of the joint cartilage have been completely worn away down to bone, and if your symptoms are also severe and have not responded to non-operative treatment, your surgeon may discuss with you the possibility of undergoing a hip replacement procedure.

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Recovery from FAI depends on the severity of the condition and the treatment chosen whether it be non-operative or operative intervention.

If surgery is not needed, you can often recover from a flare up of FAI in 3 – 6 weeks.

If surgery is needed, the recovery will depend upon the specific nature of the operation performed and can take from 3 – 6 months.  You may need to be use crutches for a period of time and will need physical therapy to fully rehabilitate from the procedure. 

You can typically return to sporting activity when you have regained your full range of motion and strength and no longer experience pain