Femoral Acetabular Impingement 

 

What is it?

Femoral acetabular impingement (FAI) is a condition of the hip joint whereby pinching of the bone ends leads to pain and inflammation. The femur is the long thigh bone and at its upper end it forms the ball part of the hip ball and socket joint. The socket part is made up of the acetabulum which is the lower part of the pelvic bone called the ilium. This condition causes abnormal rubbing of the bone surfaces together and a gradual wearing of the articular cartilage. Commonly, impingement type symptoms occur when the thigh bone is brought up into a flexed position and then turned in towards the midline (as in the position of the upper leg when crossing your legs).

Early symptoms can be managed with physiotherapy but persistent or chronic pain may require a visit to see an Orthopaedic surgeon. FAI is diagnosed using a number of investigations such as X-rays and scans. By examining the x-rays it can be seen whether there is a 'cam' or 'pincer' element to the impingement. 'Cam' comes from the Dutch word for cog and means that the femoral head (ball) is not perfectly round and therefore causes abnormal contact in certain positions with the acetabulum (socket). 'Pincer' comes from the French word to pinch and describes the excess overlay of bone which protrudes from the acetabulum which can press into the femoral neck causing impingement.

Causes

It is not clear what causes FAI but it is thought that significant sporting activity in adolescence, before the bones have fully matured may increase the likelihood of developing FAI. It is not known whether there is any genetic or familial disposition to developing the condition.
 

FAI is commonly mistaken for numerous other musculoskeletal conditions as the discomfort can refer into a range of places. It is important to ensure you have a thorough physiotherapy assessment to determine the cause of your problem as FAI can mimic symptoms of lower back pain, piriformis syndrome, sacro-iliac disorders, groin strains, sports hernias and trochanteric bursitis.
 

This condition is often associated with sports or activities which place the joint in the symptomatic position for repeated or prolonged periods of time i.e. horse riding, field hockey, ice hockey, kayaking, rowing, golf, and rugby.
 

Treatment

Initially it is important to make a clear clinical diagnosis in order to ensure a correct treatment programme. Commonly, there will be a restriction of normal movement of the hip joint and some associated muscle and soft tissue imbalances. Treatment will be aimed at abolishing symptoms whilst trying to restore improved joint movement and importantly returning normal strength and function to the joint. A tailored programme of rehabilitation will be necessary focusing on the individual’s specific requirements.
 

It may be necessary to seek Orthopaedic assessment and undergo some further investigations if symptoms are persistent or particularly intractable. There are numerous surgical options available to deal with this problem ranging from keyhole joint exploration to joint replacements and these options would be discussed with your Orthopaedic Surgeon.