Femoroacetabular Impingement in the Hip: an increasingly recognized cause of hip pain in younger patients
The past thirty years have shown an impressive evolution of our ability to treat people with hip problems as well as our understanding of the etiology of these problems. Prior to the advent of hip replacement surgery, the answer was "grab a cane and some aspirin." This was unsatisfactory for many people. Then the answer became, "wait 'til it's bad enough, then have a hip replacement (or, perhaps, more recently a hip resurfacing)." This was and remains an excellent option or for many people. However, for younger people as well for those who participate in relatively demanding activities and do not have significant arthritis, this is not the best option. It has been increasingly recognized that many of these people have symptoms caused by femoroacetabular impingement (FAI). Additionally, a consensus is growing that many of the predominantly older population who eventually go on to having hip replacements were not due to something "idiopathic", but rather had FAI as the underlying cause of their arthritis.
What is FAI?
At a fundamental level, FAI represents abnormal contact between the proximal femur and the acetabular rim. FAI is a result of excessive coverage of the femoral head by the acetabulum (Figures 2 and 3) in what is termed "pincer-type impingement", or a bony abnormality at the femoral head-neck junction (Figures 1 and 3) in what is termed "cam-type impingement." In the majority of cases, there is actually a component of both pincer- and cam-type impingement. The end result is an abutment of the femoral head-neck junction against the acetabulum during hip range of motion. Along the edge of the acetabulum is the labrum which functions as a cushion cartilage and is thought to provide a suction seal for hip stability. The current belief is that FAI leads to labral tears and the onset of degenerative arthritis.
What are the symptoms of FAI?
FAI usually presents as groin pain with activities or with hip motion. Sometimes these patients can recall a traumatic event which they note as the cause of their symptoms, but often the onset is more insidious. The most common finding is patients with pain which is reproduced when they are positions of flexion, adduction and internal rotation. The symptoms can be chronic and achy, or sharp and mechanical with certain motions. In some cases the patients will have pain which mimics or is concomitant with buttock pain (i.e. sciatica), lower abdominal pain (i.e. sports hernia), medial groin pain (i.e. adductor or iliopsoas strain or tendinitis), or lateral hip pain (i.e. trochanteric bursitis).
What is the treatment of FAI?
The most appropriate initial treatment for most patients is physical therapy focusing on hip range of motion, stretching and strengthening of core musculature. Physical therapy in combination with intermittent NSAIDs can often help alleviate symptoms for long periods of time. In select patients, sparing use of corticosteroid injections into the hip joint can be of benefit. Use of these modalities in concert with activity modification is oftentimes successful in the treatment of FAI.
In those cases where non-operative measures have failed to provide adequate relief, surgical options are considered. The goals of surgery are predominantly two-fold: 1. to remove the offending pathology which is the excess bone which is impinging-that is either from the femoral side, the acetabular side or both, and 2. to repair or debride the labral tear. These goals were initially attained and still commonly attained as an open procedure. The results from the open procedure have generally been good, but the recovery is difficult as the exposure to the hip requires a large incision, an osteotomy of the greater trochanter and a surgical hip dislocation.
With the advent of improved arthroscopic techniques and technology, performance of this surgery through two to three one centimeter incisions has become possible. Through these incisions, a camera and instruments are passed into the hip joint. An arthroscopic burr is used to remove the excess bone from the proximal femur and or the acetabulum (Figures 1-3). Using arthroscopic suturing techniques, the labrum can be repaired to the rim of the acetabulum. In contrast with the open treatment of FAI, there is little long-term data on the arthroscopic treatment of FAI. However, recent reports have been extremely encouraging in patients without advanced hip arthritis.
Artist: Marty Bee, Steadman Hawkins Clinic