Femoral-Acetabular Impingement in Runners
FAI is a growing diagnosis in people with hip pain, especially young athletes. FAI is divided into two categories, the first being of CAM type (a bony growth formation on the neck of the femur that typically only causes symptoms at the extremes of movement), and the second being of Pincer type (increased depth to the acetabulum that leads to an over-coverage of the femoral head).
In runners, any force that may cause the femoral head to be shifted forwards in its socket may contribute to symptoms of FAI. These include positions of hyper-extension, either during movement or rest, or alternatively tightness in the back of the hip. This will contribute to the symptoms as it places a greater load on the top of the acetabulum. Runners who over-extend their hip during the push-off phase of gait may be at risk of irritating a sensitive hip. The reason for this is that during hip extension the femoral head translates forwards in is socket (by a small degree). This places an increase in load bearing through the top rim of the acetabulum and the superior labrum. Some of the leading research scientists in hip impingement have shown that insufficiency (either strength or co-ordination) of the iliopsoas during hip flexion, or of the gluteus maximum during hip extension, can lead to an increase in the anterior glide of the femoral head.
Also, the acetabular labrum helps to maintain a vacuum seal on the hip joint. This vacuum helps with some of the shock absorbancy of the hip by keeping the synovial fluid in the places it is needed. Therefore, if the labrum is torn then there is likely to be a reduction in the vacuum in the hip joint and therefore a reduction in shock absorption.
From my experience and the available research on rehabilitation for FAI, physical therapy does have a place in identifying factors that may be contributing to the problem and treating those. Depending on the significant findings of the patient during the initial assessment, a combination of hip manipulation, correction of muscle imbalances, and improving the efficiency in running form can help to minimize the patient’s symptoms and maximize their potential performance.