There are many variations of the ‘normal’ hip joint and these often come under the umbrella term of femoracetabular impingement.
A Cam Lesion affects the femur and essentially refers to an extra bony prominence on the front of the femoral neck. As the hip is bent up, this bump can impact the front of the acetabulum and limit movement.
Likewise, on the acetabular side, a Pincer Lesion refers to the extra bone on the edge of the socket that again can limit movement.
Often patients have a combination of both lesions.
FAI in itself is not a pathology, it is simply an anatomical variation of the hip joint. Of the estimated 20% of the population with FAI, only 23% of this cohort complain of hip pain. Often, this issue can be successfully treated with an appropriate rehabilitation programme.