Femoroacetabular impingement (FAI) is a condition where you grow extra bone at the hip joint, giving the bones an abnormal shape. The bones can rub against each other during movement. Over time, this can damage the joint, create pain and limit function. This can result in tears or breakdown of the cartilage in the hip.
The hip is a ball-and-socket joint, formed by the acetabulum of the pelvis (socket) and the head of the femur (ball). Cartilage covers both parts of the joint creating a smooth gliding surface. There’s a fibrocartilage ring around the socket called the labrum which helps provide stability to the hip.
There are three types of FAI: cam, pincer, and combined
- Cam. With a cam deformity, bony growth alters the shape of the femoral head preventing it from moving smoothly within the socket. It can wear at the cartilage of the acetabulum.
- Pincer. With a pincer deformity, impingement occurs because bony growth extends out over the normal rim of the acetabulum. The can result in crushing of the labrum.
- Combined. In a combined presentation, both cam and pincer deformities are present.
FAI is not an acquired issue like typical osteoarthritis, but rather it usually formed during childhood. Some live their whole lives and never have an issue with it. Once symptoms develop, this typically means some damage has resulted from the FAI, such as to the articular cartilage or the labrum. FAI typically progresses from there. Active people who use their bodies more intensely may become symptomatic sooner than those who are less active.
FAI typically results in pain, hip stiffness and altered gait. The pain is often in the groin area, but can show up elsewhere as well. Pain can come from many different hip motions, but often is worst when trying to pull the knee toward the opposite shoulder. The quality of the pain can range from a dull ache to stabbing pain. Though there are orthopedic tests said to show impingement, reliable diagnosis requires imaging. The orthopedic tests are too non-specific, often showing positive with garden-variety hip compression.
The standard treatments for FAI are avoiding the offending motions, NSAID’s, physical therapy, and surgery — up to and including hip replacement. The BEST treatment in most cases is achieving and maintain stability and mobility of the structures of the hip. This can include corrective exercise, manual therapy, and mobility training. Click here for some good stretches and exercises to help.
Ideally, prevention is best. You can’t necessarily prevent FAI itself from happening, but you can often prevent it from becoming symptomatic in the first place, and ultimately from causing irreversible damage to the hip joint.