Hip Joint Anatomy Of Femoroacetabular Impingement (FAI)
Anatomically the hip joint is what is referred to as a ball and socket joint. The socket part of the joint is formed by the acetabulum, which is part of the large pelvis bone. And the ball part of the joint is the femoral head, which is the upper end of the thighbone (the Femur). Articular cartilage covers the surfaces of the ball and the socket, this is a slippery tissue helping create a smooth, low friction surface which helps the bones glide easily across each other.
The acetabulum part of the hip joint is also ringed by what is a strong fibrocartilage called the labrum. This labrum creates a tight seal around the joint as well as helping to provide stability to the joint.
Femoroacetabular Impingement (FAI), or hip impingement syndrome occurs when the ball shaped femoral head rubs abnormally or does not permit a normal range of motion in the acetabular socket. Causing the hip joint bones to impact against each other with certain movements and over time, this hitting against each other can result in damage to the labrum and the articular cartilage of the hip joint.
The Three Types Of Femoroacetabular Impingement:
Pincer: The pincer type of hip impingement occurs because extra bone extends out over the normal rim of the acetabulum (hip socket). In this situation the labrum can be crushed under the prominent rim of the hip socket.
Cam: In cam impingement the femoral head is abnormally shaped and not round and cannot rotate smoothly inside the socket. With a cam deformity simply put is characterised by extra bone formation causing a bump to form on the edge of the femoral head-neck junction that grinds the cartilage inside the socket.
Combined: Combined impingement just means that both pincer and cam types of hip impingement are present.
Femoroacetabular Impingement Is A Major Risk Factor For Osteoarthritis
In Femoroacetabular impingement, these bone spurs (bone overgrowth) that develop around the hip joint around femoral head and/or along the acetabulum basically stop the joint fitting together perfectly and these abnormal spurred surfaces rub causing damage to the joint. Research has indicated that a high number of young adults who have undergone an hip joint arthroscope for femoroacetabular impingement on examination during the procedure demonstrate signs of joint disease that reflect the early signs of hip osteoarthritis (OA). Also recently cam deformity, one of the types of femoroacetabular impingement has been identified as a major risk factor in end stage hip osteoarthritis.
Femoroacetabular impingement is often seen as a surgical problem and many people diagnosed with FAI go and see an orthopaedic surgeon looking for relief and answers however physiotherapy too can play pivotal role in the management of femoroacetabular impingement.
Disclaimer: Sydney Physio Clinic does not endorse any treatments, procedures, products mentioned. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific advice or assistance regarding Femoroacetabular Impingement should consult his or her podiatrist, sports medicine specialist or physiotherapist.