By Andrew Lay. Grad Cert Sports Physio, B.Physio (Hons)

FAI is a common hip joint condition which typically manifests as pain at the front of the hip and/or groin. It is more common in activities requiring greater hip flexibility such as dancing, gymnastics, football, soccer and repetitive squatting.

Understanding FAI requires basic knowledge of hip joint anatomy. The hip joint is comprised of a ball and socket (Figure 1), whereby the ball is formed by the head of the thigh bone (femur) and the socket is formed by the pelvic bone (acetabulum).



Figure 1: Hip joint

Pain in the front of the hip and/or groin that is coming from the hip joint can be due to (i) classic FAI or (ii) hip joint dysplasia.

Classic FAI can be due to a socket that is too big (pincer type), a ball that is too big (cam type) or a mixture of both (combined). Due to the relatively larger size of at least one of the parts that form the hip joint, hip movements can be restricted due to premature contact between the bones. As a result, people can experience a lack of joint flexibility and pain, especially during movements which bring the knee up towards the chest and across the middle of the body. In most cases, physiotherapy management involving strengthening of specific hip muscle weaknesses and treatment to loosen overactive muscles can reduce the pain and enable someone to continue with their sport and activities. Uncommonly, minor surgery may be required to address the excessive bone, however the appropriate hip muscle strengthening will be required in any case. If left unmanaged, arthritis can develop in the hip later in life.




Figure 2: Mechanisms of classic FAI

Hip dysplasia is the underdevelopment of the socket, such that the socket is unable to provide adequate coverage of the ball (Figure 3).

In these cases, the hip joint is less stable during movement and cause the ball to prematurely contact the front of the hip despite neither the ball or socket being enlarged as described in classic FAI. This can give pain which is very similar to that in classic FAI. Surgery such as that for FAI is generally not recommended in these cases.



Figure 3: Left hip dysplasia (pictured on the right) as shown by the lack of coverage of the socket over the ball compared to the right hip.

Given that the pain can be the same for both FAI and dysplasia, an assessment by a physiotherapist at PhysioHealth is recommended to determine whether pain in the front of the hip and/or groin is due to FAI, dysplasia or other potential causes not relating to the hip joint. Our physiotherapists can help you avoid unnecessary surgery and continue sports and gym activities by addressing muscle imbalances through hip strengthening and hands-on treatment.