Femoroacetabular Impingement

Femoroacetabular impingement (FAI) is a condition that presents as pain in the groin or front of the hip. It is an under-recognised condition that has become more commonly diagnosed and treated in the last 20 years ⁽²⁾. It is caused by bony anatomical variations around the hip which may result in increased contact of the ball and socket joint during movement of the hip. This, in turn, can cause irritation of the bone and soft tissues around this area which may result in pain ⁽²⁾.

There are two types of bony variation that may lead to symptoms of femoroacetabular impingement. A “cam” deformity, relating to the femoral head-neck contour (top of the thigh bone) not being completely round, and a pincer deformity which is an over-coverage of the acetabulum (socket of the hip joint). These changes to the structure of the ball and socket joint rarely occur in isolation and are often combined. Patients with femoroacetabular impingement might have a higher risk of developing osteoarthritis (OA) of the hip ⁽³⁾. Therefore, early identification of patients with groin pain related to this condition is important to delay or even prevent the development of osteoarthritis.

• Congenital – meaning you are born with changes in the appearance of the hip joint which may or may not then lead to further hip joint pain.
• Developmental – this is where the shape of your hip joint changes slightly due to the increased levels of activity in particular sport(s), e.g. hockey, basketball and football. This will usually arise from a significant amount of training. Even then, not everyone will develop the changes in the hip joint and significantly less will never experience symptoms.
• Childhood hip disorders or injury – this means that it can be a secondary consequence of a hip condition you had as a child. It may be worth asking your parents if they were aware of you having any hip joint condition when growing up.
• Mechanical factors – weakness in the muscles around the hip has also been proposed as a contributor to developing symptoms ^{(1, 2, 4)}.

Research has suggested that in the general population symptoms related to femoroacetabular impingement arise in less than 1% of people ⁽⁴⁾. However, the results of a systematic review in 2015 showed that cam and pincer deformities are present in a significant number of young adults, regardless of being an athlete or not, with up to 23.1% of people in their mid-20s having a cam deformity on imaging ⁽⁵⁾. It is more common in young athletes (between the ages of 15-30) who are heavily involved in sports that comprise of high load bending and twisting movements at the hip such as basketball, football, hockey and rugby. For example, in young footballers who train more than 12.5 hours per week, there has been shown to be an increased risk of the structural changes that could lead to symptoms of femoroacetabular impingement ⁽⁴⁾.

A musculoskeletal physiotherapist can provide you with an accurate and timely diagnosis by obtaining a detailed history of your symptoms. A series of specialised physical tests might be performed as part of your assessment to rule out other potentially involved structures and gain a greater understanding of your physical abilities. Any tests done will be considered alongside your symptoms to ensure an accurate working diagnosis.

Your physiotherapist will want to know how your condition affects your day-to-day so that treatment can be tailored to your needs and personalised goals can be established. Intermittent reassessment will ascertain if you are making progress towards your goals and will allow appropriate adjustments to your treatment to be made.

It is not necessary in most cases to order an immediate scan or X-ray, as physiotherapy will most likely be the first line of treatment. If symptoms persist or get worse, an X-ray may be considered as the first port of call which can assess the hip joint and check for the presence of cam and/or pincer deformity ⁽⁶⁾. This can be arranged in collaboration with your GP. Magnetic resonance imaging (MRI) is typically requested in circumstances where the surrounding cartilage needs examination or if surgery is being discussed.

As part of the sessions with your physiotherapist, they will help you to understand your condition and what you need to do to help the recovery from your femoroacetabular impingement. This may include reducing the amount or type of activity, as well as other advice aimed at reducing your pain. It is important that you try and complete the exercises you are provided as regularly as possible to help with your recovery. Rehabilitation exercises are not always a quick fix, but if done consistently over weeks and months then they will, in most cases, make a significant difference.

In patients who are treated for femoroacetabular impingement symptoms frequently improve, and they return to full activity, including sports. Without treatment, symptoms will most likely worsen over time. The long-term outlook for patients with femoroacetabular impingement remains unclear. However, it is likely that cam morphology is associated with the development of hip osteoarthritis. It is currently unknown whether treatment for femoroacetabular impingement prevents hip osteoarthritis.

As previously mentioned, where physiotherapy is unsuccessful in reducing symptoms and allowing a normal active lifestyle, surgery can be an option. Arthroscopy (keyhole surgery) is the most common surgical procedure for femoroacetabular impingement discussed in the literature. The exact nature of each surgery varies according to the treating surgeon’s clinical judgement but will typically involve trimming and reshaping the acetabular rim (socket edge), labral repair/debridement (articular cartilage) and/or reshaping the femoral head/neck ⁽²⁾.

It should be noted that at this stage, there has been no significant difference found between the outcomes of surgery and physiotherapy and, as such, it is recommended that physiotherapy should almost always be the first option for patients with femoroacetabular impingement ^(2,7).