Femoroacetabular Impingement
1. Introduction
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.
Frequently Asked Questions
- Femoroacetabular impingement (known as FAI) is a condition that results in pain in the groin, hip and down the front of the thigh.
- Not common – symptomatic femoroacetabular impingement is an uncommon condition accounting for less than 0.5% of all hip injuries (2).
- It makes up less than a third of all causes of hip and groin pain (1).
- It is more common in younger, active individuals, particularly in sports such as football and hockey.
- No.
- With the right rehabilitation approach femoroacetabular impingement generally recovers well without the need for further intervention.
- This condition is rarely linked to other serious medical conditions (2).
- Typically younger, active adults aged under 35.
- It is also seen in young, active adolescents (2).
- It may be seen in sports such as football, rugby and hockey where there is a lot of rotating and landing force.
- Males are more commonly affected than females (3).
- Pain in the front of the hip and inside of the groin.
- There may be an associated ‘clicking’ or ‘catching’ sensation during certain movements.
- Pain that increases with activity and prolonged periods of sitting (3).
- A feeling that the pain may cause the leg to “buckle” or give way underneath you.
- Modify or reduce the frequency and amount of activity that causes your pain.
- Increase the flexibility of muscles around the hip and groin.
- Improve the strength/stability around the hip, groin and lower limb.
- Anti-inflammatory medication can help although this should be guided by a medical professional (4).
- Advice from a qualified physiotherapist will be helpful in most cases.
- This will depend upon several factors including, but not limited to, duration of symptoms, age, adherence to rehabilitation, degree of structural changes, etc (7).
- We would expect to see improvement in symptoms within 2-3 months, and certainly no longer than 4-6 months (6).
We recommend consulting a musculoskeletal physiotherapist to ensure exercises are best suited to your recovery. If you are carrying out an exercise regime without consulting a healthcare professional, you do so at your own risk.
2. Signs and Symptoms
The primary symptom of femoroacetabular impingement is movement-related or position-related pain in the hip or groin, alongside a limited range of movement in certain positions (2). Having the hip fully bent with the knee turned inwards (internal rotation) is the position that is most frequently identified as symptomatic. Pain is typically worse while doing activities such as squatting, twisting of the hip and after prolonged periods of sitting (1,2).
Patients with the condition will describe a constant dull ache that is worse after activity. They may also describe a ‘catching’, ‘locking’ and ‘clicking’ sensation with aggravating activities. The longer symptoms go on and the more significant the irritation, the wider the area these symptoms can be experienced. It is often the case that symptoms can ‘refer’, or travel, as far down as the inside of the knee.
3. Causes
- 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).
4. Risk Factors
This is not an exhaustive list. These factors could increase the likelihood of someone developing femoroacetabular impingement. It does not mean everyone with these risk factors will develop symptoms.
- Age – this condition is more common in those aged under 35 years.
- Gender – men are more prone than women and male athletes are 3 times more likely to experience symptoms associated with femoroacetabular impingement than females.
- Childhood hip disorders – it may develop due to potential trauma or conditions that may alter the structure of the growing hip joint during childhood.
- Reduced hip flexibility – as this can increase compressive forces at the hip joint.
- Excessive training loads – this increases stress around the hip joint and leads to pain.
5. Prevalence
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).
6. Assessment & Diagnosis
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.
7. Self-Management
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.
8. Rehabilitation
It is widely agreed that the best starting point in the management of femoroacetabular impingement is physiotherapy led rehabilitation (2). This will focus on optimising the movement, flexibility, strength and stability around the lumbar spine, pelvic and hip regions.
9. Femoroacetabular Impingement
Rehabilitation Plans
Our team of expert musculoskeletal physiotherapist have created rehabilitation plans to enable people to manage their condition. If you have any questions or concerns about a condition, we recommend you book an consultation with one of our clinicians.
What Is the Pain Scale?
The pain scale or what some physios would call the Visual Analogue Scale (VAS), is a scale that is used to try and understand the level of pain that someone is in. The scale is intended as something that you would rate yourself on a scale of 0-10 with 0 = no pain, 10 = worst pain imaginable. You can learn more about what is pain and the pain scale here.
This programme focuses on strengthening muscles around the hip joint and aiming to increase the flexibility of muscles that may have become tighter due to pain. It must be understood that whilst pain during and after these exercises cannot be totally avoided, a significant increase in pain is not desirable. Pain should not exceed 3/10 on your self-perceived pain scale whilst completing this exercise programme.
- 0
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- 3
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- 8
- 910
This is the next progression. More focus is given to developing lower limb strength and stability. This programme may be performed every other day as tolerated. It is important to maintain dialogue with your physiotherapist if symptoms change because of the exercises. Pain should not exceed 3/10 on your pain scale.
- 0
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 910
This programme is a further progression with a focus on return to sporting activities and dynamic loading to ensure that your hip can tolerate the fast, high load activities required in your sport without an increase in symptoms. Pain should not exceed 3/10 on your pain scale.
- 0
- 1
- 2
- 3
- 4
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- 6
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- 8
- 910
10. Return to Sport / Normal life
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.
11. Other Treatment Options
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).
References
- Röling MA, Mathijssen NM, Bloem RM. (2016) Incidence of symptomatic femoroacetabular impingement in the general population: a prospective registration study. J Hip Preserv Surg. doi:10.1093/jhps/hnw009. 3, 203-207
- Griffin DR, Dickenson EJ, O’Donnell J, et al. (2016) The Warwick Agreement on femoroacetabular impingement syndrome (FAI syndrome): an international consensus statement. British Journal of Sports Medicine. 50, 1169-1176.
- Ganz R, Parvizi J, Beck M. et al. (2003)
- Femoroacetabular impingement: a cause of osteoarthritis of the hip. Clin Orthop Relat Res. 417, 112–20.
- Polat G, Arzu U, Dinç E, Bayraktar B. (2019) Prevalence of femoroacetabular impingement and effect of training frequency on aetiology in paediatric football players. HIP International. 10.1177/1120700018781939. 29, 204-208.
- Frank JM, Harris JD, Erickson BJ, Slikker III W, Bush-Joseph CA, Salata MJ, Nho SJ. (2015) Prevalence of femoroacetabular impingement imaging findings in asymptomatic volunteers: a systematic review. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 31, 1199-204.
- Tannast, M., Siebenrock, K. A., & Anderson, S. E. (2007). Femoroacetabular impingement: radiographic diagnosis—what the radiologist should know. American Journal of Roentgenology, 188, 1540-1552.
- Mansell NS, Rhon DI, Meyer J, Slevin JM, Marchant BG. (2018 ) Arthroscopic Surgery or Physical Therapy for Patients With Femoroacetabular Impingement Syndrome: A Randomized Controlled Trial With 2-Year Follow-up. Am J Sports Med. 1:363546517751912. 10.1177/0363546517751912.
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