Hip Impingement (Femoroacetabular impingement)

The most common movement that brings on FAI pain is hip flexion (knee towards chest). Patients will experience pain, usually in the groin, but sometimes further down the front of the thigh, side or back of the hip. There may be episodes of clicking in the hip, or the sensation that it is coming out of joint.

Certain activities, particularly those which involve hip flexion (e.g., football, cycling, dancing, ballet, and aerobics) will make FAI pain worse. Patients often find that sitting for a prolonged period, e.g., a long car journey, will bring on groin pain and they often struggle to move into a more comfortable position.

Understanding the hip’s anatomy is necessary to understanding why hip impingement occurs:

The hip is a ball-and-socket joint.

• The ball (femoral head) is the rounded top of the femur, commonly known as the thighbone.
• The socket (acetabulum) is in the side of the pelvis.
• Articular cartilage. Both the femoral head and the acetabular socket are lined with a strong, slippery material called articular cartilage. This cartilage allows the surfaces of the ball and socket to glide against each other during hip movement.
• Labrum. Another piece of cartilage, called the Labrum, rings the outer edge of the acetabulum (a bit like a washer). The Labrum deepens the socket, making the hip joint more stable, and its elasticity allows for flexibility.

The femoral head fits into the socket. The ball-and-socket anatomy allows the leg to move forward, backward, and side-to-side. It also allows for internal and external rotation (pointing the toes inward and outward).

Cartilage helps stabilize the hip joint and facilitate hip movement:

• Articular cartilage. Both the femoral head and the acetabular socket are lined with a strong, slippery material called articular cartilage. This cartilage allows the surfaces of the ball and socket to glide against each other during hip movement.

• Labrum. Another piece of cartilage, called the Labrum, rings the outer edge of the acetabulum (a bit like a washer). The Labrum deepens the socket, making the hip joint more stable, and its elasticity allows for flexibility.

There are two types of hip impingement, ‘Cam’ and ‘Pincer’.

Cam impingement

Cam impingement is caused by a jamming or squeezing of an abnormally shaped femoral head and head-neck junction into the acetabular socket during certain hip movements.

Pincer impingement

Pincer impingement occurs when there is direct contact with the femoral neck or head-neck junction with part of the acetabular socket edge and Labrum. The acetabulum appears to be ‘over deep.’

Often the Cam and Pincer forms exist together, known as mixed impingement.

There are likely to be several factors that determine whether symptoms occur. The primary problem is the subtle deformity in the joint shape, but this may or may not cause problems depending on the activity level of the patient and how easily their cartilage and Labrum are damaged.

Recent research from Oxford has shown a strong genetic predisposition to this condition.

Not everyone who has impingement will develop arthritis. In fact, one study suggests that pincer impingement protects the hip from developing osteoarthritis.

Most experts agree that there is a close association between hip impingement and hip osteoarthritis, although why most people with hip impingement develop osteoarthritis, but why others do not, is not well understood.

Initial consultation with your doctor or physiotherapist will focus on establishing if your pain is likely to be coming from the hip joint, and to rule out other sources and identify any factors making you prone to FAI.

You will then be examined, and a number of provocative manoeuvres will be performed to demonstrate any impingement.

If your symptoms remain severe despite conservative management (lifestyle and activity modification, physiotherapy +/- pain relieving medications), X-rays and scans may be required.

X-rays of the hip are taken to look for signs of arthritis, any other cause of hip pain, and the subtle bony deformities that are associated with FAI.

An MRI scan of your hip may also be done to look in detail to see if the Labrum is torn or if there is any sign of damage to the cartilage.

Sometimes a CT scan will be arranged to look at the bony anatomy in more detail. It may be that the radiologist is asked to inject local anaesthetic into the hip, to help determine if your pain is coming from within the joint.

Treatment options for FAI include conservative and non-surgical management.

Treatment very much depends on an individual’s presentation: the severity and underlying nature of the impingement; previous treatments; radiological features (i.e., x-ray and/or scan); a patient’s individual profile (including age, occupation; developmental or childhood conditions at the hip; injury history; sporting pursuits and aspirations) and any other health issues need to be considered.

Lifestyle & activity modification. This involves avoiding activities that cause your symptoms and may involve avoiding a particular sporting activity or changing your daily routine.

Physiotherapy aims to reduce pain and stiffness, optimize muscle strength and joint motion and review lifestyle factors which cause excessive contact between the impinging ball and socket.

Injection (usually with a combination of long-acting steroid and local anaesthetic). This accomplishes two things; if the pain is a result of FAI and originating from the hip joint it can provide pain relief. If successful it also rules out pain originating from the back, or any other potential source around the hip area.

Surgery. Most patients with hip impingement will not require any surgery, but for some people, the impingement may be significantly limiting their quality of life. If this is the case for you, and all other options have been tried without success, surgery may be considered. This is usually in the form of arthroscopic (or keyhole) surgery, performed by a specialist orthopaedic surgeon. Although similar in principle to arthroscopy of the knee, this surgery is quite involved and should not be deemed as a minor procedure. Rehabilitation following hip arthroscopy surgery is very important in determining the final clinical outcome and should be graded appropriately in conjunction with the surgeon’s post-operative instructions. It is generally accepted that if osteoarthritis has been established in the joint, arthroscopic treatment will be of limited value although research into this field continues.

If you have been listed for surgery, it important you look after your health to help ensure the surgery is successful and reduce the risk of complications.

Local commissioning policies are in place for this condition

Please be aware that there are local commissioning policies in place for this condition. This means that certain treatments may not be available to you on the NHS.

For full details please follow this link.

Managing your hip impingement without surgery should always be considered first, known as “conservative management”. Conservative treatment can help reduce pain and swelling in the hip joint, which can in turn help reduce the severity of painful symptoms that you may be experiencing.

Symptoms can often be resolved with rest, and physiotherapy. Some people gain relief from taking over the counter painkillers; medication options can be discussed further with your local pharmacist.

3 x 10 repetition, 3-4 times per week

Bridge from floor | Circle Health

Circle Health | published on 2 November 2016

3 x 10 repetitions, 3-4 times per week

Quads stretch with posterior tilt | Circle Health

Circle Health | published on 2 November 2016

3 x 10 repetition, 3-4 times per week

Standing Hip abduction | NHS Golden Jubilee

NHS Golden Jubilee | published on 3 August 2020

Raising your seat height and slightly reclining the back rest will open your hip angle and reduce the extent of pinching at the front of the hip joints.

You may wish to look at other options, such as hydrotherapy. You can discuss this with your physiotherapist, but please note that not all hospitals across Devon have access to hydrotherapy pools.