Femoro-acetabular Impingement Definition

Under a femoro-acetabular impingement a painful narrowing of the hip joint gap will be understood. Young athletic people are particularly affected by the syndrome.

What is Femoro-Acetabular Impingement?

Doctors also refer to femoro-acetabular impingement (FAI) as hip impingement. This means the presence of a narrow point between the acetabulum and the femoral head. Because of the constriction, the bones collide with strong flexions.

As a result, there is again the risk that structures near the joint such as cartilage or joint lip are pinched or damaged. This causes severe pain in the groin area. A distinction is made between two forms of femoro-acetabular impingement. These are the Pincer Impingement Hip (Pincer FAI) and the Cam Impingement Hip (Cam FAI).

According to Dictionaryforall, a pincer impingement hip has a normal configuration of the femoral neck, while the acetabulum is deformed and resembles a pincer. In this way, the femoral head is literally “gripped”. Because the joint head is therefore more roofed, this easily leads to the acetabular roof and the hip joint head hitting one another. The pincer impingement hip is most common in women between the ages of 30 and 40.

We speak of a cam impingement hip when the natural waistline of the hip joint head, which ensures greater freedom of movement, is no longer present due to an overgrowth. A bulge of bone narrows the joint space, which promotes the painful rubbing of the acetabular roof and the head of the femoral neck. This happens especially in young men who are physically active. Football players in particular suffer from this FAI form.


Femoro-acetabular impingement usually occurs because of a bony deformation of the acetabulum (acetabular cup roof). A joint socket that resembles a bowl is formed through the pelvic bone (os ileum). Together with the femoral head, it forms the hip joint.

If bone spurs are formed on the bony parts of the hip joint, this often leads to mechanical constriction. Young people who are active in sport often suffer from femoro-acetabular impingement, as they often expose the hip joint to increased physical strain. However, the exact cause of numerous cam impingement and pincer impingement cases could not be clarified.

As a rule, however, the bony structural changes in the majority of patients can be demonstrated. A conceivable explanation for the development of femoro-acetabular impingement are growth disorders in adolescence, which lead to a faulty closure of the growth plates.

Symptoms, ailments & signs

In many cases, the symptoms caused by femoro-acetabular impingement are only insidious. Sometimes they show sporadic pain due to the hip joint. This causes the pain to radiate into the thigh. The symptoms are further exacerbated by stress.

Many patients also have problems driving a car, taking a seated position, and climbing stairs. If the bent leg is turned inwards, this also often results in pain, which often leads to the affected person adopting a relieving posture by turning the painful leg outwards.

In some cases, patients also experience dull hip pain during intercourse or restricted movement of the hip when it is flexed. If the affected person stands or walks for a long time, this can also result in pain. In the late stage of femoro-acetabular impingement, most patients develop coxarthrosis. In younger people, too, early wear and tear on the hips is possible.


If femoro-acetabular impingement is suspected, the affected person should contact an orthopedic surgeon. He first looks at the medical history and wants to know which sports the patient does, which movement restrictions occur and whether the pain was triggered by an injury. Following the anamnesis, the doctor will conduct a physical exam.

To test hip mobility, the patient has to move his leg into different positions. If the orthopedic surgeon presses the leg against the edge of the acetabulum, this usually leads to pain. Another important exam is taking x-rays. The images enable precise detection of structural changes in the bone.

By means of a magnetic resonance imaging (MRI) is also the exact showing of the soft tissues that surround the hips, possible. About 70 to 80 percent of femoro-acetabular impingement take a positive course. After about 6 to 12 weeks, you can usually do light sporting activities again. However, around 15 to 20 percent of all patients suffer from residual symptoms.


Femoro-cetabular impingement occurs mainly in young people who are actively involved in sports. In most cases, the diagnosis is delayed because the symptoms are ambiguous and increase and become more common over time. Most of the time, however, there are sporadic pain in the hip joint, which can occur in the form of resting pain even without stress.

If the person concerned puts additional strain on the respective areas, the pain increases even further and can thus seriously impair the patient’s life, so that many postures of the body lead to pain. This includes, for example, climbing stairs or sitting while driving, which is why the person affected suffers from severe mobility restrictions. Many people also suffer from psychological complaints if the movement restrictions occur at a young age.

The pain can be treated with pain relievers, with no further complications. However, patients should avoid long-term use of pain medication. Exercises and therapies also help against the symptoms and can fight the disease. However, many patients suffer from residual symptoms and minor pain even after the treatment. Often it is no longer possible to do sports.

When should you go to the doctor?

Since this disease does not usually heal itself and the symptoms continue to increase in most cases, a doctor should always be consulted. In this way, further complications or even permanent restrictions on movement can be avoided.

A doctor should be consulted if the person suddenly suffers from severe pain in the hip joint for no particular reason. These pains can occur in the form of resting pains or stress pains and have a very negative effect on the quality of life and everyday life of the person concerned.

The pain can occur especially when sitting. The doctor should also be consulted if there are restrictions in movement. This wears out the hips faster, which can lead to further complications. Usually the condition is diagnosed and treated by an orthopedic surgeon.

Some sufferers are dependent on surgical interventions, although most complaints can be limited with the help of exercises and therapies. Sports activities should be restricted if the disease occurs. As a rule, this does not reduce the life expectancy of the person affected.

Treatment & Therapy

Surgical intervention is usually required to correct the cause of femoro-acetabular impingement. In the early stages, conservative methods are primarily used to relieve pain. For this purpose, the patient is given pain relievers such as ibuprofen or acetylsalicylic acid.

Electrotherapy, baths, putting on mud packs and performing targeted physiotherapy exercises are also considered helpful. As part of an operative therapy, hip arthroscopy (hip arthroscopy) is usually carried out.

This procedure eliminates the structural changes in the bone. If the mechanical constriction can be removed by the operation, this will in most cases lead to an improvement in the pain. Hip arthroscopy is particularly recommended for young patients because it reduces the risk of joint stiffening.

Outlook & forecast

In a large number of patients, femoro-acetabular impingement shows a favorable course of the disease and a good prognosis. Most patients can be discharged from treatment as cured within three months. However, it is often necessary to restructure the usual physical activities.

The disease occurs mainly in very active people. So that the symptoms do not recur, the activities or the practice of individual movement sequences should be changed and optimized. This can result in stopping the usual sports.

Slightly more than twenty percent of the sick complain of long-term consequences despite considerable efforts to recover. The symptoms do not completely regress with them. You get a less favorable forecast. There is a threat of a chronic course of the disease. In addition, the restrictions on everyday processes are significantly increased for them.

Pain at rest and the necessary life changes can be complications for these patients. There is a risk of psychological complaints that can trigger secondary diseases. This worsens the overall prognosis for the patient.

In exceptional cases the patient receives a poor prognosis. If the treatment reveals that the joint needs to be stiffened, healing can no longer take place. This step takes place when the symptoms continue to spread or worsen despite adequate treatment.


In order to prevent complaints caused by femoro-acetabular impingement, it is advisable to exercise moderately. Exercise is not the cause, but it often causes the pain associated with it.


In most cases, there are no follow-up measures available to those affected with this disease. The person concerned is primarily dependent on a quick and above all on an early diagnosis and subsequent treatment, so that further complications or a worsening of the symptoms can be avoided. The focus of this disease is therefore on early detection and further treatment.

The earlier it is recognized by a doctor, the better the further course is usually, since self-healing cannot occur. This disease is primarily treated by taking medication. In any case, the person affected should ensure the correct dosage and continue to take them regularly.

However, long-term use of painkillers should be avoided. Furthermore, physiotherapy measures often have a positive effect on the course of the disease. The person affected can also perform many exercises from such a therapy in their own home and thereby increase the movement of the muscles again. The life expectancy of the person affected is usually not reduced by this disease.

You can do that yourself

Despite reluctance, the patient should always pay attention to the needs of his body and react accordingly. If pain occurs, sports activities or vigorous physical activity must be reduced and stopped immediately. It is important to take care of the body so as not to cause any further complications.

In many cases it is helpful to seek help to stabilize the psyche. Cognitive procedures for realigning existing attitudes as well as relaxation techniques have proven themselves. Using methods such as yoga, autogenic training or meditation, stress can be relieved and an inner balance is established.

Conversations with therapists, mentors or relatives often help to gain new impulses for dealing with the disease. In forums or self-help groups, experiences are exchanged and tips for overcoming the challenges in everyday life are given. The patient should maintain a positive attitude.

Although beloved activities can no longer be carried out, new opportunities arise that also contribute to an increase in wellbeing. Sufficient protective clothing must be worn when performing sporting activities. Knee and elbow pads and bandages stabilize the body and have a positive influence on health. If swelling occurs, the affected person should immediately cool the area with gel pads. Cooling ointments such as aloe vera gel are also helpful.

Femoro-Acetabular Impingement