Hip impingement is a disease of the hip joint. Due to a mechanical conflict, patients experience limited mobility. This is also associated with pain.
The condition is also known as femoroacetabular impingement (FAI). It is listed in the WHO catalog under the ICD code M24.85.
FAI can affect both adolescents and adults.
In hip impingement, the hip joint shows anatomical and/or structural changes. These changes can result from impaired growth of the bones and joints during childhood, for example. In addition to genetic causes, Perthes' disease, for example, can also lead to hip impingement.

Healthy hip joints ensure smooth movement © dimdimich | AdobeStock
The hip joint is the second largest joint in the human body after the knee joint. Its bony joint partners are the femur and the pelvis.
The femur forms a ball at its upper end, the femoral head. In healthy people, this ball fits snugly into the socket of the pelvis.
Normally, the close contact between the bone partners allows the hip joint to move freely and without pain.
There are two different types of hip impingement:
- CAM impingement(also known as camshaft impingement) and
- Pincer impingement (or pincer impingement).
In CAM impingement, the femoral head is not evenly round, but has bony deposits. As a result, it no longer fits perfectly into the socket of the pelvis.
In pincer impingement, the acetabulum sits too low in the pelvis or is twisted. Here too, the joint head and socket do not fit together perfectly.
In most cases of the disease, a so-called mixed impingement is present. This is a combination of pincer impingement and CAM impingement.

Three forms of hip impingement © nmfotograf | AdobeStock
The change in shape of the hip joint impairs the joint mechanics. During leg movements, the thigh strikes the joint lip. This results in injuries to the joint lip and the cartilage surfaces of the hip joint.
If left untreated, irreversible damage to the bone and degenerative changes to the joint(hip arthrosis) occur after a while.
Hip impingement is often equated with hip dysplasia. However, hip dysplasia refers to cartilage damage due to a hip socket that is too small and/or too steeply positioned.
In rare cases, hip dysplasia and impingement can also occur at the same time, causing pain.
The changes to the hip often remain undetected for a long period of time. In athletes, hip impingement is more frequently discovered during an examination for sports injuries.
Typical pain with hip impingement occurs during movement in the groin area or on the front of the hip. Initially, it only occurs during wide movements. With advanced impingement, even small movements of the hip cause pain.
Pain at rest occurs as the disease progresses.
Other symptoms include
- Difficulty climbing stairs and sitting down: i.e. with hip flexion
- Difficulty walking or standing for long periods of time: Pain on the outside of the hip
- Pinching sensations in the groin area
- Sensitivity disorders due to irritation of the surrounding nerves
If impingement is suspected, the doctor can carry out a clinical movement test . To do this, he bends the patient's hip joint, rotates it inwards and moves it in the direction of the opposite shoulder. This triggers what is known as impingement pain in patients with hip impingement. This is a typical sign of the disease.
The anatomical abnormalities of the hip joint can also be visualized using X-rays. This also shows whether osteoarthritis has already developed as a result of the disease. Using a CT scan, the doctor can create a 3D image of the hip bone and thus detect any abnormalities more quickly.
Another method of imaging the hip joint is magnetic resonance imaging (MRI). This allows the condition of the joint labrum and articular cartilage in particular to be assessed.
The treatment of FAI depends primarily on how pronounced the deformity is. In the case of minor anatomical abnormalities, conservative treatment can already lead to improvement. Surgery is then not necessary.
As part of physiotherapy , patients learn exercises to strengthen the trunk and legs. A good balance in the muscles can support and relieve the joint in its function.
The doctor may also prescribe anti-inflammatory painkillers from the group of non-steroidal anti-inflammatory drugs (NSAIDs). Injections of anti-inflammatory drugs such as cortisone into the affected hip joint also often reduce the symptoms.

Pain therapy for hip impingement
Conservative therapy can alleviate the symptoms, but cannot eliminate the cause.
If conservative therapy is unsuccessful or the joint is more severely damaged, surgery is advisable. It is also an option if the hip joint is severely deformed so that consequential damage can be prevented.
Most operations to treat impingement are performed arthroscopically by the attending physician. During this minimally invasive arthroscopy, the patient is usually given a general anesthetic.
Two to three small incisions are usually required to operate on the joint. The complication rate of hip arthroscopy is very low.
The video shows the procedure for hip arthroscopy:
Open surgery, known as surgical hip dislocation, requires an incision around 20 centimeters long. This gives the surgeon a direct view of the surgical site. He removes the joint ball from the joint socket.
The joint head and the severed thigh muscles are then fixed in place with screws for the healing period.
The advantage of this is that the surgeon has a clear view of the joint during the operation and also has the option of treating cartilage damage at the same time. However, more tissue, for example the muscles, has to be cut through. This requires a longer healing period after the operation and the patient experiences more pain.
A hybrid form would be arthroscopically assisted surgery (mini-open technique). In this case, arthroscopic instruments are used through a small incision. However, the surgeon also uses small special instruments to treat larger malalignments.
Corrective osteotomy is another option for particularly malpositioned hip impingement. In this procedure, the surgeon realigns the joint socket after removing the bony connections between the ischium, ischium and hip joint.
- ischium,
- pubic bone and
- ilium
and ilium. The bones should then grow together in an anatomically correct position and heal.
If hip arthrosis is already present, the use of an artificial hip joint(hip prosthesis) may be advisable.

Hip prosthesis for impingement: therapy for severe joint damage © psdesign1 / Fotolia
As a rule, the patient has to stay in hospital for a few days after both arthroscopy and open surgery. They will also need walking sticks for one to two months after the operation to avoid putting too much strain on the joint. However, the healing time depends heavily on the measures taken.
After most operations, so-called passive electrical movement splints are used. These consist of sleeves or splints that are connected to each other by a joint. An electric motor moves the splint and ensures that the hip joint is passively guided through a predetermined range of movement. At the same time, the splint compensates for any existing instabilities.
With the help of the passive motion splint, the hip joint can be mobilized evenly very early after the operation. The patient does not have to actively tense their muscles for this.
After discharge, the patient should carry out further exercises at home. This can increase muscle strength and improve mobility.
Specific hip physiotherapy is also necessary. It serves
- Mobilize the hip joint,
- strengthening the muscles that stabilize the hip and
- stretching the shortened structures around the hip joint.
Exercises such as the standing balance or the one-legged bridge can also improve the stability and mobility of the hip joint.

Exercise as therapy: physiotherapy for hip impingement © Cello Armstrong / Fotolia
In up to 80 percent of patients, minimally invasive surgery can achieve a good result with significant pain relief. The result depends primarily on the patient's age and the condition of the joint cartilage before the operation.
Patients can resume light sporting activities around six to 12 weeks after the minimally invasive procedure. Competitive athletes sometimes have to refrain from competitive sports for four to six months.
Even with open surgery, the symptoms of hip impingement improve in 70 to 80 percent of patients. In most cases , the pain is significantly reduced or disappears completely. However, the final result can only be assessed after around a year.
If rehabilitation after the operation is positive, patients can resume light sport after three months. As with hip arthroscopy, the success of the operation depends primarily on the
- the age of the patient and
- and any damage to the joint cartilage prior to the operation.
before the operation.