Femoroacetabular Impingement

What is Femoroacetabular Impingement?

Femoroacetabular impingement (FAI) is a condition in which extra bone forms along one or both of the bones that form the hip joint, giving the bones an irregular shape. The bones rub against each other during movement because they do not fit together perfectly. Over time this friction can damage the joint, causing pain and limiting activity.

Types of FAI

Pincer- This type of impingement occurs because extra bone extends out over the normal rim of the acetabulum. The labrum can be crushed under the prominent rim of the acetabulum.

Cam- In cam impingement, the femoral head is not round and cannot rotate smoothly inside the acetabulum. A bump forms on the edge of the femoral head that grinds the cartilage inside the acetabulum.

Combined- A combination of Pincer and Cam-type impingements are present.

Causes

FAI occurs because the hip bones do not form normally during the childhood growing years. It is the deformity of a cam bone spur, pincer bone spur, or both, that leads to joint damage and pain. Because athletic people may work the hip joint more vigorously, they may begin to experience pain earlier than those who are less active. However, exercise does not cause FAI.

Symptoms

• Pain, and stiffness in the affected area
• Limping
• Back pains, especially in the lower back are common
• Sitting for a prolonged period may cause pain in the inner hip region
• A clicking sensation is felt in the joint
• Difficulty in wearing socks and shoes
• Difficulty in walking in the up-hill direction
• Pain at the sacroiliac joint (The sacroiliac joints link the pelvis and lower spine. These two joints are made up of the bony structure above the tailbone, known as the sacrum, and the top part of the pelvis, known as the ilium. The sacroiliac joints support the weight of the upper body when standing) is also common

Diagnosis

Initially, the Doctors will interview the patient, analyse their condition, perform a physical examination, and then proceed with some of these diagnostic procedures:

• MRA (magnetic resonance arthrography) is a special type of MRI scan. It is a non-invasive technique that uses a magnetic field as well as radio waves to evaluate the condition of the hip. It is done by injecting a dye into the joint space which helps in making the images clearer.
• FADIR (flexion, adduction, and internal rotation) test – It is a passive motion test. In this, the patient is asked to lie on his back and relax his legs, then the affected leg is raised by the doctor and hips bent at a 90-degree angle. The doctor then gently pushes the leg across the midline of the body and moves the lower calf away from the body. If the patient experiences pain at this step, it indicates a hip impingement condition.
• X-rays
• CT scans

Treatments

Some of the treatment strategies used are:

• Activity Changes: At the onset of the treatment, doctors usually ask patients to alter their daily routines and avoid activities that cause symptoms.
• Medications: Non-steroidal and anti-inflammatory drugs like ibuprofen are prescribed to help reduce pain and inflammation.
• Physical Therapy: Physical therapy involves specific exercises that can increase the range of motion and strengthen the muscles.
• Surgery: FAI is treated with surgeries like arthroscopy in severe cases.

This technique will help in treating many of the FAI issues. This procedure is performed by first creating tiny incisions. A small camera also called Arthroscope is inserted into one of the incisions to get a good view of the damaged area. Flexible and thin instruments are then inserted through these incisions and guided to the damaged area using the arthroscope.

The doctor will then clean or repair the damage present in the labrum and the articular cartilage. The FAI is then corrected by trimming the Acetabulum’s bony rim and also shaving the femoral head’s bump.

In some cases of severe nature, the doctor might perform with bigger incisions.