Femoroacetabular impingement

Femoroacetabular Impingement

File:Hip joint anatomy.png

Diagram of the hip joint showing the femur and acetabulum.

Femoroacetabular impingement (FAI) is a condition involving abnormal contact between the femur and the acetabulum of the hip joint. This contact can lead to joint damage and pain, particularly during movement. FAI is a significant cause of hip pain and can lead to early osteoarthritis in the hip.

Anatomy and Pathophysiology

The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. In a healthy hip, the femoral head fits snugly into the acetabulum, allowing smooth and pain-free movement. In FAI, however, there is an abnormality in the shape of the femoral head, the acetabulum, or both, leading to impingement.

Types of FAI

There are three main types of FAI:

• Cam impingement: This occurs when the femoral head is not perfectly round and cannot rotate smoothly inside the acetabulum. The aspherical portion of the femoral head grinds against the cartilage inside the acetabulum.

• Pincer impingement: This occurs when the acetabulum covers too much of the femoral head, leading to pinching of the labrum, the cartilage that lines the rim of the acetabulum.

• Combined impingement: This is a combination of both cam and pincer types.

Symptoms

The primary symptom of FAI is pain, which is often felt in the groin area, but can also occur on the outside of the hip or in the buttock. The pain is typically exacerbated by activities that involve hip flexion, such as sitting for long periods, running, or squatting. Patients may also experience stiffness and a limited range of motion in the hip.

Diagnosis

File:Hip X-ray showing FAI.png

X-ray of the hip showing signs of femoroacetabular impingement.

Diagnosis of FAI is based on a combination of patient history, physical examination, and imaging studies. During the physical examination, the doctor may perform specific tests to reproduce the pain and assess the range of motion. Imaging studies, such as X-rays, MRI, or CT scans, are used to visualize the shape of the femoral head and acetabulum and to assess any damage to the cartilage or labrum.

Treatment

Treatment for FAI can be conservative or surgical, depending on the severity of the condition and the patient's symptoms.

Conservative Treatment

Conservative treatment options include:

• Activity modification: Avoiding activities that exacerbate symptoms.
• Physical therapy: Exercises to improve hip strength and flexibility.
• Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation.

Surgical Treatment

If conservative treatments are not effective, surgical intervention may be necessary. The most common surgical procedure for FAI is hip arthroscopy, which involves reshaping the femoral head and/or acetabulum to eliminate the impingement. In some cases, open surgery may be required.

Prognosis

With appropriate treatment, many patients with FAI can return to their normal activities without pain. However, if left untreated, FAI can lead to progressive joint damage and early onset of osteoarthritis.

Related Pages

• Hip joint
• Osteoarthritis
• Physical therapy
• Arthroscopy