Hip Impingement (Femoroacetabular Impingement, FAI)

Hip impingement, also called femoroacetabular impingement (FAI), occurs when the ball (femoral head) and socket (acetabulum) of the hip joint do not fit together properly. This abnormal contact can damage the labrum and cartilage, leading to hip pain, stiffness, and limited mobility.

What Is Hip Impingement?

In a healthy hip, the femoral head is smooth and round, and the hip socket provides balanced coverage. With FAI, the shape of the ball, the socket, or both becomes abnormal. Instead of gliding smoothly, the bones rub against each other during movement. This irritation often leads to labral tears, cartilage injury, and progressive hip pain.

What Causes Hip Impingement?

FAI is caused by abnormal bone development during childhood and adolescence. These bony changes create uneven contact within the joint.

Common causes include:

• A socket with too much coverage over the ball (pincer deformity)
• A ball that is not perfectly round (cam deformity)
• A combination of cam and pincer deformities
• Repetitive high-impact activity during growth
• Genetic or developmental factors

These bone abnormalities can only be confirmed through imaging such as X-rays, MRI, or CT scans.

FAI commonly leads to:

• Labral tears
• Cartilage damage
• Groin and hip pain
• Reduced range of motion

Signs and Symptoms

Patients with FAI are usually active individuals between ages 15 and 50. Symptoms often develop gradually.

Common symptoms include:

• Pain in the groin or front of the hip
• Pain on the outside of the hip or in the buttock
• A deep, aching discomfort
• Clicking, catching, or stiffness in the hip
• Pain that wraps around the hip in a “C-shaped” pattern
• Pain with deep bending, twisting, or rotation
• Difficulty sitting for long periods
• Pain when getting out of a car, chair, or putting on shoes

Activities such as pivoting, cutting, running, and jumping often increase symptoms.

Labral Tear

The hip labrum is a ring of cartilage that surrounds the rim of the hip socket. It helps seal the joint, improves stability, and maintains smooth movement.

A torn labrum can cause:

• Groin pain
• Pain during daily activities
• Hip instability
• Clicking or catching sensations

Labral tears commonly occur due to cam or pincer deformities. During surgery, the labrum can be repaired using small anchors and sutures. For long-term success, the cam or pincer deformity must be corrected at the same time to prevent further tearing.

Cam Impingement

Cam impingement is the most common type of FAI. It occurs when the femoral head is not perfectly round. A bump or flat area forms on the ball of the hip.

As the hip bends, this abnormal shape:

• Pushes into the socket
• Lifts the labrum off the rim
• Causes labral tears
• Damages the cartilage

Cam deformities may develop due to genetics, childhood injury, or repetitive high-impact sports during growth.

Pincer Impingement

Pincer impingement occurs when the socket covers too much of the femoral head.

This excess coverage causes:

• Early bone-on-bone contact
• Labral pinching and tearing
• Progressive cartilage damage

Pincer deformities are often seen alongside cam impingement.

Non-Surgical Treatment

Early treatment focuses on reducing pain, improving mobility, and preventing further joint damage.

Non-surgical options may include:

• Physical therapy to improve strength and mobility
• Activity modification and rest
• Anti-inflammatory medications
• Image-guided injections
• Avoiding deep hip flexion or painful movements

Non-surgical care can relieve symptoms but cannot repair a torn labrum or correct underlying bone deformities.

Surgical Treatment

If conservative care does not relieve symptoms, surgery is a reliable option for treating FAI.

Surgical procedures may include:

• Hip arthroscopy
• Labral repair or reconstruction
• Cam resection (reshaping the femoral head)
• Pincer resection (trimming excess socket bone)
• Treatment of cartilage injury

Surgery aims to restore proper hip mechanics, protect the joint, and reduce long-term pain.

Benton A. Emblom, MD

Benton A. Emblom, MD, is a board-certified, fellowship-trained orthopaedic sports medicine surgeon who specializes in hip preservation and the management of hip impingement and labral tears. As a member of The Hip Center at Andrews Sports Medicine, he treats competitive athletes and active individuals with early hip disorders.

Dr. Emblom serves as a head team orthopaedic physician for Auburn University, the University of Alabama, Hoover High School, and several other local high schools. His expertise in hip preservation allows him to offer comprehensive evaluation and advanced surgical and non-surgical treatment options.

If you believe you may have hip impingement, a labral tear, or another hip condition and would like to request an appointment with Dr. Emblom, call (205) 939-3699 and ask to speak with his appointment scheduler.

To request an appointment online, CLICK HERE or contact Andrews Sports Medicine & Orthopaedic Center at (205) 939-3699.