Femoroacetabular Impingement (FAI)
FAI occurs when extra bone growth causes abnormal contact between the hip bones, leading to pain and joint damage. Learn about symptoms, types, and treatment options.
What is Hip Impingement?
Femoroacetabular impingement (FAI), commonly called hip impingement, is a condition where there is abnormal contact between the ball (femoral head) and socket (acetabulum) of the hip joint. This abnormal contact is caused by extra bone that develops on one or both of these structures.
During hip movement, especially flexion and rotation, this extra bone causes the hip bones to bump against each other abnormally. Over time, this can damage the labrum (cartilage ring around the socket) and the articular cartilage, potentially leading to arthritis if left untreated.
FAI is a common cause of hip pain in young, active adults, particularly athletes involved in sports requiring repetitive hip flexion such as soccer, hockey, and cycling.
Types of FAI
There are three types of FAI, based on where the abnormal bone growth occurs.
CAM Impingement
Extra bone forms on the femoral head (ball), causing it to grind against the socket during movement.
More common in young, athletic males
Pincer Impingement
The socket extends too far over the femoral head, causing the rim to pinch against the femoral neck.
More common in women, often middle-aged
Combined (Mixed)
Both CAM and Pincer abnormalities are present, the most common presentation.
Most common type overall
Symptoms
FAI symptoms typically develop gradually and may include:
- Pain in the groin, especially with hip flexion
- Stiffness or reduced range of motion
- Pain that worsens with sitting, squatting, or athletic activity
- Sharp catching or clicking sensation in the hip
- Pain after prolonged sitting
- Difficulty with movements like putting on shoes or getting in/out of a car
Who Gets FAI?
FAI is most common in:
- • Athletes, especially in high-impact sports
- • People ages 20-45
- • Those with a history of hip problems in childhood
- • Individuals with repetitive hip flexion activities
Many people have FAI anatomy but never develop symptoms.
Diagnosis
Dr. Hunter diagnoses FAI through a combination of:
- 1
Physical Examination
Impingement tests that reproduce your symptoms
- 2
X-rays
Identify the bone abnormalities causing impingement
- 3
MRI
Evaluate labral and cartilage damage
The FADIR Test
One key test for FAI is the FADIR (Flexion, Adduction, Internal Rotation) test. During this test, Dr. Hunter will:
- 1. Have you lie on your back
- 2. Flex your hip to 90 degrees
- 3. Move your leg across your body (adduction)
- 4. Rotate your foot outward (internal rotation)
Pain during this maneuver suggests hip impingement.
Treatment Options
Conservative Treatment
Physical Therapy
Strengthening and stretching to improve hip mechanics and reduce symptoms
Activity Modification
Avoiding movements that trigger impingement
Anti-inflammatory Medications
NSAIDs to reduce pain and inflammation
Injections
Corticosteroid or hyaluronic acid injections for pain relief
Surgical Treatment
When conservative treatment doesn’t provide adequate relief, hip arthroscopy may be recommended to:
- • Reshape the bone to eliminate impingement
- • Repair or trim the damaged labrum
- • Address cartilage damage
Hip arthroscopy is a minimally invasive procedure that can provide excellent results in appropriately selected patients.
Related Conditions
Get relief from hip impingement
Schedule a consultation with Dr. Hunter to discuss your hip pain and explore your treatment options.