Femoroacetabular Impingement (FAI)
Femoroacetabular impingement (FAI) is a condition where the bones of the hip joint don’t fit together properly, causing abnormal contact between the femoral head (ball) and the acetabulum (socket). This repeated pinching can damage the cartilage and labrum, leading to hip pain, stiffness, and reduced mobility.
There are two main types of FAI:
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Cam Impingement: Occurs when the femoral head (ball) isn’t perfectly round, creating friction inside the socket during movement. Common in younger athletes and often linked to labral tears.
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Pincer Impingement: Happens when the hip socket (acetabulum) has extra bone growth, causing it to cover too much of the femoral head. This leads to pinching of the labrum and reduced hip motion.
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Combined FAI: Many patients have features of both cam and pincer impingement.
FAI is common in active adults and athletes, particularly those in sports that require deep hip motion such as soccer, hockey, dance, and martial arts. If left untreated, it can contribute to labral tears and early hip arthritis.
Diagnosis of FAI
Providers may diagnose FAI through:
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Medical history review (activity level, hip pain patterns, or past injuries).
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Physical exam including the impingement test, where hip flexion and rotation reproduce pain.
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Imaging:
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X-rays to show cam or pincer bone changes.
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MRI or MR arthrogram to evaluate labral tears or cartilage damage.
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Diagnostic injections may confirm that the hip joint is the pain source.
Treatment for FAI
Physical therapy is the first-line treatment for FAI, aiming to reduce pain and protect the joint. A program may include:
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Manual therapy to restore mobility and improve joint mechanics
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Strengthening exercises for the hip stabilizers, glutes, and core muscles
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Stretching for hip flexors, hamstrings, and surrounding tissues
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Movement retraining to improve alignment and reduce pinching during activity
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Pain management techniques such as ice, heat, or ultrasound
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Education on modifying high-risk movements or sports
In more severe cases, arthroscopic surgery may be required to reshape the bone (cam or pincer correction) and repair the labrum, followed by structured rehabilitation.
Symptoms of FAI
Common signs of FAI include:
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Sharp or aching pain in the front of the hip or groin
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Pain with deep hip flexion (squatting, sitting for long periods, tying shoes)
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Stiffness and loss of range of motion
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Clicking, catching, or locking inside the hip joint
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Gradual worsening of pain, especially with sports or repetitive hip use
Prevention of FAI
To reduce the risk of worsening FAI or developing arthritis:
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Avoid repetitive deep hip bending without proper conditioning
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Strengthen hip and core muscles for stability
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Maintain flexibility in the hips and lower back
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Use proper technique in sports and lifting activities
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Address hip pain early before it leads to permanent joint damage