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Femoral Acetabular Impingement (FAI)

(A.K.A Hip Impingement Syndrome)

What Is FAI?

Femoral acetabular impingement or FAI is a condition of too much friction in the hip joint. Basically, the femoral head and socket (acetabulum) rub abnormally creating damage to the hip joint. The damage can occur to the articular cartilage or the labral cartilage. Femoral acetabular impingement occurs when there is a decrease in joint clearance between the femur and the acetabulum. FAI is associated with cartilage damage, labral tears, early hip arthritis, hyperlaxity, sports hernias, and low back pain.FAI is common in high level athletes, but also occurs in active individuals.

Types of FAI

There are two types of impingements that exist:
Pincer Impingement – occurs from an abnormal acetabulum (hip socket) with increased over-coverage over the femoral neck (thigh bone).
Cam Impingement – occurs when the femoral head has an abnormally large radius, with a loss of the normal spherical junction between the femoral head and the neck.

Signs and Symptoms of FAI

A deep interior hip pain commonly referred to the anterior groin and radiate to medial thigh. Aggravating activities such as twisting, climbing stairs and inclines and prolong sitting can be troublesome.

Who Are At Risk?

Active individuals with abnormal morphology of the joint can lead to labral and articular breakdown.
Pincer impingement is most common in middle age females participating in athletics.
Cam impingement is seen more frequently in young adult males and is also a cause of early onset osteoarthritis of men in their fifth and sixth decades.
It is understandable when looking at the schematics how impingement occurs, the unknown question is why? It is believed that many normal people have ‘bumps’ or slightly over-deep sockets and could potentially develop FAI – this is just the way we are built and develop. But the hip has to also be provoked in some way to cause damage – this explains the tendency for athletes, sporting professionals and active people to be more susceptible to this form of injury.

Treatment Options of FAI

Conservative treatment focuses on correction of lower extremity muscle imbalances to reduce episodes of impingement. Strengthening exercises focusing mainly on lower abdominal/ core and gluteal strengthening and hip flexor, quadriceps and hamstring flexibility.
Physiotherapy may reduce the local inflammatory reaction, improve core stability, improve soft tissue flexibility and assist in measures to avoid provocation. Surgical intervention is recommended if conservative treatment fails.

Concept of Movement Ltd., is a physical therapy, massage therapy and strength and conditioning centre that is focused on orthopedic and sports related injuries, movement dysfunctions, youths, sports organizations, active individuals and families.

Article Written By:

Tom Swales, PT
Registered Physiotherapist
Certified Athletic Trainer
Certified Strength & Condition Specialist
Certified in Acupuncture
Certified MovNat Trainer

1. Byrd, J.T. Thomas. Hip Arthroscopy in the Athlete. North American Journal of Sports Medicine. 2007; Vol2 #4: 217-229.

2. Dutton, Mark. Orthopedic Examination, Evaluation and Intervention 2nd Ed. New York: McGraw Hill. 2008, 892-893.