Hip Impingement

What are the causes of hip impingement?

Hip impingement can occur from deformities of the femur (cam impingement), acetabulum (pincer impingement), or as a result of a combination of the two abnormalities.

Cam impingement is caused by a squeezing or jamming of an abnormally shaped femoral head and head-neck junction into the acetabulum (socket) during certain types of motion, such as tying one's shoe, or riding a bike.

Pincer impingement is caused by direct contact between the femoral head-neck junction and a section of the acetabular rim.

Impingement of the hip can also be caused by conditions such as Legg-Calve-Perthes disease, slipped capital femoral epiphysis, misshapen femoral head, abnormally tilted head, a bump on the femoral neck, or post traumatic deformities, such as Coxa Vara.

Who is affected by hip impingement?

Femoro acetabular impingement (FAI) may begin at birth (congenital). It may also develop during growth (acquired). It is likely a combination of one's genetics and environment. Some experts believe that significant athletic activity before skeletal maturity increases the risk of FAI, but no one truly knows. Contact sports may exacerbate impingement.

What are the symptoms of hip impingement?

A primary symptom of hip impingement is stiffness in the groin or front of the thigh, and/or inability to flex the hip beyond a right angle. Frequently there is pain in the groin region during or after the hip has been in a flexed position, such as running, jumping or prolonged sitting.  

How is hip impingement diagnosed?

Your physician may diagnose Femoro acetabular impingement after a complete medical history, physical examination and imaging studies. Imaging studies may include one or more of the following diagnostic procedures.

• X-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
• Magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
• CT scan - a computerized compilation of many small X-rays taken at slightly different angles. A CT scan allows useful imaging of the interior bones and joints.

Early diagnosis of FAI is important. Left untreated FAI causes cartilage damage and osteoarthritis, which is often irreversible. The aim with surgery is to provide joint preservation options so as to avoid joint replacement.