There are generally considered to be three types of hip impingement, also known as femoroacetabular impingement (FAI). These are:
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Cam Impingement: This occurs when the femoral head (the ball of the hip joint) is not perfectly round. An excess of bone on the femoral head rubs against the acetabulum (the socket) during hip movements.
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Pincer Impingement: This type is characterized by an overcoverage of the acetabulum, essentially creating a "pincer" that clamps down on the femoral head neck.
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Combined Impingement: As the name suggests, this is a combination of both cam and pincer impingement. It means the individual has both an abnormally shaped femoral head and excessive acetabular coverage.
| Type of Hip Impingement | Description |
|---|---|
| Cam Impingement | Abnormally shaped femoral head rubs against the acetabulum. |
| Pincer Impingement | Excessive acetabular coverage clamps down on the femoral head neck. |
| Combined Impingement | Presence of both cam and pincer deformities. |
Understanding the type of hip impingement is crucial for diagnosis and treatment planning. Doctors will often use imaging techniques such as X-rays and MRIs to determine which type, or combination of types, is present.
