Femoral Acetabular Impingement Syndrome (FAI) is a condition that occurs as a result of the bones of the hip being misshaped. Due to this misshaping, the bones of the hip do not fit together as intended and causing unnatural friction of the bones and joints. Over time, this friction causes degeneration of the cartilage, bone spurs and damage to the joints.
There are three types of FAI: pincer, cam, and combined impingement.
This type of impingement occurs because extra bone or bone spurs protrudes over the rim of the acetabulum (the cup shaped cavity of the hip bone where the femur sits). The labrum becomes compressed under the extending rim of the acetabulum.
Cam impingement occurs when the head of the femur is not rounded and cannot rotate smoothly inside the acetabulum. Because of this, a protrusion forms on the head of the femur and degenerates the cartilage inside the acetabulum.
Combined impingement means that both the pincer and cam types are present.
Signs and symptoms of FAI can include:
- Pain in the groin
- Pain at the outside of the hip
- Limited range of motion
- Pain when turning or twisting
- Dull ache in the hip