Femoroacetabular Impingement (FAI)
FAI is a structural mismatch between the ball (femoral head) and socket (acetabulum) of your hip. In "Cam" impingement, the ball isn't perfectly round, causing it to jam against the socket rim during deep flexion. In "Pincer" impingement, the socket over-covers the ball, crushing the labrum. Most people have a combination of both. This is common in athletes who do a lot of squatting, cycling, or sports that require deep hip flexion and rotation.
| Feels like | Deep pinch or catch in the groin with specific movements; stiffness after sitting |
|---|---|
| Worse with | Deep squats, sitting in low chairs, bringing knee to chest, internal rotation, prolonged sitting (the "theater sign") |
| Better with | Avoiding end-range flexion, sitting with hips higher than knees, standing and moving |
| Key insight | You cannot stretch your way out of FAI. Deep hip openers in yoga often make it worse. The fix is managing positions and building hip strength around the limitation. (AAFP, 2014) |