Extra bone on the ball or around the socket 'impinges' or rubs causing damage to the cartilage in and around the hip. This is a common finding on x-rays in the general population and many people who have had replacement hips have signs of FAI.

There is growing scientific evidence that this condition leads to osteoarthritis of the hip. FAI is characterised by two main deformities which can occur in isolation or together.

Cam Type

Pincher Type

When the hip is bent or inwardly rotated the bump of the femoral neck (CAM deformity) can be jammed against the rim of the acetabulum. Similarly the rim of the acetabulum can become jammed against the femoral neck. This happens with a pincer deformity which is an over coverage of the pelvic bone around the femoral head.

The main symptoms of FAI are:

  • Groin pain or pain on the inside of the thigh (adductor pain)
  • Difficulties when putting on socks
  • Pain with prolonged sitting, tendency to walk with the foot in outer rotated position
  • Gradually reduced range of motion

When we look inside hips with keyhole surgery the FAI changes on the x-ray correlate with the expected abnormalities of the bones and soft tissues, which we can treat by trimming away the extra bone and repairing or trimming away the damaged cartilage.