What was my diagnosis?

Femoral Acetabula impingement (FAI) with a mixed impingement picture. Asphericity (lack of roundness) of the femoral head visible. Chondral (cartilage) thinning on the front of the socket with patches of osteoarthritis. Suspected labral tear at the front edge of the socket. (This is explained below)

Hip arthroscopy versus joint replacement?

My symptoms and radiology were not severe enough to warrant joint replacement. After discussion with Mr Bajwa, I decided to have a hip arthroscopy aimed at re-sculpting the bony side of things to deal with the impingement and addressing the labrum on its merits. The aim was to preserve as much as possible of the labrum and other support structures such as the ligamentum Teres .

FAI is a recently understood hip condition in which there is abnormal mechanical contact (impingement) between the “ball” and “socket” of the hip. The socket is formed by the acetabulum, the ball is the femoral head, which is the upper end of the thigh bone. Impingement is a term to describe the catching, pinching, and/or abnormal rubbing of the ball within the socket. This can lead to damage of the articular cartilage (lining) in the socket, or the labrum or both of them. Activities that involve recurrent hip motion like running or kicking increase the frequency of this abnormal contact.

The labrum is a ring of cartilage that surrounds the acetabulum , deepens the hip socket and contributes to its stability. Damage to the labrum and/or cartilage may cause pain. An abnormality in the shape of the femoral head or acetabulum may cause FAI.

There are 3 types of FAI, pincer, cam and mixed. Pincer impingement occurs because extra bone extends out over the normal rim of the acetabulum. FAI due to lack of femoral head roundness is referred to as Cam impingement. In Cam impingement the femoral head is not round and cannot rotate smoothly inside the acetabulum. A bump forms of the edge of the femoral head that grinds the cartilage inside the acetabulum and can tear the labrum. Mixed impingement suggests that both the pincer and cam types are present.