These activities push the hip to the extreme of its range of motion, and with repetition, the hip can be damaged. The hip is entirely normal, but extreme activities may damage the hip – for example repeated kicking in martial arts, lunging in racquet sports, the 'eggbeater' kick of water polo, kicking in soccer, horse riding etc. Secondary FAI, where the impingement is clearly secondary to a disease, such as a slipped upper femoral epiphysis, or injury, such as a fracture, is well-known, and various operations have been described to correct it. Primary FAI is a recently recognised condition. If the head of the femur is not round, or sits in the wrong position in relation to the rest of the femur, or the socket is either too deep or facing in the wrong direction, problems ensue. The most common form of FAI is 'primary' where the deformity does not follow a disease or injury, and is often quite subtle. The gap between the two bones consists of articular cartilage – the bearing surface of the joint – which does not show up on X-ray. The hip is a ball (yellow circle) and socket (yellow semicircle). Activities such as dance repeatedly push the hips to the extremes of motion, sometimes causing damage.įig. 1 David Claase, of the Hong Kong Ballet, back on stage after hip arthroscopy for cam impingement. The gap between the two bones is filled with articular cartilage – the bearing surface of the joint – a smooth layer a few millimeters thick covers the bone on each side of the joint. The hip joint is a ball and socket: the ball is formed by the head of the femur (thigh bone) and the socket is in the pelvis, and is known as the acetabulum, from its similarity (to early anatomists) to the shape of a Roman vinegar cruet. What is Femoro – Acetabular Impingement?įemoro - Acetabular Impingement (FAI) is a condition in which the two bones which make up the hip joint pinch against each other, or 'impinge', at the extremes of motion, causing damage to the joint. (Fig. This article is intended to give a general overview of the condition known as Femoro - Acetabular Impingement (FAI) for patients, their families and their family doctors and their physiotherapists. (Last updated on: Oct 13th 2020) What is this article?

Left hip xray normal moderate