Transient Osteoporosis of the Hip
Transient osteoporosis of the hip is a rare condition that causes bone loss temporarily in the upper part of the thighbone (femur). It is mostly found in young or middle aged men between the ages of 30 and 60, and women in their later stages of pregnancy or early postpartum period (following childbirth). It is characterized by abrupt onset of pain that increases with activity.
Avascular necrosis, also called osteonecrosis is a condition in which bone death occurs because of inadequate blood supply to it. Lack of blood flow may occur when there is a fracture in the bone or a joint dislocation that may damage nearby blood vessels. Chronic use of high doses of steroid medications and heavy alcohol consumption are the two main risk factors of avascular necrosis. Initially, small breaks appear in the bone that may eventually collapse. Hip joint is most commonly affected; however, the knee and shoulder may also be involved.
The hip joint is a "ball and socket" joint. The "ball" is the head of the femur, or thigh bone, and the "socket" is the cup shaped acetabulum. The joint surface is covered by a smooth articular surface that allows pain free movement in the joint.