What Does Hip Replacement Surgery Involve?
The hip joint is situated where the upper end of the femur (thigh bone) meets the pelvis (hip bone). A ball at the end of the femur, called the femoral head, corresponds to a socket (acetabulum) in the pelvis to enable a wide range of motion. Please refer to the figure below.
At some point in a traditional hip replacement, which can last from 1-2 hours, the surgeon creates a 6-to-8-inch incision over the side of the hip through the muscles and removes diseased bone tissue and cartilage from the hip joint, and at the same time keeping the healthy parts of the joint untouched. Next the surgeon replaces the head of the femur and acetabulum with new, artificial parts.
The brand-new hip is constructed of materials that permit a natural gliding motion of the joint.
Over the last 10 years, several surgeons started doing what is called a minimally invasive, or mini-incision, hip replacement, which needs smaller incisions and a shorter recovery time than traditional surgery. Prospects for this kind of surgery are generally age 50 or younger, of normal weight based on body mass index and healthier compared to prospects for traditional surgery.
Whether you get traditional or minimally invasive surgery, the parts used to replace the joint are the same and appear in two general types, cemented and uncemented.
Cemented parts are attached to the available healthy bone with a unique glue or cement. Hip replacement making use of these parts is called a cemented procedure.
Uncemented parts make use of a process called biologic fixation, which supports them in place. This indicates that the parts are designed with a porous surface that permits your own bone to grow into the pores and hold the parts in place. At certain times a surgeon uses a cemented femur part and uncemented acetabulur part. This combination is called a hybrid replacement.
In a total hip replacement (hip arthroplasty), the defective bone and cartilage is taken out and replaced with prosthetic components.
- The defective femoral head is removed and replaced with a metal stem that is positioned into the hollow center of the femur. The femoral stem may be either cemented or “press fit” into the bone.
- A metal or ceramic ball is placed on the top part of the stem. This ball replaces the defective femoral head that was removed.
- The defective cartilage surface of the acetabulum (socket) is removed and replaced with a metal socket. Screws or cement maybe used to secure the socket in place.
- A plastic, ceramic, or metal spacer is positioned between the new ball and the socket to allow a smooth gliding surface.
The most frequent source of chronic hip pain and disability is arthritis. Osteoarthritis, rheumatoid arthritis, and traumatic arthritis are the best known kinds of this disease.
- Osteoarthritis is an age-related “wear and tear” form of arthritis. It general sets in in people 50 years of age and older and usually in people who have a family history of arthritis. The cartilage padding the bones of the hip wears away. The bones the rub against one another, resulting in hip pain and stiffness. Osteoarthritis may also be brought about by slight abnormalities in how the hip developed in childhood.
- Rheumatoid arthritis is an autoimmune disease where the synovial membrane gets irritated and inflamed and eventually thickens. This longstanding inflammation will damage cartilage, producing pain and stiffness. Rheumatoid arthritis is the most prevalent type of a group of conditions called inflammatory arthritis.
- Post-traumatic arthritis result from a severe hip injury or fracture. The cartilage can be damaged and causes hip pain and stiffness with time.
- Avascular necrosis. When blood supply to the femoral head is compromised, the surface of the bone may collapse and arthritis results. Injuries to the hip, like a dislocation or fracture disrupt the blood supply to the joint. Certain diseases may also induce avascular necrosis.
Childhood hip disease. A number of infants and children have hip problems. Even if the problems are taken care of, they may still trigger arthritis later in life. This occurs because the hip may not develop normally and the joint surfaces are affected.