The hip is a ball-and-socket joint where the rounded head of the femur, the upper leg bone, meets the acetabulum, a cup-like area of the pelvic bone. Irreparable damage to the hip joint with persistent pain and loss of mobility may require replacement with artificial joint parts, a procedure known as hip replacement or hip arthroplasty. Different options are available for hip replacement, which vary by the type of replacement parts used.
Cemented Total Hip Replacement
A cemented total hip replacement involves removal of the head of the femur, the damaged cartilage and bone of the acetabulum. A metal rod is cemented into a cavity created in the core of the femur. The rod head bears a round ball that mirrors the head of the femur. A metal cup containing a hard plastic liner is fixed to the former site to the acetabulum to receive the metal ball of the femur rod.
An advantage of cemented hip arthroplasty is the ability to bear weight on the replacement joint almost immediately after surgery, points out the American Academy of Orthopaedic Surgeons. A potential disadvantage is the possibility of cracking in the cement, causing loosening of the femur rod over time. This complication is most likely to develop in people who are overweight or who engage in a high level of physical activity. Cemented total hip replacement is most commonly used in older patients who do not participate in strenuous physical activity.
Porous Total Hip Replacement
With a porous total hip replacement, no cement is used. The femur rod and acetabulum replacement cup contain tiny holes, or pores, into which bone can grow to fix the implants in place. A hip arthroplasty using porous implants necessitates an extended recovery period, during which time the bone grows into the implants to create a strong bond. The National Institute of Arthritis and Musculoskeletal and Skin Diseases points out that people undergoing hip replacement with porous implants typically require approximately three months of recovery before unrestricted activity can be undertaken. Limited weight bearing through use of a walker or crutches helps protect the joint during the early stages of recovery. Thigh pain may occur during the recovery period. Younger patients with strong bones who desire the capacity to participate in strenuous physical activity are the most likely candidates for porous total hip replacement, according to the American Academy of Orthopaedic Surgeons.
Hybrid Total Hip Replacement
A hybrid total hip replacement involves a combination of cemented and porous implants. According to the American Academy of Orthopaedic Surgeons, the femur rod is usually cemented, and the acetabulum replacement implant is of the porous variety. This procedure may be an option for people with limited osteoporosis.
