During a hip replacement surgery, the surgeon will replace the patient’s ball and socket hip joint with an artificial implant. The hip’s acetabulum will be replaced by the “acetabular shell” and the top of the thigh bone or femur will be replaced by a “femoral head”. Hip implants vary in terms of the size, design and material it is made of, allowing doctors to fit the patient with the best suited hip.
Currently, implants are made of ceramic, metal or polyethylene. An important decision made by the orthopedic surgeon is which “bearing surface to use”. The “bearing surface” or the area of the component where the acetabulum attaches to the femoral head component can be either a) metal on metal, b) ceramic on ceramic or c) metal or ceramic on polyethylene.
Each option has different advantages and disadvantages and the right bearing surface for a patient may be chosen on the basis of multiple factors such as the patient’s lifestyle, weight and age. The quality of a bearing is based on its durability and level of performance.
A metal on metal hip implant comprises of a metal socket component, a metal ball and a metal stem. It is sturdy, durable and decreases the risk of dislocation. However, when the patient moves, the metal socket rubs against the metal ball, causing metal debris to shed and damage surrounding bone and tissue. This can be very painful for the patient and may even lead to implant failure.
A ceramic on ceramic hip implant comprises a ceramic ball and a ceramic socket lining. Cement is one of the sturdiest and most durable materials used for a hip implant. It is extremely resistant to wear and tear and doesn’t run the risk of loosening and shedding debris in the body as in the case of a metal on metal hip implant. However, it is possible for the patient to fracture the ceramic socket and head. Also, cement on cement implants sometimes squeak, not only posing a nuisance but also increasing the chances of a revision surgery.
Metal or ceramic on polyethylene:
A metal on ceramic or a metal on polyethylene hip implant is widely known to be the “gold standard” in hip replacement implants. A metal or ceramic head will be placed in a polyethylene (a very sturdy medical grade plastic) socket. Polyethylene is extremely durable and can resist wear and tear even in the most active lifestyles. However, this type of implant may be regarded as costly by some.
While the hip implant plays an important role on the patient’s recovery and quality of life after surgery, it isn’t the only consideration. However, it is best to get all the necessary information regarding different Hip implant options to select the one that best suits the patient’s age, lifestyle, weight and hip condition.