Joint arthroplasty is a well-known surgical procedure by which a diseased and/or damaged natural joint is replaced by a prosthetic joint. The prosthetic joint may include a prosthesis that is implanted into one or more of the patient's bones. Many hip prostheses include a femoral prosthesis that is implanted into a patient's femur. A femoral prosthesis typically includes an elongated stem component that is received in the medullary canal of the patient's femur and a spherically-shaped head component that bears against the patient's acetabulum or a prosthetic replacement acetabular cup.
The elongated stem implant may be cemented into the medullary canal or may have a porous coated surface for allowing the bone to heal directly to the implant. In some prostheses, the head is attached to a neck of the elongated stem via a taper connection. It is important to assemble the head to the neck with enough force so as to limit micromotion between the head and neck. The acetabulum of the patient may also be reamed to receive a shell and liner. A polyethylene, metal or ceramic liner with a metal shell is inserted into the acetabulum and acts as socket for receiving the head on the stemmed implant.