Hip Replacement Technology

The acetabular shell (socket portion) lines the patient’s bony acetabulum. The acetabular component is typically made of a metal shell with a liner.

The shell is most often “press fit” into the patient’s acetabulum. The patient’s own bone grows to the component locking it in place for long term fixation. The acetabular shell typically has a roughened or porous surface for better interdigitation of bone. The liner may be medical grade plastic called polyethylene, metal (cobalt/chrome) or ceramic (alumina or aluminum oxide).

This liner is one side of the bearing that allows your hip the ability to move freely.

The femoral component (stem portion) is made of metal. These metals include various grades of cobalt/chrome alloy and titanium alloy. The femoral head is made either of metal or ceramic.

The precision-engineered shape of the femoral stem implant is crucial to obtaining results for the patient. The hip replacement implant is going to become part of the patient’s body, so achieving an optimal fit within the femur is key to a successful outcome. Surgeons refer to this as “fixation.”

A cemented implant is held in place by a type of epoxy cement, polymethylmethacrylate, that attaches the metal to the bone.

An uncemented implant, similar to the uncemented acetabulum, has a roughened or porous surface. The geometry and location of the ingrowth surface is dependent on the type of femoral component and the manufacturer. Nevertheless, the ingrowth surface is designed to allow bone to grow into it, thus permanently attaching the implant to the patients femur.