Four primary hip-replacement components include: femoral stem, femoral ball, liner, acetabular cup.

The Femoral Stem

The Femoral Stem is the main component of a hip replacement. Made of metals such as cobalt chrome or titanium, the stem is inserted into the femur, or thighbone. Your surgeon can choose a cemented or non-cemented prosthesis - both have different advantages for certain patient situations. The stem consists (from the top down) of a taper, neck, and stem.

Your surgeon will choose the optimum femoral stem for you based on criteria such as:

• Clinical data as reported in peer-reviewed medical journals.
• Shape, engineering and design, which allow for optimum surgical technique.
• "Fit" with the patient's anatomy.
• The implant's clinical history of stability and fixation (strength of the bond with patient's bone).
• The choice of a cemented or cementless stem implant, based on the surgeon's evaluation of the patient's needs.
• The exterior coating of the stem, which contributes to optimum fixation.
• The type of surgery - primary, revision, fracture - and the corresponding implant designed for that specific situation.
• Confidence in the manufacturer's reputation, successful clinical history, design, materials and quality.

The Femoral Head

The ball, or head, of your implant is a crucial component, replacing the top of the natural thighbone. Heads are typically made of cobalt chrome or ceramic and are produced in varying diameters and neck lengths to fit the patient's anatomy.

The Acetabular Cup and Liner Systems

The cup replaces the socket of the pelvic bone. The socket is called the acetabulum. During surgery, the natural socket is enlarged to make room for the acetabular cup.

The cup component of the hip replacement works closely in tandem with the liner, typically made of a type of plastic called ultra-high molecular weight polyethylene or special surgical metal alloy. Not all liners are alike, and the liner is vital to longevity of the implant. The best liners will produce the optimum range of motion over the longest span of time.