Components and materials used for total hip replacement

Total hip arthroplasty (THA) involves the replacement of the femoral head, which fits into an acetabular cup that is secured into the pelvis. Although hip replacements are successful in reducing pain and improving function, many patients who undergo THA must undergo revision surgery within 10 years due to complications such as infection, dislocation, or loosening. There are several designs available for hip implants, as well as different materials used for the implant components. Modular hip implants allow for the choice of different femoral neck lengths, femoral head sizes, as well as modular acetabular cups, as opposed to standard implants. Materials used for the implant components must be biocompatible, as well as resistant enough to withstand the wear and tear associated with the use of the hip. Various metals, plastics, and ceramics are used for hip implant components, each material having its own strengths and limitations. The objective of this report is to review the comparative clinical effectiveness and adverse events associated with THA using: a ceramic head on a ceramic acetabular liner or a ceramic head on cross-linked polyethylene acetabular liner versus a metal head on a cross-linked polyethylene acetabular liner; a modular primary stem versus a standard non-modular stem; or a metal femoral head of 36 mm and larger on a cross-linked polyethylene acetabular liner versus a metal femoral head of 28 to 32 mm on a cross-linked polyethylene acetabular liner.