Joint Understanding: What You Need to Know about Hip Implant Designs, Materials, and Fixation

Today’s hip implant marketplace offers a great variety of systems. More than 100 products—including total hip systems, as well as individual components—from 17 suppliers are listed in ECRI Institute’s June 2011 Healthcare Product Comparison Systemchart for hip joint prostheses.1 The available models vary in details of design, materials, and fixation methods, among other characteristics. Effective management of this technology requires an understanding of these key differentiating factors.

This is the second article in our series on total hip replacement (THR) surgery (also known as total hip arthroplasty, or THA). The first article, published in the November 2011 Health Devices, provides a broad overview of the hip replacement procedure and the basic types of prostheses. This month’s article takes a more in-depth look at implant designs, materials, and fixation methods. This article, like the first one, is intended to help educate members of a facility’s value analysis committee (and other nonsurgical personnel involved in purchasing or technology management decisions) about developments with the technology, and thereby to help inform purchasing decisions.

The most common hip prosthesis design includes a ball component that tops a metal-alloy stem that is implanted into the top of the femur; this component replaces the degenerated femoral head that is removed by the surgeon. The ball component fits into a prosthetic socket—the acetabular cup component—that the surgeon places in the pelvis. (See the illustration below.) Each component may come in a...