Modern metal-on-metal hip implants.

This Technology Overview was prepared using systematic review methodology and summarizes the findings of studies published as of July 15, 2011, on modern metal-on-metal hip implants. Analyses conducted on outcomes by two joint registries indicate that patients who receive metal-on-metal total hip arthroplasty (THA) and hip resurfacing are at greater risk for revision than are patients who receive THA using a different bearing surface combination. Data from these registries also indicate that larger femoral head components have higher revision rates and risk of revision and that older age is associated with increased revision risks of large-head metal-on-metal THA.

Failure of the modular neck in a total hip arthroplasty.

Modular femoral necks in total hip arthroplasty are promoted as giving the surgeon more options during surgery and as being safe. We report a case of fatigue fracture in the modular neck of a femoral implant 3 1/2 years after implantation. The probable design errors leading to product failure are discussed.