Oxinium knee implants: What are the facts?

Knee replacement surgery is the most common form of replacement surgery in the United States. Experts estimate that over a quarter million knee replacement procedures are performed every year in the United States.

Knee replacement surgery is helpful for many patients, allowing them significant relief from pain and permitting a return to active daily living. However, patients may face unexpected complications during and following knee replacement surgery. Often, the success of the surgery is affected both by the surgical techniques used and the type of knee replacement that the patient receives.

Smith & Nephew's Oxinium

Smith & Nephew is an internationally renowned company that grew from a small United Kingdom company to a world leader in manufacturing medical devices. Its orthopedics division, which produces hip and knee implants and trauma products, is based in Memphis, Tennessee.

One of Smith & Nephew's innovations is to produce joint implant products using Oxinium, their trade name for oxidized zirconium components. This metal was superior, in many cases, to the conventional titanium or cobalt-chromium alloys or polyethylene plastics used in implants produced by other firms. Oxinium's superiority guaranteed Smith & Nephew a substantial market for its implant products, and the company won the 2005 ASM International Engineering Materials Achievement Award for developing Oxinium.

Even with superior materials, however, mistakes can happen. In August 2003, Smith & Nephew notified the Food and Drug Administration (FDA) of a defect in its Oxinium cementless knee implants. These devices were intended to bond to bone without cement, but a design flaw meant that the implants could loosen — and, indeed, some thirty people had to have follow-up surgery to replace their Oxinium products for just that reason. The following month, the company issued a voluntary recall of the Oxinium Genesis II and Profix II knee implants — both cementless designs.

Since then, the company has been plagued by problems with defective products. In 2007, Smith & Nephew had to recall some of its hip resurfacing implants because incompatible parts were packaged together. Smith & Nephew began another voluntary recall in January of 2008 because some implants had higher-than-specified iron content. In late 2009, a Smith & Nephew knee replacement recall was issued for nearly 40,000 Journey Uni Tibial Baseplates after several complaints about the product breaking. This is a significant recall, involving some 44 different implant systems.

Smith & Nephew has continued to have problems assuring the safety of their implant devices. Officials from the FDA visited a Smith & Nephew plant in Germany in July 2010; the agency then issued a warning letter about manufacturing defects in December 2010. It should be noted that despite all the problems with various Oxinium devices, all recalls of the implants have been voluntary. The FDA has not yet compelled Smith & Nephew to withdraw its products from the market. Some experts have criticized this approach, saying that the failure to issue a government recall has undoubtedly left some patients to suffer the consequences of living with defective implants or facing reparative surgery.

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