Stryker Accolade TMZF Analysis

The Stryker Accolade® TMZF femoral stem was approved by the Food & Drug Administration in 2000, through a process called the 510(k) approval process. This is the method used by manufacturers to get a rapid approval for medical devices to be used inside patients. The 510(k) process allows the device manufacturer to file papers with the FDA claiming that the “new” device is substantially equivalent to a device already on the market and already approved by the FDA.

Stryker Accolade TMZF Hip Stem

Think of the FDA’s 510(k) process as the “10 items or less” line at your grocery store.

A 2012 study published in the Clinical Orthopaedics and Related Research journal (Clin Orthop Relat Res (2012) 470:410–417 DOI 10.1007/s11999-011-2160-z) assessed the Stryker Accolade® femoral stem on a radiographic basis, component migration analysis and gauging of aseptic stem loosening.

What were the findings? The researchers found that:

• After two years there was over a 1.5 mm subsidence in 36% of the Accolade stems (the mean acceptable range being 0 – 1.5).
• In 10% of the Accolade femoral stems, greater than 1.5 mm radiolucent lines (separation in the metal) in (3) areas of the femoral stems were found.
• The 5-year survivorship for aseptic loosening of the 367 stems was 97% with revision as end point and 95% for radiographic failure.

The researchers concluded:

“The high incidence of migration and stems with radiographic failure raises concerns about patient clinical function and long-term survivorship of this stem design. This migration pattern may be due to poor initial stability with a subsequent lack of osseointegration.”

Why might this be happening in the Stryker Accolade femoral stem; as well in many other hip implant devices having problems after being implanted in patients?

One of the common factors we see in medical devices is the 510(k) process allowing these devices to get out on the market rapidly, without clinical trials and appropriate laboratory testing.

As the authors of the above study concluded: “the gold standard for survivorship continues to be a well performed, long-term clinical follow-up” and, if that is case, rapid product approval as opposed to careful evaluation through clinical trial may be resulting in hurt patients and need for re-implantation.