By Nancy Walsh, Senior Staff Writer, MedPage Today
Innovations to devices used in joint replacement have been introduced without sufficient evidence that they are any better than existing implants, a systematic review suggested.
In fact, for one type of new device technology, hip replacements with modular femoral necks, the cumulative rates of revision surgery at 5 and 10 years were 7.4% and 10.8%, compared with rates of 3.7% and 6.4% for conventional prostheses with nonmodular necks, according to Art Sedrakyan, MD, PhD, of Weill Cornell Medical College in New York City, and colleagues.
That represented a near doubling of the adjusted 10-year revision risk (HR 1.92, 95% CI 1.76-2.10), the researchers reported online in The BMJ.
The publicity surrounding the problems associated with large-size, metal-on-metal hip replacements — high revision rates, recalls, and lawsuits — led to calls from the scientific and regulatory communities for greater oversight of orthopedic implants and other medical devices.
“This systematic review was part of a U.S. Food and Drug Administration-initiated project on comparative effectiveness and safety of orthopedic implants as a reaction to the recent disaster with metal-on-metal articulations,” the researchers wrote.
To see if more caution was indeed being exercised with these devices, Sedrakyan’s group looked at the evidence for “five substantial, innovative, relatively recent, and already widely implemented device technologies used in major total joint replacement.”
They searched the literature for comparative studies on safety and efficacy for modular femoral necks, ceramic-on-ceramic bearings, and uncemented monoblock acetabular cups used in hip replacements, and for gender-specific and high-flexion implants in knee replacements.
They also obtained data from various national registries for long-term outcomes.
For the ceramic-on-ceramic bearings, they identified 42 studies reporting on 23 cohorts. In 13 of the cohorts the comparison was with ceramic-on-polyethylene articulations, and in 10, the comparison was with metal-on-polyethylene bearings.
