NEW (POSITIVE) CERAMIC-ON-POLY DATA (Orthopedics This Week)
So how have different bearing surfaces “trended” of late? Researchers from the Keck School of Medicine of the University of Southern California in Los Angeles set out to determine how selection of such total hip arthroplasty (THA) surfaces has varied from 2007 through 2014.
The study was titled, “Total Hip Arthroplasty Bearing Surface Trends in the United States From 2007 to 2014: The Rise of Ceramic on Polyethylene,” and appears in the January 9, 2018 edition of the Journal of Arthroplasty.
Jay R. Lieberman, M.D., an orthopedic surgeon at Keck, was the senior author on the study. He told OTW, “We know that there was an uptick in the use of ceramic-on-polyethylene liners around 2008, with a decrease in metal-on-polyethylene.”
“This trend will likely continue due to taper corrosion. We do not have a secure grasp on the size of the problem, however. Some surgeons treating younger patients have halted the use of metal heads because of concerns about taper corrosion; but in older patients the use of metal heads is continuing. In addition, it looks like taper corrosion may be more common in stems made by certain manufacturers. We just do not have enough data to make definitive decisions.”
The authors wrote, “[Using] the Nationwide Inpatient Sample database, 2,460,640 Total Hip Arthroplasty discharges were identified, of which 1,059,825 (43.1%) had bearing surface data. A total of 496,713 (46.9%) Metal-on-Poly, 307,907 (29.1%) Ceramic-on-Poly, 210,381 (19.9%) Metal-on-Metal, and 44,823 (4.2%) Ceramic-on-Ceramic cases were identified.”
“Metal-on-Metal utilization peaked in 2008 representing 40.1% of total hip arthroplasty cases implanted that year and steadily declined to 4.0% in 2014. From 2007 to 2014, the use of Ceramic-on-Poly bearing surfaces increased from 11.1% of cases in 2007 to 50.8% of cases in 2014. In 2014, Ceramic-on-Poly utilization surpassed Metal-on-Poly which represented 42.1% of bearing surfaces that year.”
“It is interesting to see how behavior is influenced by just a few studies,” Dr. Lieberman told OTW. “We probably act more quickly on negative data; in general, you do not change behavior so rapidly with positive data. We need to watch what’s going on with ceramic heads as this is the only way to discern the outcomes. Maybe head size is part of the problem…perhaps with a larger head there is more torque at the head-trunnion interface.”
“Our study was limited in that it was a large administrative database that can be vulnerable to coding errors. We do not have data about age or activity levels of the patients. My advice to my colleagues is to wait and see what happens. As for now, using ceramic-on-poly in younger patients is not unreasonable.”