Sudden onset of polyethylene wear seen in acetabular liners

MADRID — Investigators have found that a polyethylene liner from the 1990s — which is no-longer available — has shown a significant amount of degradation at 13 to 14 years postoperative.

In presenting his team’s long-term follow-up data on 486 total hip arthroplasties (THAs) using the ARC2F (Osteonics) acetabular insert, George Tsakotos, of Greece, said, “All THAs performed well without signs of wear at 10 years. No implant was revised during the first decade because of mechanical loosening.”

“But, during the 13th to 14th year, a significant number of patients appeared with symptoms of polyethylene’s massive destruction and significant osteolysis at the femoral and acetabular side of the arthroplasty.”

Fifteen-year follow-up

Overall, 668 THAs with the acetabular implants matched with Omnifit femoral stems were implanted between 1989 and 1995; 182 were lost to follow-up. Mean patients age was 54 years at implantation. Preoperative diagnosis included: primary osteoarthritis in 501 cases; post-traumatic arthritis 24; hip dysplasia in 112; and avascular necrosis in 31. The average follow-up was 15 years, Tsakotos said.

“We recalled all patients that could be found,” he said. “Totally, 178 from the 486 THA’s had similar radiographic signs of wear. Only 33 of all these had initial wrong orientation of the cup.”

He said the relationship between polyethylene wear and sterilization methods is well documented.

“Despite the excellent early and middle-term results, ARC2F shows rapid and massive wear of the insert after 12 years, probably because of degeneration and loss of polyethylene’s structural integrity due to the method of sterilization,” he said. “We suggest to recall and inspect all the patients which have this kind of implant more than 12 years.”

Reference:
Macheras G, Koutsostathi S, Papadakis S, et al. ARC2F acetabular component: Sudden onset of rapid and massive polyethylene insert wear in long-term observation. Paper #F242. Presented at the EFORT Congress 2010. June 2-5, 2010. Madrid.

I think what he said was very important. We keep seeing patients with maximum polyethylene wear and surgeons in Europe still use metal with polyethylene. This is unacceptable. We have to say that this is not acceptable anymore.

– Roberto Binazzi, MD
Bologna, Italy