Study Confirms Lower Revision THA Rate with Cross-Linked Polyethylene Implants
A long-term follow-up study from Australia confirms that total hip arthroplasty (THA) patients who receive a hip implant with components made of cross-linked polyethylene (XLPE) have a substantially lower risk of undergoing revision surgery 16 years after the primary procedure than patients who receive a conventional polyethylene (CPE) implant.
The study, published in The Journal of Bone & Joint Surgery, included more than 240,000 THA patients in the Australian Orthopaedic Association National Joint Replacement Registry. These patients underwent THA for osteoarthritis of the hip between 1999 and 2016. Outcomes were analyzed according to the type of bearing surface used in the hip implant: XLPE in 199,000 procedures and CPE in 41,000 procedures.
Cross-linked polyethylene bearing surfaces were developed to address the problem of wear occurring with hip components made with CPE. In this study, use of XLPE implants increased dramatically during the study period, from approximately 9% of implants with polyethylene bearings in 2000 to 97% in 2016.
Previously published research has shown that excessive wear of CPE implants may lead to revision surgery, particularly in younger, more-active patients. That was the case in this study as well: As early as 6 months after THA, revision rates were substantially higher in patients with CPE bearings. Over the course of 16 years, the cumulative rate of revision surgery was 11.7% in the CPE group and 6.2% in the XLPE group.
After adjusting for other risk factors, the researchers found that patients with CPE implants were about 3 times more likely than patients with XLPE implants to have revision surgery after 9 years. Revisions directly related to wear of the bearing surface occurred in 0.81% of procedures that used CPE bearing versus 0.05% of procedures that used XLPE bearings.
A subgroup analysis focused on approximately 18,000 patients who underwent THA before age 55. The 15-year cumulative rate of revision was 17.4% in the CPE group versus 6.6% in the XLPE group. At 7 years, younger patients with CPE implants were about 5 times more likely to need revision surgery.
This study provides the longest follow-up in the largest series of patients reported to date. The results provide important real-world evidence that the reduced wear of XLPE bearings translates to a lower risk of revision surgery, making an effective procedure even better, the researchers said.
“Wear-related and implant-longevity issues are particularly important in younger patients, who are generally more active and have a longer life span than their older counterparts,” they concluded. “We believe that the evidence of reduced long-term wear with XLPE is now so strong that, when a polyethylene bearing surface is used in THA, it should be XLPE, particularly in younger patients.”
de Steiger R, Lorimer M, Graves SE. Cross-linked polyethylene for total hip arthroplasty markedly reduces revision surgery at 16 years. J Bone Joint Surg Am. 2018 Aug 1;100(15):1281-1288. doi: 10.2106/JBJS.17.01221.