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Crosslinked polyethylene associated with reduced revision rate for THA at long-term follow-up

In patients who underwent total hip arthroplasty for osteoarthritis, use of a crosslinked polyethylene bearing surface was linked to a significantly reduced revision rate at 16 years compared with conventional polyethylene, according to recently published results in The Journal of Bone and Joint Surgery.

Richard de Steiger photo
Richard de Steiger

“The Australian Orthopaedic Association National Joint Replacement Registry has demonstrated that in almost 200,000 primary THAs, the use of crosslinked polyethylene (XLPE) has resulted in a markedly reduced rate of revision at 16 years for all patients compared to the use of conventional polyethylene,” Richard de Steiger, MBBS, FRACS, FAOrthoA, told Healio.com/Orthopedics. “The study has demonstrated that longevity of THA is likely to be prolonged with the use of XLPE, with fewer patients undergoing revision surgery.”

de Steiger and colleagues performed an observational study of data from a national registry for all patients who underwent THA for osteoarthritis in Australia between 1999 and 2016. Results were compared between 41,171 THAs performed with conventional PE and 199,131 THAs performed with XLPE. Investigators also analyzed the impact of age, sex, femoral head size, method of acetabular and femoral component fixation, and reasons and types of revision. Kaplan-Meier estimates of survivorship were used to determine the time to first revision.

Results showed that after 6 months, XLPE correlated with a lower revision rate vs. conventional PE. Investigators noted the difference was more significant with time. In the conventional PE and XLPE groups, the 16-year cumulative revision percentage of primary THAs was 11.7% and 6.2%, respectively. After 9 years, the hazard ratio was 3.02. – by Monica Jaramillo

 

Disclosures: The researchers report no relevant financial disclosures.

In patients who underwent total hip arthroplasty for osteoarthritis, use of a crosslinked polyethylene bearing surface was linked to a significantly reduced revision rate at 16 years compared with conventional polyethylene, according to recently published results in The Journal of Bone and Joint Surgery.

Richard de Steiger photo
Richard de Steiger

“The Australian Orthopaedic Association National Joint Replacement Registry has demonstrated that in almost 200,000 primary THAs, the use of crosslinked polyethylene (XLPE) has resulted in a markedly reduced rate of revision at 16 years for all patients compared to the use of conventional polyethylene,” Richard de Steiger, MBBS, FRACS, FAOrthoA, told Healio.com/Orthopedics. “The study has demonstrated that longevity of THA is likely to be prolonged with the use of XLPE, with fewer patients undergoing revision surgery.”

de Steiger and colleagues performed an observational study of data from a national registry for all patients who underwent THA for osteoarthritis in Australia between 1999 and 2016. Results were compared between 41,171 THAs performed with conventional PE and 199,131 THAs performed with XLPE. Investigators also analyzed the impact of age, sex, femoral head size, method of acetabular and femoral component fixation, and reasons and types of revision. Kaplan-Meier estimates of survivorship were used to determine the time to first revision.

Results showed that after 6 months, XLPE correlated with a lower revision rate vs. conventional PE. Investigators noted the difference was more significant with time. In the conventional PE and XLPE groups, the 16-year cumulative revision percentage of primary THAs was 11.7% and 6.2%, respectively. After 9 years, the hazard ratio was 3.02. – by Monica Jaramillo

 

Disclosures: The researchers report no relevant financial disclosures.

    Perspective

    The excellent study by de Steiger and colleagues can be seen as a culmination and confirmation of the efforts of researchers to use radiation crosslinking to improve the wear resistance of ultra-high molecular weight polyethylene in hip replacements. As the authors (and Dr. Namba, who previously provided a commentary), stated, the study “completes the loop” on the progressive process of laboratory testing, closely monitored early clinical studies, widespread surveillance and mid-term clinical evaluation. The results show an early and consistent substantial reduction in the rate of revision of hips with highly XLPE. It is satisfying and reassuring that this confirms the trends that were reported in the great majority of shorter-term studies involving fewer patients and fewer types of hips — as well as the pre-clinical hip simulator testing.

    It also is valuable that, due to the large number of patients in the study, the authors were able to control for potentially confounding variables, including ball diameter and patient age. Another import factor was the separation of revisions due to loosening from those due to wear/lysis. Especially in the early clinical follow-up, aseptic loosening can be primarily due to problems with fixation or subluxation, when it is too soon to detect a reduction in loosening subsequent to wear-induced lysis.

    In this regard, it is important to keep in mind the complex and interactive nature of wear, lysis and loosening. For example, loosening of a cemented stem can generate third-body particles of bone cement, which then migrate to the ball-socket interface, which increases the wear (of either type of PE), which increases the production of debris, which induces osteolysis, which further undermines the fixation, which increases the loosening — ie, a classic feedback loop. Despite the potential for such complex wear scenarios, the large number of patients and the 16-year follow-up of the study by de Steiger and his colleagues provide the ability to “see through the clinical fog” and accurately discern the substantial reduction in wear and subsequent clinical complications that have been provided by the highly XLPEs.

     

    References:

    Namba RS. J Bone Joint Surg Am. 2018; doi:10.2106/JBJS.18.00416.

    McKellop HA. Biomaterial. 2007; doi:10.1016/j.biomaterials.2007.07.040.

    • Harry A. McKellop, PhD

    • Orthopaedic surgery

      University of California, Los Angeles

    Disclosures: McKellop reports he is a co-inventor of one of the highly-crosslinked polyethylenes evaluated in the study by de Steiger and colleagues, used in the Duraloc hip (DePuy Synthes) and he received royalties from the license of that technology.