Are Hooded, Crosslinked Polyethylene Liners Associated with a Reduced Risk of Revision After THA?

Abstract

Background Hooded acetabular liners and head sizes $ 32 mm have both shown to have a beneficial effect on the revision rate for dislocation in THA. Experience with noncrosslinked polyethylene (nonXLPE) raised concerns regarding the risk of impingement damage, loosening, and osteolysis with hooded liners; however, the evidence for this in crosslinked polyethylene (XLPE) is inconclusive. The interaction between different femoral head sizes and hooded liners is not well understood, and it is unclear whether hooded XLPE liners have a beneficial effect on overall long-term survivorship. Questions/purposes We analyzed a large national joint registry to ask: (1) Is the use of hooded XLPE liners associated with a reduced revision rate for dislocation compared with nonhooded liners? (2) Is there a difference in the revision rate for aseptic loosening/osteolysis? (3) Is head size associated with any difference in the revision rate between hooded and nonhooded liners? Methods The Australian Orthopaedic Association National Joint Replacement Registry longitudinally maintains data on all primary and revision joint arthroplasties with nearly 100% capture. We analyzed all conventional primary THAs performed from registry inception in September 1999 until December 31, 2016 in patients with a diagnosis of osteoarthritis who had nonhooded or hooded XLPE bearings in a cementless acetabular shell. The study group included 192,659 THA procedures with XLPE liners, of which 67,904 were nonhooded and 124,755 were hooded. The mean age of patients receiving nonhooded liners was 70 years (range, 11-100 years); 44% were males. This was similar to the patients with hooded liners, who had a mean age of 70 years (range, 16-100 years); 45% were males. The main outcome measure was the cumulative percent revision at 15 years of the THA using Kaplan-Meier estimates of survivorship. We examined reasons for revision and and performed multivariable analysis to control for the confounding factors of three head size groups (< 32mm, Each author certifies that he or she has no commercial associations (eg consultancies, stock ownership, equity interest, patent/licensing arrangements etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA approval status, of any drug or device before clinical use. Each author certifies that his or her institution approved the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research. This work was performed at the Australian Orthopaedic Association National Joint Replacement Registry.

Recent update on crosslinked polyethylene in total hip arthroplasty

“…One case (1.3%) of osteolysis was confirmed in the standard group, whereas no osteolysis was observed in the elevated-rim group. Similarly, a recent analysis based on the Australian registry [35] found that XLPE lipped liners were not associated with an increased revision rate for aseptic loosening at a mean of 5 years. Revisions for breakage of the acetabular liner were extremely rare, with 11 for lipped liners (0.009%) and four for standard liners (0.006%).…”

CORR Insights®: Are Hooded, Crosslinked Polyethylene Liners Associated with a Reduced Risk of Revision After THA?

“…However, findings like these that are hard to explain-and require so much speculation to arrive at an explanation-should also be viewed with some suspicion, as they suggest that unmeasured confounding variables might also be at work here. For that reason, even the primary study findings in the study by Bauze and colleagues [1] really should be independently confirmed if we are to have confidence in it.…”

“…Although Bauze and colleagues [1] found that hooded liners were associated with reduced revision risks, we still need to determine whether this result is implant-specific or generalizable to all hooded designs. The study included all uncemented cup designs but did not consider whether the analyzed cups were available in both hooded and nonhooded versions.…”

“…In the current study, Bauze and colleagues [1] use the Australian Orthopaedic Association National Joint Replacement Registry to compare implant survival for hooded and nonhooded HXLPE liners. Their implantsurvival analysis showed higher revision rates related to dislocation in patients who received nonhooded liners compared to those who received hooded liners.…”

“…It seems to me that the questions of whether the findings of Bauze and colleagues [1] are generalizable or implantspecific, whether they will hold true for cemented designs as well as uncemented ones, and whether there are differences in dislocation risk across different degrees of polyethylene rim elevation, can be answered only in the setting of large, national registries. Given the high number of arthroplasties needed to arrive at robust analyses, these questions might be approached through international register collaborations, by pooling individual data or aggregate data using a meta-analysis approach [9].…”