Surface damage analysis of retrieved highly crosslinked polyethylene tibial components after short‐term implantation

Abstract

The use of highly crosslinked polyethylene (PE) in the knee remains controversial, because of reduced fatigue fracture properties of the material. The current study investigated postmelt surface damage as well as potential contributors to this damage in retrieved highly crosslinked PE tibial components, after short-term in vivo durations. Retrieved conventional PE tibial components were examined for comparison, as well as unused time zero highly crosslinked and conventional PE tibial components for inherent manufacturing surface characterization. Predominant surface damage modes on highly crosslinked PE components were machine mark loss and abrasion, while conventional PE components primarily had machine mark loss, abrasion, and delamination. In vivo duration, PE thickness, and conformity of the design were significant predictors of surface damage on retrieved conventional PE components. Donor weight and the conformity of the design were significant predictors of surface damage on retrieved highly crosslinked PE components. This retrieval data on highly crosslinked PE tibial components suggest that in vivo wear occurred, observed as postmelt surface damage. The highly crosslinked Durasul material examined in this retrieval study appeared to outperform the conventional PE components made from 4150 resin, ram-extruded and gamma-sterilized in air, but not the conventional components made from 1020 resin, compression molding and gamma sterilization in nitrogen. Early retrieval data of highly crosslinked PE tibial components are important to serve as a benchmark to be compared with future longer-term retrieval studies investigating whether surface damage translates to clinically relevant particulate wear debris generation and PE clinical performance.

Oxidative properties and surface damage mechanisms of remelted highly crosslinked polyethylenes in total knee arthroplasty

“…However, the damage mechanisms observed in this cohort of retrievals exhibited mainly adhesive/abrasive wear mechanisms, as opposed to fatigue wear mechanisms. This is similar to a short-term (average implantation time=1.1 years) study that found the major damage mechanisms of remelted highly crosslinked polyethylene tibial inserts were abrasion, machine mark loss, and scratching [8]. This study also did not report delamination of the 13 HXLPE inserts that were analysed.…”

“…This study also did not report delamination of the 13 HXLPE inserts that were analysed. Interestingly, Willie et al did not observe any pitting in their retrieved specimens, although this may be attributed to the short implantation times [8]. Within both material groups in our collection, pitting, scratching, and burnishing were the predominant damage mechanisms.…”

“…While there are accepted radiographic techniques to measure wear in the hip, there are no readily available techniques to measure the wear of tibial inserts in vivo, due to their comparatively complex geometry. Thus, few studies have reported on the clinical performance of HXLPE knees [2,8]. Now, more than one decade following its introduction, knowledge of in vivo damage mechanisms and oxidative stability of remelted HXLPEs in the knee remains incomplete.…”

Comparison of polyethylene tibial insert damage from in vivo function and in vitro wear simulation

“…Several factors associated with degradation of polyethylene material properties [53][54][55][56] and fatigue-related damage modes (e.g., delamination) [57][58][59][60][61][62] existed in these inserts. All simulated and retrieved inserts were sterilized using gamma radiation, were produced using polyethylene starting resin containing calcium sterate, and had nonconforming articular surfaces with relatively small tibiofemoral contact areas.…”

Probabilistic assessment of fatigue initiation data on highly crosslinked ultrahigh molecular weight polyethylenes

“…The low conformity between the metallic femoral and the UHMWPE tibial insert shows large variations that significantly affect the contact stresses in the joint. Fatigue cracks can grow in the subsurface of UHMWPE and then propagate under cycling load leading to local fracture, pitting, and delamination, as it has been identified in retrieved implants (Liza et al, 2011;Willie et al, 2008). Most research into fatigue in polyethylenes is focused on the second step or crack propagation fatigue behavior, whereas few studies related to the total fatigue life involving the damage initiation step are to be found in the literature (Sobieraj, 2009;Oral et al, 2008;Baker et al, 2003).…”