Factors Affecting the Severity of Backside Wear of Modular Tibial Inserts

Conditt, Michael A.; Stein, Jason; Noble, Philip C.

doi:10.2106/00004623-200402000-00013

Cited by 73 publications

(65 citation statements)

References 7 publications

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“…Using the six zones, the area of polyethylene wear was then graded as negligible (0), less than 10% (1), between 10% and 50% (2), or greater than 50% (3) [14,29,36]. The depth of the major wear defect was then graded as less than 500 lm (1), between 500 lm and 1 mm (2), or greater than 1 mm (3) [8,9,25]. Depth measurements were obtained using stereomicroscopy and scanning electron microscopy for Fig.…”

Section: Methodsmentioning

confidence: 99%

“…specific defects containing volumetric loss, specifically pitting, scratching, abrasion, delamination, and burnishing. Finally, a backside wear severity score (BWSS) was obtained for each polyethylene insert by multiplying all of the grades together (eg, overall wear grade 9 wear area grade 9 wear depth grade) [8,9,29,34,36]. By quantifying the overall BWSS for each polyethylene insert, numeric values could be ascribed to each insert (Fig.…”

Section: Methodsmentioning

confidence: 99%

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Polyethylene Wear Is Influenced by Manufacturing Technique in Modular TKA

Lombardi

Ellison

Berend

2008

Clinical Orthopaedics &Amp; Related Research

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Polyethylene insert backside surface wear is implicated in osteolysis and failure of total knee arthroplasty. Manufacturing and sterilization methods reduce articular-sided wear. We questioned whether manufacturing technique influences the severity of backside wear. We examined 39 explanted tibial bearings in a blinded fashion using visual, stereomicroscopic, and scanning electron microscopic techniques. We examined 26 direct compression molded components and 13 nondirect compression molded components and applied a new backside wear severity score. The score characterized the magnitude of the various modes of wear with severity ranging from 0 (no wear) to 27 (severe wear). Time in vivo, tibial baseplate material, and manufacturing technique were used as variables for comparison. Backside wear was related to polyethylene manufacturing process with direct compression molded implants having a wear score of 2.3 and nondirect compression molded a score of 5.7. Time in vivo influenced backside wear, although direct compression molded predicted decreased backside wear independent of time in vivo. The data suggest manufacturing technique influences backside wear in total knee arthroplasty polyethylene inserts.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Polyethylene Wear Is Influenced by Manufacturing Technique in Modular TKA

Lombardi

Ellison

Berend

2008

Clinical Orthopaedics &Amp; Related Research

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“…Modular implants, however, introduce a second bearing surface that is a potential site for particle generation. Relative motion between the polyethylene insert and the tibial base plate has been shown to be a source of wear and fine polyethylene particle generation that can lead to clinically significant osteolysis and implant loosening [2,4,9,12,13]. Retrieval studies have confirmed the presence of tibial insert polyethylene backside wear and shown a relationship to the tibial insert locking mechanism and implantation time [2,4,9,12,13].…”

Section: Introductionmentioning

confidence: 99%

“…Backside wear and subsequent osteolysis were relatively rare beneath the original flat inserts but became an issue and a possible source of polyethylene wear and debris after the more rotationally conforming inserts were introduced. Although it is known that modular tibial components introduce the possibility for backside wear resulting from relative motion between the polyethylene insert and the tibial baseplate [2,4,9,12,13], it is not known to what degree that variability in the conformity of the tibial polyethylene insert itself might have on the tibial insert backside wear.…”

Section: Introductionmentioning

confidence: 99%

Does Increased Topside Conformity in Modular Total Knee Arthroplasty Lead to Increased Backside Wear?

Schwarzkopf

Scott

Carlson

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background Modular metal-backed tibia components allow surgeons intraoperative flexibility. Although it is known that modular tibia components introduce the possibility for backside wear resulting from relative motion between the polyethylene insert and the tibial baseplate, it is not known to what degree variability in the conformity of the tibial polyethylene liner itself might contribute to backside wear. Questions/purposes The purpose of this study was to determine whether a flat, cruciate-retaining tibial polyethylene bearing generates less backside wear than a more conforming (curved) tibial polyethylene bearing in an analysis of specimens explanted during revision surgery. MethodsThe study included 70 total knee inserts explanted at revision surgery, all implanted and explanted by the same surgeon. Two different cruciate-retaining insert options in an otherwise similar knee system were used: one with a curvedon-flat (17) articular geometry and one with a highly conforming curved-on-curved design (53); both groups were sequential cohorts. The composite backside wear depth for the insert as well as the volume of backside wear was measured and compared between groups. Results The median linear backside-normalized wear for the posterior lipped inserts was 0.0063 mm/year (range, 0-0.085 mm/year), which was lower than for the curved inserts at 0.05 mm/year (range, 0.00003-0.14 mm/year) (p \ 0.001). The median calculated volumetric backsideOne of the authors (RS) has received consulting fees from Smith & Nephew (Memphis, TN, USA) (less than USD 10,000). One of the authors (RDS) has received consulting fees from DePuy (Warsaw, IN, USA) (less than USD 10,000) and royalties from DePuy (greater than USD 1,000,000). One or more of the authors (EMC, JHS) has received institutional funding from DePuy, ConforMIS (Bedford, MA, USA), and Biomet (Warsaw, IN, USA). All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research 1 editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research 1 neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDAapproval status, of any drug or device prior to clinical use. Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. This work was conducted at the New England Baptist Hospital, Boston, MA USA. The biomechanical material analysis was conducted at the Thayer School of Engineering, Dartmouth College, Hanover, NH, USA. Conclusions In this retrieval study, more conforming tibial inserts demonstrated more backside-normalized wear than the flatter designs. This suggests that in this modular total knee arthroplasty design, higher articular conformity to address the issues of high bear...

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“…Modularity in total knee arthroplasty allows increased intraoperative versatility and potential polyethylene exchange as a less destructive and potentially cost-effective option for revision. Drawbacks of modularity include backside wear which can contribute to osteolysis [3,8,9,21]. It is in the younger, more active patient that differences in total knee prosthesis designs and materials may show the greatest differences in long-term durability.…”

Section: Introductionmentioning

confidence: 99%