Wear of Polyethylene in Total Joint Replacements Observations From Retrieved PCA Knee Implants

Wright, Timothy M.; Rimnac, Clare M.; Stulberg, S.D.; Mintz, Leslie J.; Tsao, Audrey K.; Klein, Robert W.; McCrae, Catharina H.

doi:10.1097/00003086-199203000-00016

Cited by 167 publications

(73 citation statements)

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“…The amount and severity of the wear damage on the tibiofemoral surface, as reflected by our subjective grading, were similar to what was previously measured [9,19,20] in a number of fixed-bearing designs using the same techniques and scoring system within our retrieval analysis system ( Table 1). The damage scores were, however, lower than those reported in the literature for the Porous-coated Anatomic (PCA 1 ) design, but this implant had several design specifications and manufacturing processes that caused it to undergo severe surface damage and debris generation [20]. In general, the fact that the damage scores were comparable to older designs that were all gamma sterilized in air and were, in some cases, materials and designs that were ultimately abandoned, raises concerns for the amount of damage seen in these mobile-bearing implants.…”

Section: Discussionsupporting

confidence: 82%

“…The implant retrieval archive at our institution is an IRB-approved, HIPAA-compliant registry of almost 20 35 of which had been retrieved with the metallic femoral components and tibial trays. Twenty-two of the implants were cruciate-retaining, 25 were posteriorstabilized, and the remaining implant was of a constrained design.…”

Section: Methodsmentioning

confidence: 99%

“…Assessments were made for each of seven wear damage modes: burnishing, scratching, pitting, delamination, surface deformation, abrasion, and third-body embedded debris. A scale of 0 to 3 was used to reflect the extent and severity of the damage; the scale of Hood et al [9] has been used to identify damage by our group [19,20] and others [5,7,10,11,14] since 1983. It is a subjective score that does not assess wear directly, but instead qualitatively identifies damage.…”

Section: Methodsmentioning

confidence: 99%

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Wear Damage in Mobile-bearing TKA is as Severe as That in Fixed-bearing TKA

Kelly

Wright

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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Background Mobile-bearing TKAs reportedly have no clinical superiority over fixed-bearing TKAs, but a potential benefit is improved polyethylene wear behavior. Questions/purposes We asked whether extent of damage and wear patterns would be less severe on retrieved mobile-bearing TKAs than on fixed-bearing TKAs and if correlations with patient demographics could explain differences in extent or locations of damage. Methods We performed damage grading and mapping of 48 mobile-bearing TKAs retrieved due to osteolysis/loosening, infection, stiffness, instability or malpositioning. Visual grading used stereomicroscopy to identify damage, and a grade was assigned based on extent and severity. Each damage mode was then mapped onto a photograph of the implant surface, and the area affected was calculated. Results Marked wear damage occurred on both surfaces, with burnishing, scratching, and pitting the dominant modes. Damage occurred over a large portion of both surfaces, exceeding the available articular borders in nearly 30% of implants. Wear of mobile-bearing surfaces included marked third-body debris. Damage on tibiofemoral and mobile-bearing surfaces was not correlated with patient BMI or component alignment. Damage on mobilebearing surfaces was positively correlated with length of implantation and was greater in implants removed for osteolysis or instability than in those removed for stiffness or infection. Conclusions Each bearing surface in mobile-bearing implants was damaged to an extent similar to that in fixedbearing implants, making the combined damage score higher than that for fixed-bearing implants. Mobile-bearing TKAs did not improve wear damage, providing another argument against the superiority of these implants over fixed-bearing implants.

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Section: Discussionsupporting

confidence: 82%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Wear Damage in Mobile-bearing TKA is as Severe as That in Fixed-bearing TKA

Kelly

Wright

et al. 2011

Clinical Orthopaedics &Amp; Related Research

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“…Subtle changes in polyethylene properties through oxidative degradation, inferior designs for the articular surfaces, poor surgical technique, and a greater mechanical burden placed on implants by young, active patients often result in unacceptably high failure rates due to wear. [6][7][8][9][10][11][12][13][14] To improve wear performance, either the stresses need to be decreased or the wear resistance of the material needs to be increased. Research and development is proceeding on both fronts to better understand, for example, the structure of UHMWPE, 15,16 its potential for improvement, [17][18][19] and its mechanical response as a function of design.…”

Section: Introductionmentioning

confidence: 99%

Retrieval, experimental, and computational assessment of the performance of total knee replacements

Rawlinson

Furman

et al. 2006

J. Orthop. Res.

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Wear mechanisms in polyethylene components for total knee replacements are inherently mechanical; the local stresses or strains exceed some material limit. Retrieval analysis and knee simulators have provided the means to quantify the damage observed in vivo or in vitro. These results have been circumstantially linked to the material stresses obtained from computational simulations using finite element analysis, knee simulator tests, and computational simulations of two condylar knee designs. We hypothesize that if an equivalent loading environment is produced in the computational simulation, we can correlate the distribution of computed stresses with observed damage of simulator specimens and further relate design differences to in vivo performance from retrieval analyses. The finite element model agreed with the knee simulator kinematics and kinetics within 2-13%, and composite FEA contact areas matched 66-90% of the damage areas due to burnishing on the simulator specimens. Burnishing was the primary mode of damage for both the simulator and retrieval specimens corresponding with the relatively low magnitudes of contact stress observed. Both the computational and experimental techniques underpredicted the amount determined from retrieval analysis, but the differences between the two designs were consistent for all three methods. Combining these techniques strengthens the applicability of the computational simulation while highlighting the complementary approach of these methods for preclinical testing and assessing the link between material state and damage.

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“…Additionally, contact radiographic analysis was useful in determining none of the pegs in any of the components had preferential attachment that might have led to stress shielding. This has occurred in some other designs with porous-coated stabilizing pegs, which can lead to preferential bone ingrowth attachment to the porous-coated pegs, causing the remainder of the undersurface face of the porous coating to be limited by fibrous tissue attachment [32].…”

Section: Discussionmentioning

confidence: 99%

Does Using Autograft Bone Chips Achieve Consistent Bone Ingrowth in Primary TKA?

Bloebaum

Koller

Willie

et al. 2012

Clinical Orthopaedics &Amp; Related Research

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Background Cementless fixation remains controversial in TKA due to the challenge of achieving consistent skeletal attachment. Factors predicting durable fixation are not clearly understood, but we presumed bone ingrowth could be enhanced by the quantity of host bone and application of autograft bone chips. Questions/purposes We asked: (1) Did the amount of bone ingrowth exceed the amount of periprosthetic and host bone with the addition of autograft bone chips?(2) Did the amount of bone ingrowth increase with implantation time? And (3) did osteolysis along the porous-coated interface and screw tracts progress with implantation time? Methods We measured the amount of bone in the porouscoated, periprosthetic, and host bone regions in 19 postmortem retrieved cementless primary total knee implants. The amount of bone in apposition to the implant surface, and alternatively lysed bone, was analyzed radiographically to assess the progression of osteolysis. Results While bone ingrowth tended to be less than periprosthetic and host bone in all three components, it was only significantly less in the patellar component. Bone ingrowth increased in all three components over time, but progression of osteolysis did not. Conclusions Even after long-term followup, the amount of bone ingrowth did not surpass host bone levels, suggesting the amount of a patient's host bone is a limiting factor in the amount of bone ingrowth achievable for this cementless design. It remains unknown whether compromised osteopenic bone could achieve the amount of bone attachment necessary to provide durable fixation over time.

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Wear of Polyethylene in Total Joint Replacements Observations From Retrieved PCA Knee Implants

Cited by 167 publications

References 0 publications

Wear Damage in Mobile-bearing TKA is as Severe as That in Fixed-bearing TKA

Wear Damage in Mobile-bearing TKA is as Severe as That in Fixed-bearing TKA

Retrieval, experimental, and computational assessment of the performance of total knee replacements

Does Using Autograft Bone Chips Achieve Consistent Bone Ingrowth in Primary TKA?

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