Differences in wear between load and displacement control tested total knee replacements

Schwenke, T.; Orozco, Diego; Schneider, Erich; Wimmer, Matthias

doi:10.1016/j.wear.2009.01.028

Cited by 21 publications

(23 citation statements)

References 5 publications

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“…The mean wear rate of 18 mm 3 per year for the nondelaminated tibial liners falls in the range of 9 and 23 mm 3 per million cycles obtained in physiologic knee simulators on the same or similar TKA designs [27,32,35] (Table 3), where 1 million cycles is considered to be approximately equivalent to 1 year in vivo. Other than the study by Knowlton and Wimmer [19], we are aware of only one other study reporting measured volumetric liner wear in retrieved TKRs [8], and it is for contemporary prosthesis designs (LCS 1 , P.F.C.…”

Section: Discussionmentioning

confidence: 86%

How Does Wear Rate Compare in Well-functioning Total Hip and Knee Replacements? A Postmortem Polyethylene Liner Study

Pourzal

Knowlton

Hall

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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Background The longevity of total hip (THR) and knee replacements (TKR) that used historical bearing materials of gamma-in-air sterilized UHMWPE was affected more by osteolysis in THRs than in TKRs, although osteolysis remains a concern in TKRs. Therefore, the study of polyethylene wear is still of interest for the knee, particularly because few studies have investigated volumetric material loss in tibial knee inserts. For this study, a unique collection of autopsy-retrieved TKR and THR components that were well-functioning at the time of retrieval was used to compare volumetric wear differences between hip and knee polyethylene components made from identical material. Questions/purposes The following questions were addressed: (1) How much did the hip liners wear and what wear patterns did they exhibit? (2) How much did the knee inserts wear and what wear patterns did they exhibit? (3) What is the ratio between TKR and THR wear after controlling for implantation time and patient age? Methods We compared 23 THR components (HarrisGalante [HG] and HG II) and 20 TKR components (MillerGalante [MG II]) that were retrieved postmortem. The components were made from the same polyethylene formulation and with similar manufacturing and sterilization (gamma-in-air) processes. Twenty-one patients (12 males, nine females) had THRs and 16 (four males, 12 females) had TKRs. Patients who had TKRs had an older (p = 0.001) average age than patients who had THRs (age, 75 years; SD, 10, versus 66 years; SD, 12, respectively). Only wellfunctioning components were included in this study. Therefore, implants retrieved postmortem from physically active patients and implanted for at least 2 years were considered. In addition, only normally wearing TKR components were considered, ie, those with fatigue wear (delamination) were excluded. The wear volume of each component was measured using metrology. For the tibial inserts an autonomous mathematic reconstruction method was used for quantification. Results The acetabular liners of the THR group had a wear rate of 38 mm 3 per year (95% CI, 29-47 mm 3 /year). Excluding patients with low-activity, the wear rate was 47 mm 3 per year (95% CI, 37-56 mm 3 /year). The wear rate of normally wearing tibial inserts was 17 mm 3 per year (95% CI, À6 to 40 mm 3 /year). After controlling for the relevant confounding variable of age, we found a TKR/THR wear rate ratio of 0.5 (95% CI, 0.29-0.77) at 70 years of age with a slightly increasing difference with increasing age. Conclusions Excluding delamination, TKRs exhibited lower articular wear rates than THRs for historical polyethylene in these two unique cohorts of postmortem retrievals.

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Section: Discussionmentioning

confidence: 86%

How Does Wear Rate Compare in Well-functioning Total Hip and Knee Replacements? A Postmortem Polyethylene Liner Study

Pourzal

Knowlton

Hall

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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“…The current study is in good agreement with wear simulator studies of similar TKR designs. Schwenke et al tested two groups of cruciate‐retaining MGII components with ISO displacement‐ and load‐controlled level walking and found steady‐state wear rates of 9.2 ± 0.9 mg/Mc and 20.9 ± 4.2 mg per million cycles, respectively . CMM measurements of a similar fixed bearing cruciate retaining design run for 5 million cycles of ISO load‐controlled level walking found a wear rate of 8.3 ± 0.9 mm 3 /million cycles and a creep volume loss of 36 ± 4 mm 3 .…”

Section: Discussionmentioning

confidence: 99%

Relationship of surface damage appearance and volumetric wear in retrieved TKR polyethylene liners

Knowlton

Bhutani

Wimmer

2016

J. Biomed. Mater. Res.

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Recently developed techniques have enabled volume loss measurements on surgically retrieved total knee replacements (TKR). However, it is not well understood how volume loss relates to polyethylene surface damage appearance. Sixty-four fixed bearing cruciate retaining components retrieved from revision and postmortem surgeries were analyzed for penetration and volume loss on the topside articular surface. An autonomous reconstruction method was used to approximate the original unworn surfaces. Surface damage patterns were also mapped using a video microscope, and each pattern’s contribution to volume loss was calculated. With consideration for creep, a total wear rate of 12.9 ± 5.97 mm3/year was found for the population. The penetration rate was 0.035 ± 0.017 mm/year medially and 0.034 ± 0.011 mm/year laterally, of which the location on the plateau varied greatly. Although striated patterns contributed to most to volume loss, damage patterns generally were only moderate predictors of material volume loss.

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“…The averaged motion data per station were then averaged to obtain overall motion profiles. Further details of the wear test are reported in Schwenke et al 2009 [16]. …”

Section: 0 Materials and Methodsmentioning

confidence: 99%

In-vivo kinematics of knee prostheses patients during level walking compared with the ISO force-controlled simulator standard

Ngai

Schwenke

Wimmer

2009

Proc Inst Mech Eng H

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Background Differences between wear-scar features of simulator-tested and retrieved tibial total knee replacement (TKR) liners have been reported. This disagreement may result from differences between in vivo kinematic profiles and those defined by the standard. Purpose To determine the knee kinematics of a TKR subject group during level walking and compare them with the motion profiles produced by a wear test conducted according to the force-controlled knee wear testing ISO 14243-1 (ISO-1)standard. Methods Ten patients with a posterior cruciate ligament-retaining TKR design were gait tested using the point cluster technique (PCT) to obtain flexion-extension (FE) rotation, anterior-posterior (AP) translation and internal-external (IE) rotation motions during a complete cycle of level walking. Motion data were directly compared against the output kinematics from the wear test. Results The subjects exhibited a FE rotation pattern similar to the output from ISO-1; however had higher midstance knee flexion angles. For both AP translation and IE rotation, the standard profiles had significantly smaller total ranges of motion than seen in vivo, with noticeably different patterns of motions. Conclusions For this particular implant design, significant differences were found in both the pattern and magnitudes of in vivo motion during level walking compared with the ISO-1 standard.

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Differences in wear between load and displacement control tested total knee replacements

Cited by 21 publications

References 5 publications

How Does Wear Rate Compare in Well-functioning Total Hip and Knee Replacements? A Postmortem Polyethylene Liner Study

How Does Wear Rate Compare in Well-functioning Total Hip and Knee Replacements? A Postmortem Polyethylene Liner Study

Relationship of surface damage appearance and volumetric wear in retrieved TKR polyethylene liners

In-vivo kinematics of knee prostheses patients during level walking compared with the ISO force-controlled simulator standard

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