Validation of a model-based measurement of the minimum insert thickness of knee prostheses

IJsseldijk, E.A. van; Harman, Melinda K.; Luetzner, Joerg; Valstar, Edward R.; Stoel, Berend C.; Nelissen, Rob G H H; Kaptein, Bart L

doi:10.1302/2046-3758.310.2000304

Cited by 6 publications

(3 citation statements)

References 17 publications

(24 reference statements)

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“…Radiostereometry (RSA) and recent developments of advanced model-based software allow for the measurement of in-vivo PE wear in the Oxford medial UKA with high accuracy (Van IJsseldijk et al. 2011, 2014).…”

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confidence: 99%

Similar polyethylene wear between cemented and cementless Oxford medial UKA: a 5-year follow-up randomized controlled trial on 79 patients using radiostereometry

et al. 2018

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Background and purpose — Hydroxyapatite (HA)-coated implants have been associated with high polyethylene wear in hip arthroplasties. HA coating as a promoter of wear in knee arthroplasties has not been investigated. We compared the wear-rate of the polyethylene bearing for cemented and cementless HA-coated Oxford medial unicondylar knee arthroplasties (UKA). Secondarily, we investigated whether wear-rates were influenced by overhang or impingement of the bearing.Patients and methods — 80 patients (mean age 64 years), treatment-blinded, were randomized to 1 of 3 Oxford medial UKA versions: cemented with double-pegged or single-pegged femoral component or cementless HA-coated with double-pegged femoral component (ratios 1:1:1). We compared wear between the cemented (n = 55) and cementless group (n = 25) (ratio 2:1). Wear, impingement, and overhang were quantified between surgery and 5-year follow-up using radiostereometry. Clinical outcome was evaluated with the Oxford Knee Score.Results — The mean wear-rate for patients without bearing overhang was 0.04 mm/year (95% CI 0.02–0.07) for the cemented group and 0.05 mm/year (CI 0.02–0.08) for the cementless group. The mean difference in wear was 0.008 mm/year (CI –0.04 to 0.03). No impingement was identified. Half of the patients had medial bearing overhang, mean 2.5 mm (1–5). Wear increased by 0.014 mm/year for each mm increment in overhang. The mean Oxford Knee Score was 39 for the cementless group and 38 for the cemented group at the 5-year follow-up.Interpretation — The wear-rates were similar for the 2 fixation methods, which supports further use of the cementless Oxford medial UKA. However, a caveat is a relatively large 95% CI of the mean difference in wear-rate. Component size and position is important as half of the patients presented with an additional increase in wear-rate due to medial bearing overhang.

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confidence: 99%

Similar polyethylene wear between cemented and cementless Oxford medial UKA: a 5-year follow-up randomized controlled trial on 79 patients using radiostereometry

et al. 2018

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“…For the Oxford unicompartmental knee arthroplasty, Horsager et al described wear rates of 40 and 50 µm per year for the cemented and cementless versions, respectively, which is slightly lower than what we have seen in our cohort [ 32 ]. The aforementioned study was conducted using the radiostereometic analysis (RSA), which has been shown to produce accurate results in total knee replacement wear analysis [ 33 , 34 ]. However, no study comparing wear assessed by RSA and subsequently by the retrieval analysis has been conducted so far, to the best of our knowledge, and a certain error in measurement has to be accepted.…”

Section: Discussionmentioning

confidence: 99%

Bearing Thickness Is Not a Predictive Factor for Damage and Penetration in Oxford Unicompartmental Knee Arthroplasty—A Retrieval Analysis

et al. 2020

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The medial Oxford unicompartmental knee arthroplasty (OUKA) shows good survivorship, as well as clinical results. Aseptic loosening, however, remains one of the main reasons for revision and polyethylene debris is known to cause aseptic loosening. The role of bearing thickness in total as well as unicondylar knee arthroplasty has been the subject of controversial discussions, especially the longevity of lower thickness bearings in total knee arthroplasty was questioned. The purpose of this study was to assess the influence of bearing thickness on time to revision, damage pattern, penetration, and volumetric material loss. A cohort of 47 consecutively retrieved medial OUKA bearings was analyzed with conventional direct light microscopy applying the Hood damage analysis, as well as measuring the penetration depth. In this retrieval cohort, a difference on survival time, damage, penetration, as well as volumetric material loss could not be seen. We conclude that low as well as high thickness bearings can safely be used in OUKA without any relevant differences in terms of wear and damage.

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“…Contact‐loss between the articulating surfaces was measured using the mJSW. The mJSW was calculated as the shortest distance between the surface of the femur CAD model perpendicular to the surface of the flat tibial CAD model, using a validated method …”

Section: Methodsmentioning

confidence: 99%

Oxford medial unicompartmental knees display contact‐loss during step‐cycle motion and bicycle motion: A dynamic radiostereometric study

Horsager

Kaptein

Jørgensen

et al. 2017

Journal Orthopaedic Research

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The Oxford medial unicompartmental knee is designed fully congruent, with the purpose of maintaining a large contact-area throughout motion and minimize wear. No other study has investigated this design feature in-vivo. We aimed to evaluate if contact-loss was introduced between the articulating surfaces of the Oxford medial unicompartmental knee during bicycle- and step-cycle motion, and whether this correlated with essential implant parameters, such as polyethylene (PE) wear, knee-loadings, and clinical outcome. To study contact-loss, 15 patients (12 males, mean age 69 years) with an Oxford medial unicompartmental knee (7 cemented, mean follow-up 4.4 years) were examined with use of dynamic radiostereometry (RSA) (10 frames/s). PE wear was measured from static RSA and clinical outcome was evaluated with American Knee Society Score (AKSS) and Oxford Knee Score (OKS). Data on knee-loadings were acquired from the literature. Contact-loss was deteced in all patients during both exercises, and the trend of contact-loss correlated with the knee-loadings. Median contact-loss was 0.8 mm (95%PI: 0.3; 1.5) for bicycle motion and 0.3 mm (95%PI: 0.24; 0.35) for step-cycle motion, and did not correlate with the PE wear rate of mean 0.06 mm/year. Possible in-congruency was seen in three patients. Clinical outcome scores correlated with contact-loss during step-cycle motion. In conclusion, contact-loss was seen in all patients indicating a clinical tolerance during load. Contact-loss followed the knee-loadings, which could explain why no correlation was seen with PE wear, as an increase in load was acommadated by an increase in contact-area (contact-loss reduction). The size of contact-loss may reflect clinical outcome. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:357-364, 2018.

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Validation of a model-based measurement of the minimum insert thickness of knee prostheses

Cited by 6 publications

References 17 publications

Similar polyethylene wear between cemented and cementless Oxford medial UKA: a 5-year follow-up randomized controlled trial on 79 patients using radiostereometry

Similar polyethylene wear between cemented and cementless Oxford medial UKA: a 5-year follow-up randomized controlled trial on 79 patients using radiostereometry

Bearing Thickness Is Not a Predictive Factor for Damage and Penetration in Oxford Unicompartmental Knee Arthroplasty—A Retrieval Analysis

Oxford medial unicompartmental knees display contact‐loss during step‐cycle motion and bicycle motion: A dynamic radiostereometric study

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