Does knee implant size affect wear variability?

Affatato, Saverio; Grillini, Laura; Battaglia, Santina; Taddei, Paola; Modena, Enrico; Sudanese, A

doi:10.1016/j.triboint.2013.05.008

Cited by 23 publications

(33 citation statements)

References 44 publications

(62 reference statements)

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“…The tested specimens had been previously subjected to an in vitro wear simulation for two million cycles (Mc). Major details are available in literature [30]. After that first test, all the components (femoral, tibial, and menisci specimens) were tested on the same knee simulator for the other two Mc (for a total of four Mc).…”

Section: Specimensmentioning

confidence: 99%

“…The second in-vitro wear test on the eight specimens previously tested in [30] was performed for the other two Mc using a "three-plus-one" stations simulator (Shore Western Mfg., Monrovia, USA). The eight specimens include four specimens (three plus one control) for each size (#2 and #6).…”

Section: Wear Test Protocolmentioning

confidence: 99%

“…Three specimens were placed on three different stations, while the fourth station was taken by the soak control specimen, to estimate the total change in mass due to lubricant absorption, according to ISO 14243-2. This wear test was performed on the same aforementioned specimens, using the same simulator, same kinematics and same lubricating conditions used in [30] as recommended by ISO 14243. In the previous study, a simplified gait cycle was reproduced, according to ISO 14243-3 and on the basis of a consolidated internal protocol [32][33][34].…”

Section: Wear Test Protocolmentioning

confidence: 99%

“…Gravimetric, roughness and micro-Raman assessments Gravimetric wear was evaluated every 0.4 Mc for two Mc, in addition to the 2 Mc previously tested in [30], to reach a cumulative wear test length of four Mc. Mass loss was determined using a microbalance (SARTORIUS AG, Göttingen, Germany) with an uncertainty of ±0.01 mg and an accuracy of 0.01 mg. Each measurement was repeated three times and mean values were used.…”

Section: Wear Test Protocolmentioning

confidence: 99%

“…The well established in vitro procedures for TKP wear simulation entail the application of the load profile recommended by the ISO 14243 standard protocol, which establishes the loading and displacement parameters for weartesting machines considering a standardised body weight. In a prior work, we analysed the behaviour of two very different TKP sizes of the same prosthesis design that underwent an in vitro testing under the simulating conditions recommended by ISO 14243 [30,31]. Following the first research, we decided to perform the wear test for a further two million cycles using this modified ISO 14243 waveform in order to evaluate the wear effects due to a higher load.…”

Section: Introductionmentioning

confidence: 99%

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Toward the interpretation of the combined effect of size and body weight on the tribological performance of total knee prostheses

Battaglia

Taddei

Tozzi

et al. 2014

International Orthopaedics (SICOT)

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Purpose The research questions of the present study were: (1) Is total knee prosthesis wear behaviour influenced by implant size, body weight and their combined effect? (2) Are these findings significant and helpful from a clinical point of view? Methods Two very different sizes of the same total knee prosthesis (TKP), previously tested with ISO 14243 parameters, were tested on a knee simulator for a further two million cycles using a modified ISO 14243 load waveform. Roughness examination was performed on the metallic components. Gravimetric and micro-Raman spectroscopic analyses were carried out on the polyethylene inserts. Results The average volumetric mass loss was 69 ± 3 mm 3 and 88 ± 4 mm 3 for smaller and bigger size, respectively. Bigger TKPs are little influenced by an increased load, while the wear trend of the smaller TKP showed a redoubled slope, and more significant morphology changes were observed. However, the two sizes seem to behave similarly when subjected to a load increase of 15 %; the slope of the volumetric mass loss trend was comparable for the two sets of inserts, which did not appear significantly different also at the molecular level. Roughness average parameters of the lateral femoral condyle support this evidence. Conclusions It can be asserted that the body weight and implant size are relevant to the understanding of TKP wear behaviour. A post-implantation body weight increase in a patient with smaller knee dimensions could results in more critical effects on prosthesis long-term performance.

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Section: Specimensmentioning

confidence: 99%

Section: Wear Test Protocolmentioning

confidence: 99%

Section: Wear Test Protocolmentioning

confidence: 99%

Section: Wear Test Protocolmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Toward the interpretation of the combined effect of size and body weight on the tribological performance of total knee prostheses

Battaglia

Taddei

Tozzi

et al. 2014

International Orthopaedics (SICOT)

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May the surface roughness of the retrieved femoral head influence the wear behavior of the polyethylene liner?

et al. 2015

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This study was aimed at determining the surface degradation occurred on retrieved ceramic and metallic heads, as well as the influence of the head surface quality on the wear of the polyethylene counterface. To this purpose, 14 ceramic and 14 metallic femoral heads retrieved at revision surgery were examined. Scanning electron microscopic analysis provided visual evidence that some metallic heads presented crescent wear more often than the ceramic ones; the former showed a higher volumetric loss (as determined by Coordinate Measuring Machine) than the latter, but less negative Rsk values. This apparent lack of correlation between volumetric loss (i.e., wear factor) and roughness data may be explained by considering that they are two temporally variant parameters. No significant differences were observed between the Ra values of the two sets of femoral heads. The cups articulating against metal heads were characterized by higher mean wear volumes than those articulating against alumina although this difference was not statistically significant; metal heads displayed significantly higher mean wear volumes than alumina heads. The micro-Raman analysis of the cup articulated against the most worn alumina femoral head showed an orthorhombic into monoclinic phase transformation that was not observed in the cups coupled to metal heads. The obtained results showed that the surface finishing of the femoral head (in terms of Rsk values) determined the morphological changes experienced by the ultra-high-molecular-weight polyethylene crystalline phase at the molecular level. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1374-1385, 2016.

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The effects of contact area and applied load on the morphology of in vitro worn ultra‐high molecular weight knee prostheses: a micro‐Raman and gravimetric study

Tozzi

Modena

Falcioni

et al. 2014

J Raman Spectroscopy

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Ultra‐high molecular weight polyethylene knee prostheses of two different sizes (i.e. characterised by different contact areas) were run on a knee wear simulator in two tests differing for the applied load. Gravimetric and micro‐Raman spectroscopic analyses were performed to investigate at macroscopic and molecular levels the effects of contact area and applied load on the morphology of the knee components. The larger prostheses showed a higher mass loss in both tests, while Raman spectroscopy showed a more significant polymer degradation in the smaller prostheses, suggesting that a lower contact area is responsible for a higher wear at the molecular wear, but for a lower gravimetric wear. Raman measurements showed that in the second test (using a higher applied load), the wear mechanism changed with respect to the first test: the less severe conditions used in the latter resulted in an increase in the orthorhombic content, while the more severe conditions used in the former determined an increase and rearrangement of the amorphous phase. The results here reported allow to gain more insights into the effects of contact area, applied load and contact stress on wear. Preliminary micro‐Raman analyses on in vivo worn knee prostheses confirmed the results obtained in vitro: the retrievals of smaller size were found more degraded at molecular level than those of larger size. These findings showed that the conditions used in the in vitro tests well simulate the knee kinematics of the knee joint and thus the in vivo wear. Copyright © 2014 John Wiley & Sons, Ltd.

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Does knee implant size affect wear variability?

Cited by 23 publications

References 44 publications

Toward the interpretation of the combined effect of size and body weight on the tribological performance of total knee prostheses

Toward the interpretation of the combined effect of size and body weight on the tribological performance of total knee prostheses

May the surface roughness of the retrieved femoral head influence the wear behavior of the polyethylene liner?

The effects of contact area and applied load on the morphology of in vitro worn ultra‐high molecular weight knee prostheses: a micro‐Raman and gravimetric study

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