The estimation of acetabular cup wear volume from two-dimensional measurements: A comprehensive analysis

Derbyshire, Brian

doi:10.1243/0954411981534060

Cited by 16 publications

(12 citation statements)

References 24 publications

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“…Many authors have studied 2D and 3D linear wear [4,13,14,21] and calculated the acetabular cup liner volume loss [3,7,10,12,[15][16][17]23]. Charnley et al [3] first pointed out that the wear trajectory of an artificial femoral head is a straight line and that the wear volume is the maximal cross-sectional area of the femoral head multiplied by the wear depth.…”

Section: Introductionmentioning

confidence: 99%

“…Kabo [16] proposed a formula and pointed out that the wear volume should be calculated from not only the wear depth, but also the direction of femoral head motion. However, Kabo's formula has been found to produce errors as high as 45% [7,23]. The formula developed by Hall [10] can be used to compute the wear volume of a cylindrically elongated liner, while the previous formulae can only be used for a hemispherical liner.…”

Section: Introductionmentioning

confidence: 99%

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Evaluating the accuracy of wear formulae for acetabular cup liners

Hsu

Chen

2009

Med Biol Eng Comput

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This study proposes two methods for exploring the wear volume of a worn liner. The first method is a numerical method, in which SolidWorks software is used to create models of the worn out regions of liners at various wear directions and depths. The second method is an experimental one, in which a machining center is used to mill polyoxymethylene to manufacture worn and unworn liner models, then the volumes of the models are measured. The results show that the SolidWorks software is a good tool for presenting the wear pattern and volume of a worn liner. The formula provided by Ilchmann is the most suitable for computing liner volume loss, but is not accurate enough. This study suggests that a more accurate wear formula is required. This is crucial for accurate evaluation of the performance of hip components implanted in patients, as well as for designing new hip components.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluating the accuracy of wear formulae for acetabular cup liners

Hsu

Chen

2009

Med Biol Eng Comput

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“…2-dimensional analysis mainly describes linear wear (the distance of motion of the femoral head relative to the acetabular cup). Several conversion formulae can be used to calculate the volumetric wear based on linear measurements (Kabo et al 1993, Charnley et al 1969, Derbyshire 1998. They all include assumption of a certain amount of cylindrical wear but some also include other factors based on different complexities of the polyethylene liner geometry and direction of wear.…”

Section: Discussionmentioning

confidence: 99%

Polyethylene acetabular wear in hip prostheses: Computer-simulated quantification of error caused by changes in pelvic orientation and direction of wear

Foss¹,

Klaksvik²,

Benum³

et al. 2008

Acta Orthopaedica

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Background and purpose Polyethylene is commonly employed for bearings in acetabular cups used in hip replacements. Assessment of in vivo wear is important for evaluation and monitoring of wear in individual patients, as well as in different implant designs. Polyethylene wear is quantified by comparisons of radiographic measurements made on sequential pelvic radiographs. Variations in pelvic orientation and variation in direction of wear may cause underestimation of polyethylene wear measurements. The purpose of this study was to quantify these effects on 2-dimensional measurements of polyethylene wear.Methods A computer program designed to simulate radiographs was employed to generate virtual radiographs of a virtual pelvis with a total hip replacement. Effects caused by variation in pelvic spatial orientation and variations in wear direction on wear measurements were analyzed separately. A Monte Carlo computational algorithm was employed to describe the combined effects of these two factors.Results Variation in pelvic orientation induced a mean underestimation of wear of 0.4% (0-2.6). Variation in direction of wear introduced a mean underestimation of 8.5% (0-42). A mean underestimation of wear of 9% (0-99) was found when varying both pelvic orientation and direction of wear simultaneously.Interpretation Errors caused by variations in pelvic orientation and wear direction are likely to be small compared to other sources of error when performing polyethylene wear measurements in acetabular components.

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“…Many studies have analyzed 2D and 3D linear wear [5,17,18,26] and focused on the calculation of the acetabular cup volume loss [4,9,14,16,19,21,23,29]. Charnley [4] first stated that the wear volume could be calculated as the maximal cross-sectional area of the femoral head multiplied by the wear depth.…”

Section: Introductionmentioning

confidence: 99%

“…However, Kabo [21] reported that the wear volume should not be based solely on wear depth, but also on the direction of femoral head movement. Nevertheless, some studies [9,29] pointed out that the Kabo formula produced errors as high as 45%. Recently, Ilchmann et al [19] compared several published formulae and proposed a new formula, which, however, has been found not to be sufficiently accurate [41].…”

Section: Introductionmentioning

confidence: 99%

Wear patterns of, and wear volume formulae for, cylindrically elongated acetabular cup liners

Hsu

Chen

2010

Med Biol Eng Comput

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This study analyzed the wear patterns of, and wear volume formulae for, cylindrically elongated acetabular cup liners. The geometric patterns of the wear surface were first classified, then wear volume formulae were derived by integral calculus. SolidWorks((R)) software or published formulae were used to verify the accuracy of the proposed formulae. The analytical results showed that the wear shape of the liner can be categorized into seven wear patterns, including the special case of wear at 90 degrees , and the seven corresponding wear formulae were derived. In addition, wear of the cylindrical elongation might add considerably to the volume loss of the liner, depending on the height and shape of the elongation and the depth and direction of the linear penetration, being maximally 21% in the investigated model. The proposed wear formulae and patterns will be useful for more accurate performance evaluation of existing hip components implanted in patients and for the designing of new hip components.

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The estimation of acetabular cup wear volume from two-dimensional measurements: A comprehensive analysis

Cited by 16 publications

References 24 publications

Evaluating the accuracy of wear formulae for acetabular cup liners

Evaluating the accuracy of wear formulae for acetabular cup liners

Polyethylene acetabular wear in hip prostheses: Computer-simulated quantification of error caused by changes in pelvic orientation and direction of wear

Wear patterns of, and wear volume formulae for, cylindrically elongated acetabular cup liners

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