Correction of acetabular cup orientation measurements for X-ray beam offset

Derbyshire, Brian

doi:10.1016/j.medengphy.2008.02.001

Cited by 29 publications

(26 citation statements)

References 13 publications

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“…Acetabular component orientation was also measured using Wrightington cup orientation software. This enables measurement of inclination and version, and corrects for angular artifact due to the central X-ray beam offset from the hip (Derbyshire and Porter 2003, Derbyshire 2008). 2 of the authors (HWJ and BD) tested the inter-observer and intra-observer reliability of this software using standard statistical techniques (Bland and Altman 1983, Ranstam et al 2000).…”

Section: Methodsmentioning

confidence: 99%

Silent soft tissue pathology is common with a modern metal-on-metal hip arthroplasty

Wynn-Jones¹,

Macnair²,

Wimhurst³

et al. 2011

Acta Orthopaedica

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Background and purposeAdverse reactions to metal debris have been reported to be a cause of pain in metal-on-metal hip arthroplasty. We assessed the incidence of both symptomatic and asymptomatic adverse reactions in a consecutive series of patients with a modern large-head metal-on-metal hip arthroplasty.MethodsWe studied the early clinical results and results of routine metal artifact-reduction MRI screening in a series of 79 large-head metal-on-metal hip arthroplasties (ASR; DePuy, Leeds, UK) in 68 patients. 75 hips were MRI scanned at mean 31 (12–52) months after surgery.Results27 of 75 hips had MRI-detected metal debris-related abnormalities, of which 5 were mild, 18 moderate, and 4 severe. 8 of these hips have been revised, 6 of which were revised for an adverse reaction to metal debris, diagnosed preoperatively with MRI and confirmed histologically. The mean Oxford hip score (OHS) for the whole cohort was 21. It was mean 23 for patients with no MRI-based evidence of adverse reactions and 19 for those with adverse reactions detected by MRI. 6 of 12 patients with a best possible OHS of 12 had MRI-based evidence of an adverse reaction.InterpretationWe have found a high early revision rate with a modern, large-head metal-on-metal hip arthroplasty. MRI-detected adverse rections to metal debris was common and often clinically “silent”. We recommend that patients with this implant should be closely followed up and undergo routine metal artifact-reduction MRI screening.

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Section: Methodsmentioning

confidence: 99%

Silent soft tissue pathology is common with a modern metal-on-metal hip arthroplasty

Wynn-Jones¹,

Macnair²,

Wimhurst³

et al. 2011

Acta Orthopaedica

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“…In CT the cup opening is seen directly in the anteroposterior direction and this causes differences in calculations assuming the parallelism of the coronal and McKibbin plane. Derbyshire described a way to estimate this error and to correct the calculated version [22]. Widmer on the other hand proposed a correction of the version by 5.46 degrees when the imaging distance is 1.15 metres [5].…”

Section: Discussionmentioning

confidence: 99%

Assessment of inter- and intra-observer reliability in the determination of radiographic version and inclination of the cup in metal-on-metal hip resurfacing

Reito

Puolakka

Paakkala

et al. 2011

International Orthopaedics (SICOT)

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Purpose Determination of the cup orientation after metal-on-metal hip resurfacing may provide important information in the postoperative follow-up. We present a mathematical method based on a previously described approach to assess the version and inclination of the cup in the metal-on-metal bearing without a separate software computation from plain radiographs. The aim of the study was to assess the intra-and inter-observer reliability of this method. Methods Calculation of version and inclination were done twice for 20 hip resurfacings by four observers. Intraobserver reliability was estimated by mean error and correlation of the two sets of measurement for version and inclination. Bland-Altman plots, intra-class coefficient and mean error were used to assess the inter-observer reliability of the measurements. Results Intra-observer correlation for version measurement ranged from 0.74 to 0.94. Correlation for inclination varied between 0.94 and 0.97. Upper and lower limits of agreement in Bland-Altman plots for version measurements between observers ranged from 4.1 to 7.2 degrees and from −3.2 to −8.3 degrees, respectively. For inclination measurements the upper and lower limits ranged from 3.1 to 5.3 degrees and from −2.7 to −6.0 degrees.Conclusions Mean errors, correlation coefficients and 95% limits of agreement were on an acceptable level. We believe that this method is applicable for clinical use.

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“…From the size, shape and position of these ellipses, the orientation of the cup (version and inclination) and the co-ordinates of the head and cup centres were determined. Algorithms in the software corrected the measured cup version and inclination for the rotation artefact caused by the offset of the central x-ray beam from the centre of the cup (11). Using the measurement of the femoral head image, each image was calibrated to the known size of the femoral head, which had been accurately measured using Vernier callipers.…”

Section: Methodsmentioning

confidence: 99%

The efficacy of a “double-D-shaped” wire marker for radiographic measurement of acetabular cup orientation and wear

Derbyshire

Raut

2013

HIP

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Historically, wire markers were attached to cemented all-plastic acetabular cups to demarcate the periphery and to measure socket wear. The wire shape was either a semi-circle passing over the pole of the cup, or a circle around the cup equator. More recently, “double-D” shaped markers were introduced with a part-circular aspect passing over the pole and a semi-circular aspect parallel to the equatorial plane. This configuration enabled cup retroversion to be distinguished from anteversion. In this study, the accuracy of radiographic measurement of cup orientation and wear was assessed for cups with “double-D” and circular markers.Each cup was attached to a measurement jig which could vary the anteversion/retroversion and internal/ external rotation of the cup. A metal femoral head was fixed within the socket and radiographic images were created for all combinations of cup orientation settings. The images were measured using software with automatic edge detection, and cup orientation and zero-wear accuracies were determined for each setting.The median error for cup version measurements was similar for both types of wire marker (0.2° double-D marker, −0.24° circular marker), but measurements of the circular marker were more repeatable. The median inclination errors were 2.05° (double-D marker) and 0.23° (circular marker). The median overall “zero wear” errors were 0.19 mm (double-D marker) and 0.03 mm (circular marker). Measurements of the circular wire marker were much more repeatable.

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Correction of acetabular cup orientation measurements for X-ray beam offset

Cited by 29 publications

References 13 publications

Silent soft tissue pathology is common with a modern metal-on-metal hip arthroplasty

Silent soft tissue pathology is common with a modern metal-on-metal hip arthroplasty

Assessment of inter- and intra-observer reliability in the determination of radiographic version and inclination of the cup in metal-on-metal hip resurfacing

The efficacy of a “double-D-shaped” wire marker for radiographic measurement of acetabular cup orientation and wear

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