Method for quantitative assessment of acetabular bone defects

Hettich, Georg; Schierjott, Ronja A.; Ramm, Heiko; Graichen, Heiko; Jansson, Volkmar; Rudert, Maximilian; Traina, Francesco; Grupp, Thomas M.

doi:10.1002/jor.24165

Cited by 29 publications

(33 citation statements)

References 34 publications

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“…In accordance with the ethics committee, anonymized CT-data was provided, and patient information was restricted to age and gender. The data sets were screened and the following exclusion criteria were applied to allow successful reconstruction with the SSM [10]: (1) Unilateral scans of the pelvis, (2) data sets with poor image quality, and (3) scans with a distinctive tilted position of the pelvis. After the application of the exclusion criteria, 50 defect hemi-pelvises were included in this study with CT scans conducted between May 2014 and November 2018.…”

Section: Methodsmentioning

confidence: 99%

“…The analysis was based on solid models of the defect pelvis and the corresponding native pelvis (Fig 1), as previously described and validated [10]. The CT-data set of the defect pelvis was segmented in Mimics 19.0 (Materialise NV, Leuven, Belgium) (Fig 1A).…”

Section: Methodsmentioning

confidence: 99%

“…For the reconstruction of the native pelvis corresponding to each defect pelvis, the pathological areas of the segmented CT-data sets were masked and excluded for each defect pelvis individually (Fig 1B). A SSM was trained based on the CT-data sets of 66 healthy pelvises [10]. The SSM is a deformable model that describes the typical 3D shape variation occurring in the training population by so called modes of shape variation that are sorted by their geometric significance.…”

Section: Methodsmentioning

confidence: 99%

“…The application of three-dimensional (3D) imaging such as Computed-tomography (CT) may help to overcome the drawbacks associated with conservative radiograph-based defect classifications [7]. Recently, some approaches towards a more quantitative defect analysis based on 3D-imaging techniques were made, including the analysis of total radial bone loss [7–9], volume loss [7, 10] and remaining bone thickness [7]. Total radial bone loss (TrABL) was among others assessed by Gelaude et al, who conducted the analysis based on segmented CT-data of the defect acetabulum and its anatomic reconstruction [8].…”

Section: Introductionmentioning

confidence: 99%

“…The possibilities to analyze volume loss and remaining bone thickness were mentioned by Horas et al [7]. Recently, Hettich et al validated a method to analyze acetabular bone defects in terms of bone volume loss and new bone formation [10]. The study was based on CT-data of defect pelvises and their anatomic reconstructions which were obtained via a statistical shape model (SSM).…”

Section: Introductionmentioning

confidence: 99%

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Quantitative assessment of acetabular bone defects: A study of 50 computed tomography data sets

et al. 2019

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ObjectivesAcetabular bone defect quantification and classification is still challenging. The objectives of this study were to suggest and define parameters for the quantification of acetabular bone defects, to analyze 50 bone defects and to present the results and correlations between the defined parameters.MethodsThe analysis was based on CT-data of pelvises with acetabular bone defects and their reconstruction via a statistical shape model. Based on this data, bone volume loss and new bone formation were analyzed in four sectors (cranial roof, anterior column, posterior column, and medial wall). In addition, ovality of the acetabulum, lateral center-edge angle, implant migration, and presence of wall defects were analyzed and correlations between the different parameters were assessed.ResultsBone volume loss was found in all sectors and was multidirectional in most cases. Highest relative bone volume loss was found in the medial wall with median and [25, 75]—percentile values of 72.8 [50.6, 95.0] %. Ovality, given as the length to width ratio of the acetabulum, was 1.3 [1.1, 1.4] with a maximum of 2.0, which indicated an oval shape of the defect acetabulum. Lateral center-edge angle was 30.4° [21.5°, 40.4°], which indicated a wide range of roof coverage in the defect acetabulum. Total implant migration was 25.3 [14.8, 32.7] mm, whereby cranial was the most common direction. 49/50 cases showed a wall defect in at least one sector. It was observed that implant migration in cranial direction was associated with relative bone volume loss in cranial roof (R = 0.74) and ovality (R = 0.67).ConclusionWithin this study, 50 pelvises with acetabular bone defects were successfully analyzed using six parameters. This could provide the basis for a novel classification concept which would represent a quantitative, objective, unambiguous, and reproducible classification approach for acetabular bone defects.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quantitative assessment of acetabular bone defects: A study of 50 computed tomography data sets

et al. 2019

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A method to assess primary stability of acetabular components in association with bone defects

Schierjott

Hettich²,

Ringkamp

et al. 2020

Journal Orthopaedic Research

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The objectives of this study were to develop a simplified acetabular bone defect model based on a representative clinical case, derive four bone defect increments from the simplified defect to establish a step‐wise testing procedure, and analyze the impact of bone defect and bone defect filling on primary stability of a press‐fit cup in the smallest defined bone defect increment. The original bone defect was approximated with nine reaming procedures and by exclusion of specific procedures, four defect increments were derived. The smallest increment was used in an artificial acetabular test model to test primary stability of a press‐fit cup in combination with bone graft substitute (BGS). A primary acetabular test model and a defect model without filling were used as reference. Load was applied in direction of level walking in sinusoidal waveform with an incrementally increasing maximum load (300 N/1000 cycles from 600 to 3000 N). Relative motions (inducible displacement, migration, and total motion) between cup and test model were assessed with an optical measurement system. Original and simplified bone defect volume showed a conformity of 99%. Maximum total motion in the primary setup at 600 N (45.7 ± 5.6 µm) was in a range comparable to tests in human donor specimens (36.0 ± 16.8 µm). Primary stability was reduced by the bone defect, but could mostly be reestablished by BGS‐filling. The presented method could be used as platform to test and compare different treatment strategies for increasing bone defect severity in a standardized way.

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Primary stability of a press‐fit cup in combination with impaction grafting in an acetabular defect model

Schierjott

Hettich²,

Baxmann³

et al. 2020

Journal Orthopaedic Research

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The objectives of this study were to (a) assess primary stability of a press-fit cup in a simplified acetabular defect model, filled with compacted cancellous bone chips, and (b) to compare the results with primary stability of a press-fit cup combined with two different types of bone graft substitute in the same defect model. A previously developed acetabular test model made of polyurethane foam was used, in which a mainly medial contained defect was implemented. Three test groups (N = 6 each) were prepared: Cancellous bone chips (bone chips), tricalciumphosphate tetrapods + collagen matrix (tetrapods + coll), bioactive glass S53P4 + polyethylene glycolglycerol matrix (b.a.glass + PEG). Each material was compacted into the acetabulum and a press-fit cup was implanted. The specimens were loaded dynamically in the direction of the maximum resultant force during level walking. Relative motion between cup and test model was assessed with an optical measurement system. At the last load step (3000 N), inducible displacement was highest for bone chips with median [25th percentile; 75th percentile] value of 113 [110; 114] µm and lowest for b.a.glass + PEG with 91 [89; 93] µm. Migration at this load step was highest for b.a.glass + PEG with 868 [845; 936] µm and lowest for tetrapods + coll with 491 [487;497] µm. The results show a comparable behavior under load of tetrapods + coll and bone chips and suggest that tetrapods + coll could be an attractive alternative to bone chips. However, so far, this was found for one specific defect type and primary stability should be further investigated in additional/more severe defects.

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Method for quantitative assessment of acetabular bone defects

Cited by 29 publications

References 34 publications

Quantitative assessment of acetabular bone defects: A study of 50 computed tomography data sets

Quantitative assessment of acetabular bone defects: A study of 50 computed tomography data sets

A method to assess primary stability of acetabular components in association with bone defects

Primary stability of a press‐fit cup in combination with impaction grafting in an acetabular defect model

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