Quantitative CT-assisted osteodensitometry of femoral adaptive bone remodelling after uncemented total hip arthroplasty

The aim of this prospective cohort study was to determine the densitometric relevance of minor design modifications of a cementless stem designed to improve proximal load transfer. We used a prospective cohort study with densitometric analysis over a five-year period of two groups of patients with primary osteoarthritis. The first group, 56 hips, received the first version of the ABG stem (ABG-I); the second group, 54 hips, had the ABG-II stem. The results obtained with the ABG-I stem showed a decrease of bone density in proximal areas that ranged from 13% to 37%. However, the new design had a decrease of the same areas that ranged from 9% to 23%. These differences were noted at the end of the first post-operative year and remained stable, except in zone 7, where they were progressive. There is little evidence that the modified stem reduces femoral bone density loss.Résumé Nous avons revu de façon rétrospective 68 hanches chez 62 patients présentant une dysplasie acétabulaire et ayant bénéficié d'une ostéotomie péri-acétabulaire. Parmi ces 68 hanches, 33 avaient en préopératoire une rétroversion acétabulaire (groupe rétroversion) et 35 une antéversion (groupe contrôle). Toutes les hanches ont été évaluées selon le score de Harris. L'évaluation radiographique de la rétroversion acétabulaire et du mur postérieur déficient ont été basées sur le signe du croisement et le signe du mur extérieur. Les scores cliniques des deux groupes au suivi final était semblable. Dans le groupe rétroversion, 12 hanches avaient antéversé leur acétabulum en post-opéra-toire le signe du mur postérieur disparaissant, mais celui-ci restant présent dans 21 hanches avec un acétabulum en rétroversion post-opératoire. Parmi les 21 hanches avec acétabulum rétroversé une coxarthrose postérieure s'est développée à 5 ans post-opératoire. Lorsque l'on réalise une correction par ostéotomie pour une hanche dysplasique avec un acétabulum rétroversé, il est important de corriger cette rétroversion de façon à prévenir une coxarthrose secondaire due à la déficience du mur postérieur.

Section: Discussionmentioning

confidence: 99%

Changes in periprosthetic bone remodelling after redesigning an anatomic cementless stem

Panisello

Canales

Herrero

et al. 2008

“…Computed tomography scans were carried out on all patients postoperatively, one year, two and five years after the index operation. The method used for qCT assessment has been already described in the one and two-year follow-up reports [8,9].…”

Section: Methodsmentioning

confidence: 99%

“…We have used geometric and density information from qCT datasets of previous osteodensitometry studies [8][9][10] to create patient-specific finite element (FE) models. The hypothesis of this study is that the combination of these two modalities, qCT and FE, allows three dimensional patient specific imaging of cortical and cancellous bone changes over time as well as the consequences of stress shielding.…”

Section: Introductionmentioning

confidence: 99%

Quantitative CT with finite element analysis: towards a predictive tool for bone remodelling around an uncemented tapered stem

Shim

Pitto

Anderson

2012

Self Cite

Purpose We used quantitative CT in conjunction with finite element analysis to provide a new tool for assessment of bone quality after total hip arthroplasty in vivo. The hypothesis of this prospective five-year study is that the combination of the two modalities allows 3D patientspecific imaging of cortical and cancellous bone changes and stress shielding. Method We tested quantitative CT in conjunction with finite elements on a cohort of 29 patients (31 hips) who have been scanned postoperatively and at one year, two years and five years follow-up. The method uses cubic Hermite finite element interpolation for efficient mesh generation directly from qCT datasets. The element Gauss points that are used for the geometric interpolation functions are also used for interpolation of osteodensitometry data. Results The study showed changes of bone density suggestive of proximal femur diaphysis load transfer with osteointegration and moderate metaphyseal stress shielding. Our model revealed that cortical bone initially became porous in the greater trochanter, but this phenomenon progressed to the cortex of the lesser trochanter and the posterior aspect of the metaphysis. The diaphyseal area did not experience major change in bone density for either cortical or cancellous bone. Conclusion The combination of quantitative CT with finite element analysis allows visualization of changes to bone density and architecture. It also provides correlation of bone density/architectural changes with stress patterns enabling the study of the effects of stress shielding on bone remodelling in vivo. This technology can be useful in predicting bone remodeling and the quality of implant fixation using prostheses with different design and/or biomaterials.

“…The technical improvements in dual-energy X-ray absorptiometry (DEXA) have made it possible to accurately measure the quantity of bone near a metallic implant [11,12,14]. Recently quantitative computed tomography (QCT)-assisted osteodensitometry has also been shown to be useful in assessing the in vivo structural bone changes after total hip arthroplasty (THA) [20,21].…”

Section: Introductionmentioning

confidence: 99%

Five-year DEXA study of 88 hips with cemented femoral stem

Digas

Kärrholm

2008

We performed repeated dual-energy X-ray absorptiometry (DEXA) measurements over five years in a homogeneous patient population to study the effect of a cemented stem on proximal femoral bone remodelling. Data from 88 patients (88 hips) implanted with total hip arthroplasty (THA) prostheses were extracted from three randomised studies. Femoral bone mineral density (BMD) was measured using a Lunar DPX-IQ densitometer for five years postoperatively. At one year the BMD changes had decreased between −2.0% [region of interest (ROI) 1] and −11.5% (ROI 7). During the follow-up period the BMD initially increased during the second year and thereafter decreased again in ROIs 5, 6 and 7. The loss of BMD at five years was more pronounced in region 7 (12.9%) and decreased with increasing age, total hip replacement (THR) on the right side and decreasing weight of the patient. We found that after the initial phase of early bone loss a period of recovery follows. Thereafter the BMD decreases again, which probably reflects the normal ageing of bone after uncomplicated cemented THA.Résumé Nous avons réalisé des examens avec des mesures répétées de densité osseuse (DEXA) sur une période de 5 ans dans une population homogène de patients ayant bénéficié de la mise en place d'une prothèse fémorale cimentée avec évaluation de remodelage osseux. Nous avons extrait les données de 88 patients (88 hanches) de trois études randomisées. La densité minérale osseuse fémorale a été mesurée par densitomètre Lunar DPX-IQ durant les cinq années post-opératoires. A un an, la densité minérale osseuse diminue de −2% (zone 1) et de −11,5% (zone 7). Durant la période d'observation la densité minérale osseuse augmente au cours de la deuxième année et puis diminue à nouveau en zones 5, 6 et 7. La perte de densité osseuse à cinq ans est moins importante en zone 7 (12,9%) et diminue lorsque l'âge augmente notamment du côté droit et en fonction du poids des patients. Nous avons ainsi montré, qu'après une phase initiale de déminéralisa-tion osseuse il existe une phase de reminéralisation puis la densité minérale osseuse diminue à nouveau ceci étant probablement dans les prothèses totales de hanches non compliquées le reflet de l'âge.