Bone mineral density: a window on cortical bone mechanical quality?

(Stage proposé aux étudiants de Master 2ème année)

Date ou durée de stage

  • 6 mois

Contexte

The bone mechanical quality strongly influences the likelihood of a person to sustain a fracture and obtain a good results from orthopedic surgery. Quantitative computed tomography (QCT) is an imaging technique providing a measure of bone mineral density (BMD). BMD can be used to predict the fracture risk of osteoporotic subjects. Some researchers have also proposed that BMD can be used to assess the chance of orthopedic fixation failing in the short an long terms. While many consider the use of BMD as a surrogate for bone mechanical quality, the relationships between BMD and mechanical properties are only partially understood.

Objectifs

The aims of the work to be conducted by the trainee are

  1. to establish the relationships between BMD and mechanical properties, essentially strength in compression and anisotropic elasticity; and
  2. to understand the observed variations of BMD and mechanical properties in terms of
    • (i) porosity and other descriptors of the bone micro-architecture, and
    • (ii) the biochemical composition of the bone.

Missions

The trainee will be involved in experimental work, data analysis (statistics), and modeling using a collection of samples which have already been prepared and measured with several non destructive modalities in the framework of a collaborative project (MULTIPS). The trainee will use an existing original setup for the mechanical testing of small bone specimens. He/she will also use a numerical model of the bone samples based on high resolution images.

The expected results are :

  1. a better knowledge of the determinants of the variations of the cortical bone strength, in particular the influence of the porous network micro-architecture and composition of the extracellular matrix;
  2. a better understanding of the implications of a low BMD for bone mechanical competence.

The trainee will work in the « Bone Quality » group in the Laboratoire d’Imagerie Biomedicale. The group is composed of seven researchers and engineers and two orthopedic surgeons. The group is developing novel quantitative imaging methods for bone, investigates the determinants of bone quality and considers applications in orthopedics and bone physiology.

Compétences

The successful candidate is expected to have a strong interest in biomedical research and to work closely with the members of the group. He/She should have basic experimental, computer, and writing skills. Ideally, he/she will have some experience in processing and analyzing multimodality data.

Rémunération

  • « Gratifications de stage » (Financial conditions follow Sorbonne Université guidelines)

Supervisor

Quentin GRIMAL
+33 1 44 27 92 19

https://134.157.99.81/~qgrimal/

Partners or collaborations :

Caroline SCEMAMA, EL-Hadi SARIALI -Service d’orthopédie, hospital Pitié Salpétrière and Laboratoire d’Imagerie Biomédicale