Freezing does not influence the microarchitectural parameters of the microstructure of the freshly harvested femoral head bone.

The femoral head is one of the most commonly used bones for allografts and biomechanical studies. However, there are few reports on the trabecular bone microarchitectural parameters of freshly harvested trabecular bones. To our knowledge, this is the first study to characterize the microstructure of femoral heads tested immediately after surgery and compare it with the microstructure obtained with conventional freezing.

Achilles tendon enthesis behavior under cyclic compressive loading: Consequences of unloading and early remobilization.

The Achilles tendon enthesis (ATE) anchors the Achilles tendon into the calcaneus through fibrocartilaginous tissue. The latter is enriched in type II collagen and proteoglycans (PGs), both of which give the enthesis its capacity to withstand compressive stress. Because unloading and reloading induce remodeling of the ATE fibrocartilage (Camy et al.

Characterization of the mechanical properties of the mouse Achilles tendon enthesis by microindentation. Effects of unloading and subsequent reloading.

The fibrocartilaginous tendon enthesis, i.e. the site where a tendon is attached to bone through a fibrocartilaginous tissue, is considered as a functionally graded interface.

Using a patient-specific cutting guide enables identical knee osteotomies: An evaluation of accuracy on sawbones.

Purpose: It was hypothesized that using a Patient-Specific Cutting Guide (PSCG) would allow the creation of sawbones model osteotomies, identical in the 3 planes and the hinge parameters, that can be used for biomechanical studies. The aim of the study was to evaluate the accuracy of the PSCG system and to introduce and assess the new hinge parameter; the hinge area.

Methods: Six identical sawbones tibia models were identically set up for identical osteotomy cuts by the same surgeon in the same session and with identical instruments.

Osteogenic Potential of a Polyethylene Glycol Hydrogel Functionalized with Poly-Lysine Dendrigrafts (DGL) for Bone Regeneration.

Resorbable hydrogels are widely used as scaffolds for tissue engineering. These hydrogels can be modified by grafting dendrimer-linked functionalized molecules (dendrigrafts). Our aim was to develop a tunable poly(L-lysine) dendrigrafts (DGL)/PEG-based hydrogel with an inverse porosity and to investigate its osteogenic potential.

Osteochondral autograft transplantation (mosaicplasty): What is the impact of plug diameter in cartilage repair?

Purpose: To compare the mechanical stress applied to our grafted defect area according to the diameter of the plugs used in the treatment of osteochondral lesion with osteochondral autograft transplantation (OAT) procedure.

Methods: A biomechanical study was conducted on eight cadaveric knees. A 20-mm defect was created in the weight-bearing zone on the medial femoral condyle then filled either with three plugs of 8 mm, or with four plugs of 6 mm, or with 6 plugs of 4 mm diameter.

Texture Parameters Measured by UHF-MRI and CT Scan Provide Information on Bone Quality in Addition to BMD: A Biomechanical Ex Vivo Study.

The current definition of osteoporosis includes alteration of bone quality. The assessment of bone quality is improved by the development of new texture analysis softwares. Our objectives were to assess if proximal femoral trabecular bone texture measured in Ultra high field (UHF) 7 Tesla MRI and CT scan were related to biomechanical parameters, and if the combination of texture parameters and areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry provided a better prediction of femoral failure than aBMD alone.

Multiscale Femoral Neck Imaging and Multimodal Trabeculae Quality Characterization in an Osteoporotic Bone Sample.

Although multiple structural, mechanical, and molecular factors are definitely involved in osteoporosis, the assessment of subregional bone mineral density remains the most commonly used diagnostic index. In this study, we characterized bone quality in the femoral neck of one osteoporotic patients as compared to an age-matched control subject, and so used a multiscale and multimodal approach including X-ray computed microtomography at different spatial resolutions (pixel size: 51.0, 4.

Mechanical Characterization at the Microscale of Mineralized Bone Callus after Bone Lengthening.

Distraction osteogenesis (DO) involves several processes to form an organized distracted callus. While bone regeneration during DO has been widely described, no study has yet focused on the evolution profile of mechanical properties of mineralized tissues in the distracted callus. The aim of this study was therefore to measure the elastic modulus and hardness of calcified cartilage and trabecular and cortical bone within the distracted callus during the consolidation phase.

Assessing the Elasticity of Child Cortical Bone.

A better understanding of the mechanical behaviour of child bone is essential to improve the diagnosis of pediatric bone disorders that may influence bone development. Even though the process of bone growth is well described, there are still lacks of knowledge on intrinsic material properties of child bone and particularly on child bone considered as "non-pathological". Geometry, material properties, microstructure and biochemical components are associated with child bone fragility and remain difficult to assess for two main reasons: the scarcity of the bone samples and their small dimensions.

In silico modelling of long bone healing involving osteoconduction and mechanical stimulation.

A lot of evidence has shown the importance of stimulating cell mechanically during bone repair. In this study, we modeled the challenging fracture healing of a large bone defect in tibial diaphysis. To fill the fracture gap, we considered the implantation of a porous osteoconductive biomaterial made of poly-lactic acid wrapped by a hydrogel membrane mimicking osteogenic properties of the periosteum.

Assessment of Bone Microarchitecture in Fresh Cadaveric Human Femurs: What Could Be the Clinical Relevance of Ultra-High Field MRI.

MRI could be applied for bone microarchitecture assessment; however, this technique is still suffering from low resolution compared to the trabecular dimension. A clear comparative analysis between MRI and X-ray microcomputed tomography (μCT) regarding microarchitecture metrics is still lacking. In this study, we performed a comparative analysis between μCT and 7T MRI with the aim of assessing the image resolution effect on the accuracy of microarchitecture metrics.

A 3-Dimensional Suture Technique for Flexor Tendon Repair: A Biomechanical Study.

Purpose: Flexor tendon injury continues to pose a number of challenges for hand surgeons. Improving mechanical properties of repairs should allow for earlier and unprotected rehabilitation. A 3-dimensional (3D) 4-strand suture technique has been proposed to combine high tensile strength and low gliding resistance without causing suture pullout due to tendon delamination.

Validation and Optimization of Proximal Femurs Microstructure Analysis Using High Field and Ultra-High Field MRI.

Trabecular bone could be assessed non-invasively using MRI. However, MRI does not yet provide resolutions lower than trabecular thickness and a comparative analysis between different MRI sequences at different field strengths and X-ray microtomography (μCT) is still missing. In this study, we compared bone microstructure parameters and bone mineral density (BMD) computed using various MRI approaches, i.

Negative impact of disuse and unloading on tendon enthesis structure and function.

Exposure to chronic skeletal muscle disuse and unloading that astronauts experience results in muscle deconditioning and bone remodeling. Tendons involved in the transmission of force from muscles to skeleton are also affected. Understanding the changes that occur in muscle, tendon, and bone is an essential step toward limiting or preventing the deleterious effects of chronic reduction in mechanical load.

Survey of MRI Usefulness for the Clinical Assessment of Bone Microstructure.

Bone microarchitecture has been shown to provide useful information regarding the evaluation of skeleton quality with an added value to areal bone mineral density, which can be used for the diagnosis of several bone diseases. Bone mineral density estimated from dual-energy X-ray absorptiometry (DXA) has shown to be a limited tool to identify patients' risk stratification and therapy delivery. Magnetic resonance imaging (MRI) has been proposed as another technique to assess bone quality and fracture risk by evaluating the bone structure and microarchitecture.

Systemic Administration of G-CSF Accelerates Bone Regeneration and Modulates Mobilization of Progenitor Cells in a Rat Model of Distraction Osteogenesis.

Granulocyte colony-stimulating factor (G-CSF) was shown to promote bone regeneration and mobilization of vascular and osteogenic progenitor cells. In this study, we investigated the effects of a systemic low dose of G-CSF on both bone consolidation and mobilization of hematopoietic stem/progenitor cells (HSPCs), endothelial progenitor cells (EPCs) and mesenchymal stromal cells (MSCs) in a rat model of distraction osteogenesis (DO). Neovascularization and mineralization were longitudinally monitored using positron emission tomography and planar scintigraphy.

Ultrasounds could be considered as a future tool for probing growing bone properties.

Juvenile bone growth is well described (physiological and anatomical) but there are still lacks of knowledge on intrinsic material properties. Our group has already published, on different samples, several studies on the assessment of intrinsic material properties of juvenile bone compared to material properties of adult bone. The purpose of this study was finally to combine different experimental modalities available (ultrasonic measurement, micro-Computed Tomography analysis, mechanical compression tests and biochemical measurements) applied on small cubic bone samples in order to gain insight into the multiparametric evaluation of bone quality.

Comparative biomechanical study of five systems for fixation of the coracoid transfer during the Latarjet procedure for treatment of anterior recurrent shoulder instability.

Purpose: This work compares the biomechanical resistance of five modes of fixation coracoid bone-block fixation during Latarjet open-air or arthroscopic procedures. The hypothesis is that these systems are equivalent.

Methods: Latarjet procedures were performed on cadavers, then the samples were subjected to an increasing tension until the fixation failed.

Presoaking of Semitendinosus Graft With Vancomycin Does Not Alter Its Biomechanical Properties: A Biomechanical In Vitro-Controlled Study Using Graft From Living Donors.

Purpose: To compare the biomechanical properties of human semitendinosus graft presoaked with or without vancomycin under a load to failure tensile test.

Methods: Thirty semitendinosus grafts harvested during anterior cruciate ligament reconstruction were included. These were dissected equally into 2 halves and subsequently randomly allocated to a vancomycin group and to a control group.