Experimental evaluation of a percutaneous injectable biomaterial used in radio-interventional bone-filling procedures.

Interventional radiology is beginning to be used in bone pathology. An injectable biomaterial Ethibloc*, composed of alcohol and a vegetal protein (zein), has been successfully used for percutaneous treatment of benign bone lesions. The reasons for this success remained unknown and needed to be understood.

Porous HA ceramic for bone replacement: role of the pores and interconnections - experimental study in the rabbit.

Hydroxyapatite (HA) porous ceramics are increasingly used in biomedical applications. Their physical characteristics, such as porous volume, require perfect control of the pore shape, as well as the number and the size of their interconnections. The aim of our study was to evaluate a new HA ceramic using polymethylmethacrylate microbeads (PMMA) as the porous agent.

Histological aspects in bone regeneration of an association with porous hydroxyapatite and bone marrow cells.

The osteogenic potential of an association of two kinds of hydroxyapatite (HA) porous ceramics with autologous bone marrow cells cultured with or without dexamethasone (10(-8)M) addition in the culture medium and non-cultured rabbit marrow stromal stem cells (MSCs) was tested after 4 weeks of implantation in the dorsal muscles of spine in rabbit. A significantly higher number of rabbits with implants containing bone tissue inside pores were obtained with 10(7) cells ml(-1) cultured treated with Dex. In the HA porous ceramic using naphtalen as porogen agent, the bone recolonization remains only at the periphery of implants and in the second row of pores, while in the HA porous ceramic using polymethacrylate (PMMA) microbeads as porogen agent, the bone recolonization is observed in the depth of implants.

Role of interconnections in porous bioceramics on bone recolonization in vitro and in vivo.

The interconnections in a porous biomaterial are the pathways between the pores. They conduct cells and vessels between pores. Thus they favour bone ingrowth inside ceramics.

Migration of polyethylene particles around nonloosened cemented femoral components from a total hip arthroplasty-an autopsy study.

Three cemented femoral components from total hip arthroplasties retrieved at autopsy were examined in regard to the migration of birefringent polyethylene particles across the fixation interfaces. They were obtained from two patients who died from unrelated causes. They had been in place, respectively, for 8 and 9 years (first patient) and for 9 years (second patient).

Migration of polyethylene debris along well-fixed cemented implants.

Implants, consisting of smooth Inox cylinders, were cemented into the lower femur and upper tibia of nine sheep to study the distal migration of polyethylene particles. Some implants had a titanium-bead porous coat at the proximal end. These were of three types: In the first type, the porous coat was covered with hydroxyapatite to obtain a bony seal; the second type was prepared for a polymethylmethacrylate seal; in the third type, the porous zone was surrounded by a 2-mm-thick space to allow the formation of a fibrous seal.

[Patellar reconstruction during total knee arthroplasty after previous patellectomy].

Purpose Of The Study: In order to limit the consequences of prior total patellectomy on knee function after total knee arthroplasty, we propose an original technique using an en bloc patellar graft to reconstruct the quadriceps lever arm. The purpose of this work was to describe the technique and present preliminary results obtained in seven patients.

Patients And Methods: Seven en bloc patellar grafts were performed in seven patients (6 women and 1 man) during total knee arthroplasty procedures for femorotibial degenerative joint disease after prior patellectectomy (mean 13 years before arthroplasty, range 5-20 years).

Influence of polymeric additives on the biological properties of brushite cements: an experimental study in rabbit.

The resorbability and ability of calcium phosphate hydraulic cements to promote new bone formation was investigated in vivo. The effects of two hydrosoluble polymeric additives (hyaluronic acid, and xanthan gum,) on the biological response of two brushite cement formulations (BHC-A vs BHC-B) was investigated. The brushite cements differed in P/Ca (0.

Bone colonization of beta-TCP granules incorporated in brushite cements.

Injectable calcium phosphate hydraulic cements are known to have a high clinical potential in bone reconstruction for mini-invasive orthopaedic surgery, interventional radiology, and rheumatology. Previous in vivo experiments in rabbit have shown that the presence of beta-TCP granules in injectable bone cement help maintain the transient biomechanical function of the implanted bone and promote the formation of good-quality new bone. Histomorphometric analysis of two brushite hydraulic cement (BHC) mixtures selected from previous results (referred to in this work as BHC-A and BHC-B) was performed at three postoperative delays (0, 12, and 24 weeks): histomorphometric analysis of bone colonization within beta-TCP shows that, just before implantation, the beta-TCP granule area is significantly higher in BHC-B; the residual granule area decreases steadily over time in BHC-A, whereas it goes through a maximum of 30% at 12 weeks in BHC-B; the residual granule porosity increases steadily up to 35% in BHC-A, whereas it goes through a maximum of 35% at 12 weeks and decreases somewhat until 24 weeks in BHC-B.

Tissue engineering and skeletal diseases.

Tissue engineering, a cross between the science of the living organism and that of engineering, aims to replace, maintain or improve human tissue functions, by means of tissue substitutes containing living elements. Thus, it is about production of artificial tissue, using (alone or in combination) cells, matrix or bioactive factors. Their association gives rise to a hybrid biomaterial combining biological components (cells, growth factors or adhesion proteins) and materials (polymers, ceramics).

Raman microspectrometry studies of brushite cement: in vivo evolution in a sheep model.

Calcium phosphate hydraulic cements are promising synthetic bone grafting materials. Brushite-based cements were implanted for 6 and 12 months in the distal condyle of sheep femur, and their in vivo evolution was investigated by Raman microspectrometry. This new technique can probe small volumes in the cubic micrometer range.

Association of porous hydroxyapatite and bone marrow cells for bone regeneration.

The preparation of hybrid material with osteoinductive capacity may be achieved by association of cultured autologous bone cells with a porous ceramic vehicle. We optimized culture conditions for rabbit marrow stromal stem cells (MSCs), notably by selection from batches of fetal calf serum. Rabbit MSCs formed colony-forming unit-ribroblastic (CFU-Fs) in vitro.

Volume effect on biological properties of a calcium phosphate hydraulic cement: experimental study in sheep.

Injectable calcium phosphate hydraulic cements (CPHC) are a new family of bone substitutes within the class of bone reconstruction biomaterials. In this work, CPHC were tested in two consistencies (preset blocks or liquid paste) in an experimental model of cancellous bone defect in sheep. The defects were eight times larger than those investigated previously in rabbits.

[Development of a model which makes it possible to test injectable bone substitutes and evaluation of a calcium phosphate cement].

New percutaneous filling techniques are beginning to be used in bone tumor pathology. The purpose of this study was to develop a reproducible model for testing new injectable bone substitutes. A closed cancellous bone defect was created in the distal femoral condyles of rabbit.

Comparative study of tissue reactions to calcium phosphate ceramics among cancellous, cortical, and medullar bone sites in rabbits.

In order to understand the influence of the implantation site on bone biomaterial evaluation, we implanted cylinders of HA and beta-TCP ceramics in the femoral diaphysis and condyle of rabbits. After 3, 8, 12, and 24 weeks of implantation, histological investigation and histomorphometry were performed on undecalcified samples. Our results show that spontaneous bone healing in the empty cavities is significantly different (p < 0.

Intramural injection of biodegradable microspheres as a local drug-delivery system to inhibit neointimal thickening in a rabbit model of balloon angioplasty.

Restenosis remains the major limitation of coronary angioplasty. The objective of this study was to develop microspheres able to be delivered at the angioplasty site for long-term drug release and to test their effects in a model of balloon angioplasty. Polylactic-co-glycolide acid microspheres (5-10 microm in diameter) were prepared by using an oil-in-water emulsion-solvent evaporation method.

Biomechanical characterization of a biodegradable calcium phosphate hydraulic cement: a comparison with porous biphasic calcium phosphate ceramics.

Biomechanical properties of a biodegradable calcium phosphate hydraulic cement (CPHC) were tested with rabbits. The cement was composed of beta-tricalcium phosphate (beta-TCP), monocalcium phosphate monohydrate (MCPM), and calcium sulfate hemihydrate (CSH), beta-TCP-MCPM-CSH cement. Cylinders of 4.

[Fatigue rupture of a Harris-Galante shell in contact with an autograft of the femur head. Analysis of bone, mechanical and metallurgical factors].

We observed, after 38 months of follow-up, the rupture of the metallic shell of a Harris-Galante cup implanted in a dysplastic acetabulum augmented with a femoral head autograft. Bone ingrowth was extended to 53% of the porous surface, but only in the areas in contact with the true acetabulum. No bone ingrowth was identified in the fiber mesh in contact with the autograft.

[Structural MRI study of the Achilles tendon. Correlation with microanatomy and histology].

On T1 and T2 weighted MR Imaging, normal Achilles tendon is generally described as a homogeneous low signal structure. However, punctuate and/or short linear high signal foci are often seen, especially on the anterior part of axial sections. These images are not artifacts.

Resorption of, and bone formation from, new beta-tricalcium phosphate-monocalcium phosphate cements: an in vivo study.

Hard cylinders (4.7 x 10 mm) of two kinds of beta-tricalcium phosphate-monocalcium phosphate monohydrate-calcium sulfate hemihydrate (beta-TCP-MCPM-CSH) cements with and without beta-TCP granules (500-1000 microns) were implanted into holes drilled in rabbit femoral condyles for up to 16 weeks. Empty cavities were used as control.

Experimental model of posterolateral spinal arthrodesis in sheep. Part 2. Application of the model: evaluation of vertebral fusion obtained with coral (Porites) or with a biphasic ceramic (Triosite).

Objectives: The authors evaluated two bone substitutes in a posterolateral spinal arthrodesis (PSA) model in sheep: coral porites (99% calcium carbonate, Biocoral, Inoteb, France) and a biphasic ceramic (BCP) (65% hydroxyapatite and 35% B tricalcium phosphate, Triosite, Zimmer International).

Summary Of Background Data: Bone substitutes would be of great interest for PSA. Previous trials began with two kinds of biomaterials: natural coralline calcium carbonate, and phosphate calcium ceramic.

Experimental model of posterolateral spinal arthrodesis in sheep. Part 1. Experimental procedures and results with autologous bone graft.

Objectives: The authors evaluated the reliability in obtaining a posterolateral spinal arthrodesis (PSA) with autologous bone graft.

Summary Of Background Data: Posterolateral spinal arthrodesis using autogenous cancellous bone graft is the most simple and efficient technique to get a spinal graft. No extensive biomechanical study of PSA is available.

Microradiographic aspect on iliac bone tissue in postmenopausal women with and without vertebral crush fractures.

Bone mass, microstructure and microconnectivity of cancellous bone tissue, microporosity, and microdensity of cortical bone have been evaluated with an image analysing computer on microradiographs in 34 iliac crest bone biopsies from two individual, paired age-matched groups of postmenopausal women. Group 1 comprised 17 cases without vertebral crush fractures (mean age 66 years, range 45-80 years) and time since menopause 20.5 +/- 11.

Effects of glucocorticoids on skeletal growth in rabbits evaluated by dual-photon absorptiometry, microscopic connectivity and vertebral compressive strength.

The effects of corticosteroid on bone were examined in female growing rabbits treated with 0.7 mg/kg per day prednisolone for 5 months. The evolution of whole-body total bone mineral measured by dual-photon absorptiometry showed a significant difference between the prednisolone-treated group and the control group from the first to the fifth month.

Osteomesopyknosis: report of a new case with bone histology.

A new case of osteomesopyknosis, a rare autosomal dominant axial osteosclerosis is reported, with 4 affected members of the same family. Biochemical investigations, bone mineral content (BMC) measurement, 99mTc HMDP bone scan and microscopy of iliac crest bone and femoral head have been performed on 1 subject. A marked increase of BMC was found, without abnormality of biochemical data.