Narrow Results

To obtain TiNi foams with interconnected pores that have surface quality necessary for bone growth in addition to required mechanical performance, sintering with the space holder technique was employed in this study, which aimed to evaluate the bone healing process of TiNi graft materials. For this purpose, processed TiNi foams with three different porosities were placed into the created defects in the femur of rats. Moreover, the mechanical properties of the processed TiNi foams were conducted via monotonic compression tests in order to evaluate mechanical biocompatibility.

Anterior cruciate ligament (ACL) reconstruction is a significant clinical problem. Clinical studies reveal that 11%–32% of patients show an unsatisfactory prognosis and that up to 10% may require surgical revision. Graft-tunnel healing is one of the major factors affecting the outcome of ACL reconstruction. Given that there is no analog like tendon insertion in the bone tunnel in animal or human, it is necessary to establish an appropriate animal model for a better understanding of the biology of graft-tunnel healing; in particular, the structure of the tendon insertion site in the bone tunnel should be known in prior. Recently, a protocol for establishing ACL reconstruction animal models has been developed after a critical review of the literature in the past decades. The assessment protocol consists of three-dimensional (3D) structural analysis of bone ingrowth by micro-computed tomography (micro-CT), two-dimensional (2D) structural analysis of newly formed tendon insertion in the bone tunnel by routine histology, and mechanical testing of the strength of the graft–tunnel complex as the endpoint evaluation. Densitometric evaluation is also used to assess the changes of pre-existing bone with graft–tunnel healing by peripheral quantitative computed tomography (pQCT). In this chapter, we also discuss several aspects on the application of this experimental model for developing therapeutic strategies to enhance graft–tunnel healing.

A macroporous titanium surface layer formed on titanium substrate was subjected to 5.0M-NaOH treatment at 60°C for 24 h and heat treatment at 600°C for 1 h. The NaOH and heat treatments produced an amorphous sodium titanate layer uniformly on the surface of the porous titanium. The sodium titanate induced a bonelike apatite formation in a simulated body fluid. Apatite layer could be thus formed uniformly along the surface morphology of the porous titanium. It is expected that the porous titanium layer subjected to the NaOH and heat treatments will not only enhance bone ingrowth into the porous structure, but also provide a biological integration with bone via apatite formation on its surface in the body.

Three kinds of bioactive particles of 45S5 Bioglass®, synthetic hidroxyapatite and A-W glass ceramic were implanted into 6 mm diameter holes made in the femoral condyles of mature rabbits. Bone-ingrowth rate was measured by means of an image processor for analytical pathology. 45S5 Bioglass® led to the most rapid bone proliferation, and at later periods found to be more resorption than A-W glass ceramic though synthetic hydroxyatatite was not resorbed.

If the calcium phosphate ceramics are the more common bone substitute used in human surgery, the process and kinetics of resorption and bone ingrowth at the expense of the material still not enough determined. The present study is a retrospective study of more than 300 implants of macroporous biphasic calcium phosphate used both in human and in some animal experiments. The bone ingrowth during the first year in both human and animal is limited to 2.5mm from the surface of the implants. The bone ingrowth over 2.5mm depends of the mechanical strain on the implantation site acting on the remodeling of the first bone ingrowth filling the macroporores. The image analysis revealed in cortical site after one year (both in human and animals) 50% of the ceramic was replaced by cortical lamellar bone. In cancellous bone, large differences appeared between animal species and in human, due to differences in cell recruitments.