Laser-engineered net shaping (LENS) of coated surfaces can overcome the limitations of conventional coating technologies. We compared the The Objectives
Methods
The plasma spray(TPS) has come to be accepted as one of the more reliable methods of porous coating of prosthesis, it is not without some technical limitations, especially with regard to precise modulation of pore size, porosity, and roughness. However, the plasma spray(TPS) not often but seriously faces problems such as bead detachment related poor osteointegration, weakness of metal strength and high manufacturing costs in addition to its various technical limitations. Currently, there has been much research into developing a more economical and effective method for porous coating of the prosthesis. In light of such demand, 3D Printing with DMT Technology has been introduced into the field of surface treatment of prosthesis with promising expectations. DMT technology -an additive fabrication process that uses high-power laser and various metal powders in order to produce fully dense and geometrically complex metal components, molds, and dies directly from digital CAD model data of 3D subjects aims to help overcome many of the problems associated with plasma spray and thereby open a new chapter of endless possibilities for coating technology. In this study, the porous coating specimen using 3-D DMT metal printing was characterized morphologically as well as biomechanically, in terms of 1) pore size 2) porosity 3) tensile strength 4) shear strength 5) roughness respectively. The biological cyto-compatibility was evaluated by culturing human osteoblast-like cells(Saos-2: ATCC HTB85) on the surface of round discs with porous coating to demonstrate the biological influence on the porosity of the specimens with different surface treatment for comparative analysis. The evaluation was accompanied by assessment of cell proliferation and morphology with arrangement of actin filament and expression of adhesion molecule with αvβ3 integrin. While 3-D DMT coating specimen showed relatively regular porosity in the range of 150–500µm with the increase of porosity about 83%, the mechanical behavior remarkably improved, compared to TPS: shear strength 13%, fatigue failure 30%, roughness 16%, respectively. Also worth noting, the tensile strength was unable to be measured because the glue for test had fallen off. (Fig. 1) There is no transitional zone underneath the porous coating layer.(Fig. 2) From the aspect of biocompatibility, 3-D coating showed better cell attachment, spreading of cytoskeleton, cell proliferation, and expression of osteogenic markers than TPS, even if not significantly.(Fig. 3) Additionally, cell migration assay was performed with double chamber study, and gene expression was evaluated by measuring alkaline phosphatase(ALP) levels and analyzing mRNA expression for ostepontin(OPG) and osteocalcin(OC). In conclusion, the study reinforces the popular stance that the implementation of 3-D DMT could open up new possibilities for coating technology and form a new chapter in the history of prosthesis development.
To minimize leg length discrepancies (LLD), preoperative measures are taken using the PACS; the head center to the proximal end of the lesser trochanter distance (HLD) of the opposite side of the operating limb are calculated, while during operation, the modular neck selection is adapted to equal the opposing limb's length. The purpose of this study was to see whether the HLD method would show far less occurrences of LLD, in comparison to the conventional method(preoperative templating and shuck test). 349 (412 hips) patients who had undergone THRA were divided into two groups based upon which methods they had used to equalize limb length during operation: (1) HLD method, and (2) conventional methods. Six months after surgery, using the PACS system, LLD's of the two groups were compared.Introduction
Method
Ion implantation with a high kinetic energy has advantages in controlling the size and distribution of coating materials, helping to overcome the limitations of conventional methods. This method resulted in uniformly and homogeneously distributed in a CoCr alloy even without a further annealing process. The study was to investigate the wear rate of UHMWPE on CoCr alloy for metal head by plasma immersion ion implantation (PIII) treatments. Commercially CoCr alloy (ISO 5832-12, ASTM F1537, alloy 1) were used as the substrate. PIII surface treatments were performed in a high-vacuum chamber with a radio frequency plasma source. We divided with two groups: PIII CoCr alloy, CoCr ally as control. Wear amount of UHMWPE (ISO 5834-2, ASTM F648, Type 1) on CoCr alloy specimens (three samples per group) was evaluated after 500,000 and 1,000,000 cycles using pin-on disk wear tester. After test, surface morthology was examined by SEM, and surface roughness was calculated in both groups.Purpose
MATERIALS AND METHODS
Inspired by mussel-adhesion phenomena in nature can integrate inorganic hydroxyapatite crystals within versatile materials. This is a simple, aqueous, two-step functionalization approach, called polydopamine-assisted hydroxyapatite formation (pHAF), that consists of i) the chemical activation of material surfaces via polydopamine coating and ii) the growth of hydroxyapatite in a simulated body fluid (SBF). We presumed polydopamine coating on the surface of titanium alloy would improve the ability of cementless stems to osseointegrate. We therefore compared the in vitro ability of cells to adhere to polydopamine coated Ti alloy and machined Ti alloy. We performed energy-dispersive x-ray spectroscopy and scanned electron microscopy investigations to assess the structure and morphology of the surfaces. Biologic and morphologic responses to osteoblast cell lines (MC3T-E1) were then examined by measuring cell proliferation, cell differentiation (alkaline phosphatase activity), and avb3 integrin.Introduction
Method
