In order to improve fast osseointegration, to modulate inflammatory response and to avoid biofilm formation, several attempts of surface modifications of titanium alloy in term of surface topography and chemistry have been performed over years, but this is still an open issue. In our research work, a patented chemical treatment was developed and tailored to improve fast osseointegration and to allow further surface functionalization in order to get a multifunctional surface. After the chemical treatment, Ti6Al4V shows a micro and nano-textured surface oxide layer with high density of hydroxyls groups, as summarized Figure 1: it is able to induce apatite precipitation (during soaking in Simulated Body Fluid), high wettability by blood, specific protein adsorption, positive osteoblast response and surface mechanical resistance to implantation friction. Hydroxyl groups exposed by the treated surface also allow binding natural biomolecules such as polyphenols, which can further improve the rate and quality of osseointegration by adding anti-inflammatory, antibacterial and antitumoral effects suitable for implants in critical situations. Polyphenols have the further added value of being a low cost and eco-sustainable product, extractable from byproducts of wine and food industry. On the chemically treated and functionalized samples, the surface characterization was performed using Folin&Ciocalteu test, fluorescence microscopy and XPS analysis in order to check the presence and activity of the grafted biomolecules (polyphenols from red grape pomace and green tea leaves). Cell tests were performed with Kusa A-1 cells highlighting the ability of polyphenols to improve osteoblasts differentiation and deposition of mineralized extracellular matrix. Surface functionalization can also be performed with chitin derived biomolecules to reduce inflammation. With the purpose of obtaining the antibacterial effect, during the chemical treatment a silver precursor can also be added to obtain The results showed that the patented chemical treatment can improve the response of osteoblasts to titanium alloy implants, but is also a promising way to obtain multifunctional surfaces with antibacterial, antioxidant, anti-inflammatory and antitumoral properties that can be the future of orthopedic implants.
To compare the effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament (ACL) reconstruction animal model. Anterior cruciate ligament reconstruction using the plantaris tendon as graft material was performed on both knees of 24 rabbits (48 knees) to mimic ACL reconstruction by two different suspensory fixation devices for graft fixation. For the adjustable fixation device model (Socket group; group S), a 5 mm deep socket was created in the lateral femoral condyle (LFC) of the right knee. For the fixed-loop model (Tunnel group; group T), a femoral tunnel penetrating the LFC was created in the left knee. Animals were sacrificed at four and eight weeks after surgery for histological evaluation and biomechanical testing.Objectives
Methods
The aim of this study was to investigate the effect of granulocyte-colony stimulating factor (G-CSF) on mesenchymal stem cell (MSC) proliferation MSCs from rabbits were cultured in a control medium and medium with G-CSF (low-dose: 4 μg, high-dose: 40 μg). At one, three, and five days after culturing, cells were counted. Differential potential of cultured cells were examined by stimulating them with a osteogenic, adipogenic and chondrogenic medium. A total of 30 rabbits were divided into three groups. The low-dose group (n = 10) received 10 μg/kg of G-CSF daily, the high-dose group (n = 10) received 50 μg/kg daily by subcutaneous injection for three days prior to creating cartilage defects. The control group (n = 10) was administered saline for three days. At 48 hours after the first injection, a 5.2 mm diameter cylindrical osteochondral defect was created in the femoral trochlea. At four and 12 weeks post-operatively, repaired tissue was evaluated macroscopically and microscopically.Objectives
Methods
Recently many implants for ankle arthroplasty have been developed around the world, and especially some mobile bearing, three-component implants have good results. Nevertheless, at our institution fixed two-component, semi-constrained alumina ceramic total ankle arthroplasty (TAA) with TNK Ankle had been performed since 1991 and led to improved outcomes. We report clinical results and in vivo kinematic analyses for TNK Ankle. Between 1991 and 2006, total ankle arthroplasties with TNK Ankle were performed with 102 patients (106 ankles) with osteoarthritis at our institution. There were 91 women and 11 men. The mean age was 69 years and mean follow-up was 5.4 years. These cases were evaluated clinically and radiographically. Besides in vivo kinematics, in TNK Ankle was analysed using 3D-2D model registration technique with fluoroscopic images. Between 2007 and 2008, prospectively ten TAA cases examined with fluoroscopy at postoperative one year.Introduction and aims
Method
We have performed two-component total ankle arthroplasty (TNK ankle) since 1991 and reported good clinical results. However, in vivo kinematics of this implant are not well understood. The purpose of this study was to measure three-dimensional kinematics of total ankle arthroplasty during non-weightbearing and weightbearing activities. Forty-seven patients with a mean age of 71 years were enrolled. Preoperative diagnosis was osteoarthritis in 36 patients and rheumatoid arthritis in 11 patients, and the mean followup was 50 months. Radiographs were taken during nonweightbearing maximal dorsiflexion and plantarflexion, and weightbearing maximal dorsiflexion and plantarflexion. Three-dimensional kinematics were determined using 3D-2D model registration techniques. Anatomic coordinate systems were embedded in the tibial and talar implant models, and they were projected onto the radiographic image. Three-dimensional positions and orientations of the implants were determined by matching the silhouette of the models with the silhouette of the image. From non-weightbearing dorsiflexion to plantarflexion, the talar implant showed 18.1, 0.3, and 1.2 degrees of plantarflexion, inversion, and internal rotation respectively. It also translated 0.8mm posteriorly. There was not significant difference between non-weightbearing and weightbearing kinematics except for the plantarflexion angle (p = 0.007). Posterior hinging, in which tibiotalar contact was seen at only the posterior edge of the talar implant, was observed in 16 patients at either non-weightbearing or weightbearing plantarflexion. There was significantly larger plantarflexion in patients with posterior hinging than patients without hinging (p <
0.001). Nine patients showed anterior hinging at maximum dorsiflexion, and 11 patients showed talar lift-off at maximum plantarflexion. More than half of the patients showed anterior or posterior edge contact, which might cause excessive contact stress and lead to implant failure in the longer term. This phenomenon is due to the difference in rotation axis between the natural ankle and the implant ankle arthroplasty.
Titanium alloys such as Ti-6Al-4V and Ti-6Al-7Nb have been widely used as orthopedic implants such as artificial hip joint, because of their high mechanical strengths and good biocompatibilities. Recently, new kinds of titanium-based alloys free from elements such as V and Al, which are suspicious for cytotoxicities, are being developed. Ti-15Zr-4Ta-4Nb (Ti-15-4-4) is one of such alloys and shows high mechanical strength and corrosion resistance which are comparable to those of the Ti-6Al-4V alloy. In the present study, chemical treatments for providing bone-bonding ability to this alloy were investigated. Apatite-forming ability in a simulated body fluid (SBF) was used as an indication of the bone-bonding ability. Ti-15-4-4 alloy plates 10×10×1 mm3 in size were soaked in 5M-NaOH solution at 60 °C for 24 h, soaked in 100mM-CaCl2 solution at 40 °C for 24 h, heated at 600 °C for 1 h and then soaked in hot water at 80 °C for 24 h. Surface structural changes of the alloy with these treatments were analyzed by a field emission scanning electron microscope (FE-SEM) attached with an energy-dispersive X-ray spectrometer (EDX), Thin-film X-ray diffraction (TF-XRD) and Fourier transform confocal laser Raman spectroscopy (FT-Raman). Scratch resistance of surface layer of the alloy was measured by a thin-film scratch tester. Apatite-forming ability of the specimens was examined by soaking them in SBF for 3 days. Long-term stability of the apatite-forming ability was examined after keeping the specimens in an incubator with relative humidity of 95 % at 80 °C for 1 week. A sodium hydrogen titanate layer about 500 nm in thickness was formed on the surface of the alloy by the NaOH treatment. This specimen formed some amounts of apatite in SBF within 3 days, but its scratch resistance was as low as less than 10 mN. When the NaOH-treated specimen was subsequently heat treated, the sodium hydrogen titanate transformed into sodium titanate to give scratch resistance as high as 92 mN, but lost its apatite-forming ability. When the NaOH-treated specimen was soaked in CaCl2 solution, the sodium hydrogen titanate was isomorphously transformed into calcium hydrogen titanate. Thus treated specimen increased its apatite-forming ability, but its scratch resistance was still low. When the NaOH- and CaCl2-treated specimen was subsequently heat treated, the calcium hydrogen titanate transformed into calcium titanate to give scratch resistance as high as 169 mN. However, its apatite-forming ability was lost. Thus treated specimen was then soaked in hot water. As a result, its apatite-forming ability remarkably increased without decreasing scratch resistance. It showed high apatite-forming ability even after a long-term-stability test. The NaOH-, CaCl2-, heat- and hot-water-treated Ti-15-4-4 alloy is believed to be promising materials for artificial joints, because of its high apatite-forming ability with long-term stability as well as high scratch resistance.
