Early Fixation of Cobalt-Chromium Based Alloy Surgical Implants to Bone Using a Tissue-engineering Approach

Abstract

To establish the methods of demonstrating early fixation of metal implants to bone, one side of a Cobalt-Chromium (CoCr) based alloy implant surface was seeded with rabbit marrow mesenchymal cells and the other side was left unseeded. The mesenchymal cells were further cultured in the presence of ascorbic acid, β-glycerophosphate and dexamethasone, resulting in the appearance of osteoblasts and bone matrix on the implant surface. Thus, we succeeded in generating tissue-engineered bone on one side of the CoCr implant. The CoCr implants were then implanted in rabbit bone defects. Three weeks after the implantation, evaluations of mechanical test, undecalcified histological section and electron microscope analysis were performed. Histological and electron microscope images of the tissue engineered surface exhibited abundant new bone formation. However, newly formed bone tissue was difficult to detect on the side without cell seeding. In the mechanical test, the mean values of pull-out forces were 77.15 N and 44.94 N for the tissue-engineered and non-cell-seeded surfaces, respectively. These findings indicate early bone fixation of the tissue-engineered CoCr surface just three weeks after implantation.

Osteogenic Matrix Cell Sheet Transplantation Enhances Early Tendon Graft to Bone Tunnel Healing in Rabbits

“…Briefly, primary bone marrow cells aspirated from the humeral heads of rabbits were cultured in regular medium consisting of Earle's Minimal Essential Medium (Nacalai Tesque, Kyoto, Japan) with 15% fetal bovine serum (JRH Bioscience, Lenexa, KS) and antibiotics (100 U/mL penicillin and 100  μ g/mL streptomycin; Nacalai Tesque) for 2 weeks [18, 19]. After reaching confluence, the cells were released and seeded at 1 × 10 4 cells/cm 2 onto 10 cm culture dishes (Falcon, BD Biosciences, Franklin Lakes, NJ) in the above medium supplemented with 10 nM dexamethasone (Dex; Sigma, St. Louis, MO) and 82  μ g/mL ascorbic acid phosphate (Asap; L-ascorbic acid phosphate magnesium salt n -hydrate; Wako Pure Chemical Industrials, Kyoto, Japan) for 14 days.…”

“…The proximal tibiae were harvested 3 weeks after the operation [11, 19]. The tibiae for histological evaluation were fixed in 10% neutral buffered formalin, decalcified in EDTA solution, and embedded in paraffin.…”

“…At 3 weeks after the operation [11, 19], 10 rabbits were sacrificed for biomechanical tensile tests. After harvesting proximal tibiae, all soft tissues except the EDL were removed.…”

Mesenchymal stem cells in the aseptic loosening of total joint replacements

“…Transplanted MSCs significantly improved the implant integration evident by increased bone formation and enhanced bone/implant contact area. Ogawa et al seeded rabbit MSCs on the surface of CoCr implant and differentiated them into bone forming osteoblasts in vitro prior to implantation in vivo . Implant integration to bone was significantly enhanced as evaluated by histomorphometry and mechanical testing of the bone implant interface.…”

Application of Bioreactor Concept and Modeling Techniques to Bone Regeneration and Augmentation Treatments

“…However, it has been demonstrated that both osteoblast activity and blood vessel formation are improved by the addition of this platelet concentrate, possibly leading to better bone quality, attributing these characteristics to the early release of GFs from the platelet granules during platelet interactions with agents such as collagen or thrombin within the first days after supply. The advantage is that the autologous nature of PRP causes no risk of allergies or tissue versus host reactions [98] in contrast with other osteoinductive agents. Additionally, it has been demonstrated that each of the GFs contained in the platelet granules may produce different positive effects on new bone formation [99].…”