Significance of Nano- and Microtopography for Cell-Surface Interactions in Orthopaedic Implants

Cell-surface interactions play a crucial role for biomaterial application in orthopaedics. It is evident that not only the chemical composition of solid substances influence cellular adherence, migration, proliferation and differentiation but also the surface topography of a biomaterial. The progressive application of nanostructured surfaces in medicine has gained increasing interest to improve the cytocompatibility and osteointegration of orthopaedic implants. Therefore, the understanding of cell-surface interactions is of major interest for these substances. In this review, we elucidate the principle mechanisms of nano- and microscale cell-surface interactions in vitro for different cell types onto typical orthopaedic biomaterials such as titanium (Ti), cobalt-chrome-molybdenum (CoCrMo) alloys, stainless steel (SS), as well as synthetic polymers (UHMWPE, XLPE, PEEK, PLLA). In addition, effects of nano- and microscaled particles and their significance in orthopaedics were reviewed. The significance for the cytocompatibility of nanobiomaterials is discussed critically

Spinning around or stagnation - what do osteoblasts and chondroblasts really like?

<p>Abstract</p> <p>Objective</p> <p>The influcence of cytomechanical forces in cellular migration, proliferation and differentation of mesenchymal stem cells (MSCs) is still poorly understood in detail.</p> <p>Methods</p> <p>Human MSCs were isolated and cultivated onto the surface of a 3 × 3 mm porcine collagen I/III carrier. After incubation, cell cultures were transfered to the different cutures systems: regular static tissue flasks (group I), spinner flasks (group II) and rotating wall vessels (group III). Following standard protocols cells were stimulated lineage specific towards the osteogenic and chondrogenic lines. To evaluate the effects of applied cytomechanical forces towards cellular differentiation distinct parameters were measured (morphology, antigen and antigen expression) after a total cultivation period of 21 days in vitro.</p> <p>Results</p> <p>Depending on the cultivation technique we found significant differences in both gen and protein expression.</p> <p>Conclusion</p> <p>Cytomechanical forces with rotational components strongly influence the osteogenic and chondrogenic differentiation.</p

Migration pattern of cementless press fit cups in the presence of stabilizing screws in total hip arthroplasty

The aim of this study was to evaluate the initial acetabular implant stability and late acetabular implant migration in press fit cups combined with screw fixation of the acetabular component in order to answer the question whether screws are necessary for the fixation of the acetabular component in cementless primary total hip arthroplasty. One hundred and seven hips were available for follow-up after primary THA using a cementless, porous-coated acetabular component. A total of 631 standardized radiographs were analyzed digitally by the "single-film-x-ray-analysis" method (EBRA). One hundred 'and one (94.4%) acetabular components did not show significant migration of more than 1 mm. Six (5.6%) implants showed migration of more than 1 mm. Statistical analysis did not reveal preoperative patterns that would identify predictors for future migration. Our findings suggest that the use of screw fixation for cementless porous- coated acetabular components for primary THA does not prevent cup migration

Non-Hematopoietic Essential Functions of Bone Marrow Cells: A Review of Scientific and Clinical Literature and Rationale for Treating Bone Defects.

Hematopoiesis as the only essential function of bone marrow cells has been challenged for several decades through basic science (in vitro and in vivo) and clinical data. Such work has shed light on two other essential functions of bone marrow cells: osteopoiesis and angio-genesis/vasculogenesis. Clinical utility of autologous concentrated bone marrow aspirate (CBMA) has demonstrated both safety and efficacy in treating bone defects. Moreover, CBMA has been shown to be comparable to the gold standard of iliac crest bone graft (ICBG), or autograft, with regard to being osteogenic and osteoinductive. ICBG is not considered an advanced therapy medicinal product (ATMP), but CBMA may become regulated as an ATMP. The European Medicines Agency Committee for Advanced Therapies (EMA:CAT) has issued a reflection paper (20 June 2014) in which reversal of the 2013 ruling that CBMA is a non-ATMP has been proposed. We review bone marrow cell involvement in osteopoiesis and angiogenesis/vasculogenesis to examine EMA:CAT 2013 decision to use CBMA for treatment of osteonecrosis (e.g, of the femoral head) should be considered a non-ATMP. This paper is intended to provide discussion on the 20 June 2014 reflection paper by reviewing two non-hematopoietic essential functions of bone marrow cells. Additionally, we provide clinical and scientific rationale for treating osteonecrosis with CBMA