Bone reaction to a biomimetic third-generation hydroxyapatite coating and new surface treatment for the Symax hip stem

Department of Orthopaedic Surgery, Maastricht University Medical Centre, P O Box 5800, 6202AZ Maastricht, The Netherlands.
The Bone & Joint Journal (Impact Factor: 2.8). 06/2011; 93(6):760-8. DOI: 10.1302/0301-620X.93B6.24986
Source: PubMed

ABSTRACT Four uncemented Symax hip stems were extracted at three weeks and nine, 13 and 32 months, respectively, for reasons other than loosening. The reasons for implant removal were infection in two cases, recurrent dislocation in one and acetabular fracture in one. They were analysed to assess the effect and behaviour of an electrochemically deposited, completely resorbable biomimetic BONIT-hydroxyapatite (HA) coating (proximal part) and a DOTIZE surface treatment (distal part) using qualitative histology, quantitative histomorphometry and scanning electron microscopy (SEM). Early and direct bone-implant bonding with signs of active remodelling of bone and the HA coating were demonstrated by histology and SEM. No loose BONIT-HA particles or delamination of the coating were observed, and there was no inflammation or fibrous interposition at the interface. Histomorphometry showed bone-implant contact varying between 26.5% at three weeks and 83.5% at 13 months at the HA-coated implant surface. The bone density in the area of investigation was between 24.6% at three weeks and 41.1% at 32 months. The DOTIZE surface treatment of the distal part of the stem completely prevented tissue and bone apposition in all cases, thereby optimising proximal stress transfer. The overall features of this implant, in terms of geometry and surface texture, suggest a mechanically stable design with a highly active biomimetic coating, resulting in rapid and extensive osseo-integration, exclusively in the metaphyseal part of the stem. Early remodelling of the HA coating does not seem to have a detrimental effect on short-term bone-implant coupling. There were no adverse effects identified from either the BONIT-HA coating or the DOTIZE surface treatment.

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    ABSTRACT: PhD thesis Doctoral advisors: Prof. dr. G.H.I.M. Walenkamp Dr. T.J.M. Welting Dr. J.J.C. Arts
    1 03/2015; , ISBN: 978-90-9028864-2
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    ABSTRACT: To enhance biocompatibility between the orthopedic implant stem and obsteoblast cells, bone-forming cells, micro-size holes are patterned in Ti plate surface. Initially, the house built laser power stabilization system is applied to the laser micro patterning machine to convince repeatable result. Various pulse widths are irradiated Ti plate and relationship between diameters of patterned holes and pulsed width is derived. Effect of multi pulse is observed and optimal pulse number is considered to avoid heat affected zone. After MG-63 osbeoblast cells are cultured, micro patterned Ti plates are compared with control plates. In SEM image, cells are well aligned and aggregation is observed in both 60, and patterned plates. Finally, free form surface stem model is prepared to test micro hole patterning.
    05/2014; 31(5). DOI:10.7736/KSPE.2014.31.5.375
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    ABSTRACT: Background Since the introduction of uncemented hip implants, there has been a search for the best surface coating to enhance bone apposition in order to improve retention. The surface coating of the different stems varies between products. The aim was to assess the retention force and bone adaption in two differently coated stems in a weight-bearing goat model.Materials and methodsHydroxyapatite (HA) and electrochemically deposited calcium phosphate (CP; Bonit®) on geometrically comparable titanium-based femoral stems were implanted into 12 (CP group) and 35 (HA group) goats. The animal model included physiological loading of the implants for 6 months. The pull-out force of the stems was measured, and bone apposition was microscopically evaluated.ResultsAfter exclusion criteria were applied, the number of available goats was 4 in the CP group and 11 in the HA group. The CP-coated stems had significantly lower retention forces compared with the HA-coated ones after 6 months (CP median 47 N, HA median 1,696 N, p¿=¿0.003). Bone sections revealed a lower degree of bone apposition in the CP-coated stems, with more connective tissue in the bone/implant interface compared with the HA group.Conclusion In this study, HA had better bone apposition and needed greater pull-out force in loaded implants. The application of CP on the loaded titanium surface to enhance the apposition of bone is questioned.
    Journal of Orthopaedic Surgery and Research 08/2014; 9(1):69. DOI:10.1186/s13018-014-0069-4 · 1.58 Impact Factor


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