Orthopaedic Implant Technology: Biomaterials from Past to Future

Department of Orthopaedic Surgery, National University Health System, Singapore.
Annals of the Academy of Medicine, Singapore (Impact Factor: 1.15). 05/2011; 40(5):237-44.
Source: PubMed


Orthopaedic implant technology is heavily based on the development and use of biomaterials. These are non-living materials (e.g. metals, polymers and ceramics) that are introduced into the human body as constituents of implants that fulfill or replace some important function. Examples would be prosthetic joint replacements and fracture fixation implants. For orthopaedic biomaterials to succeed in their desired functions and outcomes in the body, a number of factors need to be considered. The most obvious mechanical properties of the implants are that they need to suit their intended function, and various classes and types of biomaterials have been developed and characterised for use in different implant components depending on their demands. Less well understood but no less important are the interactions that occur between the constituent biomaterials and the living cells and tissues, both of the human host as well as pathogens such as bacteria. Biomaterials used for orthopaedic applications are generally considered to be biocompatible. However, adverse effects arising from interactions at the implant interface can result in various modes of implant failure, such as aseptic loosening and implant infection. This review paper uses the illustrative example of total hip replacement (which has been called the operation of the century) to highlight key points in the evolution of orthopaedic biomaterials. It will also examine research strategies that seek to address some of the major problems that orthopaedic implant surgery are facing today.

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    • "Recently, regenerative medicine has perfectly aided biomedical sciences by introducing new avenues for efficient tissue reconstruction. Moreover, this has influenced lot of attention towards biomaterial science thereby influencing tissue engineering offering new and promising alternatives for existing traditional implants [1], prostheses in orthopedics [2], dentistry [3] and organ and tissue replacement [4]. Further, among various existing biomaterials such as bovine bone, recent trend shows that calcium phosphate is often used as bone substitute mainly due to its chemical similarities with that of mineral component of bones and hard tissues, therefore, proved to improve bone healing in rabbit calvaria [5]. "
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    ABSTRACT: Tricalcium phosphate is the most commonly used biomaterial because of its good biocompatibility. However, its poor mechanical strength under complex stress and powder-like appearance hinder its application. The use of a composite biomaterial which maintains a fine balance between excellent mechanical properties and biocompatibility can be a solution to this problem. In the present study, we aimed to fabricate porous composite scaffolds via phase-inversion technique without using any additional toxic chemicals which can interfere with their biocompatibility. The composite materials fabricated of poly (vinylidene fluoride) and tricalcium phosphates were prepared, using polyvinyl pyrrolidone as a dispersant. The resulting scaffolds were characterized by using attenuated total reflection infrared spectroscopy (FTIR-ATR), scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and universal tensile strength (UTM) analysis. The composites showed well blend of materials and internal porous structures. The XRD results indicated a mixture of α and β-phases due to successful incorporation of tricalcium phosphate in polymer blends, thereby, exhibiting a crystalline structure. The fabricated composites showed an efficient thermal stability at around 400 °C. The tensile strength of scaffolds increased from 140±1.6 to 148±2.2 g/mm2, which makes the composite scaffold potential candidate for hard tissue applications.
    Full-text · Article · Feb 2015 · Ceramics International
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    • "The most common is total hip joint replacement but similar surgical procedures are performed on other joints such as, the knee, shoulder, and elbow. On the world scale, approximately one million artificial hips are implanted annually [1] [2] [3] [4] [5]. "
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    ABSTRACT: Abstract Background The main objective of the present study was to investigate chemical composition and possible cyto/genotoxic potential of several medical implant materials commonly used in total hip joint replacement. Methods and Results For that purpose medical implant metal alloy (Ti6Al4V and CoCrMo) and high density polyethylene particles were analyzed by energy dispersive X-ray spectrometry which showed that none of the elements identified deviate from the chemical composition defined by appropriate ISO standard. Toxicological characterization was done on human lymphocytes, as sensitive biomarkers of exposure, using multi-biomarker approach, showing that the tested materials were non-cyto/genotoxic as determined by the comet and cytokinesis-block micronucleus (CBMN) assay. Although orthopaedic implants proved to be non-cyto/genotoxic, in tested concentration (10 μg/ml) there is a constant need for monitoring of patients that have implanted artificial hips or other joints, to minimizing the risks of any unwanted health effects. Particle morphology was found (by using scanning electron and optical microscope) as flat, sharp-edged, irregularly shaped fibre-like grains with the mean particle size less than 10 μm; this corresponds to the so-called “submicron wear”. The very large surface area per wear volume enables high reactivity with surrounding media and cellular elements. General significance The fractal and multifractal analyses, performed in order to evaluate the degree of particles shape effect, showed that the fractal and multifractal terms are related to the “remnant” level of the particles toxicity especially with the cell viability (trypan blue method) and total number of nucleoplasmic bridges and nuclear buds as CBMN assay parameters.
    Full-text · Article · Jan 2014 · Biochimica et Biophysica Acta (BBA) - General Subjects
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    • "Growth factors (GFs) are expressed during different phases of tissue healing and are therefore a key element in promoting tissue regeneration [4]; in fact, GFs carried on orthopaedic devices have been reported to enhance osteoblastic activity and favour implant integration [5,6]. "
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    ABSTRACT: Several bone implants are applied in clinical practice, but none meets the requirements of an ideal implant. Platelet-rich plasma (PRP) is an easy and inexpensive way to obtain growth factors in physiologic proportions that might favour the regenerative process. The aim of this review is to analyse clinical studies in order to investigate the role of PRP in favouring bone integration of graft, graft substitutes, or implants, and to identify the materials for which the additional use of PRP might be associated with superior osseo- and soft tissues integration. A search on PubMed database was performed considering the literature from 2000 to 2012, using the following string: ("Bone Substitutes"[Mesh] OR "Bone Transplantation"[Mesh] OR "Bone Regeneration"[Mesh] OR "Osseointegration"[Mesh]) AND ("Blood Platelets"[Mesh] OR "Platelet-Rich Plasma"[Mesh]). After abstracts screening, the full-texts of selected papers were analyzed and the papers found from the reference lists were also considered. The search focused on clinical applications documented in studies in the English language: levels of evidence included in the literature analysis were I, II and III. Literature analysis showed 83 papers that fulfilled the inclusion criteria: 26 randomized controlled trials (RCT), 14 comparative studies, 29 case series, and 14 case reports. Several implant materials were identified: 24 papers on autologous bone, 6 on freeze-dried bone allograft (FDBA), 16 on bovine porous bone mineral (BPBM), 9 on beta-tricalcium phosphate (beta-TCP), 4 on hydroxyapatite (HA), 2 on titanium (Ti), 1 on natural coral, 1 on collagen sponge, 1 on medical-grade calcium sulphate hemihydrate (MGCSH), 1 on bioactive glass (BG) and 18 on a combination of biomaterials. Only 4 papers were related to the orthopaedic field, whereas the majority belonged to clinical applications in oral/maxillofacial surgery. The systematic research showed a growing interest in this approach for bone implant integration, with an increasing number of studies published over time. However, knowledge on this topic is still preliminary, with the presence mainly of low quality studies. Many aspects still have to be understood, such as the biomaterials that can benefit most from PRP and the best protocol for PRP both for production and application.
    Full-text · Article · Nov 2013 · BMC Musculoskeletal Disorders
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