Preparation and characterisation of new titanium based alloys for orthopaedic and dental applications

Various types of titanium alloys with high strength and low elastic modulus and, at the same time, vanadium and aluminium free have been developed as surgical biomaterials in recent years. Moreover, porous metals are promising hard tissue implants in orthopaedic and dentistry, where they mimic the porous structure and the low elastic modulus of natural bone. In the present study, new biocompatible Ti-based alloy foams with approximate relative densities of 0.4, in which Sn and Nb were added as alloying metals, were synthesised through powder metallurgy method.
The new alloys were prepared by mechanical alloying and subsequently sintered at high temperature using a vacuum furnace. The characteristics and the processability of the ball milled powders and the new porous titanium-based alloys were characterised by X-ray diffraction, optical
microscopy and scanning electron microscopy .The mechanical properties of the new titanium alloys were examined by Vickers microhardness measurements and compression testing.

Sol-gel derived HA/TiO2 double coatings on Ti scaffolds for orthopaedic applications

Hydroxyapatite/titania (HA/TiO₂) double layers were coated onto Ti scaffolds throughout for orthopaedic applications by sol-gel method. Differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and X-ray diffractometry (XRD) were used for the characterisation of the phase transformations of the dried gels and coated surface structures. Scanning electron microscope (SEM) equipped with energy dispersive spectrometry (EDS) was used for the observation and evaluation of the morphology and phases of the surface layers and for the assessment of the in vitro tests. The in vitro assessments were performed by soaking the HA/TiO₂ double coated samples into the simulated body fluid (SBF) for various periods. The TiO₂ layer was coated by a dipping-coating method at a speed of 12 cm/min, followed by a heat treatment at 600 °C for 20 min. The HA layer was subsequently dipping-coated on the outer surface at the same speed and then heat-treated at difference temperatures. The results indicat that the HA phase begins to crystallize after a heat treatment at 560 °C. The crystallinity increases obviously at 760 °C. SEM observations find no delamination or crack at the interfaces of HA/TiO₂ and TiO₂/Ti. The HA/TiO₂ coated Ti scaffolds displays excellent bone-like apatite forming ability when it is soaked into SBF. Ti scaffolds after HA/TiO₂ double coatings can be anticipated as promising implant materials for orthopaedic applications

Biomimetic porous titanium scaffolds for orthopaedic and dental applications

The development of artificial organs and implants for replacement of injured and diseased hard tissues such as bones, teeth and joints is highly desired in orthopedic surgery. Orthopedic prostheses have shown an enormous success in restoring the function and offering high quality of life to millions of individuals each year. Therefore, it is pertinent for an engineer to set out new approaches to restore the normal function of impaired hard tissues.

Over the last few decades, a large number of metals and applied materials have been developed with significant improvement in various properties in a wide range of medical applications. However, the traditional metallic bone implants are dense and often suffer from the problems of adverse reaction, biomechanical mismatch and lack of adequate space for new bone tissue to grow into the implant. Scientific advancements have been made to fabricate porous scaffolds that mimic the architecture and mechanical properties of natural bone. The porous structure provides necessary framework for the bone cells to grow into the pores and integrate with host tissue, known as osteointegration. The appropriate mechanical properties, in particular, the low elastic modulus mimicking that of bone may minimize or eliminate the stress-shielding problem. Another important approach is to develop biocompatible and corrosion resistant metallic materials to diminish or avoid adverse body reaction. Although numerous types of materials can be involved in this fast developing field, some of them are more widely used in medical applications. Amongst them, titanium and some of its alloys provide many advantages such as excellent biocompatibility, high strength-to-weight ratio, lower elastic modulus, and superior corrosion resistance, required for dental and orthopedic implants. Alloying elements, i.e. Zr, Nb, Ta, Sn, Mo and Si, would lead to superior improvement in properties of titanium for biomedical applications.

New processes have recently been developed to synthesize biomimetic porous titanium scaffolds for bone replacement through powder metallurgy. In particular, the space holder sintering method is capable of adjusting the pore shape, the porosity, and the pore size distribution, notably within the range of 200 to 500 m as required for osteoconductive applications. The present chapter provides a review on the characteristics of porous metal scaffolds used as bone replacement as well as fabrication processes of porous titanium (Ti) scaffolds through a space holder sintering method. Finally, surface modification of the resultant porous Ti scaffolds through a biomimetic chemical technique is reviewed, in order to ensure that the surfaces of the scaffolds fulfill the requirements for biomedical applications.

Particulate-reinforced titanium composites for orthopaedic implants

In the present study, to enhance the strength of porous pure titanium scaffolds with high porosity, new particulate-reinforced Ti-based composites with the addition of biocompatible oxide particles such as TiO₂, SiO₂, ZrO₂ and Nb₂O₅ were prepared using a powder metallurgical method. The strengths of the new particulate-reinforced titanium composites were found to be significantly higher than that of pure titanium with an excellent biocompatibility. SaOS-2 osteoblast-like cells grew and spread well on the surfaces of the new particulate-reinforced titanium composites. The present study illustrated the feasibility of using the particulate-reinforced titanium composites as an orthopaedic implant material.

Cross-sectional analysis of association between socioeconomic status and utilization of primary total hip joint replacements 2006-7 : Australian orthopaedic association national joint replacement registry

Background The utilization of total hip replacement (THR) surgery is rapidly increasing, however few data examine whether these procedures are associated with socioeconomic status (SES) within Australia. This study examined primary THR across SES for both genders for the Barwon Statistical Division (BSD) of Victoria, Australia.

Methods Using the Australian Orthopaedic Association National Joint Replacement Registry data for 2006–7, primary THR with a diagnosis of osteoarthritis (OA) among residents of the BSD was ascertained. The Index of Relative Socioeconomic Disadvantage was used to measure SES; determined by matching residential addresses with Australian Bureau of Statistics census data. The data were categorised into quintiles; quintile 1 indicating the most disadvantaged. Age- and sex-specific rates of primary THR per 1,000 person years were reported for 10-year age bands using the total population at risk.

Results Females accounted for 46.9% of the 642 primary THR performed during 2006–7. THR utilization per 1,000 person years was 1.9 for males and 1.5 for females. The highest utilization of primary THR was observed in those aged 70–79 years (males 6.1, and females 5.4 per 1,000 person years). Overall, the U-shaped pattern of THR across SES gave the appearance of bimodality for both males and females, whereby rates were greater for both the most disadvantaged and least disadvantaged groups.

Conclusions Further work on a larger scale is required to determine whether relationships between SES and THR utilization for the diagnosis of OA is attributable to lifestyle factors related to SES, or alternatively reflects geographic and health system biases. Identifying contributing factors associated with SES may enhance resource planning and enable more effective and focussed preventive strategies for hip OA.

Return to pre-injury health status and function 12 months after hospitalisation for sport and active recreation related orthopaedic injury

Background Hospitalised sport and active recreation injuries can have serious long-term consequences. Despite this, few studies have examined the long-term outcomes of these injuries. The purpose of this study was to establish whether patients hospitalised with orthopaedic sport and active recreation injuries, have returned to their pre-injury levels of health status and function, 12 months post injury and identify factors associated with poor outcomes. The present work was a cohort study with retrospective assessment of pre-injury status and prospective assessment of outcome at 12 months post injury.

Methods Adults with orthopaedic sport and active recreation injuries, captured by the Victorian Orthopaedic Trauma Outcomes Registry were recruited to the study. Pre-injury and 12-month outcomes were assessed using the 36-item Short Form Health Survey (SF-36) and the extended Glasgow Outcome Scale. Differences in pre-injury and post-injury SF-36 scores were examined and demographic, injury, hospital and physical activity variables were assessed for associations with outcome using multivariate linear regression.

Results Of the 324 participants 98% were followed-up at 12 months post injury. At 12 months, participants reported a mean 7.0-point reduction in physical health (95% CI 5.8 to 7.8) and a 2.5-point reduction in mental health (95% CI 1.2 to 3.0), with 58% (95% CI 52.6% to 63.4%) reporting reduced function. Sporting group (p=0.001), Injury Severity Score >15 (p=0.007) and high pre-injury vigorous activity levels (p=0.04), were related to poorer physical health outcomes.

Conclusions At 12 months post injury, most participants reported large reductions in physical health and reduced function. This information is important for furthering our understanding of the burden of sport and active recreation injury and setting priorities for treatment and rehabilitation.

Associations between socioeconomic status and primary total knee joint replacements performed for osteoarthritis across Australia 2003-10: data from the Australian Orthopaedic Association National Joint Replacement Registry

Relatively little is known about the social distribution of total knee joint replacement (TKR) uptake in Australia. We examine associations between socioeconomic status (SES) and TKR performed for diagnosed osteoarthritis 2003-10 for all Australian males and females aged ≥30 yr.

Narratives of recovery from traumatic injury: issues in the nursing care of patients in rehabilitation

Patients who sustain multiple orthopaedic injuries through trauma frequently undergo lengthy rehabilitation. There is little information available about how patients experience hospital rehabilitation programs. In particular, not much is known about factors that inhibit or facilitate the rehabilitation process. This paper describes a qualitative study that explored the rehabilitation  experiences of thirteen patients who had serious orthopaedic injuries.  In-depth interviews revealed issues about good and bad care, the importance of mateship, getting through the day and living with pain. In addition, participants spoke of the impact that the accident and resulting injuries had on their relationships, their experience of loss, how difficult it was to manage everyday issues and the ways in which the accident changed them. The findings of the study have been set into a framework of therapeutic emplotment, a novel way to view the role of the rehabilitation nurse.

Defining the scope of practice of the emergency nurse practitioner role in a metropolitan emergency department

This study examined the emergency nurse practitioner candidate (ENPC) scope of practice in a Victorian emergency department (ED). The emergency nurse practitioner (ENP) role is relatively new in Victoria and the scope of the ENP(C) practice is yet to be defined. International research literature regarding the ENP role has focused on outcomes such as patient satisfaction, waiting times and/or ED length of stay, accuracy and adequacy of documentation, use of radiography, and patient education, health promotion and communication issues. A prospective exploratory design was used to conduct this cohort study. There were 476 ENPC-managed patients between 14 July 2004 and 31 March 2005 with an average age of 29 years. The majority (77.2%) of ENPC-managed patients were discharged from the ED. The majority of the ENPC time was devoted to clinical practice (55%) and development of clinical practice guidelines (25%). Of patients managed by the ENPC, 49.6% required medications, 51% required diagnostic imaging and 8.6% required pathology testing during their ED stay. The most common discharge referrals were made to local medical officers (73.5%) and the most common referrals made for patients requiring admission were made to the plastic surgery (37.3%) and orthopaedic (35.5%) units. Extensions to the current scope of emergency nursing practice are pivotal to effective management of specific patient groups by ENP. The ENP model of care is an important strategy for the management of increased service demands in Victoria; however, little is known about the scope of the ENPC practice and many outcomes of the ENP care are yet to be defined. Further research to better understand the relationships between ENP outcomes is required if the contribution that ENPs make to emergency care is to be accurately quantified.