Effect of six weeks of dura disc and mini-trampoline balance training on postural sway in athletes with functional ankle instability

Lateral ankle sprain (LAS) is one of the most common injuries incurred during sporting activities, and effective rehabilitation programs for this condition are challenging to develop. The purpose of this research was to compare the effect of 6 weeks of balance training on either a mini-trampoline or a dura disc on postural sway and to determine if the mini-trampoline or the dura disc is more effective in improving postural sway. Twenty subjects (11 men, 9 women) with a mean age of 25.4 ± 4.2 years were randomly allocated into a control group, a dura disc training (DT) group, or a mini-trampoline (MT) group. Subjects completed 6 weeks of balance training. Postural sway was measured by subjects performing a single limb stance on a force plate. The disbursement of the center of pressure was obtained from the force plate in the medial-lateral and the anterior-posterior sway path and was subsequently used for pretest and posttest analysis. After the 6-week training intervention, there was a significant (p < 0.05) difference in postural sway between pre- and posttesting for both the MT (pretest = 56.8 ± 20.5 mm, posttest = 33.3 ± 8.5 mm) and DT (pretest = 41.3 ± 2.6 mm, posttest = 27.2 ± 4.8 mm) groups. There was no significant (p > 0.05) difference detected for improvements between the MT and DT groups. These results indicate that not only is the mini-trampoline an effective tool for improving balance after LAS, but it is equally as effective as the dura disc.

Highlights from the tennis Australia heritage collections : mini-exhibition in the player cafe, Rod Laver Arena

Summary : This 'mini-exhibition' arose as an opportunity to showcase recent acquisitions as well as established holdings of significant items of tennis related heritage within the Tennis Australia Heritage Collections. In general, the Collections have two main strengths, and the mini-exhibition was designed to communicate these. The first strength is the ability to show the evolution of tennis technology and practices over time, from the beginnings of modern tennis in the 1860s, to today. This evolution is a result of tennis being influenced by changes in the wider world, such as the Industrial Revolution. The second strength of the Collections is in showing the impact and influence of tennis on society. Many items in the Collections are evidence of the immense and enduring popularity of the sport across the world. The Collections contain many beautiful, rare and fascinating items of decorative arts, fashion, literature and social history which feature tennis as a motif. These items show the reverse influence - the deep impression tennis has made outside of the sport itself.  This mini-exhibition focuses on these two themes. Some displays focus on the first theme. They demonstrate the evolution of tennis racquets, tennis balls, instructional publications and other tennis related equipment over the past century and a half. Other displays focus on the second theme. There are cases which examine tennis' influence upon global popular culture, in board games, fashion and decorative arts from around the world.  The mini-exhibition includes items from the U.s, U.K., Germany, France, Austria, Japan and Australia, demonstrating the global phenomenon that tennis quickly became, and showcasing the international scope of the Collections.  Each case contains text panels listing the objects and their specifications, and panels providing contextual information about the display. The miniexhibition is expected to be on display until November 2009. A case-bycase breakdown of objects, with images and a layout map follows.

Multiple mini-interview : how long is long enough?

Objectives The multiple mini-interview (MMI) overcomes the limitations of the traditional panel interview by multiple sampling to provide improved objectivity and reliability. Reliability of the MMI is affected by number of stations; however, there are few data reporting the influence of interview duration on MMI outcome and reliability. We aimed to determine whether MMI stations can be shortened without affecting applicant rankings or compromising test reliability.
Methods A total of 175 applicants were interviewed and assessed at 10 8-minute stations. Applicants were scored once after 8 minutes at five control stations and twice after 5 minutes and 8 minutes at five experimental stations. Scores at 5 and 8 minutes were compared using t-tests and correlation coefficients. Rankings of applicants based on 5- and 8-minute scores were compared using Spearman's rank order coefficient. The reliability of the MMI was examined for 5- and 8-minute scores using generalisability theory.
Results Mean scores at 5 minutes were lower than mean scores at 8 minutes. Cumulative scores at 5 minutes were also lower. There were highly significant correlations between 5- and 8-minute scores at all experimental stations (0.82–0.91; P < 0.01) and between the cumulative scores at 5 and 8 minutes (0.92; P < 0.01). There was a strong correlation between applicant rankings based on cumulative 5- and 8-minute scores (Spearman's rank order coefficient 0.92). Reliability was not affected.
Conclusions Reducing the duration of MMI stations from 8 to 5 minutes conserves resources with minimal effect on applicant ranking and test reliability.

Finite element modeling of a generic stemless hip implant design in comparison with conventional hip implants

In this study, the finite element modeling and comparison of the stress and strain analyses were carried out for three different structures that are intact bone, stemless implant and stemmed one. Currently proposed stemless design studied here is the generic concept of stemless implant. This generic stemless implant reconstruction was numerically compared to the conventional stemmed implant and also to the intact bone as control solution. Two loading conditions were applied to the most proximal part of the models, while the most distal part was fixed for all degrees of freedom. The models were divided into two regions and studied along two paths of medial and lateral aspect. The results of this study showed that the stemless implant had less deviation from the control solution of the bone in all regions and in both loading conditions, comparing to the large deviation of the stemmed implant from the intact bone. However, it was shown that the fixation of this type of implant and its effect on sub-trochanter region must be carefully considered for designing the final product of any specific design of stemless implant.

Biomechanical properties of porous metal scaffolds as implant materials

The results obtained from this work reveal that high porous titanium foams have fracture mechanical properties that meet and exceed the required properties of both cortical and cancellous bones. With their good biocompatibility, light weight, strong structural integrity and possibility of bone in-growth these foams are suitable for biomedical applications.

Biodegradable Mg-Zr-Ca alloys for bone implant materials

Mg–Zr–Ca alloys were developed for new biodegradable bone implant materials. The microstructure and mechanical property of the Mg–xZr–yCa [x=0·5, 1·0% and y=1·0, 2·0% (wt-% hereafter)] alloys were characterised by optical microscopy, compressive and hardness tests. The in vitro cytotoxicity of the alloys was assessed using osteoblast-like SaOS₂ cells. The corrosion behaviour of these alloys was evaluated by soaking the alloys in simulated body fluid (SBF) and modified minimum essential medium (MMEM). Results indicated that the mechanical properties of the Mg–Zr–Ca are in the range of the mechanical properties of natural bone. The corrosion rate and biocompatibility decreases with the increase in the Ca content in the Mg–Zr–Ca alloys. The solutions of SBF and MMEM with the immersion of the Mg–Zr–Ca alloys show strong alkalisation. The Zr addition to the Mg–Zr–Ca alloys leads to an increase in the corrosion resistance, compressive strength and the ductility of the alloys, and a decrease in the elastic modulus of the Mg–Zr–Ca alloys.

Mg-Zr-Sr alloys as biodegradable implant materials

Novel Mg–Zr–Sr alloys have recently been developed for use as biodegradable implant materials. The Mg–Zr–Sr alloys were prepared by diluting Mg–Zr and Mg–Sr master alloys with pure Mg. The impact of Zr and Sr on the mechanical and biological properties has been thoroughly examined. The microstructures and mechanical properties of the alloys were characterized using optical microscopy, X-ray diffraction and compressive tests. The corrosion resistance was evaluated by electrochemical analysis and hydrogen evolution measurement. The in vitro biocompatibility was assessed using osteoblast-like SaOS2 cells and MTS and haemolysis tests. In vivo bone formation and biodegradability were studied in a rabbit model. The results indicated that both Zr and Sr are excellent candidates for Mg alloying elements in manufacturing biodegradable Mg alloy implants. Zr addition refined the grain size, improved the ductility, smoothed the grain boundaries and enhanced the corrosion resistance of Mg alloys. Sr addition led to an increase in compressive strength, better in vitro biocompatibility, and significantly higher bone formation in vivo. This study demonstrated that Mg–xZr–ySr alloys with x and y ⩽5 wt.% would make excellent biodegradable implant materials for load-bearing applications.

The multiple mini-interview (MMI) in medical student selection

An historical survey of medical student selection identified the multiple mini-interview (MMI) as a promising tool for the assessment of non-cognitive qualities. The Deakin MMI was found to be reliable and useful in predicting performance during the medical course when used with other established selection criteria such as GPA.

Zirconium, calcium, and strontium contents in magnesium based biodegradable alloys modulate the efficiency of implant-induced osseointegration

Development of new biodegradable implants and devices is necessary to meet the increasing needs of regenerative orthopedic procedures. An important consideration while formulating new implant materials is that they should physicochemically and biologically mimic bone-like properties. In earlier studies, we have developed and characterized magnesium based biodegradable alloys, in particular magnesium-zirconium (Mg-Zr) alloys. Here we have reported the biological properties of four Mg-Zr alloys containing different quantities of strontium or calcium. The alloys were implanted in small cavities made in femur bones of New Zealand White rabbits, and the quantitative and qualitative assessments of newly induced bone tissue were carried out. A total of 30 experimental animals, three for each implant type, were studied, and bone induction was assessed by histological, immunohistochemical and radiological methods; cavities in the femurs with no implants and observed for the same period of time were kept as controls. Our results showed that Mg-Zr alloys containing appropriate quantities of strontium were more efficient in inducing good quality mineralized bone than other alloys. Our results have been discussed in the context of physicochemical and biological properties of the alloys, and they could be very useful in determining the nature of future generations of biodegradable orthopedic implants.