TORU projects

Pickles Knee Study—A prospective imaging study of cruciate retaining and substituting knee replacement, in osteoarthritis and healthy aging

This study aims to examine knee kinematics before and after knee arthroplasty and compare those to the kinematics of knees in a non-arthritic age-matched cohort. In the past the only way of measuring knee kinematics accurately in three planes was to implant RSA beads or use of bone pins These methods are both highly invasive.  In this study we aim to overcome this problem by using an image registration technology developed at TORU by Prof Smith, Assoc Prof Jennie Scarvell and Assoc Prof Mark Pickering by combining 3D CT and 2D video fluoroscopy. This study is unique because, for the first time, knee replacement patients will have their knee kinematics accurately measured both before and after surgery. Recruitment is nearly finished for for both the total knee replacement patients and healthy controls. Volunteers participating range from 20 to 90.

Participants have their knee is scanned while they perform a number of loaded end-of-range activities which will us to see how the knee kinematics change following surgery compared to normal. OA patients are randomised to receive one of three different design of implant. Postoperative testing is being done by the TORU staff in combination with the medical imaging department at The Canberra Hospital. This will make up the bulk of Catherine Galvin’s PhD work.

This study has been funded by the Canberra hospital Private Practice Fund, the University of Canberra and Biomet.

Femoroacetabular Impingement—Outcomes and Imaging

Femoroacetabular impingement (FAI) is characterised by abnormal morphology of the femur and/or acetabulum causing abutment up against each other during hip movements causing injury. FAI is suspected of affecting 10-15% of the population and is thought to be the most common cause of hip pain in young adults and predisposes to osteoarthritis of the hip. Surgery involves trimming the bone that prevents normal movement. Although the aim of the surgery is to change the mechanics of the joint we still know very little about what it actually achieves, and if we can better predict who is going to have a positive result. Correct patient selection is critical for good outcomes.  While we know younger patients, no sign of arthritic changes, shorter duration of symptoms, and lower preoperative pain and functional scores are associated with better outcomes, there is still a group of patients who do not have a good outcome. We are using preoperative imaging in an attempt to predict 1 year iHOT-33 outcomes. Results of this could help improve our ability to select patients who will have a good surgical outcome.

A novel image registration technique is being used to investigate 3D hip kinematics which involves fitting a 3D CT scan to 2D dynamic fluoroscopic images. This study will implement this novel method for investigating hip kinematics in FAI. In conjunction with this project, we are looking at the effect of a 3D planning software on outcomes and complications of FAI. Initial results indicate that the planning software can help reduce complications related to under resection.

iFracture

The Canberra Hospital is a Level 1 Trauma Centre which treats approximately 4000 fracture trauma cases per year. The cost of this service exceeds $55 million per annum with a staff compliment of 12 VMOs, 13 registrars and 6 interns. The treatment data for these patients is curated within the medical record in a way which is difficult/time consuming to retrieve and often inaccurately coded. Further there is no facility to evaluate patient outcomes except in cases of complaint. Therefore the utility of this record for evaluation and research is minimal.

Canberra Hospital is not alone in this. It is well recognized that there is an urgent need for precise, intuitive and clinically meaningful data collection instruments which engage the clinician and inform the administration. It is on this background that iFracture was built.

The longitudinal measurement of patient-reported outcomes is a common currency by which treatment efficacy can be measured across a number of clinical disciplines. By separating the clinician from the outcome assessment there is less bias and more signal accuracy. Administrative instruments are primarily concerned with activity and expenditure-related outcomes which are of secondary interest to the clinicians. The clinicians do not engage comfortably in this process and therefore information is often poorly characterized. However, by collecting clinically meaningful outcomes with the precision that the clinical environment can confer (i.e. complete and accurate coding), there is the added opportunity for administrative records to be optimized for greater precision and accuracy. The data management teams in our organization are very interested in this.

iFracture leverages the internet to allow clinicians and patients to populate the data fields thereby minimising the costs of data management staff and potentially leads to much higher response rates, though this needs to be tested). iFracture has been developed in the ACT over 10 years and offers a powerful solution to many of the data resource issues that are being faced around the world.

iFracture is currently being used by the orthopaedic team at Canberra Hospital. In a nutshell iFracture puts the clinician in the driving seat while supplying data deliverables which are of intense interest to the administrative sector.

Functional Strontium Phosphate Coated Magnesium Alloys for Orthopaedic Use

Fractures are common in Australia and of particular concern with the aging demographic with fractures associated with osteoporosis. The incidence of hip fractures has been projected to increase by 15% every 5 years an estimated 150,000 fractures by 2026 and over 200,000 by 2050. Fracture management frequently requires the implantation of internal fixation devices such as plates, rods and screws in order to stabilise the injury. Traditionally, such implants are made of materials such as stainless steel, titanium or cobalt-chromium alloys. These materials differ substantially to mechanical properties of bone. In particular these materials have a significantly higher tensile properties than bone, producing stress shielding around implants. In addition, concerns have arisen over the release of toxic elements of the existing internal fixation devices and the low bone-tissue-growth rate over their surface. As such, addressing these issues in implant design should consider the development of techniques and materials to promote bone growth for more assured recovery.

This project aims to: (1) Develop a functional strontium (Sr)-release surface upon magnesium-based orthopaedic implants to suppress the rapid degradation rate of Mg; (2) Facilitate new bone formation and ultimately shorten healing process. The project will increase our understanding of the formation mechanisms in Sr-releasing coatings, and determine the critical release rate of Sr to activate bone cell responses (Figure 1). This project addresses two key issues: (1) The inherent high degradation rate of magnesium-based biomaterials for orthopaedic uses; and (2) The low bone growth rate at bone-implant interface.

The knowledge will form a scientific basis to engineer more advanced biomedical materials from the ‘bottom up”, provide the necessary demonstrations, and establish a commercial product protocol. The project is significant for the development of practical, bone-favourable and degradation-inhibiting surfaces for magnesium implants, which are in demand and can bring significant patient benefits.

The project has forged new and important collaborations among Australian National University, Monash University, Canberra Hospital and Signature Orthopaedics Pty Ltd and will provide an output for biomedical technology locally and internationally.

Can bone cells be “programmed” by electromagnetic fields?

In 1979, FDA approved the usage of pulsed electromagnetic fields for the treatment of delayed or non-healing fractures. However, the underlying mechanisms at a cellular level are still not completely understood. Both in vitro and vivo, research findings have revealed that certain electromagnetic fields, can enhance bone fracture healing and bone formation by bone marrow derived osteoblasts. Researchers also found that electromagnetic fields can either accelerate apoptosis, enhance cell proliferation  or suppress cell proliferation  of osteoclasts depending on the strength and frequency of the field. This indicates that electromagnetic fields could be a function generator which manipulates bone cells by different combinations of its physical parameters. If so, can we program bone cells by electromagnetic fields, such as switching the mode of osteoblasts from proliferation to apoptosis and then back to proliferation?  

We developed a system to generate electromagnetic fields within an incubator. This system is capable of switching from static electromagnetic fields to pulsed electromagnetic fields and monitoring the induced magnetic field’s intensity and frequency. We studied osteoblasts and osteoclasts separately under different combinations of induced magnetic field intensity and frequency, as well as osteoblasts and osteoclasts co-culture. Based on the experiment data, we built several mathematical models trying to explain the underlying mechanism of bone cells at cellular level in an explicit formulation.

We found that exposure time of electromagnetic fields on bone cells showed no statistically significant differences. The influence of induced magnetic strength on osteoblast proliferation can be formulated with two postulated parameters of osteoblasts: (1) Adhesive coefficient and; (2) Diffusion coefficient. Alteration of these two parameters by changing induced magnetic intensity, direction and frequency can switch the mode of osteoblasts between proliferation and apoptosis. The osteoclasts have a more complicated mechanism than osteoblasts in electromagnetic fields and future research will attempt to find a targeted parameter to control.

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