Dr Todd Stewart

<h3>Why did I study Medical Engineering?</h3>

<p>I grew up on a small cattle/grain farm in Canada; our garage walls were covered in sketches of farm equipment my father would design/manufacture. I fondly remember misplacing a green coloured action figure and later seeing a remarkably similar coloured bearing used in the baler; since at harvest time, my father could not wait for spare parts he would commonly make them.&nbsp; Incidentally, the polyethylene material was very durable and ideal for bearing applications. Polyethylene is used in medicine for ~70% of all joint replacement implant bearings and is also used as the durable base layer in skis. Not surprisingly I studied Engineering but I always had a strong interest in medicine, delivering calves from the age of 8 years old.&nbsp; We made splints out of cardboard for some calves with weak ankles, much like an inexpensive cast they would eventually fall off by themselves. Thinking back, as they became loose they transferred more and more strain back to the soft tissue structures allowing them to heal slowly but effectively. Raw cardboard, like paper, also degrades quickly in the environment, leaving no waste, and as it was used over the fur biocompatibility was not a significant issue.&nbsp;</p>

<h3>What is my definition of Medical Engineering?</h3>

<p>Medical Engineering involves the Understanding of Interactions of Materials, Design, Mechanics, Dynamics, Fluid Mechanics and Thermodynamics towards the Design of a Medical Device that operates within a biological / patient specific / constantly adapting environment and is governed by a strict regulatory umbrella to prevent harm.</p>

<h3>Why study at Leeds?</h3>

<p>My early research career was spent focussing on the tribology (lubrication, materials, wear, stress) of ceramic on ceramic hip joint replacements. We were the first centre in the world to introduce &lsquo;Micro-separation&rsquo; into pre-clinical testing of implants. This allowed the clinical mechanisms of wear to be replicated in a laboratory environment and paved the way for the development of new ceramic materials [Biolox Delta] that have now replaced 90% of the entire world market.&nbsp;&nbsp; The impact of this research to patients can be seen when looking at the joint registries [www.njrcentre.org.uk] as implant failure rates in patients under the age of 65 that were previously &gt;25% after 10 years are now less than 6%.&nbsp; Research findings such as these are reflected in our teaching and our past students now work at most of the major implant manufacturers with jobs ranging from test engineers, global product directors, and VP&rsquo;s of R&amp;D. Our teaching at undergraduate and postgraduate level is a vital part in translating our knowledge around the world leading to improved products with better patient outcomes.&nbsp;</p>

<h3>What does a Medical Engineer do?</h3>

<p>I am interested in patient motion and how this influences tribology/implant wear.&nbsp; I collaborate with many experts in their fields including medicine (musculoskeletal disease), sports scientists (movement) biological sciences (immunology), and the National Health Service (surgeons, radiologists) to solve current medical problems.&nbsp;&nbsp; Whilst the surgeon has the problem, the engineer is the person whom generally brings the experts together and comes up with a solution/product.&nbsp; For example, we found recently that parts of surgery are very subjective and therefore are time consuming to teach junior doctors.&nbsp; By applying engineering design we manufactured a device to quantify these surgical procedures. This device is now under a clinical trial (being used on patients) and should make clinical results more repeatable improving patient satisfaction and reducing litigation.&nbsp; As an engineering student, you will learn about manufacturing, design, and the specific standards that are applied to medical products. Leeds hosts a <a href="//leedsbrc.nihr.ac.uk/">NiHR Biomedical Research Centre</a>&nbsp;focussed on musculoskeletal research which in turn ensures clinical relevance to our teaching and research.</p>

<p>Tissue Engineering and Cartilage Substitution therapies are growing research areas for our staff in iMBE and we offer teaching modules focussed&nbsp;in these areas. I have partnered with Sports Science to consider the activities that may be completed by patients undergoing these novel treatments. This patient group is younger and more active than a joint replacement group and thus will place a greater demand on their joints.&nbsp; We are studying how the biomechanics of sport changes with age, to then analyse the demands of force and motion on soft tissue structures. The data will be passed to colleagues in biological sciences to help define the pre-clinical testing regimes required for these implants to ensure that the commercial products developed are fit for purpose.&nbsp;</p>