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Paul studied for a BEng in Mechanical Engineering at the University of Birmingham, graduating in 1999. He then moved on to complete an MSc in Engineering Design and Its Management at the University of Huddersfield, graduating in 2000.
As a direct result of his MSc work Paul went to work for DePuy International Ltd, a leading orthopaedics manufacturing company and part of the Johnson and Johnson group of companies. His work there led on to a PhD with the Surface Metrology Group at the Centre for Precision Technologies under the supervision of Prof Liam Blunt and Prof Jane Jiang with most of the project work completed at DePuy in Leeds and leading to graduation in 2008. Paul's PhD work involved the development of methods for the simulation and characterisation of wear in orthopaedic knee replacement joints.
In 2007 Paul was taken on as a Research Fellow at the Centre for Precision Technologies and is now a Senior Research Fellow within the EPSRC Centre for Innovative Manufacturing in Advanced Metrology with involvement in interdisciplinary research groups in such diverse areas as Arms and Armour and Skin Interface Science.
His current research interests include measurement of clinical wear in retrieved bearings, three-dimensional ballistics measurement, developing metrology techniques for medical applications, metrology for archaeology, fusion of metrological data and industrial metrology training.
Outside of his research Paul has keen interests in music and sport, and is a long suffering supporter of Barnsley FC.
Paul is a Senior Research Fellow in the EPSRC Centre for Innovative Manufacturing in Advanced Metrology and his main research interests lie in the application of metrology to assess functionality of components and surfaces. His current projects are in the area of forensic metrology for ballistics, characterization of retrieved orthopaedic implants, application of metrology to healthcare product development and industrial metrology education. The majority of Paul’s work is in the area of form measurement, encompassing the measurement and specification of geometry and surface characterization.
Paul has recently received a research grant as part of an EU project involving leading European universities and national institute partners to create a training course on the subject of measurement uncertainty. He is also the registered UK tutor for one EU wide metrology education ‘driving licence’ known as ‘CMTrain’ which was developed out of a European Commission, Leonardo da Vinci Programme project known as “EUKOM”.
The characterisation of orthopaedic implants, retrieved from patients at revision and the subsequent determination of their performance in vivo is the only way to truly understand their life in service and ultimately improve their longevity. Currently there is no standardized way of determining this accurately and Paul’s research in this area is to this end, using traceable metrology to fully map bearing surface and taper junction geometry and wear whilst highlighting measurement best practice encapsulating factors such as measurement uncertainty. Furthermore Paul is currently working with the London Implant Retrieval Centre and colleagues at Imperial College and University College London to develop a best practice method for determining the geometry of retrieved implants and determining their ultimate mode of failure.
The overall aim of this research is to produce an overarching measurement methodology that is established from first principles and can be universally applied to the measurement of retrieved hip replacements. This is the first study to join biological and engineering analysis through use of best practice techniques to understand the performance of a biomechanical joint replacement by building a correlation between blood ion levels and material loss. The furthering of understanding in this area has great implications for society through the ability to close the loop of understanding and develop more effective, longer lasting joint replacements.
Paul, with colleague Dr Leigh Fleming of the EPSRC CIMAM is leading a consortium to promote and publish good practice in the surface measurement of orthopaedic implants.
Lou, S., Jiang, X., Bills, P. and Scott, P. (2013) ‘Defining True Tribological Contact Through Application of the Morphological Method to Surface Topography’ Tribology Letters , 50 (2), pp. 185-193. ISSN 1023-8883
Racasan, R., Bills, P., Blunt, L. and Xiao, S. (2013) ‘Measurement of material loss’. In: Are Modular Hip Junctions An Issue?, 29th April 2013, The Royal Society of Medicine, London
Bills, P., Blunt, L., Racasan, R., Skinner, J. and Hart, A. (2013) ‘Accurate determination of material loss at the taper interface of retrieved metal-on-metal hip replacements’. In: 19th International Conference on Wear of Materials, 14-18th April 2013, Portland, Oregon USA
Hart, A., Matthies, A., Bills, P., Racasan, R., Blunn, G., Blunt, L. and Skinner, J. (2013) ‘The taper junction contributes one third of the total volumetric material loss in large diameter metal-on-metal hip arthroplasties’. In: American Academy of Orthopaedic Surgeons Annual Meeting, March 19-23 2013, Chicago, IL, USA
Hart, A., Matthies, A., Racasan, R., Bills, P., Panagiotidou, A., Blunt, L., Blunn, G. and Skinner, J. (2012) ‘Taper wear contributes only a third of the total volumetirc material loss in large head metal on metal hip replacement’. In: British Orthopaedic Research Society Annual Meeting, September 24th-25th 2012, London, UK
Matthies, A., Racasan, R., Bills, P., Panagiotidou, A., Blunt, L., Skinner, J., Blunn, G. and Hart, A. (2012) ‘Corrosion is the main mechanism of material loss at the taper junction of large head metal on metal hip replacements’. In: British Orthopaedic Society Annual Meeting, September 24th-25th 2012, London, UK
Bills, P., Racasan, R., Hart, A., Skinner, J., Jiang, X. and Blunt, L. (2012) ‘Using metrology to bridge the gap in understanding between engineering and biological failure: the case of metal-on-metal hip replacements’. In: 1st Annual EPSRC Manufacturing the Future Conference, 19th-20th September 2012, Loughborough, UK
Bills, P., Racasan, R., Hart, A., Skinner, J. and Blunt, L. (2012) ‘Accurate determination of clinical wear in retrieved metal-on-metal hip replacement joints’. In: Euro-Mediterranean Conference on Bioengineering and Biomaterials, 4th-6th July 2012, Fes, Morocco
Bills, P. and Blunt, L. (2012) ‘Measurement of Bearing Surfaces’. In: Metal-on-Metal Hip Replacements: Re-solving The Uncertainties, 28th May 2012, Royal College of Surgeons of England, London
Blunt, L., Bills, P. and Racasan, R. (2012) ‘Measurement of Tapers’. In: Metal-on-Metal Hip Replacements: Re-solving The Uncertainties, 28th May 2012, Royal College of Surgeons of England, London
Bills, P., Racasan, R., Skinner, J., Hart, A. and Blunt, L. (2012) ‘Effect of Uncertainty on Wear Measurement of Metal-on-metal Total Hip Replacement Components’. In: ASTM Symposium on Metal-on-Metal Total hip Replacement Devices, 8th May 2012, Phoenix, AZ, USA
Hexter, A., Blunn, G., Bills, P., Panagiotidou, A., Matthies, A., Skinner, J. and Hart, A. (2012) ‘The Definition of Taper Failure in Metal-On-Metal Modular Total Hip Replacement’. In: ASTM Symposium on Metal-on-Metal Total Hip Replacement Devices, 8th May 2012, Phoenix, AZ, USA
Bills, P., Lou, S. and Jiang, X. (2012) ‘Development of morphological filtering method for specification and characterisation of hip replacement taper junctions’. In: 12th International Conference of the European Society for Precision Engineering and Nanotechnology, 4th-8th June 2012, Stockholm, Sweden
Bills, P., Racasan, R., Underwood, R., Cann, P., Skinner, J., Hart, A., Jiang, X. and Blunt, L. (2012) ‘Volumetric wear assessment of retrieved metal-on-metal hip prostheses and the impact of measurement uncertainty’ Wear , 274, pp. 212-219. ISSN 0043-1648
Bills, P. and Blunt, L. (2011) ‘Wear Measurement of MoM Hips’. In: Orthopaedic Research UK Meeting Metal-on-Metal Hip Replacements: Solving The Uncertainties, 14th December 2011, Royal College of Surgeons, London, UK
Bills, P., Underwood, R., Sayles, R., Cann, P., Hart, A., Blunt, L. and Jiang, X. (2011) ‘Taper Wear in Large Head Metal-on-Metal Hips’. In: International Conference on BioTribology 2011, 18th - 21th September 2011, Imperial College
Zeng, S., Blunt, L., Jiang, X. and Bills, P. (2010) ‘Investigation of the material removal characteristic for polishing CoCr alloy’. In: Future Technologies in Computing and Engineering: Proceedings of Computing and Engineering Annual Researchers' Conference 2010: CEARC10. Huddersfield: University of Huddersfield. pp. 177-182. ISBN 9781862180932
Bills, P., Underwood, R., Cann, P., Hart, A., Jiang, X. and Blunt, L. (2010) ‘What is required to measure the wear of explanted metal-on-metal hips?’. In: British Orthopaedic Research Society Annual Meeting, 12th-13th July 2010, Cardiff University
Bills, P. and Cunningham, J. (2009) ‘Determination of clinical wear in retrieved total hip replacement joints using shadowgraph and co-ordinate measurement methods’. In: Internatiional Conference on Bioengineering and Biomaterials, 18 - 20 March 2009, ENSAM, Meknes, Morocco
Blunt, L., Bills, P., Jiang, X., Hardacker, C. and Chakrararty, G. (2009) ‘The role of tribology and metrology in the latest development of bio-materials’ Wear , 266 (3-4), pp. 424-431. ISSN 0043-1648
Blunt, L., Bills, P., Jiang, X. and Chakrabarty, G. (2008) ‘Improvement in the assessment of wear of total knee replacements using coordinate-measuring machine techniques’ Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine , 222 (3), pp. 309-318. ISSN 0954-4119
Bills, P., Blunt, L. and Chakrabarty, G. (2008) ‘Developing techniques for the dimensional assessment of true clinical wear in retrieved total joint replacements’. In: Materials for Improved Wear Resistance of Total Artificial Joints. Eibar, Spain: Tekniker. pp. 109-118. ISBN 978-84-932064-4-4
Bills, P., Blunt, L. and Jiang, X. (2007) ‘Development of a technique for accurately determining clinical wear in explanted total hip replacements’ Wear , 263 (7-12), pp. 1133-1137. ISSN 0043-1648
Bills, P (2007) The development of a geometric methodology for the determination of volumetric wear in total joint replacements & development of a total knee replacement joint using new and novel measurement techniques. Doctoral thesis, University of Huddersfield.
Bills, P., Blunt, L. and Jiang, X. (2006) ‘A metrology solution for determination of form deviation and wear in orthopaedic joint replacements’. In: 33rd Leeds-Lyon Symposium on Tribology, Tuesday 12th - Friday 15th September 2006, Trinity and all Saints College, Leeds
Blunt, L., Bills, P., Hardaker, C. and Pantelis, C. (2006) ‘The use of CMM techniques to assess the wear of total knee replacements ’. In: Nodtrib 2006 - The 12th Nordic Symposium on Tribology. Lyngby, Denmark: DTU Tryk. p. 61. ISBN 87-90416-17-1
Bills, P., Brown, L., Jiang, X. and Blunt, L. (2005) ‘A metrology solution for the orthopaedic industry’ Journal of Physics , Series 13, pp. 316-319. ISSN 1742-6596
Bills, P., Blunt, L. and Hardaker, C. (2004) ‘The use of CMM techniques to assess the functionality of total knee replacements’. In: 8th International Symposium on Measurement and Quality Control in Production. Dusseldorf, Germany: VDI Verlag GmbH. pp. 73-80. ISBN 3-18-091860-8
Paul is a reviewer for the following journals: Wear, Tribology International, Precision Engineering