Research at the heart of the Implant Development Centre
At the heart of the Implant Development Centre (IDC), one of the technology hubs for Smith & Nephew, is the desire to advance the understanding of how implants perform in vivo in hips.
It all started back during the design conception of the BIRMINGHAM HIP™ Resurfacing system, which was developed based on forensic analysis of retrieved historical metal-on-metal devices.
Following this tradition, the Implant Development Centre has become a worldwide recognised research centre with its state-of-the-art facilities equipped with cutting edge scientific equipment. The IDC is recognised as one of the most advanced hip arthroplasty research facilities in the world.
The understanding gathered through the research is then applied to solutions to better improve the quality of life of the patients.
Independent accredited research
This research would be pointless unless it is structured to be independent, unbiased and scientific.
A number of accreditations certify the independency of our research.
The IDC is the only UKAS accredited hip wear and friction simulator testing centre in the world.
The IDC is also ILAC accredited – ILAC is an international cooperation of laboratory and inspection accreditation bodies formed more than 30 years ago.
These accreditations ensures that the hip wear and friction simulator studies carried out at the IDC have been assessed against internationally recognised standards to demonstrate the centre’s technical competence, impartiality and performance capability.
The Research
Our current aims at the IDC are:
- To provide a retrieval analysis service for all hip arthroplasty surgeons
- To provide scientific tests that replicate clinical environments
- To publish regularly our scientific findings at national, international and global meetings
- To undertake retrospective scientific studies to further understand clinical outcomes
- To study relevant hip biomechanics, kinetics and kinematics
- Synthesis and investigation of new biomaterials, potentially useful in joint arthroplasty
- Facilitating partnership with surgeons and other parties to further these areas of interest
- Enhancement and validation of current manufacturing techniques.
Achievements
The IDC has over 40 publications in either peer reviewed journals, conference presentations and posters, as well as having contributed to a number of orthopaedic text books.
One of the most powerful investigations coming out of the Implant Development Centre is the development of a physiological relevant hip simulator protocol.
A modern hip simulator test cell with reservoir of lubricant (Bovine Serum) containing implants being tested.
The use of hip simulators to validate the performance of prosthesis has frequently highlighted disparities between the results from the laboratory and the performance in-vivo.
In some circumstances the hip simulators may artificially produce an exaggerated lubrication regime and potentially underestimate the amount of wear and that would explain these disparities the between in-vivo and in-vitro settings.
The physiologically relevant test protocol developed at the IDC reproduces daily activities, stop/start motion, and various kinetics and kinematics that may break down the fluid film to provide a realistic picture of how an implant might behave in-vivo.
The validity of the physiological relevant test protocol was validated for first time when it demonstrated in- vitro the difference in wear between “heat treated” vs “as cast” bearings. These results more accurately correlate to clinical metal ion data comparing “as cast” and “heat treated” devices.
Other IDC studies:
- The tribology performance and wear of heat treated vs as-cast CoCr metallurgy
- The wear of low clearance MoM bearings in hip simulator contrasted with clinical results
- The tribiological performance using a worn BHR acetabular cup with a new femoral head in cases of femoral neck fracture
- The effect of acetabular cup orientation on wear in hip simulators
- Friction experienced in various bearings using different physiologically relevant lubricants
- The clinical effect of acetabular cup deformation and deflection on cup insertion
- The effect of microstructure on wear characteristics
The validity of the work carried out at the Implant Development Centre is endorsed by substantial contributions to a number of major orthopaedic books, including “Modern Hip Resurfacing “ by Derek McMinn with several chapters on hip joint tribology, corrosion and its contribution to metal release and retrieval analysis.
Last year the IDC was approached by EFORT to contribute in their forthcoming “Tribology in Total Hip Arthroplasty” book with a chapter devoted to the tribology of Metal on Metal bearings (chapter 4).
Next year will see the publication of “Mastering Orthopaedic Techniques in Total Hip Arthroplasty” in which the editors also approached the IDC to contribute to a full chapter devoted to tribology and bearing materials (chapter 2).
The Retrieval analysis project
From the design conception of the BIRMINGHAM HIP™ Resurfacing system, forensic analysis of retrieved historical metal-on-metal devices was an integral piece of the puzzle when gaining an understanding of the recipe to success.
From the intimate comprehension of this process and continued pursuit for insight, the retrieval analysis project was initiated as a scientific resource in July 2000 with the intention of studying retrieved hip arthroplasty devices to gain a further insight into their function and performance within the body.
Example of a patient walking on a treadmill to simulate running speed of hip simulator.
It now has one of the largest explant collections in the world that are analysed with state of the art equipment (SEM with EDX for materials analysis, Optical microscopes, Taylor Hobson roundness profiler, Redlux 3D profiler, Surface roughness profiler etc)
The IDC offers to the orthopaedic community explant testing and implant analysis service with several, reliable, replicable, accurate and standardised examination methods to investigate the explants including:
- Metrology – including roundness and linear wear, surface analysis, dimensions, geometries and clearances
- Material composition and microstructure: using cutting edge equipment such as scanning electron microscope (SEM) and Energy dispersive x-ray (EDX)
- Radiographic analysis – 3d component alignment/positioning of the device
- Histology
It is evident that at the heart of the Implant Development Centre is the desire to push the boundaries of orthopaedic research. It is also evident that the dedication and devotion of all the individuals involved in it and the quality of their work that makes possible the development of future advanced bearing technologies and developing knowledge, by forming partnerships within the medical and scientific community to achieve common goals.
