Implanted prosthetic devices are materials that are inserted into tissues for functional, cosmetic or therapeutic purposes; this encompasses many types of devices such as breast implants, catheters, and knee replacements. Hip and knee replacements have become increasingly common in the UK, with around 102,000 knee replacements and 91,000 hip replacements performed in England, Wales, Northern Ireland and the Isle of Man in 2017 [1]. The annual demand for hip and knee replacements is projected to increase by 174% and 673% respectively [2][3]. These replacements do not come without risk, with both treatments are associated with a significant morbidity rate, or high risk for complications (including infection, rejection and amputation) [3]. Prosthetic joint infections are one of the most common reasons for failure of the implant, it is reported that deep infections in prosthetic knee replacements affect 4% of primary replacements and 15% of knee replacement revisions [3]. There is a significant increasing burden from these infections to the patients quality of life, on the demand for health services and economically with regards to extensive, expensive continued treatment [4].
Your company has been tasked with designing a new method/procedure for protecting patients from infections following a total hip replacement or total knee replacement by considering the application and materials used. This solution must enable patients to have a lower risk of infection and reduce the burden on the NHS. You should also consider the long-term sustainability of the project and any technologies that may be in place. You should begin by researching the types of implants used currently and consider the cost and availability of materials. Your solution should decrease the chances of infection and rejection whilst being highly biocompatible to ensure no adverse effects on the patient.
You should create a solution that does not harm the user at all, with implanted devices it is important that there are no potential interactions between a new device and patient. Where can you access this information? Is there a database you can check?
There are many different types of infection, so it would be useful to understand the process of infection of prostheses. This could include a diagram on the ‘road to infection’. What are the risks of infection? At what stage do they happen? What types of bacteria cause these infections?
When designing healthcare and medical devices it is pertinent to consider the population that will be using the device. What is the average age of those receiving implants? Are there any health conditions that are prevalent in these patients? Could this have an impact on the solution?
Cost of the materials and manufacture are things to consider, if there is a solution that works better but costs 10 times the price is it worth it?
Consider the number of implants needed for use and the length of the implant life. What is in current use and are there several different devices? Are there different methods of putting the devices in? Does it vary from patient to patient or regionally?
Consider how this solution is future-proofed and minimizes any detriment to future generations.
[1] The National Joint Registry Editorial Board, “15th Annual Report 2018,” Natl. Jt. Regist. England, Wales, North. Irel. Isle Man, vol. 15, 2017. [Online]. https://www.hqip.org.uk/wp-content/uploads/2018/11/NJR-15th-Annual-Report-2018.pdf
[2] B. D. Springer, S. Cahue, C. D. Etkin, D. G. Lewallen, and B. J. McGrory, “Infection burden in total hip and knee arthroplasties: an international registry-based perspective,” Arthroplast. Today, vol. 3, no. 2, pp. 137–140, Jun. 2017. [Online]. doi: 10.1016/j.artd.2017.05.003.
[3] E. Lenguerrand et al., “Risk factors associated with revision for prosthetic joint infection following knee replacement: an observational cohort study from England and Wales,” Lancet Infect. Dis., vol. 19, no. 6, pp. 589–600, Jun. 2019. [Online]. doi: 10.1016/S1473-3099(18)30755-2,
[4] A. J. Tande and R. Patel, “Prosthetic joint infection,” Clin. Microbiol. Rev., vol. 27, no. 2, pp. 302–345, 2014. [Online]. doi: 10.1128/CMR.00111-13.