In the first reporting period, the team consulted with the clinician panel to determine a suitable joint to demonstrate the concept. initially, the digital hinge joints of the hand were selected, and the thumb metacarpophalangeal (MCP) joint was identified as an appropriate candidate based on its geometry, size, and the lack of an existing dedicated solution for thumb MCP arthritis. Patient public involvement strategies were undertaken to gain an understanding of the problems faced by patients, and get an idea of which potential benefits were most important to them. Computational modelling of the thumb joint led to the development of a statistical shape model that helped the team understand how the shape of the joint varies between individuals. Design and manufacturing strategies were assessed and generated new IP for Aurora Medical. Bespoke test rigs were designed so the device could assessed under typical loading and kinematic conditions. Concepts for external fixation and internal lubricious coatings were proposed and optimised over the course of the project.
A project website was created and regularly populated with new information. The communication, dissemination, and exploitation strategy was refined, and Key Exploitable Results established. A Project Management Platform was constructed to assist with the management of the project.
Over the two remaining reporting periods, surface treatments and fixation techniques were developed that enabled the implant to function as intended, that is, with very low friction while retaining its position in the joint. Biocompatibility testing of the surface treated and untreated implant materials showed that the materials were tolerated in vivo. Mechanical testing on artificial bones showed that the implant was able to function efficiently for over one million loading cycles. Once the concept was proven in the laboratory, cadaver trials were undertaken at two centres. These trials demonstrated the effectiveness of the APRICOT implant, highlighting its ultra-low invasiveness, its ability to remain in place and supported by the surrounding soft tissue, and its ability to restore the full kinematic function of the joint over a wide range of flexion/extension angles and with smooth, almost frictionless movement. An unexpected benefit of the device was the very short surgery time.
At project conclusion, the consortium achieved the objective of proving the APRICOT concept in two ways: (i) via testing in the lab under long term repeated loading in artificial bone joints, and (ii) via testing in cadaver joints to demonstrate the restoration of full joint function. The cadaver tests illustrated that the implantation was simple, rapid (< 10 minutes), and involved little to no trauma. These very encouraging results place the project in a suitable position to progress towards clinical trails in the next phase of work. This will involve producing demonstrator APRICOTs for the other hands in the joint, building up a regulatory file and a business case, and performing a first in human clinical trial.
While a lot of the work in this project has had to be protected due to its very novel nature, the research institutes have been able to disseminate in their specialist areas, and to date, they have achieved 7 peer reviewed journal publications in open access journals with further publications in preparation, 10 international conference presentations, conducted extensive outreach activities, and developed a strong social media presence. Significant IP has been generated by the lead industrial partner to ensure the technology is protected as we progress it to clinical use.
