Intervention for early stage osteoarthritis or cartilage injury

Orthopaedic surgeons treat a wide variety of patients with cartilage damage, from young athletes with cartilage injury to elderly patients with advanced osteoarthritis. There are a variety of treatment options, and these are chosen based on the age of the patient. For patients under the age of 35, biological repair is successful. Biological repair includes techniques that try and make the cartilage heal itself by stimulating regenerative cells from the underlying bone (microfracture) or removing healthy cartilage cells from a non load bearing part of the joint, growing them in the laboratory, and re-implanting in the defect. For older patients, total or partial joint replacement is more reliable. The average age of total hip and knee replacement patients in the UK is 69 and 70 years respectively, and these have remained constant over the past five years indicating no trend for surgeons to replace joints of younger patients. There is therefore a wide gap in the treatments available for patients in the 35 to 60 year age bracket who are considered too old for biological repair, but too young to be considered ideal candidates for joint replacement. The aim of the fellowship is to develop the technology for patients in this age group that can replace the cartilage surface without removing bone stock such that any future partial or total joint replacements can be performed as a normal index procedure.

To achieve this aim, the fellowship will use advanced materials and manufacturing techniques to create the technology required for cartilage substitution implants with ultra low friction and wear properties that will protect the device from the service loads it will experience in use. In addition to providing the orthopaedic surgeon with a treatment option for the 35-60 year old patient, developing this technology will have application across the whole orthopaedic field. It will generate the mechanical boundary conditions and test methods for further development of biological repair scaffolds and repair material (currently mostly fibrocartilage rather than the desired hyaline cartilage) for patients under 35 years old. The development of polymer technology will provide the information required for low cost all polymer implants that would be suitable for less functionally demanding patients. The manufacturing methods may also be suitable for interpositional implants with tailored frictional properties and morphology to prevent dislocation. Each of these themes will be pursued within the fellowship.

There are few options available to the orthopaedic surgeon to treat cartilage damage or disease in patients who are in the 35 to 60 year age bracket. Biological repair is most successful in patients under the age of 35 years, and the average age of hip and knee replacement is 69 and 70 years respectively. The proposed fellowship will provide new options to the orthopaedic surgeon in the management of chondral defects or early osteoarthritis by developing several different technologies that will lead to a new interventional stage after a failed biological repair, but without compromising later partial or total joint replacement. These new options will be perfect for patients in the 35-60 year age bracket who are usually in full time employment and have families, such that restoration of their active lifestyles is beneficial to society and the economy.

By providing new early interventional options, the technology developed during the fellowship will help the current generation of total joint replacements become the salvage procedure. This is particularly beneficial for knee replacement patients where kinematics are clearly not being restored - over 40% find a simple task like kneeling down and standing back up again either 'extremely difficult' or 'impossible' (study of 16,000 patients, New Zealand Joint Registry 2010). This represents a contribution to the health of the nation with societal and economical benefits as mentioned above.

The fellowship also develops different additive manufacturing processes including laser melting and customised injection moulding. Additive manufacture is likely to become a key technique in the future of orthopaedic device manufacture as the cartilage replacement concept would be difficult or impossible by milling due to the thinness of the part. Developing this in the UK will benefit UK orthopaedic manufacturing, and the know-how developed will have application in other engineering fields and has the potential to increase the value of UK manufactured exports across engineering disciplines which would benefit the economy. The partnership with Renishaw is a strength in this regard, as they have a presence across engineering disiplines.

The route to commercialisation of academic research is usually through licensing or the formation of spin-out companies, and this is the likely route for the joint repair concepts developed in the proposal, under the guidance of Imperial Innovations, the university's technology transfer company. Orthopaedics is a multi-billion dollar industry, and acquisitions worth over £50m have been made for exciting technology, sometimes even with very limited supporting clinical data. A spin out company that owns the intellectual property generated during, and after the fellowship could eventually be acquired in a similar manner, therefore have tremendous benefit to the UK economy.

The potential of improving biological repair of chondral defects, or repair through cartilage substitution, has applications in sports medicine, and could be beneficial to the treatment of elite athletes. The performance of elite athletes can have great benefit to national pride, as exemplified by the recent success of Britain's elite athletes at the London Olympics.