Degenerative joint conditions are an unavoidable problem in an ageing society, and include disorders of the hip joint and the back, or damage to knee cartilage. Introducing a replacement implant may be a solution for patients, but these implants have a limited lifespan. Ultimately, a worn or damaged implant may cause even greater bone defects requiring major repeat surgical interventions. The ideal remedy would be for the body itself to grow new bone cells at the location of the damage. Scientists are currently well on the way to making this type of treatment possible through the use of 3-D printed implants.

3-D Printing
Traditional implants are made from titanium or plastic and are intended to stabilise the joint. There are few varieties available, which means that almost every patient gets the same treatment. ‘Smart’ implants are made of titanium too, but nevertheless have exceptional properties that stimulate the growth and attachment of bone cells. With the development of 3-D printing, it is therefore possible to make a unique implant for every individual patient based on MRI or CT scans, for example. ‘Every patient is different and each has specific bone requirements’, says principal researcher Dr Chris Arts, an expert in the field of applied biomaterials. ‘Age, weight, bone density and individual capacity for recovery are all factors that affect the joint and the treatment required.’

Clinical application
The 3-D printed implants have a web-like structure, with intervening spaces. A unique, microscopically detailed framework is created to which bone cells can attach and grow optimally. The implants can also be given an antibacterial coating so that joint infections can be prevented. Furthermore, work is underway to develop a new generation of biodegradable implants which are completely replaced by the body’s own cells. The advantages are numerous, says Dr Arts: ‘Patient rehabilitation will be more successful, the risk of infection reduced, and the effect of implant wear and tear minimal.’ Prof. Lodewijk van Rhijn, head of the Department of Orthopaedics at Maastricht UMC+ added: ‘This project demonstrates in an innovative fashion how we can translate fundamental knowledge about biomaterials and cell growth into clinical patient applications.’ The researchers hope to be able to present the first clinical results of the implants in four years’ time.

Partners
The project is entitled PRosPERoS (PRinting PERsonalized orthopaedic implantS) and is in close alignment with the agreement made by the provinces of Flemish-Brabant and Limburg (the Netherlands) to reinforce developments in the field of regenerative medicine in the region. In addition to Maastricht UMC+ and Maastricht University, four other university institutions (the Catholic University of Leuven, Utrecht University Medical Centre, Delft University of Technology and Uniklinik RWTH Aachen) and seven partners from small and medium-sized companies in the region (3D Systems, Medanex Clinic BVBA, 2Move Implants BV, Xilloc Medical BV, 4WEB EU. B.V., PCOTech, Antleron BVBA) are also well represented. The project will also provide direct and indirect employment opportunities for the companies and knowledge institutions involved. PRosPERoS will create at least 20 new jobs in the European region of Flanders-The Netherlands alone.