Regenerative Medicine Utrecht


27 September 2018
Academie Gebouw

Willemijn Boot

Thesis: Recent developments in diagnosis and prophylaxis of orthopaedic implant-related infections

Promotoren: prof.dr. W.J.A. Dhert, prof.dr. R.M Castelein
Copromotors: dr. H. Ch. Vogely, dr. ir. D. Gawlitta
Defense date: 27 September 2018

My thesis focuses on the diagnosis and the prevention of implant-related infections. Although infections of orthopaedic implants (e.g. prosthetic joints) only occur in 1-4% of cases, it is a big problem. These infections are a huge burden for patients due to prolonged hospital stay, possible multiple revisions of their implants, and an increased mortality. Furthermore, implant-related infections are a challenge to treat and expensive for the health-care system. To decrease the number of patients with infections, it is important to be able to diagnose them accurately, and to prevent them.

Part 1 of my thesis focuses on diagnosis of infection. Bacterial infections are not always easy to diagnose and, in some cases, they might be missed. In a clinical follow-up study of 176 patients, we found that these missed infections did not have a negative influence on extra revisions of these patients’ implants. Furthermore, a rapid molecular technique was tested to improve diagnosis of infection. The time-to-result was very fast compared to currently used techniques, but the molecular technique needs to be optimised before it is ready to use in clinical diagnostics. Part 2 of the thesis focuses on infection prevention. A hydrogel was tested as local carrier of antibacterial agents around an implant to prevent implant-related infection. We found out that local administration of an antibiotic is a successful method of infection prevention. Part 3 of the thesis focuses on bone. For the stability of an implant, a healthy bone stock is important. We investigated the influence of the hydrogel used in part 2 on bone quality and found out that it does not have any negative effects. Moreover, infection can have a destructive effect on bone, but sometimes it also stimulates bone formation. We tried to harness the bone-stimulating effects with bacterial cell wall extract. This cell wall extract has shown to increase bone volume without inducing severe osteolysis. By investigating this effect more in-dept, it might give insight for future therapies for bone defects.