**5. Conclusion**

Both osteointegration and infections are of concern in implants and prosthesis used in the field of orthopaedic and trauma surgery. Metallic alloys used for plating and nailing of fractures and joint replacements are the largest group of these implants. Hydroxyapatite coatings have proven to be successful to promote osseous integration of uncemented total hip prosthesis. During the last years the focus on coating development has shifted from osteoconductive coatings (like hydroxyapatite) towards osteoinductive coatings to support bone remodeling (like RGD and BMP coatings) and antimicrobial coatings for implant infection treatment and prophylaxis (like silver or antibiotic releasing coatings).

Plasma spraying is the most used and accepted method for hydroxyapatite coatings. Other coating techniques which do not require high temperatures are necessary for the application of bioactive coatings that promote osteogenesis and/or prevent infections.

With the current palette of *in vitro* (e.g. MTT, ALP and SEM), *in vivo* (e.g. ESR, CT and PET) and *ex vivo* techniques (e.g. bacterial culture, calcium binding fluorophores and histology), we can thoroughly evaluate novel implant coatings in a qualitative and quantitative fashion. The strength of such an evaluation will always lie in the combination of the individual methods, leading to a complete, broad-spectrum analysis on coating toxicity and efficacy.
