Some different biodegradable vehicles have been tried in vitro and in vivo as possible methods of local antibiotic therapy.

The aim of this study is to evaluate the effectiveness of collagen-gentamicine (Collatamp^®) to eradicate bacterial colonisation of different biomaterials used in orthopaedic surgery in an in vitro study.

Three samples of similar shapes and dimensions of 4 different materials: stainless steel screw, titanium screw, titanium canulated screw and a cylinder of polyethylene were used. Three different solutions of 49 cc of thioglicolate plus 1cc of solution of methicillin-susceptible and methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis (MacFarland: 3) were prepared. Each solution received one sample of each material so that every material be tested in all 3 preparations. After incubation during one week and confirmation of bacterial colonisation of each sample by swabbing cultures, all of them were introduced in an individual receptacle containing 50 cc of thioglicolate and a piece of 5x5 cm of collagen-gentamicine (corresponding to 650 mg/ml of gentamicine). After incubation we analysed results by new swabbing cultures of all samples.

All samples were highly contaminated with different bacteria before introducing them in thioglicolate with the piece of collagen-gentamicine. After one week all samples were free of bacteria.

This in vitro study demonstrates the effectiveness of collagen-gentamicine in order to eliminate colonisation of different biomaterials used in orthopaedic surgery by most frequent bacteria.