METS Modular Implants

Agluna® Technology To Reduce Infection Risk

This device is not yet cleared for sale in the USA.

A silver enhancement service is now available for all Stanmore Implants titanium alloy patient specific made prostheses. The key advantage to the surgeon is the reduction of infection risk around the implant.

silver enhanced implantThis will be particularly beneficial to patients who have had implants fail due to previous bacterial infection.

Infected mega prostheses are notoriously difficult to treat using systemic antibiotics due to encapsulation of the implant by fibrous tissue, biofilms and antibiotic resistant bacteria. Stanmore Implants collaborated with Accentus Medical to modify the implant surface by incorporating a bactericidal agent.

Ionic silver is a well known antibacterial agent. Previously, electroplating techniques had been used to produce a thin coating of silver on metallic orthopaedic devices. Delamination due to corrosion of the substrate has resulted in the decline of the technique for implantable devices.

Accentus Medical developed a novel process to “stitch in” ionic silver to the surface of titanium alloy. This process known as Agluna® produces a biocidal surface by anodisation of the titanium alloy followed by absorption of silver from an aqueous solution. The engineered surface modification is integrated into the substrate and loaded with silver by an ion exchange reaction.

Using this technique, the maximum inventory of silver for typical mega prosthesis is 6mg which is greater than 300 times lower than the No Observable Adverse Effects Level (NOAEL) standard. Scanning electron microscopy revealed that the silver was concentrated in pits forming reservoirs of ionic silver which is exposed to the body tissues.

Laboratory based studies focussing on the safety and efficacies of silver as a bactericidal agent have been undertaken and produced very exciting results. Invitro biocidal effects have been seen with Staphylococcus epidermidis, (MRSE), Escherichia coli and Streptococcus pyrogenes and biostatic effects with Staphylococcus aureus (MRSA) and Candida albicans.

Additional studies have included investigation into cytotoxicity using fibroblast and osteoblast cell lines. Histological studies were also performed to examine the impact of silver on osseointegration. Further studies examined the impact of silver in reducing corrosion and laboratory testing to establish if the modified surface has an effect on wear and mechanical characteristics.

Research into silver elution profiles for both silver loaded and HA coating over a silver loaded surface is ongoing. Early results are encouraging, showing that the HA coating of a silver loaded surface does not seal in the silver.

Early clinical studies of patients at high risk of infection indicate that the infection rate is halved – a major advance in reducing this devastating condition. For further information please visit www.agluna.com