Evaluation and testing of polymethylmetacrylic (PMMA) bone cements with admixed Amphotericin B.

BACKGROUND

Amphotericin is admixed to Polymethylmethacrylic (PMMA) spacers for fungal periprosthetic joint infections (PJI) during two-stage exchanges. We aimed to analyse the mechanical properties of PMMA cement with admixed Amphotericin B.

MATERIALS AND

METHODS

We tested Amphotericin in PMMA cement mechanically, its elution properties in vitro and present two cases of fungal PJI treated with Amphotericin B powder in Copal cement in vivo.

RESULTS

Sterile Amphotericin B is not available as a pure substance but only as powder for infusions. PMMA mixed with such pharmaceutical Amphotericin B formulations colored the cement orange. Compression strength was slightly decreased, bending and impact strength significantly decreased whereas bending modulus was increased. Drug elution was high within the first 24 h and decreased over time until day 5. Amphotericin B in combination with Copal was successfully used in two cases with Candida ssp.

INFECTIONS: No negative side effects, especially no nephrotoxic effects, were observed. Sterile Amphotericin B powder for preparing an infusion solution contains only small amounts of pure drug. In vivo polymicrobial Candida-infections with bacterial co-infection were successfully treated using the combination of Copal cements with added Amphotericin B without systemic nephrotoxic impact.

CONCLUSIONS

The addition of Amphotericin B to PMMA cement affects the cement's properties in vitro whereas in vivo the combination with Copal is clinically successful in treating complex cases of fungal PJI.

LEVEL OF EVIDENCE: Level IV.