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.