Biofilm Growth on Orthopaedic Cerclage Materials: Non-metallic Polymers Are Less Resistant to Methicillin-Resistant Staphylococcus Aureus Bacterial Adhesion

Kyle H Cichos; Matthew C Christie; Brent A Ponce; Elie S Ghanem

doi:10.1016/j.arth.2024.04.042

Biofilm Growth on Orthopaedic Cerclage Materials: Non-metallic Polymers Are Less Resistant to Methicillin-Resistant Staphylococcus Aureus Bacterial Adhesion

J Arthroplasty. 2024 Apr 18:S0883-5403(24)00364-4. doi: 10.1016/j.arth.2024.04.042. Online ahead of print.

Authors

Kyle H Cichos¹, Matthew C Christie², Brent A Ponce³, Elie S Ghanem⁴

Affiliations

¹ Hughston Foundation, Columbus, Georgia, USA; Hughston Clinic, Columbus, Georgia, USA. Electronic address: kcichos@hughston.com.
² Southern Joint Replacement Institute, Nashville, TN, USA.
³ Hughston Clinic, Columbus, Georgia, USA.
⁴ Department of Orthopaedic Surgery, University of Missouri, Columbia, Missouri, USA.

PMID: 38642854
DOI: 10.1016/j.arth.2024.04.042

Abstract

Introduction: Data on bacterial adhesion to cerclage cables is sparse. We aimed to compare five cerclage products for methicillin-resistant Staphylococcus aureus (MRSA) adhesion to determine: Are non-metallic polymer cables more resistant to bacterial adhesion than common metallic wires and cables?

Materials and methods: The following five cerclage products were compared: 1) monofilament stainless steel (SS) wires; 2) multifilament SS cables; 3) multifilament cobalt chrome (CoCr) cables; 4) multifilament Vitalium alloy (cobalt-chrome-molybdenum [Co-Cr-Mo]) cables; and 5) multifilament non-metallic polymer cables. Each was cut into 2 cm lengths and placed into 12-well plates. Of the wells, five were wire or cables in trypticase soy broth (TSB) with MRSA, with the remaining wells being appropriate controls incubated for 24 hours at 37 degrees C and 5% CO2 with shaking. Wires and cables were prepared, and randomly imaged via scanning electron microscopy (SEM), with bacterial counts performed on 3 images of 3 different wires or cables per study group. The SEM technician and counting investigator were blinded. Additionally, SS wire and polymer cables were analyzed by microcalorimetry for metabolic activity and bacterial load.

Results: Bacterial attachment differed significantly between study groups in the middle section (P = 0.0003). Post-hoc comparison showed no difference between groups individually (all P > 0.05) apart from polymer cables (median 551 bacteria) having significantly increased attached bacteria compared to the Vitallium alloy cable (157, P = 0.0004), SS cable (101, P = 0.0004), and SS wire (211, P = 0.0004). There was no difference between polymer and CoCr cables (133, P = 0.056). Microcalorimetry supported these results, as polymer cables had a shorter time to max heat flow (6.2 versus 7.5 hours, P = 0.006), increased max heat flow (117 versus 64 uW, P = 0.045), and increased colony-forming units, indicating an increased bacterial load compared to SS wires. ConclusionThis in vitro study demonstrates that polymer cables have increased MRSA adhesion compared to common metallic wires and cables. Future studies are necessary to confirm the translation of increased bacterial adherence on polymer cables to increased rates of orthopaedic infections.

Keywords: attachment; biofilm; cable; calorimetry; cerclage; infection; metal; polymer; wire.