Abstract
Antibiotic loaded bone cements (ALBCs) are used to prevent or treat orthopaedic infections, but antimicrobial resistance threatens the sustainability of this approach. One potential strategy to address this is to substitute antibiotics with other antimicrobials.One possible alternative is chlorhexidine (CHX), a common, broad-spectrum antiseptic. CHX is not currently used in bone cements, since common CHX salts exhibit unfavourable properties for this application. CHX polyphosphates are novel salts which can provide sustained CHX release from biomaterials; with appropriate dosage, CHX polyphosphates could be suitable for use in orthopaedic bone cements to provide antimicrobial efficacy over the necessary durations.
The aim of this research was to investigate incorporation of CHX triphosphate (CHX-TP), into a clinical bone cement formulation (Palacos R), and explore the antimicrobial release, antimicrobial efficacy, mechanical properties and setting properties of the resulting cements, compared to Palacos R and to a clinical cement formulation containing gentamicin (Palacos R+G).
Bone cements loaded with CHX-TP showed sustained CHX release for up to 761 days and sustained antimicrobial efficacy (6 weeks or 18 weeks) against common orthopaedic pathogens. Compressive strength, setting time, maximum temperature and doughing time (all measured to ISO 5833:2002 protocols) for cements loaded with CHX-TP were not significantly different to Palacos R or Palacos R+G, and all formulations performed within ISO 5833:2002 requirements for these properties.
Bending strength with CHX-TP loading ≥ 4 % w/w was significantly reduced compared to Palacos R and Palacos R+G (and was below the ISO 5833:2002 minimum requirement), and compressive strength was significantly reduced after CHX-TP release for 18 weeks with ≥ 7 % loading (although remained above the ISO 5833:2002 minimum requirement).
Although further study is needed, these findings suggest that, with appropriate CHX-TP loading, cements containing CHX-TP may have potential as alternatives to ALBCs, particularly as short-term implants for infection treatment.
| Date of Award | 21 Jun 2022 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Michele E Barbour (Supervisor), Darryl J Hill (Supervisor) & Annela M Seddon (Supervisor) |