Optimizing the Disinfection of Devitalized Bone for Retained Use in Open Fractures: An In Vitro Study.

OBJECTIVES

To compare several methods of disinfection of a grossly contaminated cortical fragment with regard to residual bacterial load and mechanical properties.

MICROBIOLOGIC TESTING: Sixty (0.5 × 0.5 × 0.5 cm) cortical pieces of cadaveric femora were immersed in live Staphylococcus aureus ( 1 × 10 8 CFU/mL) for 60 minutes. Samples were randomized to no treatment, saline irrigation, povidone-iodine, chlorohexidine, pasteurization, or autoclave treatment and underwent bacterial enumeration using serial dilution and plating as well as broth turbidity testing.

MECHANICAL TESTING: Separately, 60 diaphyseal cortical beams were created (2 × 2 × 3 cm) and underwent the aforementioned treatments, and subsequently were mechanically tested using 4-point bending.

MICROBIOLOGIC TESTING: Mean bacterial load was not significantly different with saline irrigation (4 × 10 7 CFU/mL) versus no treatment (5 × 10 7 CFU/mL), ( P = 1). Povidone-iodine (90 CFU/mL), pasteurization (250 CFU/mL), autoclave (0.6 CFU/mL), and chlorohexidine (0 CFU/mL) treatments significantly decreased bacterial load compared with the no treatment and saline groups ( P = 0.002). Samples treated with autoclave (0.6 CFU/mL) and chlorohexidine (0, 0 CFU/mL) achieved near-complete or complete disinfection.

MECHANICAL TESTING: Autoclave treatment decreased maximum force to failure compared with no treatment (84 vs. 100 N, respectively, P = 0.012). No significant difference was noted in this parameter for the remaining groups ( P = 1). No difference was noted among groups for bending stiffness ( P = 0.318), work to failure ( P = 0.720), or flexural rigidity ( P = 0.235).

CONCLUSIONS

Chlorohexidine treatment achieved complete disinfection of a grossly contaminated cortical segment without affecting mechanical properties. Povidone-iodine, chlorohexidine, pasteurization, and autoclave disinfection achieved profound reductions in bacterial load. Autoclave treatment modestly decreased the mechanical properties of cortical bone.