Systemic antibiotics reduce infection in open fractures. Local delivery of antibiotics can provide higher doses to wounds without toxic systemic effects. This study investigated the effect on infection of combining systemic with local antibiotics via polymethylmethacrylate (PMMA) beads or gel delivery. An established Staphylococcus aureus contaminated fracture model in rats was used. Wounds were debrided and irrigated six hours after contamination and animals assigned to one of three groups, all of which received systemic antibiotics. One group had local delivery via antibiotic gel, another PMMA beads and the control group received no local antibiotics. After two weeks, bacterial levels were quantified. Combined local and systemic antibiotics were superior to systemic antibiotics alone at reducing the quantity of bacteria recoverable from each group (p = 0.002 for gel; p = 0.032 for beads). There was no difference in the bacterial counts between bead and gel delivery (p = 0.62). These results suggest that local antibiotics augment the antimicrobial effect of systemic antibiotics. Although no significant difference was found between vehicles, gel delivery offers technical advantages with its biodegradable nature, ability to conform to wound shape and to deliver increased doses. Further study is required to see if the gel delivery system has a clinical role.
Antibiotic delivery to the wound using a chitosan sponge is compatible with NPWT and is more effective than PMMA antibiotic depot. The chitosan sponge works in conjunction with NPWT and may improve the outcomes of open fracture wounds.
ObjectivesThe purpose of this study was to refine an accepted contaminated
rat femur defect model to result in an infection rate of approximately
50%. This threshold will allow examination of treatments aimed at
reducing infection in open fractures with less risk of type II error.Methods Defects were created in the stablised femurs of anaethetised
rats, contaminated with Staphylococcus aureus and
then debrided and irrigated six hours later. After 14 days, the
bone and implants were harvested for separate microbiological analysis.
This basic model was developed in several studies by varying the
quantity of bacterial inoculation, introducing various doses of
systemic antibiotics with and without local antibiotics.Results The bacterial inoculation associated with a 50% infection rate
was established as 1 × 102 colony forming units (CFU). With
an initial bacterial inoculum of 1 × 105 CFU, the dose
of systemic antibiotics associated with 50% infection was 5 mg/Kg
of cafazolin injected sub-cutaneously every 12 hours, starting at
the time of the first debridment and continuing for 72 hours (seven
doses). The systemic dose of cafazolin was lowered to 2 mg/Kg when
antibiotic polymethyl methacrylate beads were used concurrently
with the same amount of bacterial inoculation.ConclusionThis model of open fracture infection has been further refined
with potential for local and systemic antibiotics. This is a versatile
model and with the concepts presented herein, it can be modified
to evaluate various emerging therapies and concepts for open fractures.Cite this article: Bone Joint Res 2014;3:187–92.
The importance of early transit times to Role 3 capabilities for definitive surgical care has been underlined. Novel and superior methods of antibiotic and growth factor delivery, compared with current clinical standards of care, have been shown. There is the potential for translation to clinical studies to promote infection control and bone healing in these devastating injuries.
This case report demonstrates and emphasises the unusual radiographic appearance of silver nitrate treatment in a 30-year-old patient, who subsequently underwent excision biopsy of a presumed potentially malignant lesion.
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