From model to molecules: the development and experimental manipulation of an in vivo contaminated extremity war wound.

Wound infection is a key determinant of outcome in survivors of armed conflict. One factor having potential for promoting healing, decreasing bacterial burden and influencing prognosis is the dressing that covers the ballistic-injured extremity. Although antiseptic and silver dressings are applied to acute wounds, evidence to support their use is scarce with no controlled studies reported of antimicrobial wound dressings in extremity trauma. Given the recent burden of ballistic extremity injury, the requirement to investigate the role of antimicrobial dressings in contaminated wounds is transparent. This paper details a programme of work undertaken at the Defence Science and Technology Laboratory of developing and trialling a recovery model to investigate the early management of contaminated war wounds. A New Zealand White rabbit flexor carpi ulnaris muscle belly, isolated and then injured by a drop rig mechanism, was contaminated with Staphylococcus aureus to provide a reproducible contaminated muscle wound. This model was developed to support a series of randomised controlled trials to determine the impact of antimicrobial dressings on decreasing the bacterial burden of combat related extremity wounds. The results of the initial trial indicated that over a 48-h period, dressings augmented with antiseptic or silver offer no advantage over saline-soaked gauze in reducing the bacterial burden of a contaminated soft tissue injury. The model has subsequently been used to investigate the efficacy of dressings over a 7-day study period and impact of antibiotics and to evaluate biofilm formation and wound cytokines.

The development of an experimental model of contaminated muscle injury in rabbits.

Extent of tissue trauma and contamination determine outcome in extremity injury. In contrast to fracture, osteomyelitis, and closed muscle injury studies, there are limited small animal models of extremity muscle trauma and contamination. To address this we developed a model of contaminated muscle injury in rabbits. Twenty-eight anesthetized New Zealand White rabbits underwent open controlled injury of the flexor carpi ulnaris (FCU). Twenty-two animals had subsequent contamination of the injured muscle with Staphylococcus aureus. All animals were sacrificed at 48 hours and the level of muscle injury and contamination determined by quantitative histological and microbiological analysis. A 1-kg mass dropped 300 mm onto the mobilized FCU resulted in localized necrosis of the muscle belly. Delivery of a mean challenge of 3.71 × 10(6) cfu/100 µL S aureus by droplet spread onto the injured muscle produced a muscle contamination of 8.79 × 10(6) cfu/g at 48 hours. Ipsilateral axillary lymph nodes demonstrated clinically significant activation. All animals had normal body temperature and hematological parameters throughout and blood and urinalysis culture at autopsy were negative for organisms. This model allows reproducible muscle injury and contamination with the organism ubiquitous to extremity wound infection at a level sufficient to allow quantitative assessment of subsequent wound care interventions without incurring systemic involvement.

Bioabsorbable interference screw fixation of distal biceps ruptures through a single anterior incision: a single-surgeon case series and review of the literature.

INTRODUCTION: We present a single-surgeon series of 14 acute ruptured distal biceps tendons repaired using a biotenodesis screw through a single anterior incision. PATIENTS: The demographics of this population reveal a typical injury pattern and reflect the preponderance of distal biceps ruptures in the middle aged, active male. Goniometric post-operative assessment of flexion, pronation and supination range demonstrates excellent clinical function in these patients. METHOD: Subjective analysis is afforded by DASH and MEPS scoring at the 6-month follow-up. RESULTS: The results are discussed in relation to previous studies utilising disparate repair methods. This is the first prospective clinical series to be reported using this combination of fixation and approach. Clinical and patient assessed functions are excellent and complications are minimal. CONCLUSION: This is a safe and successful technique for the management of distal biceps tendon ruptures.