Crown copyright 2009. Published with the (permission of the Defence Science and Technology Laboratory on behalf of the Controller of HMSO. Introduction. The optimum strategy for the care of war wounds is yet to be established. A need exists to model complex extremity injury, allowing investigation of wound management options. Aim. To develop a model of militarily relevant extremity wounding. Study Design. Laboratory study with New Zealand White Rabbits. Methods. Phase 1. Development of injury. Following induction of general anaesthesia, a muscle belly on the flexor aspect of the forelimb of the rabbit was exposed. This was achieved by creating a fascial tunnel under the belly of flexor carpi ulnaris (FCU). Utilising a custom built drop test rig a high energy, short duration impact was delivered. To replicate casualty evacuation timelines, the animal was maintained under anaesthesia for three hours and recovered. The wound was dressed with saline soaked gauze and supportive bandaging. 48 hrs later, the animal was culled and the muscle harvested for histological analysis. Analgesia was administered once a day. Animals were checked by experienced staff at least twice a day and body temperature recorded by a subcutaneous transponder. Phase 2. Contamination of muscle injury. Sequential animals had inoculums of 1×102/100μl, 1×106/100μl and 1×108/100μl of Staphylococcus aureus administered to the muscle immediately after injury. Animals were recovered from anaesthetic and monitored as per phase 1. Delivery was evaluated by droplet spread and via injection by fine bore needle into the muscle belly. At the 48 hour point, the animals were culled, dressings removed, the muscle harvested and auxiliary lymph nodes sampled. Quantitative microbiological analysis was performed to determine colony forming unit counts (CFU) at 24 hours post-collection. Results. Phase 1. Six animals were exposed to a loading of 0.5kg. Histological analysis demonstrated a consistent injury pattern with 20% of the muscle belly becoming necrotic. Following discussion with subject matter experts this was found to be representative of the nature of injury from ballistic limb trauma and was adopted as standard. Phase 2. Twenty-two animals were exposed to the standardised injury and then inoculated at the prescribed challenge doses and delivery methods. A challenge dose of 1×106/100μl S. aureus delivered by droplet provided the greatest consistency. A group of six animals with an average challenge dose of 3.3×106/100μl yielded growth at 48hrs on average of 9.2×106 CFU. There were no adverse effects on animal welfare throughout, with body temperatures within normal limits at all times. Discussion. The use of rabbits in the investigation of musculoskeletal injury and infection is well established. No study to date however has addressed high energy complex soft tissue wounding, contamination and its optimum management. Considering the current burden of such wounds the need for this question to be answered in a research setting is transparent. This model enables a significant, reproducible, contaminated soft tissue injury to be delivered in vivo. It will allow the investigation of complex wound management options including wound coverage and fracture fixation

Objectives . Rotator cuff tears are among the most common and debilitating upper extremity injuries. Chronic cuff tears result in atrophy and an infiltration of fat into the muscle, a condition commonly referred to as ‘fatty degeneration’. While stem cell therapies hold promise for the treatment of cuff tears, a suitable immunodeficient animal model that could be used to study human or other xenograft-based therapies for the treatment of rotator cuff injuries had not previously been identified. Methods . A full-thickness, massive supraspinatus and infraspinatus tear was induced in adult T-cell deficient rats. We hypothesised that, compared with controls, 28 days after inducing a tear we would observe a decrease in muscle force production, an accumulation of type IIB fibres, and an upregulation in the expression of genes involved with muscle atrophy, fibrosis and inflammation. Results . Chronic cuff tears in nude rats resulted in a 30% to 40% decrease in muscle mass, a 23% reduction in production of muscle force, and an induction of genes that regulate atrophy, fibrosis, lipid accumulation, inflammation and macrophage recruitment. Marked large lipid droplet accumulation was also present. Conclusions . The extent of degenerative changes in nude rats was similar to what was observed in T-cell competent rats. T cells may not play an important role in regulating muscle degeneration following chronic muscle unloading. The general similarities between nude and T-cell competent rats suggest the nude rat is likely an appropriate preclinical model for the study of xenografts that have the potential to enhance the treatment of chronically torn rotator cuff muscles. Cite this article: Bone Joint Res 2014;3:262–72

The treatment of extremity ballistic injury is challenging in that the zone of injury can be extensive and determining the surgical exposure can be difficult. We describe a method of pre-operative evaluation of the zone of injury in conjunction with the regional anesthesiologist utilizing ultrasound to determine the presence of nerve disruption. This non-invasive method of examination may elucidate whether significant nerve exists and may also serve to pinpoint the location of injury. Such information allows the surgeon to more effectively and efficiently surgically expose the zone of injury and understand the boundaries of the nerve outside the zone of injury. Moreover, such preoperative evaluation may at times obviate the need for exploratory surgery at all. It is important for the anesthesiologist and surgeon to work together with respect to the ability to both interpret the ultrasound images and to clinically correlate the findings. The zone of tissue disruption in ballistic injuries is extremely variable. It is beneficial to both the surgeon and patient to engage in a collaborative effort with an experienced regional anesthesiologist who is well-versed in interpretation of ultrasound images and tissue plane disruption in an effort to minimize surgical time and the potential unintended consequences of unnecessary exploration. We present a series of cases representing instances wherein the zone of injury was small, extensive, and a unique situation in which there was in fact no injury present despite clinical symptoms and MRI consistent with radial nerve disruption

Summary. open tibia fractures are best treated in an orthopaedic-plastic surgical multidisciplinary setting. Introduction. Open fractures of the leg represent a severe trauma. It is often stated that combining the skills of Plastic and Orthopaedic surgeons can optimise the results of limb salvage in complex limb injury. The multidisciplinary approach, shared between plastic and orthopaedic surgeons, is likely to provide the optimal treatment of these injuries, although this mutidisciplinary simultaneous treatment is not routinely performed. Given the relatively low incidence of these traumas, a multicentric recruitment of these patients can contribute in providing an adequately numerous cohort of patients to be evaluated through the long process of soft tissue and bone healing following an open tibia fracture. We compared three centres with different protocols for management of these challenging cases. Patients & Methods. The following trauma centres, either orthoplastic or orthopaedic, were involved in a prospective observational study: Rizzoli Orthopaedic Institute/University of Bologna (leading centre) and Maggiore Hospital (Bologna), Frenchay Hospital (Bristol, Regno Unito), Jinnah Hospital (Lahore, Pakistan), a centre in the developing world who have adopted an Ortho-Plastic approach. From 01/01/2012, all patients consecutively hospitalised in the mentioned centres due to Gustilo grade 3 tibial open fractures were included in the study and propspectively followed. Demographics, mechanism of the trauma, type of lesion, timing and way of transfer to the trauma centre, as well as timing and techniques of bone and soft tissue treatment were recorded. The considered outcome measures were duration of hospitalization (main outcome measure), rate of reintervention, Enneking score at 3, 6 and 12 months, the incidence of osteomyelitis, non union, amputation and other complications. Results. The number of patients included in the first 6 months was 42. Mechanism, severity of injury and techniques regarding definitive bone reconstruction were similar accross the three centres. The main difference occured in soft-tissue management with VAC therapy being utilised by the Italian centre compared to vascularised tissue transfer in Pakistan and Britain. The mean duration of hospital stay in the Italian centre was 72 days compared with 24 days in Pakistan and 25 days in Britain. Patients treated in a centre with an orthoplastic team, therefore, spent an average of 46 fewer days in hospital (P<0.005, 95% CI −69 to −24days). Discussion. From an initial analysis of data, the duration of hospitalization is strongly influenced by the fact that a plastic procedure is performed or not. The first evaluations on the hospital management of these injuries show a relevant advantage deriving from a combined orthoplastic approach, evenwhen applied into a comparatively hostile cohort

Objectives

The aim of the current study was to assess whether calcaneal broadband ultrasound attenuation (BUA) can predict whole body and regional dual-energy x-ray absorptiometry (DXA)-derived bone mass in healthy, Australian children and adolescents at different stages of maturity.