Abstracts / Injury Extra 43 (2013) 71–127 111 due to medical co-morbidities. Four patients had additional iden- tifiable risk factors for AVN. Conclusion: Our cohort demonstrates a small but significant risk of developing AVN after internal fixation with a DHS. This is cer- tainly higher than limited published reports. The rate of AVN may be therefore underestimated (previous evidence suggesting 0.8%). We suggest this risk should be included when obtaining consent for surgery, particularly for those who have predisposing risk factors. A diagnosis of AVN should be considered in all patients presenting with hip pain following DHS fixation. http://dx.doi.org/10.1016/j.injury.2012.07.313 [P 5.3] Biomechanical comparison of the APTUS and DVR plates S. Patil 1,* , J. Stone 2 , T. Joyce 2 , A. Mahon 1 1 University Hospital of North Durham, United Kingdom 2 Newcastle University, United Kingdom Introduction: The aim of our study was to compare the stability offered by two different types of locking plates (APTUS, variable angle locking plates, vs DVR fixed angled locking plates) when used to fix unstable distal radius fractures. Methods and results: 12 left Sawbone (fourth generation) syn- thetic radii were obtained from Sawbones ltd. An unstable 23C2.1 type fracture was created 1 cm from the wrist joint surface. A 5 mm dorsally based wedge was excised to represent dorsal comminu- tion. 6 DVR plates and 6 APTUS plates were used to fix the fractures. Seven screws were used to fix the distal fragments (three into the lunate fossa and four into the scaphoid fossa) and three were placed in the proximal shaft. Each Sawbone radius was fixed with plaster of Paris and mounted into a resin cylinder. Each bone was loaded cyclically (250 N, 5000cycles) using Instron MTS. The displacement with each cycle was noted. The displacement of the fragments after cyclical loading was measured using an electronic Vernier calliper. Each bone was then loaded dorsally (100 N), volarly (100 N), over scaphoid fossa (250 N) and over the lunate fossa (250 N). A load dis- placement curve was plotted. A permanent displacement of 2 mm or more or implant breakage was considered as failure. The APTUS plate showed significant displacement (p = 0.001, Mann Whitney U test) at the fracture site on cyclical loading (mean 2.53 mm, 1.5–3.5 mm) compared to the DVR plate (mean0.96 mm, 0.6–1.1). The fracture fragments were significantly more displaced in the APTUS group when measured at the end of cyclical load- ing (p = 0.02). Three APTUS plate fixations failed as the fracture fragments displaced more that 2 mm. Conclusion: The DVR plate provides a stiffer fixation for com- minuted fractures of the distal radius when tested in vivo. http://dx.doi.org/10.1016/j.injury.2012.07.314 [P 6.1] Cambridge limb early warning score (CLEWS © ) – A new limb observation scoring system for trauma and orthopaedics L. Brown * , E. Costello, G. Curran, P. Johnston, C. Whybrow Addenbrooke’s Hospital, Cambridge, United Kingdom There are currently no standardised systems for limb observa- tions. Usual markers are of limb perfusion and neurological status. In our institution we have piloted an early warning scoring system designed to identify patients at risk of life- or limb-threatening complications following trauma. Our aim is to validate this sys- tem and determine scores which predict need for intervention (e.g. revascularisation or fasciotomy) in the acutely injured limb. The Cambridge Limb Early Warning Score (CLEWS) uses the following observational parameters, recognised as important in assessment for neurovascular compromise, to give a total score for each limb out of 13: colour, warmth, sensation, movement, capil- lary refill, pulse. The document is Trust-wide and currently under evaluation for sensitivity, reliability and ease of use. Early results for the first 260 patients scored show that the CLEWS scoring system is easy to administer, reliable and sensitive to change. The score generates a meaningful threshold which can be used to trigger escalation to medical staff to promote prompt assessment of at-risk patients, especially if their clinical situa- tion deteriorates. A standardised scoring system allows ease of communication of the patient’s clinical state between health care providers. We have developed an easily-administered, reliable and valid scoring system which has been trialled successfully in one clinical delivery unit and now has been adopted Trust-wide. Ongoing evaluation is being undertaken of the CLEWS’ predic- tive values across a wider variety of patients. We aim to provide threshold values to predict the need for surgical intervention, as well as escalation for further assessment. http://dx.doi.org/10.1016/j.injury.2012.07.315 [P 6.2] Change in the gap index to assess the adequacy of plaster cast on follow-up radiographs and its co-relation in predicting fracture stability S. Gudipati, T. Madhu * , P. Templeton, B. Scott Leeds Teaching Hospitals, Leeds, United Kingdom Aims of study: To investigate the sensitivity of gap index mea- sured on follow-up radiographs to predict the reduction of swelling in the plaster cast thereby increasing the risk of re-displacement following closed reduction. Patients and methods: A cohort of children presented with a trau- matic displaced fracture of distal radius who were treated with closed manipulation alone was selected for this study. Cast index and Gap index was measured in the intra-operative radiograph and at one and two-weeks follow-up to note the change in these indices. A cast index of 0.7 and gap index of <0.15 at the fracture site was considered to be a satisfactory moulded cast. Results: With a mean age of 9 years (range 4–15 years), there were 41 children admitted between Jan 2008 and Feb 2010. Serial radiographs show a gradual loss of reduction in 34 (83%) children and 17 (41%) of these required a second surgery. As the plaster cast was not changed, the cast index remained same while the gap index increased as the swelling subsided on the follow-up X-rays. The intra-operative gap index was <0.14, which increased to 0.18 (n = 7, p) in children whose fracture remained in a satisfactory position, while in children whose fracture displaced, the gap index increased to 0.20 at one-week and to 0.26 at two-week follow-up (n = 34, p = 0.0092). Conclusion: Gap index which can be measured easily on follow- up radiographs can assess the adequacy of plaster cast before the fracture reduction is lost. It is sensitive to change in the gap between the skin and plaster as the swelling subsides. http://dx.doi.org/10.1016/j.injury.2012.07.316