A number of classification systems exist for posterior malleolus fractures of the ankle. The reliability of these classification systems remains unclear. The primary aim of this study was to evaluate the reliability of three commonly utilised fracture classification systems of the posterior malleolus. 60 patients across 2 hospitals sustaining an unstable ankle fracture with a posterior malleolus fragment were identified. All patients underwent radiographs and computed tomography of their injured ankle. 9 surgeons including pre-ST3 level, ST3-8 level, and consultant level applied the Haraguchi, Rammelt, and Mason & Molloy classifications to these patients, at two timepoints, at least 4 weeks apart. The order was randomised between assessments. Inter-rater reliability was assessed using Fleiss’ kappa and 95% confidence intervals (CI). Intra-rater reliability was assessed using Cohen's Kappa and standard error (SE). Inter-rater reliability (Fleiss’ Kappa) was calculated for the Haraguchi classification as 0.522 (95% CI 0.490 – 0.553), for the Rammelt classification as 0.626 (95% CI 0.600 – 0.652), and the Mason & Molloy classification as 0.541 (95% CI 0.514 – 0.569). Intra-rater reliability (Cohen's Kappa) was 0.764 (SE 0.034) for the Haraguchi, 0.763 (SE 0.031) for the Rammelt, 0.688 (SE 0.035) for the Mason & Molloy classification. This study reports the inter-rater and intra-rater reliability for three classification systems for posterior malleolus fractures. Based on definitions by Landis & Koch (1977), inter-rater reliability was rated as ‘moderate’ for the Haraguchi and Mason & Molloy classifications; and ‘substantial’ for the Rammelt classification. Similarly, the intra-rater reliability was rated as ‘substantial’ for all three classifications

Management of complex posterior malleolar fractures requires a detailed appreciation of ligamentous and bony anatomy for optimal fracture fixation and restoration of articular congruency. Pre operative planning is vitally important to determine the surgical strategy for complex ankle fractures. We evaluated pre operative planning strategy pre and post implementation of BOAST 12 guidelines (2016) focussing on pre operative CT scans prior to definitive fixation at a major trauma centre. A multi-surgeon retrospective review of prospectively collected data from 2013 to 2018 was performed at a major trauma centre. Patients who had sustained a posterior malleolar fracture and definitive fixation were identified. Information was collated from PICS, PACS, the trauma database and operative notes. 134 patients were identified over a 5 year period who had sustained a posterior malleolar fracture and had definitive fixation. (Pre BOAST guidelines = 61, Post BOAST guidelines = 73). Prior to the implementation of BOAST guidelines ¼ with posterior malleolar fractures did not have a pre operative CT scan (15/61). Post implementation of BOAST 12 90% (66/73)patients with fixation of posterior malleolus fractures had a pre operative CT scan. Posterior malleolus surgery most commonly took place In patients between 18–30 years. Following implantation of BOAST 12 guidelines there was a 15% increase in pre operative CT scanning for ‘complex ankle fractures'. Changes in national guidelines have heavily influenced pre operative planning strategy for ankle fractures at University Hospitals Birmingham. A detailed appreciation of fracture pattern pre operatively helps guide surgical strategy