Abstract. Objectives. Up to 19% of patients who undergo surgery for an acute hip fracture are readmitted to the hospital within three months of the index operation. We aimed to identify risk factors for unplanned clinic attendance, readmission, and mortality within the first 12 months postoperatively and subsequently determine if there is a role for routine follow-up. Methods. Patients greater than 65 years old who underwent hip hemiarthroplasty using an uncemented Thompson implant for treatment of a traumatic non-pathological hip fracture were identified from a prospectively maintained database at a single institution between August 2007 and February 2011. Patient demographics, comorbidities, place of residence, mobility status, unplanned attendance to an orthopaedic clinic with symptoms relating to the respective limb, readmission, and mortality were recorded. Results. Five hundred and fifty-four consecutive patients were identified. Unplanned clinic attendance was correlated to age (p = 0.000, B = −0.0159, 95% confidence interval (CI): −0.200 to −0.65), with patients between the ages of 65 – 70 years most likely to require unplanned clinic review postoperatively. The American Society of Anesthesiologists (ASA) grade (p = 0.019, 95% CI: 0.014 to 0.163) and frequency of unplanned outpatient attendance (p = 0.000, 95% CI: 0.120 to 0.284) were significantly associated with increased readmission within 12 months of the index procedure with patients who were regarded as ASA > 2 most likely to require readmission within the first postoperative year. Conclusion. To our knowledge, this is the first piece of research that identifies causative factors for unplanned clinic attendance and acute readmission during the first postoperative year in acute hip fracture patients treated by hemiarthroplasty. Routine scheduled follow-up of patients based on risk stratification may be effective in reducing the financial burden of unplanned clinic attendance. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

The calcar femorale or ‘true neck’ of the femur has a role in transmitting load from the cantilevered neck to the femoral shaft (Zhang 2009). It can appear as a distinct condensation in clinical CT images because its structure is very similar to compact bone (Aspden 1998). Harty (1957) proposed that the calcar acts as a ‘spike’ in certain fall situations, contributing to splitting of the trochanter. We hypothesised that among elderly fallers, the size of the calcar would influence whether fractures occurred in the trochanteric (TR) or femoral neck (FN) site. We also asked whether patients who sustained a fracture had more or less calcar bone than frailty-matched controls that fell but didn't fracture. The FEMCO study is designed to investigate male (M) and female (F) patients with acute hip fracture with multi-detector CT, before they undergo surgery. It includes an age, sex and frailty-matched control group (who have sustained at least one injurious fall without hip fracture). The fractured hip is reconstructed in 3D for classification of fracture type (FN or TR). For the present pilot study, there were 14 cases (5TR, 9FN mean 80+/−8.5yrs. 7M, 7F) and 11 controls (83+/−7.0yrs. 3M, 8F). Axial CT slices where a calcar was visible were opened in Stradwin 4.1 software (Treece 2011). The calcar femorale was semi-automatically selected with the flood fill tool. Each axial image that contained a visible calcar was included in the analysis, so that for each femur a single calcar volume was generated. Results were examined using ANOVA. Combining male and female results, there was a non-significant trend towards a higher calcar volume in patients sustaining trochanteric rather than femoral neck fractures (0.73cm3 +/− 0.26 vs 0.61cm3 +/−0.14, p=0.27) but no difference between cases and controls. Males had a significantly higher calcar volume than females (mean 0.82cm3 +/− 0.24 vs 0.59cm3 +/− 0.13, p=0.005). Further studies are now planned in larger samples of each sex, to examine the role of the calcar in fracture mechanics. Three-dimensional visualisations provide a novel insight into the damage patterns and resultant fragment locations