Chertsey Outcome Score for Trauma: Development and validation of a new unifying patient reported outcome measure for orthopaedic trauma

<italic>Purpose:</italic> Lately there is an increasing tendency of using Patient Reported Outcome Measures (PROMs) as a final indicator of the outcome of many surgical treatments in orthopaedics and in other medical specialties. Currently there are many outcome scores in orthopaedics and most of them are site specific. In the contrary there is a lack of trauma specific outcome scores. <italic>Methods:</italic> We have designed a new PROM especially for orthopaedic trauma patients, in order to measure in what extent the patients manage to return to their pre-injury state. This score uses as baseline the preinjury status of the patient and has the aim to determine the percentage of rehabilitation after treatment for any injury. <italic>Results:</italic> A total of 60 Chertsey Outcome Score for Trauma (COST) questionnaires were gathered in our outpatients department. The participants were 57% male (aged 46.81 years ± 18.5 years) and the questionnaires collected at mean 10 months post-injury. A Cronbach’s Alpha value of 0.89 was identified for the whole construct. The three dimensions of the scale had good internal consistency as well (Cronbach’s Alpha test values 0.74, 0.84 and 0.81 for symptoms, function and mental status respectively). Strong/moderate correlation (Spearman’s Rho test 0.43-0.65) was observed between the respective physical/mental dimensions of the COST and SF-12v2 questionnaires. <italic>Conclusion:</italic> There is a need among the orthopaedic trauma society for a specific PROM of trauma. COST is a useful and easy to use tool for every trauma surgeon.