BACKGROUND: The purpose of this study was to determine the prevalence of posttraumatic stress disorder among patients seen following an orthopaedic traumatic injury and to identify whether injury-related or demographic variables are associated with the disorder. METHODS: Five hundred and eighty patients who had sustained orthopaedic trauma completed a Revised Civilian Mississippi Scale for Posttraumatic Stress Disorder questionnaire. Demographic and injury data were collected to analyze potential variables associated with posttraumatic stress disorder. RESULTS: Two hundred and ninety-five respondents (51%) met the criteria for the diagnosis of posttraumatic stress disorder. Patients with posttraumatic stress disorder had significantly higher Injury Severity Scores (p = 0.04), a higher sum of Extremity Abbreviated Injury Scores (p = 0.05), and a longer duration since the injury than those without posttraumatic stress disorder (p < 0.01). However, none of these three variables demonstrated a good or excellent ability to discriminate between patients who had posttraumatic stress disorder and those who did not. The response to the item, "The emotional problems caused by the injury have been more difficult than the physical problems," was significantly associated with the presence of posttraumatic stress disorder (p < 0.0001) and showed a fair ability to identify patients with the disorder. CONCLUSIONS: Posttraumatic stress disorder is common after orthopaedic trauma. Patients who respond positively to the item, "The emotional problems caused by the injury have been more difficult than the physical problems," may meet diagnostic criteria for this disorder and should be evaluated further.