The Influence of Chronic Pain on Postoperative Pain and Function After Hip Surgery: A Prospective Observational Cohort Study

Pre-existing or chronic pain is an established risk factor for severe postoperative pain. In this prospective observational cohort study, we investigated whether a history of chronic pain, beyond the presence of hip-related pain, affected other postoperative factors including early mobilization, function, and psychological distress after hip surgery. Patients who underwent total hip replacement surgery were observed from the preoperative day until the seventh postoperative day. Before surgery, they were characterized by their pain history, pain intensity, function, and psychological characteristics. Postoperatively, pain intensity was evaluated on day 1, 3, 5, and 7 and the analgesic consumption was recorded for each of these days. Measures of function (functional questionnaire, ability to mobilize and to climb stairs, and range of hip motion) and psychological distress were re-evaluated on day 7. A history of chronic pain was associated with slower postoperative mobilization, poorer physical function, and greater psychological distress in addition to increased postoperative pain intensity. The comorbidity of a chronic pain disorder resulted in greater pain intensity after surgery, and also impeded postoperative rehabilitation. Identification of patients with a chronic pain disorder is necessary preoperatively so that appropriate pain management and rehabilitation can be planned to facilitate recovery. (C) 2016 by the American Pain Society