June 2, 2010 — Psychosocial factors may predict persistent pain after non–life-threatening acute orthopaedic trauma, according to the results of a study reported in the May issue of The Journal of Pain.
"The early identification of those at risk of ongoing pain is of particular importance for injured workers and compensation systems for whom pain management and durable return to work are important outcomes," write Fiona J. Clay, from Monash University in Clayton, Victoria, Australia, and colleagues. "The study quantifies the association between a range of bio-psychosocial factors and the presence of persistent pain, pain severity and pain interfering with normal work activities in a cohort of 168 patients with a range of non-life-threatening orthopaedic injuries."
Patients presenting to 1 of 4 Victoria hospitals for treatment of their injury were recruited and were observed until 6 months after injury. Factors predicting pain outcomes at 6 months postinjury were identified with multivariate analysis.
More than half (54%) of participants reported having persistent pain at 6 months, and most (87%) reported having pain that interfered with their usual work activities. Significant independent predictors of pain outcomes were high levels of initial pain, external attributions of responsibility for the injury, and psychological distress.
Pain-related work disability was also significantly predicted by poor recovery expectations, and pain severity was significantly predicted by being injured at work. Because many of these factors are potentially modifiable, the clinician should be aware of them to be able to intervene appropriately to prevent the development of pain chronicity.
"This study has quantified determinants of pain, 6 months after non-life-threatening acute orthopaedic trauma," the study authors write. "Psychosocial factors strongly predicted persistent pain, pain-related work disability, and pain severity. These findings may assist clinicians to determine the need for, and likely effectiveness of, individual pain-management approaches in this population."
Limitations of this study include small sample size, limiting statistical power; lack of a measure of the impact of the event or of the number of pain sites; and use of a single item from the 36-item Short-Form Health Survey as a measure of pain-related work disability. In addition, the interpretation of external attributions of responsibility was not based on a validated scale.
"The results of this study need to be confirmed in larger studies and more homogenous injury populations," the study authors conclude. "An assessment of the extent of hospital-based medical treatment and pre- and post-hospital based rehabilitation and medication use would enable us to understand the importance of these factors in managing problems with pain."
The Transport Accident Commission and the Monash University Postgraduate Students Fund supported this study. Dr. Clay received a NHMRC Public Health scholarship and a VIC Health scholarship. The remaining study authors have disclosed no relevant financial relationships.
J Pain. 2010;11:420-430. Abstract
Learn more about chronic pain online at the National Institute of Neurological Disorders and Stroke Web site.
Pain is one of the most common presenting symptoms and is often associated with acute orthopaedic events. Despite physical healing, some individuals continue to have persistent pain and disability and a reduced capacity for functioning. Previous prospective studies focusing on major trauma populations have suggested that factors other than the physical injury are important in the development of persistent pain. A number of factors measured during the course of recovery including high initial pain intensity, posttraumatic stress disorder, compensation status, education, and depression have demonstrated to independently predict ongoing pain and disability. However, there still remains a lack of follow-up studies that evaluate predictors of pain outcomes after non-life-threatening orthopaedic injuries.
The aim of this study was to quantify the association between a range of biopsychosocial factors and the presence of persistent pain, pain severity, and pain interfering with normal work activities in a cohort of patients with a range of non-life-threatening orthopaedic injuries.
- In this prospective study, 168 participants were recruited after presentation to 1 of 4 Victoria hospitals for treatment of their injury and were observed until 6 months postinjury between March 2005 and October 2006.
- The inclusion criteria were people aged 18 to 64 years who had been employed for a wage during the 4 weeks before the injury, with English-language skills sufficient to allow completion of questionnaires.
- Injury factors were retrieved from the patient medical record to allow for coding of the injury according to the Abbreviated Injury Scale and the calculation of the Injury Severity Score.
- Multivariate analysis was used to determine factors associated with pain outcomes 6 months postinjury.
- The short-form McGill Pain Questionnaire was used to assess current pain severity and at 6 months after injury. A single-item question on pain as it affects normal work from the 36-item Short-Form Health Survey was used to measure the extent of pain interfering with work activities at 6-month follow-up.
- Data on pain outcomes at 6 months were available for 150 participants (89%).
- The prevalence of pain was common; 54% of participants reported the presence of persistent pain at 6 months, with the majority (87%) reporting that pain interfered to an extent with their normal work activities.
- High initial pain, external attributions of responsibility for the injury, and psychological distress were all found to be significant independent predictors of the presence of all 3 outcomes.
- Other significant associations for the persistent pain included being injured at work and sustaining an injury to the lower extremity.
- In addition, poor recovery expectations, female sex, education less than a university level, having at least 1 comorbid condition, and having sustained a lower extremity injury were found to be significant predictors of pain-related work disability.
- Also, injury at work, increasing age, and the presence of a fracture were significant predictors of pain severity.
- During the course of recovery after a major trauma, factors that include high initial pain intensity, posttraumatic stress disorder, compensation status, education, and depression have demonstrated to independently predict ongoing pain and disability.
- High initial pain, external attributions of responsibility for the injury, and psychological distress are factors that strongly predict persistent pain, pain-related work disability, and pain severity in patients with a range of non-life-threatening orthopaedic injuries.