Determining Prognosis for Injuries from Repetitive Tasks
Many people engaged in repetitive tasks such as supermarket cashiers, assembly-line workers, and workers in the food or meat packing industry develop work-related upper extremity musculoskeletal disorders (UEMS). Symptoms include shoulder, elbow wrist, and/or hand pain and dysfunction. The natural history or clinical course (what is likely to happen) for UEMS is unknown. Giving a patient an idea of a prognosis is difficult.
The authors of this study tried to put this condition into perspective. They looked at a three-year period of time and described patient outcomes when they were exposed to highly repetitive work. They gave 700 workers a survey to fill out.
The survey had a variety of questions about pain, discomfort, ache, and other symptoms. The workers reported areas(s) affected and symptoms present. Information about the workers was also collected (e.g., age, gender, work satisfaction, changes in work tasks, previous surgery or other treatment).
Everyone was also examined by an occupational physician at the start of the study. From the information gathered between the survey and the exam, they were able to classify patients into one of three groups.
Group 1 had a clear diagnosis of upper extremity musculoskeletal disorder (UEMS). Group 2 had a diagnosis of UEMS, which was made before by a specialist or had been present in the last six months. With group 3, it was a little less clear what was going on. Workers in this group didn't have any active symptoms of UEMS, but they had a history of UEMS in the recent past (last six months). To simplify the names given each group, group 1 had a proven UEMS, group 2 had a suspected UEMS, and group 3 had a prior UEMS.
In the natural history of a condition, we find out what happens over time. Does the problem get better and go away? Does it get worse? Does it stay the same? What are the risk factors for a poor prognosis? What are the predictive factors for a good prognosis?
The answers to these questions would be very helpful for physicians and workers when the worker first develops this problem. Together, they can develop a plan of care that might include time off from work or a change in workload or work tasks. Type of treatment (conservative care versus surgery) can be anticipated as well.
According to the results of this study, the recovery rate actually depends on the site of the disorder (not on which group the patient was in). Elbow pain and dysfunction had the best prognosis for recovery, whereas problems in more than one area were less likely to clear up. Recovery rates for neck, shoulder, wrist, and hand fell somewhere between the results for elbow and the outcomes for multisite disorders.
Workers with multiple UEMS disorders were more likely to have persistent problems or recurrent symptoms compared with workers who had single-site involvement. Those with multiple UEMS had more pain that lasted longer. Older workers (defined in this study as over 30 years of age) were more likely to fall into the category of multiple UEMS compared with younger patients (under 30 years).
The original thought in dividing the patients into three separate diagnostic categories was to see if the results varied based on that classification scheme. In other words, workers with active symptoms were expected to have a worse prognosis. Workers with a past history but no current symptoms would do better.
There was some truth to that idea. Workers with symptoms but no previously diagnosed UEMS disorder did end up having a better prognosis when compared with workers who already had a known or diagnosed condition. But the authors felt there needs to be more research in sorting out differences in outcomes over time between the groups. This was especially true for those workers who had single site problems. It was clear that multiple site injuries came out the worst in all cases.
Alexis Descatha, MD, et al. Description of Outcomes of Upper-Extremity Musculoskeletal Disorders in Workers Highly Exposed to Repetitive Work. In The Journal of Hand Surgery. May/June 2009. Vol. 34A. No. 5. Pp. 890-895.