A Population-Based Study of Ulnar Neuropathy at the Elbow in Washington State Workers' Compensation

Background There are no population-based studies of return to work after ulnar neuropathy at the elbow (UNE). We examine the predictors of return to work following a diagnosis of work-related UNE. Methods Workers diagnosed with work-related UNE between 1995 and 2000 were identified from the administrative records of the Washington State workers' compensation system (n = 2,863). The medical records of 250 randomly selected surgical cases were reviewed. The end of wage replacement, our primary outcome, is a surrogate marker of the potential ability to return to work. Cox proportional hazards regression analyses were used to model duration of wage replacement as a function of select sociodemographic, clinical, electrodiagnostic, and disability predictors. Results The mean wage replacement and medical benefits paid per case were $19,100 and $15,200, respectively. Older age, concomitant carpal tunnel syndrome, receipt of wage replacement benefits prior to diagnosis, and longer diagnostic delays were associated with lower return to work potential after injury. Type of treatment (surgical or conservative care) was not associated with return to work. Among surgically treated workers, receipt of wage replacement before establishing a diagnosis was inversely associated with return to work in multivariate models that included clinical severity and electrodiagnostic criteria. Conclusion Work-related UNE is a common and costly occupational health challenge. Efforts to accurately diagnose UNE and maximize functional recovery should start in the first medical encounter. Older workers, those who have concomitant carpal tunnel syndrome, or who are already receiving wage replacement benefits at the time of diagnosis deserve special attention. Am. J. Ind. Med. 53: 1242-1251, 2010. (C) 2010 Wiley-Liss, Inc.