Objectives: To compare days on sick leave and assess predictors of return to work following shoulder surgery.

Design: A secondary analysis of a randomised controlled trial.

Setting: Orthopaedic Department.

Participants: 114 patients with type II superior labral tear from anterior to posterior (SLAP) lesions of the shoulder.

Interventions: Labral repair, biceps tenodesis or sham surgery.

Outcome measures: Sick leave was obtained from national registers for the last year before and two years following surgery. Total and shoulder related number of days on sick leave were obtained, using international diagnostic codes. We applied the difference-in-difference (DID) approach to compare the differences in the change in mean work days on sick leave between groups over time, backwards logistic regression and lasso regression to evaluate predictors.

Results: Mean total number of work days on sick leave during the 2 years after surgery was 148 (range 0 to 460) days. More than 80% of the sick leave days were taken by 25% of the patients. Days on sick leave classified as shoulder-related constituted 80% of the total. In all three treatment groups, the mean total number of days on sick leave doubled the year after surgery. Sick leave for the 2-year postoperative period was not significantly different between groups when adjusted for days of sick leave the year before surgery. Predictors of return to work at 2 years analysed by logistic regression were no sick leave (OR 8.0, 95% CI 2.4 to 26.0) and moderate symptoms of anxiety or depression (OR 0.16, 95% CI 0.05 to 0.5) at inclusion. Similar results were obtained by lasso regression but manual work was an additional predictor.

Conclusions: In this study, sham surgery and labral repair were significantly different from biceps tenodesis in terms of post-operative days on sickness absence.  Sick leave, symptoms of anxiety and depression and manual work at inclusion predicted work status 2 years after surgery.