We investigated whether short-term versus long-term sick leave after orthopaedic inpatient rehabilitation can be predicted by initial assessment information, the clinical status at discharge, or whether the follow-up interval is crucial for later sick leave. We examined 214 patients from an orthopaedic rehabilitation hospital at admission, discharge and 1-year follow-up. Outcome measures included disability, depression, self-efficacy, health status and attitudes towards work. Later short-term versus long-term sick leave was not significantly predicted by pretreatment and posttreatment scores. Surprisingly, both groups improved comparably during treatment. The long-term sick leave group deteriorated on most of the variables at follow-up, whereas the short-term sick leave group maintained the improvements. Rehabilitation interventions should not only focus on inpatient treatment but also on the follow-up interval to prevent relapses and maintain success reached during treatment.