BackgroundIn the UK 17.8 million people have musculoskeletal pathophysiology, which becomes universal with age. Levels of discomfort and incapability correlate with symptoms of anxiety and depression. People with sufficient symptoms who seek care can benefit from collaborative diagnosis and treatment of mental and physical health organised by a case manager. This paper presents the protocol for a feasibility trial of collaborative care in an orthopaedic setting.AimsTo determine the feasibility and acceptability of providing collaborative care for patients with musculoskeletal conditions and co-existing symptoms of anxiety and depression identified on a screening tool in a physical and occupational therapy out-patient setting.MethodA two-arm parallel-group randomised controlled trial will recruit 40 adult out-patients with at least moderate anxiety and depression, who have been referred for physiotherapy and occupational therapy. Participants will be allocated on a 1:1 ratio to collaborative care or to usual care. Co-primary outcomes will be key feasibility indicators collected at baseline and at 6 months. A qualitative study will be conducted post-intervention to explore the acceptability and potential improvements to the collaborative care model.ResultsThis study will investigate the use of the collaborative care model for patients with musculoskeletal and co-existing moderate or severe levels of anxiety or depression.ConclusionsThe results will provide important evidence to determine a future trial.