Why participants in The United Kingdom Rotator Cuff Tear (UKUFF) trial did not remain in their allocated treatment arm: a qualitative study.

The UKUFF trial was a three-way parallel group randomised trial comparing surgical and non-surgical treatments for people with rotator cuff tears of their shoulder. High crossover between arms in the UKUFF led to the original trial design being reconfigured; 'Rest then Exercise' was halted. This study explored why participants recruited did not remain within allocated treatment arms and explored crossover and surgical decision making.