There has been much recent debate on the impact of competition on the English National Health Service (NHS). However, studies have tended to view competition in isolation and are controversial. This study examines the impact of programme theories associated with the health system reforms, which sought to move from a dominant target-led ‘central control’ programme theory, to one based on ‘market forces’, on orthopaedics across six case-study local health economies. It draws on a realistic evaluation approach to open up the policy ‘black box’ across different contexts using a mixed methods approach: analysis of 152 interviews with key informants and analysis of waiting times and admissions. We find that the urban health economies were more successful in reaching the access targets than the rural health economies, although the gap in performance closed over time. Most interviewees were aware of the policies to increase choice and competition, but their role appeared comparatively weak. Local commissioners’ ability to influence demand appeared limited with providers’ incentives dominating service delivery. Looking forward, it is clear that the role of competition in the NHS has to be considered alongside, rather than in isolation from, other policy mechanisms.