The use and creation of knowledge by practitioners is complex. There is a contemporary emphasis on the implementation of knowledge, or evidence, derived from outside the immediate practice environment. However, there is also an appreciation of the context-specific nature of practitioner knowledge that they use to inform patient care, and that is derived from their intimate contact with patients. This paper described one study that sought to analyse the impact of developments in practice on the wider professional and organisational community. Three case study sites were identified through a multidimensional sampling matrix, and interviews conducted with 41 practitioners of various organisational positions and professions. The primacy of context-specific, or proximal knowledge was highlighted, together with a manipulation of evidence and policy to fit understandings of local patient need.