BackgroundAlthough the increasing complexity and expansion of the body of knowledge in physical therapy have led to specialized practice areas to provide better patient care, the impact of specialization on guideline implementation has been scarcely studied. ObjectivesThe objective of this study was to identify the similarities and differences in barriers to the implementation of a Dutch rheumatoid arthritis (RA) guideline by generalist and specialist physical therapists. DesignThis observational study consisted of 4 focus group interviews in which 24 physical therapists (13 generalist and 11 specialist physical therapists) participated. MethodsPhysical therapists were asked to discuss barriers to the implementation of the RA guideline. Data were analyzed qualitatively using a directed approach to content analysis. Both the interviews and the interview analysis were informed by a previously developed conceptual framework. ResultsBesides a number of similarities (eg, lack of time), the present study showed important, although subtle, differences in barriers to the implementation of the RA guideline between generalist physical therapists and specialist physical therapists. Generalist physical therapists more frequently reported difficulties in interpreting the guideline (cognitive barriers) and had less favorable opinions about the guideline (affective barriers) than specialist physical therapists. Specialist physical therapists were hampered by external barriers that are outside the scope of generalist physical therapists, such as a lack of agreement about the roles and responsibilities of medical professionals involved in the care of the same patient. ConclusionsThe identified differences in barriers to the implementation of the RA guideline indicated that the effectiveness of implementation strategies could be improved by tailoring them to the level of specialization of physical therapists. However, it is expected that tailoring implementation strategies to barriers that hamper both generalist and specialist physical therapists will have a larger effect on the implementation of the RA guideline.