Barriers to the effectiveness of any intervention in OA. 
One of the main barriers to the effectiveness of interventions in osteoarthritis (OA) is adherence to treatment interventions and advice.  Estimates suggest that adherence to any intervention in OA is between 50 and 95% but many of these estimates are derived from clinical trials and the real levels in clinical practice may be much lower.  The factors influencing adherence are complex and multifactorial and, although information is available from other diseases, little is known about the relative contribution of these factors in adherence to treatment in OA.  Few interventions to improve adherence have been evaluated in OA, and such studies would be limited by the lack of an accurate method for assessing adherence.