 The study aims to investigate the natural course and the results of operative treatment of chronic tennis elbow TE. Chronic is defined as symptoms having lasted for more than a year. The investigators will also study the effect of pain catastrophising on the subjective outcome, the patient acceptable symptomatic state and the response shift phenomenon in TE. The study will also ascertain the feasibility of a multi-center randomised, controlled trial RCT, and test and refine the co-operation and interaction of the planned RCT centers. 