Published by Maney Publishing (c) W. S. Maney & Son Limited Phys. Ther. Rev. 1996; 1: 23-34 lateral epicondylalgia I: epidemiology, pathophysiology, aetiology and natural history This paper deals with the phenomenon of lateral epicondylalgia or tennis elbow. This is a relatively common disorder with a well defined clinical presentation. It has been used extensively as a clinical model in studies evaluating the nature of musculoskeletal pain and dysfunction, and the factors contributing to the development of such dysfunction. It might be anticipated that this body of research would have provided a sound understanding of the epidemiology, pathophysiology, aetiology and natural history of this disorder. This paper presents a critical review of the available research which suggests that many questions remain unaddressed or unanswered. Widespread preconceptions such as the widely accepted belief in the role of inflammation in the pathogenesis of lateral epicondylalgia may need to be re- appraised. Existing research is critiqued and directions for future research including improvements in research methodology are proposed. Bill Vicenzino and Anthony Wright Department of Physiotherapy, University of Queensland, Queensland, Australia 4072 Key words: aetiology; epidemiology; epicondylalgia; lateral epicondylitis; musculoskeletal pain; natural history; pathophysiology; tennis elbow Introduction Lateral epicondylalgia or tennis elbow is a common disorder which significantly impacts on the com- munity. There is relatively little dispute as to the clinical presentation which constitutes this disorder. It is usually defined as pain over the lateral epi- condyle which is reproduced by digital palpation over the lateral epicondyle, resisted wrist extension, middle finger extension and gripping.! The relative simplicity of the clinical presentation belies the com- plexity of the underlYing pathophysiological and aetiological processes. This review seeks to critically appraise the literature pertinent to the epidemiology, pathophysiology, aetiology and natural history of lateral epicondylalgia. In particular, current evidence 1083-3196/96/010023 + 12 $12.00/0 23 on the involvement of the nociceptive system in chronic pain states is used to provide some alternative theories of the pathophysiology underlYing lateral epicondylalgia. Nomenclature Tennis elbow, lateral epicondylitis and lateral epi- condylalgia are some of the terms which are used interchangeably in the description of what is es- sentially the same condition. 'Tennis elbow' has gained widespread acceptance through historical pre- cedence but is often misleading as it refers to only one potential cause. 2 -4 References to medial and lat- eral tennis elbow by some authors5-9further confuse © 1996 W.B. Saunders Company Limited