Microscopic histopathology of chronic refractory lateral epicondylitis.

The histopathologic features from 11 patients who were treated surgically for lateral epicondylitis were graded and compared to similar tissue from 12 cadaveric specimens. All studies were done by a single pathologist who had no knowledge of the origin of the specimen. The surgical specimens were interpreted as abnormal in all 11 specimens, and all 12 of the control specimens were reported as being without histologic abnormality. Vascular proliferation was present in 10 of 11 and focal hyaline degeneration was recorded in all 11 of the surgical specimens. Neither feature was present in any of the control material (P < 0.001). These data suggest that chronic refractory lateral epicondylitis requiring surgery is a degenerative rather than inflammatory process. This may account for the lack of response to rest and antiinflammatory medication.