抄録
This study was aimed to clarify the pathogenesis of the calcification in a rotator cuff tear (CR) and a calcifying tendinitis (CT). Eighty stumps of torn rotator cuff tendons were obtained from 80 shoulders during surgery. The stumps of the cuff tendons were cut into 5 strips along the tendon fiber direction. All specimens were sectioned at a 3 μm and stained histochemically and immunohistochemically. The CR cases were divided into two groups as follows : A- 15 cases with calcium deposits in torn tendons ; B- 65 cases without any calcium deposits. The clinico-pathological features were investigated and compared between the two groups. Eight cases of calcifying tendinitis (group C) were examined by the similar methods. Calcified deposits in the CR were microscopically observed as free and scattered micro-calculi among the fibroblasts and collagen fibers particularly at the torn ends of a cuff, accompanied by other degenerative changes. Histologically, remarkable thinning and disorientation of collagen fibers, and intense myxoid degeneration in the tendons were found in group A. CR was found in the cases with a longer duration of symptoms and frequently found in the cases with a massive tear. In CT, calcification appeared in the aggregated globular pattern and was always found with the degenerative collagen fibers. There were some histiocytes and vascular proliferations as reparative reaction, and no evidence of inflammation around the calcified areas. In conclusion, calcification in CR was considered to be dystrophic and may be one of the chronic pathological changes correlated with the long duration of the degenerative processes or aging. CT seemed to be characterized by direct calcium deposits between or on the degenerated collagen fibers without any inflammatory change or enchondral calcification. CT may occur in association with a trigger of micro-trauma probably due to genetic factor or joint laxity.
