Is supraspinatus pathology as defined by magnetic resonance imaging associated with clinical sign of shoulder impingement?

To examine the association between supraspinatus pathology and clinical sig n of impingement, 42 workers with and 31 age-matched workers without signs of subacromial impingement had their shoulder examined by magnetic resonanc e imaging. All subjects were selected From an epidemiologic study evaluatin g the risk of shoulder impingement syndrome in relation to ergonomic exposu re. Physical examination was conducted according to the same protocol and i ncluded assessment of shoulder function. Magnetic resonance images were eva luated in a blinded manner with regard to clinical status and age. Twenty-t wo (55%) subjects in the impingement group and 16 (52%) subjects in the con trol group had a pathologic supraspinatus tendon (odds ratio 1.13 [95% conf idence interval 0.45 to 2.88]). The prevalence of supraspinatus pathology i ncreased from 32% in the youngest to 48% in the middle and 72% in the oldes t age group. The results of this study indicate that supraspinatus patholog y is related to age rather than to clinical sign of impingement.