The purpose of this study was to evaluate the changes in several parts of the shoulder region in the series of individuals suffering from rotator cuff tears and to elucidate the pathogenesis. The BMD was measured by DEXA. In 26 cases of rotator cuff tear, all patients were right-dominant,12 men and 14 women, divided into 4groups,7 men were affected in the right shoulder (group 1),5 men were affected in the left shoulder (group 2),10 women were affected in the right shoulder (group 3) and 4 women were affected in the left shoulder (group 4), BMD of the head of the humerus, greater tubercle of the humerus, minor tubercle of the humerus, surgical neck of the humerus and humeral shaft were evaluated. The average age was 61.5 ± 11.6 years old in men and 63.5 ± 7.4 years old in women. In all groups there were no significant differences (P<0.05) of BMD between the affected side and the unaffected side. However, BMD of all regions in the affected side were lower than those in the unaffected side in men. On the other hand, BMD of all regions in the left side were lower than those in the right side regardless of the affected or the unaffected in women. Then we calculated the mean side-to-side BMD difference (the affected side BMD minus the unaffected side BMD / the unaffected side BMD x 100 (%)). There is significant difference between the group 1 and the group 3, but there is no significant difference between the group 2 and the group 4 in the mean side-to-side BMD difference. In this study there were various patterns in BMD of the shoulder region in rotator cuff tear patients.
