Quantitative morphology of full thickness rotator cuff tears.

The occurrence of full thickness rotator cuff tears (RCTs) at time of death, the size and distribution of those tears among the tendons of the rotator cuff, and the anterior to posterior and medial to lateral dimensions of the RCTs were determined. A subset of 57 shoulders from a group of 414 were found to have full thickness rotator cuff tears. The three-dimensional coordinates of specific bony landmarks and points defining the circumference of the RCT were digitized using a Flock of Birds DC electromagnetic tracking device. Bony landmarks were used to determine the separation between adjacent tendons of the rotator cuff. Points describing the circumference of the RCT were used to calculate the area of the tear. The majority of tears occurred in the supraspinatus tendon alone (25), or in both the supraspinatus and infraspinatus tendons (22). The areas of the RCTs ranged from 0.07 cm(2) to 19.17 cm(2) with an average of 4.43 cm(2). The mean anterior to posterior length was 1.95 cm. The mean medial to lateral length was 1.98 cm.