BIOLOGY OF THE ROTATOR CUFF TENDON

Tendons are complex composite material composed primarily of water, co llagen, proteolycans, and cells, designed to transmit tensile loads fr om muscle to bone. Although rotator cuff tendons differ in many ways f rom other tendons in the body, a knowledge of basic tendon structure a nd function is helpful in understanding rotator cuff tendon biology, i njury, and repair. Ln addition to type I collagen, rotator cuff tendon s contain small amounts of type III collagen, which play a role in hea ling and repair. In comparison with other tendons, the increased glyco saminoglycan and proteoglycan content seen in rotator cuff tendons may be adaptive, pathologic, or both. The etiology of rotator cuff pathol ogy is probably related to trauma, aging, and degeneration. As our und erstanding of these processes increases, we will be able to develop an d implement improved preventative and therapeutic interventions for ro tator cuff pathology.