Progress in research into tendon-to-bone attachment, from structure, development, treatment to animal models

Tendon-to-bone attachment, the junction of tendon and bone, is a special complex structure which spreads stress from skeletal muscles to bone, effectively reducing the stress concentration and balancing elastic modulus between tendon and bone. Injury to its interface is a kind of trauma in sports, such as rotator cuff tear, ACL/PCL tear and the Achilles tendon injury. The enthesis is not regenerated after injury and the healing enthesis consists of disorganized scar tissue, resulting in a high rate of rupture recurrence. Given a high incidence of tendon and ligament injuries and complex structural and cellular composition of the native enthesis, the reparative strategies for tendon-to-bone attachment are facing great dificulties. Although injury to tendon-to-bone attachment is always a major concern and challenge in sports medicine, not much is known about its pathogenesis. In this review, we summarize the recent literature published at home and abroad from 4 perspectives of structure, development, treatment and animal models of enthesis. We hope this review may help clinical professionals understand more about the tendon-to-bone attachment. Key words: Bones; Tendons; Wounds and injuries; Therapy; Models, animal