BIOLOGIC CHARACTERISATION OF ROTATOR CUFF TISSUE REPAIR: DO MECHANICAL STRAIN AND VITAMIN C MAKE A DIFFERENCE?

Rotator cuff repair is performed to treat shoulder pain and disability. Failure of the tendon repair site is common; one strategy to improve healing is to enforce a period of post-operative immobilisation. Immobilisation may have unintended effects on tendon healing. Tenocytes under uniaxial strain form more organised collagen and up regulate expression of proliferative genes. Vitamin C (ascorbic acid), an anti-oxidant that is a co-factor for collagen synthesis, has also been reported to enhance collagen deposition and organisation. The purpose of this study was to compare human tenocyte cultures exposed to uniaxial cyclical strain with or without slow-release ascorbic acid (ascorbyl-2 phosphate) to determine their individual and combined effects on tissue remodelling and expression of tissue repair genes.Rotator cuff tissues were collected from degenerative supraspinatus tears from eight patients. Tenocytes were incorporated into 3D type I collagen culture matrices. Cultures were divided into four groups...