Differences in proliferative rate and collagen lattice contraction between endotenon and synovial fibroblasts

Injured and surgically repaired tendons heal with the formation of scar tissue. Scar tissue represents 1 of the most unpredictable factors contributing to postoperative morbidity. The main cell involved in scar formation is the fibroblast. The relative activity of fibroblasts from the fibro-osseous sheath (the tissue surrounding the tendon in zone II) and the endotenon (the core of the tendon) with respect to proliferation and the ability to contract a collagen lattice were compared in vitro. The fibroblasts derived from the fibro-osseous sheath were more active in both these respects. In addition, the amount of matrix metalloproteinase activity was found to be greater for the fibro-osseous sheath fibroblasts, implying a greater capacity to degrade and disorganize connective tissue and thus migrate. These results imply that the fibro-osseous fibroblasts represent a more active population of cells compared with endotenon fibroblasts, and perhaps should be specifically targeted in future modes of therapy.