Advances in the biology of zone II flexor tendon healing and adhesion formation.

There has been dramatic improvement in the results of zone II tendon surgery in the last three decades. This improvement was brought, to a great extent, by the better understanding of the mechanisms of tendon healing. This article provides an overview of the mechanism of intrasynovial tendon healing, the role and origin of fibroblasts, and the effects of extracellular components and various growth factors on tendon healing. It also sheds light on the incidence and significance of tendon adhesions. An account of the ultrastructure of the synovial sheath is presented.