Primary tendon healing: a review

Clinical and experimental studies on primary tendon healing are reviewed and correlated. Emphasis is placed on the importance of blending the extratendinous and intratendinous elements of tendon healing to obtain optimal functional results. Studies which demonstrate the ability of tendon cells to metabolize, proliferate, and secrete collagen when isolated from paratendinous tissue are cited along with those which demonstrate the importance of the microcirculation of the tendon in tendon healing. Those factors which interfere with intratendinous healing are discussed, such as invasive suture techniques, tension on the area of repair, and interference with segmental blood supply within zone II. The importance of the synovial sheath and synovial fluid in nourishing tendon cells and the effect of ischemia in stimulating the ingrowth of adhesions are brought out. Discussion includes such factors involved in the postoperative management of tendon repairs as those which affect the strength of tendon repairs and quantitative and qualitative methods of modifying adhesion formation.