Studies on tendon healing. A comparison between suturing techniques.

An experimental study comparing Kessler's and Tsuge's techniques for tendon suture was undertaken in dogs. Both second and fifth flexor digitorum profundi tendons of the left forepaw were divided in the segment corresponding to zone 2 of human hands. Following division, the tendons to the second digit were repaired by Kessler's technique and those to the fifth digit by Tsuge's method. Results were evaluated by means of standard and polarized--light microscopy, intravascular dye injections and tensile strength tests. Both ordinary and polarized--light microscopy showed that a microscopical gap develops between the tendon ends, being filled in with healing tissue which undergoes progressive maturation. The tensile strength tests showed that the deformation (elongation) progress directly with load, up to the point of rupture; the suture thread does not interfere with this. Furthermore, strength increases with time. Intravascular dye injection showed that a net of newly formed blood vessels develops at the site of section and suture, previously destitute of macroscopical vessels. The new vessels tended to redistribute them selves to resemble the pattern in normally vascularized regions. It was not possible to detect, by means of the methods employed, any important difference between Kessler's and Tsuge's techniques for tendon suture.