Effect of absorbable polydioxanone flexor tendon repair and restricted active mobilization in a canine model

We performed an experimental study to evaluate the mechanical and histologic healing process of flexor tendon repair using absorbable polydioxanone monofilament followed by active mobilization. Sixty-four canine flexor digitorum profundus tendons were repaired using polydioxanone monofilament or control braided polyester. Animals were evaluated 7, 14, 28, and 42 days after surgery with 12 day 0 control tendons. All repaired tendons healed without rupture or gap formation. Mechanically, all specimens had adequate tensile strength enabling active mobilization. The tendons that were repaired using braided polyester healed without initial tensile depression; however, the ultimate tensile strength values of polydioxanone specimens showed a significant decrease at day 14. Histologically, an inflammatory response was observed around the polydioxanone monofilament; this reaction increased from day 14 to day 42. However, the inflammatory response did not cause large adhesions or large tendon callus formation. This method of using absorbable suture material for tendon repair has the potential for use in the clinical setting.