Surgical intervention and implantation of the collagen prosthesis (Methods section: Injury induction and surgical reconstruction). Plantar part of the Achilles tendon was prepared aseptically (A). After skin incision the left Achilles structure was exposed (B). The temperature of the surface of the Achilles tendon was measured by a digital laser thermometer (C). Two cm of the Achilles tendon between the gastrocnemius and calcaneus was measured using digital caliper (D). This part of the tendon was surgically cut and discarded (E). The remnants of the Achilles structures were maintained in their normal anatomical direction by application of the Kessler suture (F). The collagen implant was then implanted in the defect area and the suture was led to pass throughout the implant (G&H). The skin over the lesion was closed in a simple interrupted manner, with low tension on the sutures (I).