Gross pathological findings (Results section: Gross pathological findings). A severe inflammation was seen after 10 days following surgical implantation of the collagen implant (A). This healing tendon was cut longitudinally to find the remnants of the collagen implant in the injured area at 10 DPI. The granulation tissue was formed around this implant and the size of the implant was decreased (B). After 30 days following injury, the collagen implant was completely absorbed at gross level and a transparent but tendinous like tissue was formed in the injured area (C). At 120 DPI, the ICTs showed muscle fibrosis and disuse atrophy. The tendon edges were not connected by the newly regenerated tendinous tissue and the transverse diameter of the injured area in this group was decreased (D&E). The gross appearance of the tendons is hyperemic and a loose areolar connective tissue has filled the gap. Generally this tissue is not similar to the tendon and is more similar to an unorganized fascia (D&E). At this stage, the ITTs was completely formed and no remnant of the collagen implant was seen in the defect. Also the gross appearance of the newly regenerated tendon in the defect (F) is similar to the NCTs (G). No characteristic muscle fibrosis or atrophy in the ITTs is seen (F).