Collagen Scaffold Bioaugmentation for ATFL Repair in Chronic Ankle Instability

This is a multicenter, randomized, controlled clinical trial comparing two surgical techniques for the treatment of chronic ankle instability (CAI). CAI is a condition in which the outer ligaments of the ankle remain loose and the ankle continues to give way after repeated sprains, causing pain, swelling, and difficulty with sports and daily activities. About 30-40% of patients who sprain an ankle go on to develop CAI. All patients in this study receive arthroscopic repair of the anterior talofibular ligament (ATFL) - the main ligament on the outside of the ankle - together with an Internal Brace, a high-strength suture tape that provides immediate mechanical reinforcement. In the experimental group, an absorbable type I collagen scaffold (REGENETEN) is additionally wrapped onto the repair to promote the regrowth of ligament-like tissue. Patients in the control group receive the Internal Brace repair alone. Eligible patients are aged 18 to 65 with chronic lateral ankle instability that has not improved with standard non-surgical treatment and in whom the ATFL tissue is of poor quality or a previous repair has failed. Participants are randomly assigned 1:1 to one of the two groups, and treatment is assigned by a central computer-generated schedule stratified by study site. Both groups follow the same standardized surgical steps and the same post-operative rehabilitation program. The main question is whether adding the collagen scaffold leads to better ankle function and stability 12 months after surgery. Patient-reported function, pain, return to sport, MRI evidence of ligament healing, and any complications will be followed for up to 24 months.