Anterior Cruciate Ligament Repair Augmented With a Polyethylene Terephthalate Band Supports Biomechanical Stability During the Early Healing Phase in a Rabbit Model

Background: Augmented repair is an alternative strategy for the treatment of acute ligament and tendon injuries that imparts time-zero biomechanical strength to allow early loading, thereby protecting the repaired structures during the early healing process. Purpose: To investigate the biomechanical properties and biological healing process after suture repair of acute anterior cruciate ligament (ACL) tears with polyethylene terephthalate (PET) augmentation and compare the findings with those obtained without PET augmentation. Study Design: Controlled laboratory study. Methods: A total of 48 rabbits were assigned to 3 groups: a PET-augmented group, a nonaugmented suture repair group, and a natural (control) group. All 3 groups were evaluated at 4, 12, and 16 weeks after surgery. Biomechanical performance was assessed using tensile strength testing, and ACL healing and maturation were assessed using histological assessments. Results: The PET-augmented group showed less anterior knee laxity at 30° of knee flexion and superior structural continuity compared with the suture group. ACL repair with PET augmentation yielded recovery of the maximum tensile load as early as 4 weeks compared with that of the natural group (110.5 ± 6.5 vs 129.0 ± 8.6 N, respectively; P = .29) and a gradual improvement in linear stiffness from 4 weeks (58.4 ± 3.9 N/mm) to 16 weeks (83.1 ± 5.1 N/mm; P = .04), approaching that of the natural group (106.7 ± 5.8 N/mm). Furthermore, histological analyses revealed that in the PET-augmented group, the ACL healed back to the proximal insertion as early as 4 weeks with angiogenesis and collagen regeneration, and the increased ligament maturity score indicated a gradual healing process from 4 to 16 weeks. Conclusion: Compared with nonaugmented repair, repair augmented with a PET band enhanced early ACL stability and supported healing of ACL tears in a rabbit model. Clinical Relevance: The biomechanical and histological findings support subsequent clinical investigations using PET augmentation in patients with acute ACL tears.