Effects of administration of exogenous growth factors on biomechanical properties of the elongation-type anterior cruciate ligament injury with partial laceration

BACKGROUND: No studies have been conducted to clarify the in vivo effect of growth factor application on healing in the injured anterior cruciate ligament. HYPOTHESIS: Administration of exogenous growth factors significantly increases the structural properties of the injured anterior cruciate ligament. STUDY DESIGN: Controlled laboratory study. METHODS: Thirty-six rabbits were randomly divided into 4 groups of 9 animals each after an overstretched injury was made in the right anterior cruciate ligament. In group 1, no treatment was applied around the injured anterior cruciate ligament. In group 2, 0.2 mL fibrin sealant was applied around it. In group 3, 4 ng transforming growth factor-beta1 mixed with 0.2 mL fibrin sealant was applied. In group 4, 20 microg platelet-derived growth factor-BB mixed with 0.2 mL fibrin sealant was applied. Each rabbit was sacrificed at 12 weeks after the surgery. In addition, 9 knees randomly harvested from all the left knees were used to obtain normal control data. The femur-anterior cruciate ligament-tibia complex specimens were biomechanically and histologically evaluated. RESULTS: Concerning the maximum load and the stiffness, group 3 was significantly greater than groups 1 and 2, whereas there were no significant differences among groups 1, 2, and 4. Groups 1, 2, 3, and 4 were significantly lower than the control group. CONCLUSIONS: The application of 4 ng transforming growth factor-beta1 significantly enhances healing in the injured anterior cruciate ligament. CLINICAL RELEVANCE: Administration of certain growth factors is of value to be studied as one of the future therapeutic options for the overstretched anterior cruciate ligament injury.