A Biomechanical Study of Achilles Tendon Repair Augmentation Using GraftJacket Matrix

Background: Ruptured Achilles tendons benefit from primary repair by decreasing re-rupture rates and allowing earlier range of motion. A stronger repair might allow for more aggressive rehabilitation decreasing postoperative stiffness, calf atrophy, and repair site gapping. The hypothesis of this study was that human dermal allograft augmentation of an Achilles repair would significantly increase repair strength and stiffness. This study evaluated strength and stiffness of an Achilles tendon repair augmented with a human dermal allograft (GraftJacket). Materials and Methods: Eight matched pairs of human cadaver legs were used. Simulated Achilles tendon ruptures were created 4 cm proximal to the calcaneal insertion. All tendons were repaired with a Krackow locking loop stitch. One of each matched pair was augmented with GraftJacket. Each construct was pre-loaded at 10 N and cyclically loaded (20 cycles) from 2 N to 30 N at a rate of 5 N/sec on an Instron machine. This was followed by testing to failure at a displacement rate of 6 mm/sec. Results: The ultimate failure load in the control group was 217 N ± 31 compared to 455 N ± 76.5 in the GraftJacket group (p < 0.001). The mean stiffness in the control group was 4.3 ± 0.83 N/mm which was significantly less than the 12.99 ± 5.34 N/mm in the GraftJacket group (p = 0.002). Conclusion: The augmentation of an Achilles tendon repair with GraftJacket significantly increased repair strength and stiffness. Clinical Significance: These findings suggest that a GraftJacket augmented Achilles tendon repair could acutely withstand a more aggressive rehabilitation program, potentially decreasing ankle stiffness and allowing earlier return to full activities.