Biomechanical Comparison of Nonlocked Minimally Invasive and Locked Open Achilles Tendon Simulated Rupture Repairs

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Sports Medicine

Background:

• Open Achilles tendon repair carries risks of infection and wound complications.
• Percutaneous repair methods aim to reduce these complications but may increase nerve injury risk.
• This study compares gapping resistance between open and percutaneous Achilles tendon repairs.

Purpose of the Study:

• To evaluate the gapping resistance of percutaneous nonlocking Achilles tendon repair against standard open repair.
• To simulate conditions of typical postoperative physiotherapy to assess repair integrity.

Main Methods:

• Ten pairs of cadaver Achilles tendons were transected and repaired using either open Krackow locking loop or percutaneous Achillon system.
• Tendons underwent 1000 tensile loading cycles simulating passive range-of-motion physiotherapy.
• Gapping was measured at various load cycles, and ultimate tensile strength was determined via failure testing.

Main Results:

• Percutaneous repairs exhibited greater gapping than open repairs at multiple load cycles.
• Four of ten percutaneous repairs failed during cyclic loading, while all open repairs succeeded.
• Open repairs withstood 66% greater tensile load before failure compared to percutaneous repairs.

Conclusions:

• Open Krackow Achilles tendon repairs offer superior resistance to gapping during simulated physiotherapy compared to nonlocked percutaneous repairs.
• Locking suture techniques are recommended to maintain repair integrity during early postoperative motion.