Cyclic loading of 3 Achilles tendon repairs simulating early postoperative forces

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Regenerative Medicine

Background:

• Accelerated rehabilitation protocols after Achilles tendon repair are increasingly advocated.
• However, these protocols can impose significant biomechanical forces on the repair site.
• The strength of current Achilles tendon repair techniques may be insufficient to withstand these early postoperative forces.

Purpose of the Study:

• To evaluate the biomechanical strength and gap resistance of augmented versus non-augmented Achilles tendon repair techniques.
• To compare the cyclic loading performance of percutaneous, standard Krackow, and augmented Krackow Achilles tendon repairs.

Main Methods:

• A controlled laboratory study was conducted on fifteen Achilles tendons.
• Tendons underwent either percutaneous, 4-strand Krackow, or augmented 4-strand Krackow repair after a 4-cm incision.
• Repaired tendons were subjected to cyclic loading at 100 N, 190 N, and 369 N to assess cycles to initial gapping, 5-mm gapping, and total failure.

Main Results:

• Augmented Krackow repairs demonstrated significantly greater gap resistance (2208 cycles) compared to non-augmented Krackow (502 cycles) and percutaneous repairs (5 cycles).
• All percutaneous repairs failed at 100 N, while non-augmented Krackow repairs failed at 190 N.
• Augmented Krackow repairs remained intact after 190 N loading, with some failing at 369 N, indicating superior strength and durability.

Conclusions:

• Epitendinous cross-stitch weave augmentation significantly enhances the strength and gap resistance of Achilles tendon repairs.
• This augmented technique may provide the necessary repair integrity to facilitate earlier controlled stretching and ambulation post-surgery.
• The findings support the use of augmented repairs for patients undergoing accelerated rehabilitation programs.