Method for setting total graft force and load sharing in augmented ACL grafts.

Area of Science:

• Biomechanical Engineering
• Orthopedic Surgery

Background:

• Anterior cruciate ligament (ACL) injuries are common, necessitating surgical reconstruction.
• Achieving optimal immediate postoperative mechanical function after ACL reconstruction is challenging.

Purpose of the Study:

• To develop and demonstrate a controllable and reproducible method for setting the immediate postoperative mechanical state of ACL reconstructions.
• To validate a force-setting technique for composite grafts using patellar tendon (PT) and a ligament augmentation device (LAD).

Main Methods:

• A novel force-setting technique was applied to composite ACL grafts (PT and LAD).
• Total graft force was matched to intact ACL force at 30° flexion under standardized load.
• Load sharing between PT and LAD components was controlled at 50/50, 25/75, and 75/25 ratios.
• Forces and 3D knee motion were measured under various flexion angles and tibial loads.

Main Results:

• The force-setting technique consistently achieved total graft force within 2% of the intact ACL force at 30° flexion.
• Load sharing between graft components was accurately set within 5.1% of the desired ratio at 30° flexion.
• The method demonstrated reproducibility in setting graft forces and load distribution.

Conclusions:

• The developed force-setting technique offers a reliable method for achieving predictable mechanical states in ACL reconstructions.
• This technique allows for precise control over graft tension and the balance between biological and augmentation components.
• Controllable and reproducible immediate postoperative mechanical states are achievable, potentially improving surgical outcomes.