Compressive Graft Fit Promotes Tendon-to-Bone Integration After Anterior Cruciate Ligament Reconstruction

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Tissue engineering

Background:

• Tendon graft integration into bone tunnels is crucial for anterior cruciate ligament reconstruction (ACLR) success.
• Poor integration can lead to cyst formation and tunnel widening, often requiring revision surgery.
• The influence of graft fit on tendon-to-bone integration remains unclear.

Purpose of the Study:

• To investigate how graft fit within bone tunnels affects zonal tendon-to-bone integration.
• To test the hypothesis that a tight graft fit promotes integration and reduces cyst formation in a murine ACLR model.

Main Methods:

• A controlled laboratory study using a murine anterior cruciate ligament reconstruction (ACLR) model.
• Graft fit was manipulated: compressive fit (1 mm graft in 0.413 mm tunnel) versus loose fit (wider tunnel or smaller graft).
• Tunnel integration and cyst formation were assessed at 28 days post-surgery using cryohistology.

Main Results:

• Compressive graft fit led to higher friction during insertion, indicating a tighter fit.
• Mineralized fibrocartilage formation, indicating integration, was improved with compressive fit.
• Loose-fit tunnels, particularly wider ones, showed significantly increased cyst formation.

Conclusions:

• A compressive fit of tendon grafts in bone tunnels enhances zonal tendon-to-bone integration after ACLR.
• Minimizing graft-bone gaps reduces cyst formation, suggesting improved healing.
• Optimizing graft sizing for a compressive fit is a critical factor for successful ACLR outcomes.