Gap Formation During Cyclic Testing of Flexor Tendon Repair

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Tendon Biomechanics

Background:

• Tendon healing is crucial for restoring function after injury.
• Gap formation in repaired tendons is a potential concern for healing outcomes.
• Understanding the mechanical behavior of repaired tendons under load is essential.

Purpose of the Study:

• To investigate the relationship between gap formation and repair failure in flexor tendons during cyclic loading.
• To identify biomechanical indicators of impending repair failure.

Main Methods:

• Thirty-five porcine flexor tendons underwent surgical repair.
• Repaired tendons were subjected to cyclic loading until failure or 500 cycles.
• Specimens were categorized into Sustained, Fatigued, and Disrupted groups based on failure patterns.

Main Results:

• A 'fatigue point' indicating plastic deformation and elongation was observed in the Fatigued group before failure.
• Substantial gap formation consistently followed the fatigue point, leading to repair failure.
• Sustained repairs showed no fatigue point or significant gapping during loading.

Conclusions:

• The emergence of a fatigue point and subsequent gap formation during cyclic loading predicts flexor tendon repair failure.
• Inadequate tendon repairs susceptible to gapping are at high risk of mechanical failure.