Annular Ligament Instability in Lateral Elbow Pathology: Objective Confirmation Through a Cadaveric Study.

Area of Science:

• Orthopedic biomechanics
• Elbow joint anatomy
• Ligamentous stabilization

Background:

• The annular ligament is crucial for elbow stability.
• Its biomechanical behavior during forearm rotation is not well understood.
• Interindividual variability and association with chondral lesions require investigation.

Purpose of the Study:

• Quantify annular ligament tension variability during forearm rotation.
• Validate arthroscopic findings with objective measurements.
• Explore links between ligament laxity, chondral lesions, and elbow instability.

Main Methods:

• Cross-sectional anatomical study of 25 cadaveric upper limbs.
• Standardized dissection preserving ligamentous and muscular integrity.
• Measurement of ligament displacement using a custom apparatus and micrometer under varying loads and forearm positions (neutral, pronation, supination).

Main Results:

• Significant interindividual variation in annular ligament displacement, maximal in supination (mean 1.23 mm at 3 kg).
• Pronounced differences in displacement across all forearm positions and load levels (p < 0.001).
• Chondral lesions observed in three specimens with ligament laxity and reduced radial head coverage.

Conclusions:

• First objective evidence of annular ligament tension variability during forearm rotation.
• Ligament laxity is associated with lateral elbow instability and cartilage degeneration.
• Reinforces the annular ligament's role as a key secondary elbow stabilizer.