Is Ulnar Collateral Ligament Strength Proportional to Height and Weight?

Area of Science:

• Orthopedics
• Biomechanics
• Sports Medicine

Background:

• Ulnar collateral ligament (UCL) surgeries are increasing in baseball pitchers.
• Pitcher size has increased, raising questions about UCL strength relative to body size and elbow varus torque.
• Debate exists on whether pitching kinetics should be reported as torque or normalized torque.

Purpose of the Study:

• To quantify the relationship between pitcher body size and UCL mechanical properties.
• To test the hypothesis that larger body size correlates with greater UCL strength, stiffness, and cross-sectional area.

Main Methods:

• Ultrasound measurements of UCL thickness and length in 20 cadaveric male elbows.
• Mechanical testing to failure of the UCL at 90° flexion.
• Linear regression analysis to correlate geometric and biomechanical data.

Main Results:

• No significant correlation was found between UCL failure torque and pitcher height, weight, or height × weight.
• UCL stiffness also showed no significant correlation with body size parameters.
• UCL cross-sectional area did not significantly correlate with body height, weight, or height × weight.

Conclusions:

• Pitcher body size is not correlated with ulnar collateral ligament strength or stiffness.
• Clinicians should avoid assuming larger athletes possess stronger UCLs.
• Normalization of elbow varus torque by body weight and height is not recommended for adult athletes.