Axial load transmission through the elbow during forearm rotation

Area of Science:

• Biomechanics
• Orthopedic Research
• Human Anatomy

Background:

• Forearm rotation is crucial for axial force transmission in the elbow joint.
• Understanding force distribution across radiocapitellar and ulnotrochlear joints is vital.

Purpose of the Study:

• To investigate force transmission across the radiocapitellar and ulnotrochlear joints during forearm rotation.
• To quantify changes in contact mechanics within the elbow joint during pronation and supination.

Main Methods:

• Utilized ten human cadaveric upper limbs on a custom apparatus.
• Applied a 160 N axial load during cyclic forearm rotation.
• Measured joint force, contact pressure, and contact area using a force-sensitive transducer.

Main Results:

• Radiocapitellar joint force showed no significant difference between pronation and supination (P=.3547).
• Pronation resulted in significantly larger contact area (P=.0001) and lower contact pressure (P=.0001) at the radiocapitellar joint.
• No significant differences in contact pressure, area, or force were observed at the ulnotrochlear joint between pronation and supination.

Conclusions:

• Elbow joint contact mechanics, specifically at the radiocapitellar joint, vary with forearm rotation.
• Lower mean contact pressure in pronation, attributed to increased contact area, may offer joint protection.
• Findings suggest the pronated elbow's protective role in high-impact scenarios like martial arts or falls.