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Load mechanics of the midcarpal joint
S F Viegas1, R M Patterson, P D Todd
1Division of Orthopaedic Surgery, University of Texas Medical Branch, Galveston 77551.
The Journal of Hand Surgery
|January 1, 1993
Summary
The midcarpal joint transmits load through specific areas, not the entire surface, even under significant weight. This research details these distinct contact zones and their load distribution.
Area of Science:
- Orthopedic biomechanics
- Anatomy of the wrist
Background:
- The midcarpal joint is crucial for wrist function.
- Understanding its load transmission is vital for diagnosing and treating wrist injuries.
Purpose of the Study:
- To analyze the contact areas and load distribution within the human midcarpal joint.
Main Methods:
- Utilized fresh cadaver upper extremities.
- Employed a static positioning frame and pressure-sensitive film.
- Analyzed contact prints using a microcomputer.
Main Results:
- Identified four primary contact areas: scaphoid-trapezium-trapezoid, scaphoid-capitate, lunate-capitate, and triquetrum-hamate.
- Contact areas comprised less than 40% of the joint surface, even under 118 pounds of load.
- Load distribution was detailed across these areas (e.g., scaphoid-capitate 28%, lunate-capitate 29%).
Conclusions:
- The midcarpal joint, similar to the radiocarpal joint, transmits loads through specific, distinct regions.
- A relatively small percentage of the total joint surface handles the load.
- Findings provide insight into wrist biomechanics and injury mechanisms.