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Trapeziometacarpal joint loading during key pinch grip: A cadaver study.
L Athlani1, M Bergere2, D Motte2
1Department of Hand Surgery, Division of Orthopedics and Trauma Surgery, Geneva University Hospitals, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva 14, Switzerland; Department of Anatomy, Faculty of Medicine, University of Geneva, Rue Michel Servet 1, 1206 Geneva, Switzerland.
Hand Surgery & Rehabilitation
|December 13, 2021
Summary
This study directly measured trapeziometacarpal joint loads during key pinch, finding lower loads than biomechanical models suggest. These findings are crucial for understanding thumb joint mechanics and improving future models.
Area of Science:
- Orthopedics
- Biomechanics
- Anatomy
Background:
- The trapeziometacarpal joint is crucial for thumb function.
- Previous estimations of loads in this joint during key pinch have relied on biomechanical models.
- Direct in-situ measurements of these loads are lacking.
Purpose of the Study:
- To directly measure the load within the trapeziometacarpal joint during isometric key pinch.
- To compare these measured loads with existing biomechanical model estimations.
Main Methods:
- A cadaveric study was conducted on 10 fresh-frozen adult forearms and hands.
- Thumb key pinch was simulated by loading the primary actuator tendons.
- Loads were measured internally within the trapeziometacarpal joint using a force-sensing resistor.
Main Results:
- Median loads in the trapeziometacarpal joint were 1.9kg, 3kg, and 4.1kg for 0.5kg, 1kg, and 1.5kg key pinch forces, respectively.
- Measured loads were substantially lower than those predicted by biomechanical models (which often exceed 10kg for a 1kg pinch).
- High consistency was observed between repeated trials for each specimen.
Conclusions:
- Directly measured trapeziometacarpal joint loads during key pinch are lower than previously estimated.
- Intersubject variability may explain discrepancies between experimental data and biomechanical models.
- This pilot study provides a foundation for future research comparing models and experimental data.
