[Biomechanical evaluation of the first carpometacarpal joint stability by using different reconstruction methods]

Area of Science:

• Orthopedics
• Biomechanics
• Anatomy

Background:

• The first carpometacarpal (CMC) joint is crucial for thumb function.
• Instability of the CMC joint can result from ligamentous injury.
• Understanding biomechanical stability is key for effective treatment strategies.

Purpose of the Study:

• To compare the biomechanical stability of the first CMC joint using different ligament reconstruction methods.
• To provide a theoretical basis for selecting optimal reconstruction techniques in clinical practice.

Main Methods:

• Twelve fresh adult cadaver upper limb specimens were used.
• Specimens were divided into normal, injury, and three reconstruction groups (palmar, dorsal, palmar-dorsal ligaments).
• Biomechanical testing involved load-displacement curves and elastic modulus calculations after creating dislocation models and performing reconstructions.

Main Results:

• All reconstruction methods significantly improved first CMC joint stability compared to the injury group (P<0.05).
• The elastic modulus values indicated significant differences between groups.
• Volar-dorsal ligament reconstruction yielded the highest elastic modulus, suggesting superior stability, though not fully normalizing it.

Conclusions:

• Reconstruction of volar, dorsal, or both volar and dorsal ligaments enhances first CMC joint stability.
• Volar-dorsal ligament reconstruction provides the most significant improvement in stability.
• Despite improvements, current reconstruction methods do not fully restore the joint to its normal stability levels.