Flexor tendon grafts for pulley reconstruction - Morphological aspects

Area of Science:

• Orthopedic surgery
• Hand surgery
• Biomaterials science

Background:

• Finger joint motion relies on pulley function, essential for hand dexterity.
• Pulley damage causes significant functional impairment, often necessitating surgical reconstruction.
• Flexor tendon grafts, like flexor digitorum superficialis (FDS) and palmaris longus (PL), are used for reconstruction, but their suitability is not fully understood.

Purpose of the Study:

• To compare the micromorphology of human pulleys with common flexor tendon grafts (FDS and PL).
• To evaluate the suitability of FDS and PL tendons for pulley reconstruction through detailed analysis.

Main Methods:

• Cadaveric study analyzing human A2 and A4 pulleys alongside FDS and PL tendons.
• Utilized scanning electron microscopy (SEM), histology, and immunohistochemistry.
• Assessed surface morphology, core structure, and vascularization (CD31+ microvessels).

Main Results:

• SEM revealed distinct surface morphologies between pulleys and tendons.
• Pulleys exhibit lamellar collagen sheets; FDS shows individual fibrils, PL a less hierarchical structure.
• Similar microvessel density (CD31+) was observed in pulleys and tendons, indicating comparable vascularization.

Conclusions:

• Provides novel SEM and immunohistochemical data on human pulley and tendon micromorphology.
• Intrasynovial flexor tendons, particularly FDS, appear suitable for pulley reconstruction.
• Preserving the paratenon is critical for successful graft revascularization in pulley reconstruction.