STRUCTURAL CHARACTERISATION OF TENDONS: Uncovering Characteristics of Human Tendons and Ligaments Commonly Injured or Used as Grafts in Orthopaedic Surgery

Abstract

Tendons play a major role in musculoskeletal functioning. Tendon and ligament disease (including degeneration, rupture, traumatic injury, etc.) affects multiple different tendons throughout the body and is increasing in prevalence. Many patients require surgical reconstruction or tendon/ligament replacement with graft tissue, but long-term outcomes of such treatment is poor. The key to improving treatment outcomes is knowledge of underlying differences in physiology and structure-function aspects of different tendons/ligaments. As knowledge of “normal” tendon structure is lacking, the aim of this project was to compare the structures of normal (healthy) human cadaveric tendons and ligaments of the upper and lower limbs using consistent methodologies and donor tissue source.

However, as current histopathological scoring systems for tendon research focus on classification of pathology rather than utility as a generalised histo-morphologic characterisation tool, this project also aimed to develop a novel scoring system suitable for charactering differences between normal tendons/ligaments.

This study incorporated histological investigations conducted on 48 different tendons/ligaments harvested from left or right (randomised) upper and lower limbs of 8 human (male and female) cadaveric tissue donors.

The newly developed scoring system – which successfully addressed gaps underexplored by currently available methodologies, providing a valuable tool for future work and exploration – revealed numerous and vast differences/similarities in tendon/ligament structural characteristics. Cell characteristics, architectural features, proteoglycan content, interfascicular regions and crimp properties all exhibited variations between different tissues.

Overall, these findings provide critical information for understanding the normal structure and physiology of tendons and ligaments, aiding research into appropriate prevention and repair strategies for various injuries or pathologies.