Ligaments

Ligaments are dense bands of fibrous connective tissue that connect bone to bone, contributing to joint stability and guiding joint motion. They are composed primarily of type I collagen, with some type III collagen, organized in a crimped pattern that allows elasticity and load absorption.

Ligaments contain fibroblasts (ligamentocytes), extracellular matrix components, and have limited vascular supply. Their biomechanical strength varies based on location and function—e.g., the anterior cruciate ligament (ACL) has high tensile strength but poor intrinsic healing potential.

Healing occurs via:

1. Inflammatory phase – clot formation and cell infiltration.

2. Proliferation phase – fibroblast proliferation and matrix deposition.

3. Remodeling phase – collagen alignment and maturation.

Extra-articular ligaments (e.g., MCL) heal better than intra-articular ligaments (e.g., ACL). Surgical reconstruction is often needed for the latter. Current research explores biological augmentation, scaffolds, and gene therapy to improve healing outcomes.