Intra-articular ligaments, arthroscopic observations and treatment

Anatomy and physiology

Ligaments associated with joints can be extra-articular, peri-articular or intra-articular. Extraarticular ligaments frequently are blended with, or form part of the fibrous capsule. In other cases they are quite distinct. Peri-articular ligaments lie within the fibrous capsule; those that connect directly apposing surfaces of bone are termed interosseous ligaments. Both intra and periarticular ligaments are covered by a thin layer of synovial membrane. This makes their thecal surfaces arthroscopically visible. There is also evidence that infusion from synovial fluid is a significant pathway for delivery of nutrients.

Ligament attachments to bone are more complex than simple penetration of Sharpey's fibres into the cortex. Superficial collagen fibres blend with periosteum, whereas deeper fibres go through four transition zones as they enter bone. These are made of ligament, fibrocartilage, mineralised fibrocartilage and bone. This arrangement minimises stress concentration at the ligament-bone interface. Equine dissections have determined that fibres of nerves that supply the joints are also distributed to articular ligaments. 

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