Collagen organisation in the fibrous joint capsules in the digits of the human hand.

Normal function of the hand and, in particular, the finger joints is fundamental to the activities of daily life. Deterioration of hand and finger function can be detrimental and lead to poor quality of life. There are multiple causes of hand and finger dysfunction that can lead to pain and disability. In this review, we will consider the role of collagen and its organization within the finger joint capsules and adjacent entheses, particularly in the proximal interphalangeal joints, and aim to address three questions: (1) What are the main collagen orientations in the interphalangeal joint capsules of the human hand? (2) Is there a relationship between collagen orientation and joint function? (3) How could altering the orientation of collagen fibers affect the functional performance of the joint following injury or surgical intervention? To answer these questions, we will consider the evidence for the main collagen orientations in the finger joint capsules and entheses and investigate the relationships between structure and function. We will then consider how collagen organization is disrupted following injury and what may be potential modulators. This will provide a better understanding of how common surgical interventions affect collagen orientation in the joint capsules and highlight some implications for post-surgical outcomes.