Abstract
Serious knee pain and related disability have an annual prevalence of approximately 25% on those over the age of 55 years. As curative treatments for the common knee problems are not available to date, knee pathologies typically progress and often lead to osteoarthritis (OA). While the roles that the meniscus plays in knee biomechanics are well characterized, biological mechanisms underlying meniscus pathophysiology and roles in knee pain and OA progression are not fully clear. Experimental treatments for knee disorders that are successful in animal models often produce unsatisfactory results in humans due to species differences or the inability to fully replicate disease progression in experimental animals. The use of animals with spontaneous knee pathologies, such as dogs, can significantly help addressing this issue. As microscopic and macroscopic anatomy of the canine and human menisci are similar, spontaneous meniscal pathologies in canine patients are thought to be highly relevant for translational medicine. However, it is not clear whether the biomolecular mechanisms of pain, degradation of extracellular matrix, and inflammatory responses are species dependent. The aims of this review are (1) to provide an overview of the anatomy, physiology, and pathology of the human and canine meniscus, (2) to compare the known signaling pathways involved in spontaneous meniscus pathology between both species, and (3) to assess the relevance of dogs with spontaneous meniscal pathology as a translational model. Understanding these mechanisms in human and canine meniscus can help to advance diagnostic and therapeutic strategies for painful knee disorders and improve clinical decision making.
Highlights
The knee is one of the joints most commonly affected by osteoarthritis (OA), usually secondary to anterior cruciate ligament (ACL), meniscal injuries, trauma, or overuse [1]
The knee joint is composed of the fibrous joint capsule, the synovial membrane, the joint cavity with synovial fluid (SF), menisci, ligaments, and bones lined with articular cartilage
Synovial macrophage-like cells that produce tartrate-resistant acid phosphatase (TRAP) and cathepsin K are significant features of the CCL ruptures in dogs, but not in humans, suggesting species-specific differences in immune responses associated with cruciate ligament ruptures [33]. These findings provide first evidence on the involvement of immune cells in inflammation and cartilage destruction, exact mechanisms and relative contribution to OA remain unknown in both species
Summary
The knee is one of the joints most commonly affected by osteoarthritis (OA), usually secondary to anterior cruciate ligament (ACL), meniscal injuries, trauma, or overuse [1]. 25% of people over the age of 55 have suffered from a significant episode of knee pain in the past year of their life, with half of these people reporting associated disability [1]. As curative treatments for these common knee problems are not available to date, the diseases typically progresses, often leading to OA and the associated chronic pain and disability. The knee joint is composed of the fibrous joint capsule, the synovial membrane, the joint cavity with synovial fluid (SF), menisci, ligaments, and bones lined with articular cartilage.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
