provides stability to the patella as it glides over the patellofemoral groove and femoral condyles. The medial and lateral collateral ligaments are extracapsular ligaments that protect the medial and lateral sides of the knee from a contralateral outside or inside bending force, respectively. The anterior and posterior cruciate ligaments are intracapsular ligaments that stabilize the knee during rotation and bending. Together, these tissues contribute significantly to normal knee function. The connective tissues of the knee joint are known to derive their mechanical properties from their biochemical components, but precise structure-function relationships remain elusive beyond general notions of the role of the extracellular matrix. Structurally, each of these tissues is hypocellular and possesses an ECM rich in collagen, with varying amounts of glycosaminoglycans . In general, collagen is known to be largely responsible for the tensile integrity of these tissues, while GAGs, predominant in hyaline cartilage and sparse in fibrous tissues, contribute to compressive strength. In addition to total collagen content, the amount of crosslinking present in the collagen network has been shown to play an important role in tissue tensile properties. In examining tissue tensile properties, two important measures of tensile integrity are Young��s modulus and ultimate tensile strength. Young��s modulus is a measure of a material��s tensile stiffness, and the UTS is the maximum stress a material can withstand. Though collagen content and crosslinking are known to play a role in tensile mechanics, their precise structure-function relationships with respect to Young��s modulus and UTS remain unclear. Pyridinoline crosslinks have been shown to correlate with both tensile strength and stiffness in articular cartilage, but there is a dearth of literature describing the contribution of pyridinoline crosslinks to the mechanical behavior of fibrocartilage or ligament tissues. In humans, conditions afflicting the connective tissues of the knee, such as traumatic injury and Publications Using Abomle ZM447439 osteoarthritis, contribute to substantial healthcare costs and work-related disability. The field of tissue engineering aims to improve orthopaedic medicine by providing functional replacements for damaged or diseased joint tissues. Recent tissue engineering efforts have focused on major connective tissues such as hyaline cartilage, meniscus, tendon, and ligament. Although various approaches have been employed to engineer these tissues, it has been difficult to reproduce native collagen organization and attain native mechanical properties. Various types of mechanical and biochemical stimuli have been studied to improve construct properties, and both scaffold-free and scaffold-based approaches have been investigated for connective tissue engineering applications. An additional consideration in these tissue engineering efforts has been the cell source used to produce constructs. Comparisons of cell types have shown that immature cells exhibit increased biosynthesis, making them promising candidates for tissue engineering. Immature cells have been used to produce constructs with clinically relevant dimensions and mechanical properties on par with native tissue. To make informed cell source choices, it is necessary to establish a comprehensive understanding of the physiology of immature joint tissues.