Maturation-related biochemical changes in swine anterior cruciate ligament and tibialis posterior tendon.

In order to determine the differences between ligaments and tendons in terms of change in biochemical composition during maturation, the biochemical characteristics of the anterior cruciate ligament and tibialis posterior tendon of swine were studied. The collagen content of the tibialis posterior tendon was found to increase rapidly with growth of the body, reaching a plateau prior to maturation. In contrast, the rate of increase in the anterior cruciate ligament was slow, indicating that maturation of this tissue is delayed. The quantity of glycosaminoglycan in both the anterior cruciate ligament and the tibialis posterior tendon decreased with growth. In mature animals, glycosaminoglycans in the anterior cruciate ligament included chondroitin sulfate, hyaluronic acid, and dermatan sulfate, but only trace amounts of chondroitin sulfate were found in the tibialis posterior tendon. Although the ratio of dermatan sulfate to hyaluronic acid generally increased with growth, this increase was more conspicuous in the tibialis posterior tendon than in the anterior cruciate ligament. The anterior cruciate ligament and tibialis posterior tendon both contained collagen of types I, III, and V. In mature swine, type III was increased in the anterior cruciate ligament but not in the tibialis posterior tendon. These findings demonstrate slower maturation for ligament than for tendon with regard to the changes in biochemical constituents, especially those in collagen type and glycosaminoglycan, during the growth process, and also suggest that the composition of these tissues changes in accordance with their changing functional requirements.