Showing papers by "Jukka S. Jurvelin published in 1986"
TL;DR: Effects of immobilization with a splint for 11 weeks on the stiffness of the articular cartilage in the canine knee were investigated and influenced the quality and quantity of articular Cartilage.
Abstract: Using the indentation method, effects of immobilization with a splint for 11 weeks on the stiffness of the articular cartilage in the canine knee were investigated. Stiffness was determined for femoral, tibial, and patellar articular cartilages with nine, eight, and three test points, respectively, in the form of elastic moduli. Immobilization, without causing any macroscopic changes on cartilage surface, influenced the quality and quantity of articular cartilage. Immobilization caused significant softening of the femoral and tibial cartilages. The rate of deformation under the test load increased (42%) and the average thickness of the cartilage decreased (9%) as compared with the controls. Normal cartilage stiffness remained in the contact area between the patella and patellar surface of the femur, probably as a consequence of the sustained, but not forceful, loading between the femur and the patella produced by the flexion of the knee joint.
163 citations
TL;DR: Stiffening and alteration in the biomechanical property were considered to be typical responses of articular cartilage to an increased, but physiologic loading pattern.
Abstract: Using the indentation method, we investigated the effects of physical exercise (treadmill running 4 km/day for 15 weeks) on stiffness of the articular cartilage in the canine knee. Considering cartilage to be an elastic material with homogeneity and isotropy, we calculated elastic moduli for femoral, tibial, and patellar cartilages using instant and 15-s deformations after load application. Although the elastic moduli do not represent, because of the non-equilibrium condition, true elastic properties of articular cartilage, they characterize, together with the retardation time spectrum, the integrated response of articular cartilage during the first 15 s after load application. The moderate loading used in our training program caused no macroscopic changes on the articular surface. In running dogs, the mean stiffness of articular cartilage increased by 6% as compared with the controls. Stiffening, which was attributed to the decreased fluid flow in the cartilage, was significant (P less than 0.05) on the patellar surface of the femur and on the tibial condyles. In general, stiffness increased more (approximately 10%) in the cartilage areas, which were repeatedly heavily loaded during running exercise. This alteration in the biomechanical property as well as an increase (approximately 11%) in thickness were considered to be typical responses of articular cartilage to an increased, but physiologic loading pattern.
95 citations
TL;DR: The articular cartilage of the lateral tibial condyle of control and of both splinted and contralateral knee joints were studied using a stereological method, which allowed the authors to derive, from quantitative histologic measurements, three-dimensional parameters defining the tissue structure.
Abstract: Eight young New Zealand White rabbits were immobilized by splinting the hind limb to extension for eight weeks. Eight mobile animals served as controls. The articular cartilage of the lateral tibial condyle of control and of both splinted and contralateral knee joints were studied using a stereological method, which allowed the authors to derive, from quantitative histologic measurements, three-dimensional parameters defining the tissue structure. Qualitatively, osteoarthrotic changes occurred in both the splinted and the contralateral knee joints. Quantitatively, osteoarthrotic changes produced an increase in cell density but a decrease in cell size in the superficial zone of articular cartilage, and an increase in cell size in the deep zone. Combined qualitative and quantitative histologic characteristics were also analyzed. Different types of osteoarthrosis were observed in the splinted and the contralateral knees.
27 citations