The effect of storage on the biomechanical behavior of articular cartilage--a large strain study

The transplantation of stored shell osteochondral allografts is a potentially useful alternative to total joint replacements for the treatment of joint ailments. The maintenance of normal cartilage properties of the osteochondral allografts during storage is important for the allograft to function properly and survive in the host joint. Since articular cartilage is normally under large physiological stresses, this study was conducted to investigate the biomechanical behavior under large strain conditions of cartilage tissue stored for various time periods (i.e., 3, 7, 28, and 60 days) in tissue culture media. A biphasic large strain theory developed for soft hydrated connective tissues was used to describe and determine the biomechanical properties of the stored cartilage. It was found that articular cartilage stored for up to 60 days maintained the ability to sustain large compressive strains of up to 40 percent or more, like normal articular cartilage. Moreover, the equilibrium stress-strain behavior and compressive modulus of the stored articular cartilage were unchanged after up to 60 days of storage.