Matrix stabilization using glutaraldehyde and glycation: Effects on the material properties of the knee meniscus

The knee meniscus transmits loads, acts as a shock absorber, is a secondary stabilizer, and facilitates joint lubrication and nutrition. Unfortunately, injury reduces its functionality, which over time leads to bone remodeling and degenerative joint disease. Meniscus transplantation using allografts is gaining momentum for injury treatment. Short-term results show favorable incorporation into the joint, and patients report pain relief and increased mobility. However, objective analyses have shown that many allografts suffer some degree of deterioration believed to be a result of enzymatic attack. These findings encourage research into stabilization methods that render the allograft resistant to biodegradation but at the same time retain native material properties to preserve normal function.; The first objective of this research was to characterize the material properties of normal porcine and human menisci in order to provide a basis for the subsequent evaluation of stabilization effects. The second objective was to determine the effects of glutaraldehyde- and glycation-induced matrix stabilization on the material properties of porcine meniscus. All specimens were tested in confined compression under three applied stresses (0.066, 0.196, and 0.326 MPa) to measure effects on aggregate modulus, permeability, and equilibrium strain.; Aggregate modulus and equilibrium strain generally increased and permeability decreased with increasing contact stress for both porcine and human menisci. No interspecies variations were detected, justifying porcine use in subsequent tests. Repeated testing of porcine menisci had no effect on material properties, so specimens served as their own controls for subsequent experiments.; Stabilization using dual-cycle heart valve protocols increased aggregate modulus by 213% and decreased equilibrium strain by 57%. Reducing the glutaraldehyde concentration produced smaller changes, and one treatment (0.02%/1d) did not alter aggregate modulus and equilibrium strain. For glycation, three treatments (15mM/2d, 15mM/10d, 30mM/2d) did not alter aggregate modulus and equilibrium strain. However, all stabilization treatments increased permeability by at least 108%.; This study reveals a dose-dependent relationship between meniscal material properties and certain stabilization conditions and identifies treatments that minimally affect these properties. Further research is necessary to determine whether these treatments prevent enzymatic degradation before and after surgical implantation in the knee.