Meniscal tissue regeneration using a collagenous biomaterial derived from porcine small intestine submucosa.

PURPOSE: The present investigation is a preliminary study designed to evaluate the use of a collagen-based biomaterial, chemically unaltered porcine small intestine submucosa (SIS), as a scaffold for meniscal tissue regeneration. TYPE OF STUDY: Basic research. METHODS: Surgical defects were created in the lateral menisci of 12 mature New Zealand white rabbits. The defects were repaired with a similarly shaped and sized wedge of a new collagenous biomaterial (SIS) and sutured in place. The opposite knees served as controls by creating a defect in the lateral meniscus without filling with SIS graft. Full cage activity was allowed until the animals were killed at 4, 12, and 24 weeks. RESULTS: At 4 weeks, the graft material retained its physical position and grossly appeared soft and translucent. Histologically, cellular elements had infiltrated between the laminates of the graft. At 12 weeks, the graft grossly appeared more solid and opaque. Histologically, the host meniscal fibrochondrocytes were seen streaming into the peripheral margin of the graft. Early repopulation of the graft with apparently differentiated meniscal tissue was observed. At 24 weeks, the meniscus defect was grossly healed across and looked virtually normal: the normal meniscal shape, contour, consistency, and color had been replicated. Histologically, the healing tissue showed infiltration of what appeared to be meniscal fibrochondrocytes and connective tissue resembling the host meniscal tissue. The graft was nearly totally replaced by host tissue. CONCLUSIONS: This pilot animal study demonstrates that the multilaminated collagenous graft is conducive for cellular repopulation with host meniscal elements, and, by 24 weeks, is capable of supporting complete healing of a large meniscal defect.

The effect of in vitro fluoride ion treatment on the ultrasonic properties of cortical bone.

The mechanical properties of composites are influenced, in part, by the volume fraction, orientation, constituent mechanical properties, and interfacial bonding. Cortical bone tissue represents a short-fibered biological composite where the hydroxyapatite phase is embedded in an organic matrix composed of type I collagen and other noncollagenous proteins. Destructive mechanical testing has revealed that fluoride ion treatment significantly lowers the Z-axis tensile and compressive properties of cortical bone through a constituent interfacial debonding mechanism. The present ultrasonic data indicates that fluoride ion treatment significantly alters the longitudinal velocity in the Z-axis as well as the circumferential and radial axes of cortical bone. This suggests that the distribution of constituents and interfacial bonding amongst them may contribute to the anisotropic nature of bone tissue.