Porcine Small Intestine Submucosa for Repair of Goat Meniscal Defects

This study evaluated the effectiveness of small intestine submucosa used as a graft to fill surgically created meniscal defects in a large animal model. Four goats underwent unilateral interior subtotal meniscectomies (approximately 70%) within the avascular portion of the medial meniscus. The contralateral meniscus acted as a control. Grafts of porcine small intestine submucosa were trimmed to fill the resected defects and sutured into place. After surgery the operated knees were casted in partial flexion to limit weight bearing on the affected limb. All of the animals were sacrificed at 12 weeks at which point meniscal regeneration and articular cartilage degradation were evaluated by gross and histologic examination. Grossly, the defects in the small intestine submucosa-grafted goats were partially filled with meniscal-appearing connective tissue. Histologically, the replacement tissue was typified by the presence of dense, cellular, irregularly organized connective tissue. Evaluation of the articular cartilage displayed increased degeneration in the grafted compartment of the operative knees. Each of the operative menisci partially regenerated. The grafts were conducive to repopulation with host meniscal elements. Despite partial meniscal regeneration, comparatively more articular cartilage degeneration in the treated knees was observed than in the untreated contralateral controls.