Evaluation of Histological Properties of Human Meniscal Grafts Stored in a Tissue Bank

Abstract

Objectives: The present paper aims to evaluate and compare the histological features of fresh and frozen menisci stored in a tissue bank for 1 month and for 5 years. Methods: The meniscal grafts were subjected to a histological study. A total of 10 menisci were evaluated; 2 were frozen for 5 years, 4 were frozen for 1 month, and 4 were fresh, recently harvested specimens. Histological properties were evaluated in sections stained with hematoxylin and eosin and Masson trichrome methods. Results: The menisci frozen for 1 month showed partially preserved collagen fiber structure and no significant hydropic tissue degeneration. The menisci frozen for 5 years presented an evident dissociation of collagen fibers and multiple foci of hydropic degeneration. Discussion: Degeneration was much more significant in menisci stored for 5 years, indicating that a long freezing period results in substantial progression of tissue deterioration. This may suggest that the 5-year period, considered the maximum time for graft storage before transplant, is too long. Conclusion: Grafts stored for 1 month showed a slight degenerative change in collagen fibers, whereas menisci frozen for 5 years presented significant tissue degeneration.