Collagenous Ultrastructure of the Discoid Meniscus: A Transmission Electron Microscopy Study:

Background:The collagen ultrastructure of the discoid lateral meniscus (DLM) has not been precisely defined.Purpose:To investigate the ultrastructure of the DLM, focusing on its collagen fibers, and to compare the collagen net architecture between intact and torn DLMs using the Collagen Meniscal Architecture (CMA) scoring system.Study Design:Descriptive laboratory study.Methods:Thirty specimens were taken from 30 patients with a diagnosis of a complete DLM using a 1-piece technique. The collagen ultrastructure of the DLMs was assessed with transmission electron microscopy. To evaluate the meniscal ultrastructure, the degree of collagen disruption, intrafibrillar edema, loss of banding, degree of collagen packing, and fibril size variability were assessed and graded from 1 (normal) to 3 (severe disarray) according to the CMA scoring system. The DLM specimens were divided into 3 groups according to the intrasubstance tear: the intact group (group I) had no tear; the simple tear group (group S) had a radial,...