Department of Orthopaedic Surgery, Graduate School of Medical Science Kanazawa University, 13-1 Takara-machi, 920-8641, Kanazawa, Japan.
Department of Orthopaedic Surgery, Graduate School of Medical Science Kanazawa University, 13-1 Takara-machi, 920-8641, Kanazawa, Japan.
J Orthop Sci. 2022 Mar;27(2):478-485. doi: 10.1016/j.jos.2021.01.012. Epub 2021 Mar 10.
Poor outcomes associated with anterior cruciate ligament reconstruction in paediatric patients are a major concern. The tendon structure and its cellular characteristics are key factors that affect the mechanical properties of tendons. This study aimed to evaluate the effects of growth on the cellular and microstructural properties of the tendon of the semitendinosus muscle in humans.
Semitendinosus muscle tendon samples from 76 patients who underwent ligament reconstruction were examined and divided into three groups: immature (10.8 ± 2.7 years old), young (16.5 ± 1.8 years old), and adult (35.2 ± 8.6 years old), based on age and the state of the epiphyseal plate in the distal femur. The number of tendon cells per unit area was assessed, and the major-to-minor-length ratio of the tendon cell nuclei was calculated to evaluate the shape of the nuclei using haematoxylin and eosin staining. The collagen fibril diameter and distribution were determined using electron microscopy.
The major-to-minor-length ratio of the tendon cell nuclei significantly increased with age (p-value; immature vs. young: 0.018, young vs adult: 0.001, immature vs adult: 0.001). The shape of the tendon cell nuclei was rounder in the immature group and more elongated in the adult group. A significant decrease in the number of tendon cells was observed with age (immature: 565 ± 134/mm, young: 356 ± 105/mm, adult: 272 ± 81/mm; p-value: immature vs young: 0.001, young vs adult: 0.012, immature vs adult: 0.001). The mean fibril diameter in the immature group was significantly smaller (p-value: immature vs young: 0.018, young vs adult: 0.001, immature vs adult: 0.001). The distribution of the collagen fibrils changed from right skewed in the immature group to flat in the adult group.
The characteristics of the tendon cells and the microstructure of collagen in muscle tendons significantly changed with age.
儿童前交叉韧带重建术后效果不佳是一个主要关注点。肌腱结构及其细胞特性是影响肌腱力学性能的关键因素。本研究旨在评估生长对人类半腱肌腱肌腱细胞和微观结构特性的影响。
对 76 例行韧带重建术的患者的半腱肌腱样本进行检查，并根据年龄和股骨远端骺板的状态将其分为三组：未成熟组（10.8±2.7 岁）、年轻组（16.5±1.8 岁）和成年组（35.2±8.6 岁）。评估单位面积内的肌腱细胞数量，并通过苏木精和伊红染色计算肌腱细胞核的长径与短径之比，以评估细胞核的形状。使用电子显微镜确定胶原纤维直径和分布。
肌腱细胞核的长径与短径之比随年龄增长而显著增加（p 值；未成熟组与年轻组：0.018，年轻组与成年组：0.001，未成熟组与成年组：0.001）。肌腱细胞核的形状在未成熟组中更圆，在成年组中更细长。随着年龄的增长，肌腱细胞数量显著减少（未成熟组：565±134/mm，年轻组：356±105/mm，成年组：272±81/mm；p 值：未成熟组与年轻组：0.001，年轻组与成年组：0.012，未成熟组与成年组：0.001）。未成熟组的平均纤维直径显著较小（p 值：未成熟组与年轻组：0.018，年轻组与成年组：0.001，未成熟组与成年组：0.001）。胶原纤维的分布从未成熟组的右偏分布变为成年组的平坦分布。
肌腱细胞的特性和肌肉肌腱胶原的微观结构随年龄显著变化。
