Mechanical stimuli play an important role in the homeostasis of trabecular bone and marrow adipose tissue, particularly for the weight-bearing skeleton. Prolonged immobilization and disuse have been shown to reduce trabecular bone content and increase marrow adipose tissue in the bones of lower limb joints such as the knee. However, details on the temporal response of this relationship to prolonged immobilization and its reversibility is limited. Forty rats had one knee immobilized at 45° of flexion for 2, 4, 8, or 16 weeks and subsequently remobilized for 0 or 8 weeks. The contralateral knees were used as controls. Histomorphometric measures of trabecular bone and marrow adipose tissue (MAT) areas were conducted in the epiphysis of the proximal tibia. Knee immobilization for 4, 8, and 16 weeks significantly reduced trabecular bone area by -0.125, -0.139, and -0.161 mm²/mm², respectively, with corresponding 95 % CIs of [-0.012, -0.239], [-0.006, -0.273], and [-0.101, -0.221]. MAT area significantly increased at 2 and 16 weeks by +0.008 and +0.027 mm²/mm², respectively, with 95 % CIs of [0.014, 0.002] and [0.039, 0.016]. Remobilization for 8 weeks restored trabecular bone area compared to the contralateral knee and the magnitude of change was significantly greater for 8 and 16 weeks of immobilization with effect sizes of 1.69 and 1.86, respectively. The difference in MAT area between immobilized and contralateral knees were eliminated with remobilization. These results characterize the temporal response of trabecular bone and MAT in the epiphysis of the proximal tibia to joint immobilization and remobilization.

机械刺激在小梁骨和骨髓脂肪组织的稳态中起着重要作用，特别是对于承重骨骼。长期固定和废用已被证明会减少小梁骨含量并增加下肢关节（如膝盖）骨骼中的骨髓脂肪组织。然而，关于这种关系对长时间固定及其可逆性的时间响应的细节是有限的。40 只大鼠的一个膝盖固定在 45° 屈曲 2、4、8 或 16 周，然后再活动 0 或 8 周。对侧膝关节用作对照。在胫骨近端的骨骺处进行小梁骨和骨髓脂肪组织 (MAT) 区域的组织形态测量。膝关节固定 4、8 和 16 周使骨小梁面积显着减少 -0.125，² /mm ²分别为 [-0.012, -0.239]、[-0.006, -0.273] 和 [-0.101, -0.221] 的相应 95% CI。MAT 面积在第 2 周和第 16 周时分别​​显着增加了 +0.008 和 +0.027 mm ² /mm ²，95% CI 分别为 [0.014, 0.002] 和 [0.039, 0.016]。与对侧膝关节相比，再活动 8 周恢复了小梁骨面积，并且固定 8 周和 16 周的变化幅度显着更大，效应大小分别为 1.69 和 1.86。固定膝关节和对侧膝关节的 MAT 面积差异通过再活动消除。这些结果表征了胫骨近端骨骺中的小梁骨和 MAT 对关节固定和再活动的时间响应。