Department of Radiology and Imaging, MRI Laboratory, Hospital for Special Surgery, New York City, New York, USA.
Department of Biomechanics, Hospital for Special Surgery, New York City, New York, USA.
J Orthop Res. 2024 Dec;42(12):2646-2658. doi: 10.1002/jor.25956. Epub 2024 Aug 23.
The objective of the study was to evaluate tibial cartilage thickness (TCT), T1ρ and T2 values within both loaded and baseline configurations in a cadaveric knee model using a 3D bone based tibial coordinate system. Ten intact cadaveric knees were mounted into an magnetic resonance imaging (MRI) compatible loading device. Morphologic and quantitative MRI (qMRI) images were acquired with the knee in a baseline configuration and after application of 50% body weight. The morphologic images were evaluated for cartilage degeneration using a modified Noyes scoring system. A 3D bone-based tibial coordinate system was utilized to evaluate regional changes of tibial T1ρ, T2, and cartilage thickness values among regions covered and uncovered by the meniscus. Inter-regional differences in medial and lateral MRI outcomes were found between loaded and baseline configurations. Cartilage regions covered by the meniscus demonstrated disparate qMRI and TCT results as compared to cartilage regions not covered by the meniscus. The regions covered by meniscus experienced a ~3.5%, ~0.5%, and ~5.5% reduction of T1ρ (p < 0.05, medial and lateral compartments), T2 and TCT, respectively, in both compartments while regions not covered by the meniscus experienced larger reductions of ~10%, ~2%, and ~10.5% reduction of T1ρ (p < 0.05, medial and lateral compartments), T2 and TCT (p < 0.05, lateral compartment only), respectively, in both compartments. T1ρ and T2 decreases following application of 50% body weight load were substantially larger in the tibial regions with modified Noyes grade 3 (n = 2) compared to either healthy regions (n = 85, p < 0.0.003) or regions with modified Noyes grade 2 (n = 13, p < 0.004). Interregional differences in MRI outcomes reflect variations in structure and function, and largely followed a pattern in cartilage regions that were covered or not covered by the meniscus. Results of the current study suggest that ΔT1ρ and ΔT2 values may be sensitive to superficial fissuring, more than baseline or loaded T1ρ or T2 values, or TCT alone, however future studies with additional specimens, with greater variability in OA grade distribution, may further emphasize the current findings.
本研究的目的是在一个使用基于 3D 骨骼的胫骨坐标系统的尸体膝关节模型中，评估负重和基线配置下胫骨软骨厚度（TCT）、T1ρ 和 T2 值。将 10 个完整的尸体膝关节安装到磁共振成像（MRI）兼容的加载装置中。在基线配置和施加 50%体重后，获得形态学和定量 MRI（qMRI）图像。使用改良的 Noyes 评分系统评估形态图像的软骨退变情况。使用基于 3D 骨骼的胫骨坐标系来评估半月板覆盖和未覆盖的胫骨 T1ρ、T2 和软骨厚度值的区域变化。在负重和基线配置之间发现了内侧和外侧 MRI 结果的区域间差异。与未被半月板覆盖的软骨区域相比，半月板覆盖的软骨区域的 qMRI 和 TCT 结果存在差异。半月板覆盖的区域经历了 T1ρ（内侧和外侧隔间，p < 0.05）、T2 和 TCT 分别减少约 3.5%、0.5%和 5.5%，而未被半月板覆盖的区域经历了更大的减少，T1ρ（内侧和外侧隔间，p < 0.05）、T2 和 TCT（外侧隔间，p < 0.05）分别减少约 10%、2%和 10.5%，在两个隔间中。与健康区域（n=85，p<0.003）或改良 Noyes 等级 2 区域（n=13，p<0.004）相比，应用 50%体重负荷后 T1ρ 和 T2 的降低在改良 Noyes 等级 3（n=2）的胫骨区域中要大得多。MRI 结果的区域间差异反映了结构和功能的变化，并且在很大程度上遵循了半月板覆盖或未覆盖的软骨区域的模式。本研究的结果表明，ΔT1ρ 和 ΔT2 值可能对表面裂隙敏感，比基线或负重 T1ρ 或 T2 值或 TCT 更敏感，然而，具有更大 OA 等级分布变异性的额外标本的未来研究可能会进一步强调当前的发现。
