2022年 · 第102卷第09期

The lesions of tendons, ligaments and their attachment points are closely related to many inflammatory and degenerative diseases of the musculoskeletal system. MRI has great advantages in the diagnosis of osteomuscular and soft tissue lesions because of its good tissue resolution, but the transverse relaxation time of normal tendons and attachment points (T₂At present, conventional MRI sequences have almost no signal, which brings great difficulties to the study of MRI characteristics of tendons and attachment points. The study used a novel 3.0 T magnetic resonance three-dimensional ultrashort echo time (3D UTE) sequence and a 11.7 T conventional MRI sequence to display normal tendon and attachment point structures. In this study, five ankle specimens [2 males and 3 females, mean age (35.4 ± 5.0) years] were scanned using a 3D UTE sequence of 3.0 T magnetic resonance to investigate the T of the Achilles tendon and attachment points₂*, T₁And magnetization transfer rate (MTR), and macromolecular proton component MT modeling was performed. At the same time, it was morphologically observed using 11.7 T conventional MRI sequence, and the mechanical properties of Achilles tendon and attachment points were studied by indentation test, and histological analysis was performed by pathological sections. T of the Achilles tendon and attachment point₂*Values were (0.93 ± 0.48) ms and (2.77 ± 0.79) ms, respectively, T₁The values were (644 ± 22) ms and (780 ± 55) ms, the MTR was 0.373 ± 0.030 and 0.244 ± 0.009, the average power was 1 000°, the frequency offset was 2 kHz, and the macromolecular proton fraction was (18.0 ± 2.2) % and (13.9 ± 1.9) %, respectively. Compared to the Achilles tendon, the attachment point usually has a longer T₂* and T₁Values, lower MTR and macromolecular proton fraction, and higher Young's modulus and stiffness. This study provides baseline values for the Achilles tendon and attachment sites in normal subjects, which can be used for the diagnosis of seronegative arthritis and other terminal diseases.

Finite element technology plays an important role in digitized orthopedic research. Among them, as the largest weight-bearing joint in human body, the finite element analysis related to hip joint has been the focus of research. The researchers conducted mechanical studies on the standing hip joint model and realized that in the standing posture, the contact area of the femoral head and the weight-bearing area are the direct acting surfaces of forces, and their position distribution and magnitude directly affect the stress distribution of the femoral head. However, in most studies related to FEM of the femur, the division of this region is vague, imprecise, and non-individualized. To investigate the effect of the load-bearing area of the femoral head in the standing position and the positional distribution and magnitude of the direct moving surface of the force on the results of finite element analysis, five adult volunteers were recruited for X-ray and CT examination with a patented device in the same simulated bipedal standing position. The two-dimensional weight-bearing area on the X-ray image is calculated, and the three-dimensional model of proximal femur is reconstructed according to the CT data, and it is registered to realize the conversion from the two-dimensional weight-bearing area to the three-dimensional quantized area. One of the three-dimensional models of the proximal femur was randomly selected for finite element analysis, three different loading surfaces were defined, and their finite element results were compared. The results showed that five volunteers constructed a total of 10 weight-bearing surfaces, mainly distributed in crescent shape in the dome and anterolateral side of the femoral head, ranging from 1 218.63~1 871.06 mm²。 The stress magnitude and distribution of the proximal femur finite element model are significantly different under three different loading conditions, and the loading conditions of quantifying the load-bearing area are more in line with the physical phenomena of the hip. In this study, a set of simple methods was used to quantify the position distribution and size of the weight-bearing area of the femoral head while standing, and the individualized reconstruction of the proximal femoral finite element model was realized. This method can define more reasonable load surface settings without increasing the difficulty of actual modeling.