ObjectiveTo observe the in vivo three-dimensional (3-D) transient motion characteristics of the subaxial cervical spine in healthy adults. MethodsSeventeen healthy volunteers without cervical spine related diseases were recruited for this study, including 8 males and 9 females with a mean age of 26 years (range, 23-41 years). The vertebral segment motion of each subject was reconstructed with CT, and Rhinoceros 4.0 solid modeling software were used for 3-D reconstruction model of the subaxial cervical spine. In vivo cervical vertebral motion in flexionextension, left and right bending, left and right rotation was observed with dual fluoroscopic imaging system (DFIS). Coordinate systems were established at the vertebral center of C3-7 to obtain the intervertebral range of motion (ROM) and displacement at C3, 4, C4, 5, C5, 6, and C6, 7. The X-axis pointed to the left along the coronal plane, the Y-axis pointed to the back along the sagittal plane, and the Z-axis perpendicular to the X-Y plane pointed to the head. The ROM along X, Y, and Z axises were represented by rotation in flexion-extension (α), in left-right bending (β), and in left-right twisting (γ) respectively, and the displacement in left-right direction (x), in anterior-posterior direction (y), and in proximaldistal direction (z), respectively. ResultsIn flexion and extension, the displacement in anterior-posterior direction of C6, 7 was significantly less that of other segments (P<0.05), but the displacements in left-right direction and in proximaldistal direction showed no significant difference between segments (P>0.05); the ROM values in flexion-extension of C4, 5 and C5, 6 were significantly larger than those of C3, 4 and C6, 7 (P<0.05), and the ROM value in left-right twisting of C4, 5 was significantly larger than those of C5, 6 and C6, 7 (P<0.05), but the ROM value in left-right bending showed no significant difference between segments (P>0.05). In left and right bending, there was no significant difference in the displacement between other segments (P>0.05) except that the displacement in anterior-posterior direction of C3, 4 was significantly larger than that of C4, 5 (P<0.05), and that the displacement in proximal-distal direction of C6, 7 was significantly less than that of C3, 4 and C4, 5 (P<0.05); no significant difference was shown in the ROM value between segments (P>0.05), except that the ROM value in left-right twisting of C3, 4 was significantly larger than that of C5, 6 and C6, 7 (P<0.05). In left and right rotation, the ROM value in left-right twisting of C3, 4 was significantly larger than that of C4, 5 and C6, 7 (P<0.05), and the displacement and ROM value showed no significant differece between other segments (P>0.05). ConclusionThe intervertebral motions of the cervical spine show different characters at different levels. And the 6-degree-of-freedom data of the cervical vertebrae are obtained, these data may provide new information for the in vivo kinematics of the cervical spine.
The technical deficiencies in traditional medical imagining methods limit the study of in vivo ankle biomechanics. A dual fluoroscopic imaging system (DFIS) provides accurate and non-invasive measurements of dynamic and static activities in joints of the body. This approach can be used to quantify the movement in the single bones of the ankle and analyse different morphological and complex bone positions and movement patterns within these organs and has been widely used in the field of image diagnosis and evaluation of clinical biomechanics. This paper reviews the applications of DFIS that were used to measure the in vivo kinematics of the ankle in the field of clinical and sports medicine. The advantages and shortcomings of DFIS in the practical application are summarised. We further put forward effective research programs for understanding the movement as well as injury mechanism of the ankle in vivo, and provide constructive research direction for future study.
ObjectiveTo review the researches of in vivo kinematics in lumbar degenerative spondylol isthesis (DS). MethodsRelated literature concerning the in vivo kinematics in patients with lumbar DS was extensively reviewed and comprehensively analyzed in 4 terms of the instabil ity of lumbar DS, vertebral motion pattern, the morphological changes of spinal canal, and intraoperative biomechanical measurement. ResultsWhether there is lumbar segmental instabil ity in lumbar DS patients is still controversial, which should be based on degenerative stage of lumbar spine and grade of slip. The hypomobility of the lumbar spinous processes and the facet joint is seen in DS. The diameter, cross-sectional area, and volume of spinal canal in lumbar DS patients are significantly smaller than those of the normal control. Because of its invasive procedure and medical ethics, the use of the intraoperative measurement device is limited. These reported researches of in vivo kinematics in DS are almost on the sagittal plane. However, few data have been reported on the 6-degree-of-freedom (6DOF) kinematics of the diseased levels under physiological loading conditions. ConclusionThe 6DOF kinematics data can accurately reflect the segmental motion characteristics in lumbar DS patients, recent studies have been reported, further studies are still needed.
Objective To discuss the effect of the calcaneocuboid arthrodesis on three-dimensional kinematics of talonavicular joint and its clinical significance. Methods Ten freshfrozen foot specimens, three-dimensional kinematics oftalonavicular joint were determined in the case of neutral position, dorsiflexion, plantoflexion, adduction, abduction, inversion and eversion motion by meansof threedimensional coordinate instrument（Immersion MicroScribe G2X） before and after calcaneocuboid arthrodesis under non-weight with moment of couple, bending moment, equilibrium dynamic loading. Calcaneocuboid arthrodesis was performed on these feet in neutral position and the lateral column of normal length. Results A significant decrease in the three-dimensional kinematics of talonavicular joint was observed（P＜0.01）in cadaver model following calcaneocuboid arthrodesis. Talonavicular joint motion was diminished by 31.21%±6.08％ in sagittal plane; by 51.46%±7.91％ in coronal plane; by 36.98%±4.12％ in transverse plane; and averagely by 41.25%±6.02％. Conclusion Calcaneocuboid arthrodesis could limite motion of the talonavicular joints, and the disadvantage of calcaneocuboid arthrodesis shouldn’t be neglected.
Gesture imitation is a common rehabilitation strategy in limb rehabilitation training. In traditional rehabilitation training, patients need to complete training actions under the guidance of rehabilitation physicians. However, due to the limited resources of the hospital, it cannot meet the training and guidance needs of all patients. In this paper, we proposed a following control method based on Kinect and NAO robot for the gesture imitation task in rehabilitation training. The method realized the joint angles mapping from Kinect coordination to NAO robot coordination through inverse kinematics algorithm. Aiming at the deflection angle estimation problem of the elbow joint, a virtual space plane was constructed and realized the accurate estimation of deflection angle. Finally, a comparative experiment for deflection angle of the elbow joint angle was conducted. The experimental results showed that the root mean square error of the angle estimation value of this method in right elbow transverse deflection and vertical deflection directions was 2.734° and 2.159°, respectively. It demonstrates that the method can follow the human movement in real time and stably using the NAO robot to show the rehabilitation training program for patients.
Objective To analyze the kinematic changes of the hip joint after total hip arthroplasty (THA) through three-dimensional gait analysis. Methods Patients with hip joint diseases admitted between October 2022 and June 2023 were selected as the subjects. The patients who met the selective criteria were finally included in the THA group. The healthy volunteers matched with the THA group in the same age were included as the control group. Baseline data including age, gender, body mass index (BMI), and laterality were compared between the two groups. The Harris hip score (HHS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score were recorded preoperatively and at last follow-up in the THA group. Three-dimensional motion capture system was utilized to collect spatiotemporal parameters and kinematic data during walking, including stride length, cadence, and maximum/minimum values, range of motion (ROM) in hip joint abduction/adduction, external/internal rotation, and flexion/extension, as well as gait scores. Differences between the two groups were analyzed. Additionally, the correlation between gait scores and postoperative HHS and WOMAC scores were analyzed in the THA group. Finally, the kinematic data of each degree of freedom (DOF) were fitted into a gait diagram, and the dynamic changes of the 3-DOF of the hip joint during the gait cycle were quantitatively analyzed. ResultsThere was no significant difference in gender, age, laterality, and BMI between the two groups (n=20, P>0.05). The mean follow-up time in the THA group was 9.9 months (range, 6-12 months). The HHS and WOMAC scores at last follow-up in the THA group showed significant improvement when compared with preoperative scores (P<0.05). Gait scores were positively correlated with postoperative HHS score (r=0.585, P=0.007) and negatively correlated with WOMAC score (r=–0.619, P=0.004). There was no significant difference in stride length and cadence between the THA and control groups (P>0.05), but gait score was significantly lower in the THA group than in the control group (P<0.05). There was no significant difference in maximum and minimum values of flexion/extension, external/internal rotation, and abduction/adduction between the two groups (P>0.05); however, ROM in the THA group was significantly lower than that in the control group (P<0.05). There were significant differences between the two groups of flexion/extension in multiple phases of the gait cycle (P<0.05). ConclusionEarly post-THA hip joint kinematics exhibit relative adduction, external rotation, and flexion during the gait cycle compared to normal individuals, with incomplete recovery of kinematic parameters in three degrees of freedom. Significant differences in flexion are observed at multiple phases of the gait cycle compared to normal individuals.
Objective To develop a Matlab toolbox to improve the efficiency of musculoskeletal kinematics analysis while ensuring the consistency of musculoskeletal kinematics analysis process and results. Methods Adopted the design concept of “Batch processing tedious operation”, based on the Matlab connection OpenSim interface function ensures the consistency of musculoskeletal kinematics analysis process and results, the functional programming was applied to package the five steps for scale, inverse kinematics analysis, residual reduction algorithm, static optimization analysis, and joint reaction analysis of musculoskeletal kinematics analysis as functional functions, and command programming was applied to analyze musculoskeletal movements in large numbers of patients. A toolbox called LLMKA (Lower Limbs Musculoskeletal Kinematics Analysis) was developed. Taking 120 patients with medial knee osteoarthritis as the research object, a clinical researcher was selected using the LLMKA toolbox and OpenSim to test whether the analysis process and results were consistent between the two methods. The researcher used the LLMKA toolbox again to conduct musculoskeletal kinematics analysis in 120 patients to verify whether the use of this toolbox could improve the efficiency of musculoskeletal kinematics analysis compared with using OpenSim. Results Using the LLMKA toolbox could analyze musculoskeletal kinematics analysis in a large number of patients, and the analysis process and results were consistent with the use of OpenSim. Compared to using OpenSim, musculoskeletal kinematics analysis was completed in 120 patients using the LLMKA toolbox with only 2 operations were needed to enter the patient body mass data, operating steps decreased by 99.19%, total analysis time by 66.84%, and manual participation time by 99.72%, just need 0.079 1 hour (4 minutes and 45 seconds). Conclusion The LLMKA toolbox can complete a large number of musculoskeletal kinematics analysis in patients with one click in a way that is consistent in process and results with using OpenSim, reducing the total time of musculoskeletal kinematics analysis, and liberating clinical researchers from cumbersome steps, making more energy into the clinical significance of musculoskeletal kinematics analysis results.
ObjectiveTo observe vertebral three-dimensional motion characteristics of adjacent segments in patients with symptomatic L4 isthmic spondylolisthesis (IS). MethodsFourteen symptomatic L4 IS patients who underwent surgery treatment (trial group) and 15 asymptomatic volunteers without back pain and other lesions of spine (control group) were recruited. There was no significant difference in gender, age, body mass index, and bone mineral density between the two groups (P>0.05). The three-dimensional reconstruction model of lumbar spine was acquired from the thin slice CT of the lumbar spine of the subjects by combining dual-X-ray fluoroscopy imaging system with spiral CT examination. The model was matched to the double oblique X-ray fluoroscopy images captured by dual-X-ray fluoroscopy imaging system at different active positions of the lumbar spine to reproduce the three-dimensional instantaneous of lumbar spondylolisthesis at different state of motion. The motion and relative displacement of adjacent segments (L3, 4 and L5, S1) of spondylolisthesis were measured quantitatively by establishing a three-dimensional coordinate system at the geometric center of the vertebral body. The results were compared with those of the control group. ResultsWhen L3, 4 in the control group were flexed flexion-extension, left-right twisting, and left-right bending, and when L5, S1 in the control group were flexed left-right twisting and left-right bending, the activity along the main axis of motion (main axis of motion) tended to increase compared with that along the corresponding coupled axis of motion (secondary axis of motion); however, this trend disappeared in the trial group, and the main and secondary movements were disordered. Because of the coronal orientation of the facet joints of L5, S1, the degree of motion along the main axis of motion decreased during flexion and extension, but this trend disappeared in the trial group. Compared with the control group, L3, 4 in the trial group exhibited displacement instability in flexion-extension, left-right twisting, and left-right bending (P<0.05); there was no significant difference in the relative displacement of L5, S1 intervertebral bodies along x, y, and z axes between the trial group and the control group in flexion-extension, left-right twisting, and left-right bending curvature (P>0.05). ConclusionPatients with symptomatic L4 IS have disorders of primary and secondary movement patterns in adjacent segments, while IS showed significantly displacement instability in L3, 4 and significantly decreased motion in L5, S1.
Based on the biomechanical simulation curve of OpenSim, an open source software of biomechanical model, a spherical exoskeleton parallel mechanism with two degrees of freedom for hip joint is proposed in this paper for the rehabilitation therapy of patients with impaired leg motor function or elderly people with walking dysfunction. Firstly, the parallel mechanism is modeled and the position inverse solution of the parallel mechanism is obtained using inverse kinematics analysis. The velocity analysis expression of the mechanism is derived by deriving the inverse kinematics solution. The model is imported into the mechanical system dynamics analysis software ADAMS and matrix processing analysis software MATLAB to carry out simulation experiments. The correctness of the velocity analysis is verified by comparing the velocity simulation results of the two methods. Then, three singular types of the mechanism are analyzed according to the obtained Jacobian matrix. According to the inverse solution of the mechanism, the reachable workspace of the mechanism is obtained by programming in MATLAB with given mechanism parameters and restriction conditions. Finally, the prototype platform is built. The experimental results show that the exoskeleton hip joint using this parallel mechanism can satisfy the requirement of rotation angle of human hip joint movement, but also can be good to assist patients with leg flexion-extension movement and adduction-abduction movement, and it is helpful to carry out corresponding rehabilitation training. It also has theoretical significance and application value for the research work of human hip exoskeleton parallel mechanism.
ObjectiveTo investigate the short-term effectiveness of total knee arthroplasty (TKA) assisted by three-dimensional (3D) printing osteotomy navigation template.MethodsA retrospective study was performed on 60 patients with osteoarthritis bewteen January 2016 and June 2017. Thirty cases underwent TKA assisted by 3D printing osteotomy navigation template (3D printing group) and 30 cases underwent the conventional TKA (conventional TKA group). There was no significant difference in gender, age, body mass index, surgical side, and disease duration between 2 groups (P>0.05). The operation time, the pre- and post-operative hemoglobin values, the amount of drainage, the Hospital for Special Surgery (HSS) score and Knee Society Score (KSS) of knee joint before operation and at 3 months after operation were observed. And 6 freedom degrees of knee (the varus and valgus angle, the internal and external rotation angle, the antero-posterior displacement, the proximal-distal displacement, the flexion and extension angle, and the internal and external displacement) before operation and at 3 months after operation were recorded by Opti-Knee (the knee 3D motion analysis system). The values of 2 groups were compared with 30 healthy adults (<60 years).ResultsThe operation time was shorter in 3D printing group than that in conventional TKA group (t=5.833, P=0.000). The hemoglobin values at 1 and 3 days after operation were higher in 3D printing group than those in conventional TKA group (P<0.05). The amount of drainage was less in 3D printing group than that in conventional TKA group (t=5.468, P=0.000). All patients were followed up 6-9 months (mean, 7.3 months). There was no significant difference in pre- and post-operative HSS score and KSS clinical score between 2 groups (P>0.05). There was no significant difference in preoperative KSS function score between 2 groups (P>0.05), but the KSS function score of 3D printing group at 3 months after operation was higher than that of conventional TKA group (P<0.05). Before operation, the varus and valgus angle, the internal and external rotation angle, the antero-posterior displacement, the proximal-distal displacement of 3D printing group and conventional TKA group were larger than that of the healthy adults (P<0.05); there was no significant difference in the flexion and extension angle and the internal and external displacement between 2 groups and healthy adults (P>0.05). At 3 months after operation, compared with healthy adults, the varus and valgus angle of conventional TKA group was increased, the flexion and extension angle of conventional TKA group was decreased (P<0.05); the proximal-distal displacement and the internal and external displacement of 2 groups were decreased (P<0.05); there was no significant difference in other freedom degrees between groups (P>0.05). No sign of prosthesis loosening was observed by X-ray examination.ConclusionCompared with the traditional TKA, TKA assisted by the 3D printing osteotomy navigation template had such advantages as shorter operation time, less postoperative blood loss, and well postoperative recovery.