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28 March 2026, Volume 30 Issue 9 Previous Issue    Next Issue

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Tail anchoring technique of vertebroplasty in treatment of osteoporotic vertebral compression fractures with intravertebral cleft: a finite element analysis Chen Huiting, Zeng Weiquan, Zhou Jianhong, Wang Jie, Zhuang Congying, Chen Peiyou, Liang Zeqian, Deng Weiming 2026, 30 (9):  2145-2152.  doi: 10.12307/2025.873 Abstract ( 198 )   PDF (2904KB) ( 0 )   Save BACKGROUND: Percutaneous vertebroplasty is an effective surgical method for treating osteoporotic vertebral compression fractures. However, for patients with vertebral compression fractures accompanied by intravertebral clefts, how to reduce cement loosening and displacement after vertebroplasty has become one of the difficulties for spinal surgeons. OBJECTIVE: To explore the biomechanical stability of tail anchoring technique in the treatment of vertebral compression fractures with intravertebral cleft.  METHODS: A finite element model of the T10-L2 segment was established using CT scan data from a patient with osteoporotic vertebral compression fractures. On Solidwork software, the intravertebral intravertebral cleft was simulated and five sets of three-dimensional models were constructed: (1) osteoporotic vertebral compression fractures model with intravertebral cleft; (2) percutaneous vertebroplasty model of 2.5 mL bone cement; (3) 2.5 mL bone cement + percutaneous vertebroplasty model with trailing anchoring; (4) percutaneous vertebroplasty model of 4.6 mL bone cement; (5) 4.6 mL bone cement + trailing anchored percutaneous vertebroplasty model. Then, the model was imported into Ansys software, and structures such as ligaments were added and assigned values for finite element analysis. The loading conditions were as follows: a 400 N vertical downward load was applied to the upper surface of T10 vertebral body to simulate the weight of the upper body, and a moment of 7.5 N·m was applied in different directions to simulate movements such as spinal flexion, extension, and rotation. The differences in motion range, deformation degree, maximum equivalent stress, and bone cement stress were compared between different models.  RESULTS AND CONCLUSION: (1) In terms of the range of motion of fractured vertebral bodies, osteoporotic vertebral compression fractures models with intravertebral clefts had the greatest range of motion, reaching 4°-7° in all directions. Although the 2.5 mL bone cement model and the 2.5 mL bone cement + trailing anchor model could partially reduce abnormal movement of fractured vertebrae, their stability was still poor, with a motion range of up to 3°-4° during flexion, extension, and rotation. In the 4.6 mL bone cement + trailing anchor model, the mobility of fractured vertebral bodies was significantly reduced and relatively stable. The motion range of fractured vertebrae decreased by 81%, 83%, 77%, 69%, 76%, and 79% compared with the osteoporotic vertebral compression fractures model with intravertebral cleft, indicating that it had the best biomechanical stability. (2) In terms of the maximum equivalent stress and deformation degree of fractured vertebral bodies, the results were as follows: osteoporotic vertebral compression fractures model with intravertebral cleft > 2.5 mL bone cement model > 2.5 mL bone cement + trailing anchor model > 4.6 mL bone cement model > 4.6 mL bone cement + trailing anchor model, indicating that when there was a small amount of bone cement, the use of only trailing anchoring technology could not effectively stabilize fractured vertebrae. When the amount of bone cement in front of the vertebral body reached 4.6 mL, combined with trailing anchoring technology, it could significantly reduce the maximum equivalent stress and deformation degree of the vertebral body. (3) It is noteworthy that in both sets of tail-anchored models, the maximum equivalent stress of bone cement significantly increased, primarily concentrated in the mid-to-posterior region of the trailing bone cement. (4) In general, with a certain amount of bone cement in the vertebral body, the trailing anchoring technique could significantly enhance the stability of fractured vertebrae and reduce their abnormal movement and stress concentration within the vertebral body. It is a surgical technique worth trying. However, it should be noted that the stress of bone cement in the trailing anchoring part increases significantly. If patients do not pay attention to protection after surgery, there may be a risk of fracture of bone cement at the anchoring site. Figures and Tables | References | Related Articles | Metrics

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Two lumbar rotary manipulation techniques in treating lumbar disc herniation: a finite element analysis of biomechanical differences Zeng Xuan, Weng Rui, Ye Shicheng, Tang Jiadong, Mo Ling, Li Wenchao 2026, 30 (9):  2153-2161.  doi: 10.12307/2026.313 Abstract ( 9 )   PDF (2435KB) ( 0 )   Save 1Third Clinical Medical College of Guangzhou University of Chinese Medicine, Guangzhou 510145, Guangdong Province, China; 2School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, Guangdong Province, China; 3Department of Spine Orthopedics, Third Affiliated Hospital of Guangzhou University of Chinese Medicine (Guangdong Provincial Institute of Traditional Chinese Medicine and Traumatology), Guangzhou 510145, Guangdong Province, China  Figures and Tables | References | Related Articles | Metrics

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Finite element analysis of novel variable-diameter screws in modified cortical bone trajectory of lumbar vertebrae Cheng Qisheng, Julaiti·Maitirouzi, Xiao Yang, Zhang Chenwei, Paerhati·Rexiti 2026, 30 (9):  2162-2171.  doi: 10.12307/2026.580 Abstract ( 11 )   PDF (4687KB) ( 2 )   Save BACKGROUND: In osteoporotic patients, cancellous bone is insufficient to maintain screw grip and the failure rate of internal spinal fixation is high. Traditional trajectory and cortical bone trajectory screw placement techniques are still insufficient. The modified cortical bone trajectory technique has been proven to have good performance, but requires screws that match its characteristics. OBJECTIVE: To compare the performance of three new variable-diameter all-cortical bone threaded screws with nonvariable-diameter all-cortical bone threaded screws in modified cortical bone track placement technique by finite element analysis. METHODS: Based on the CT data of an adult osteoporosis wet body specimen (male, 63 years old), the L1-L5 lumbar vertebral and sacral model was established, and three new variable-diameter all-cortical bone thread screws (single thread screw, 45 mm in overall length, 5.5 mm in diameter for thicker rods, 4.35 mm in diameter for finer rods, and uniformly variable diameter at two-thirds, one-half, and one-third of the variable-diameter segments of 8 mm in length, respectively), were used in a modified cortical bone-track nailing technique, respectively. With the non-variable diameter full cortical bone threaded screw (single threaded screw, 45 mm in overall length, and 5.5 mm in diameter) in the lumbar spine L4-L5 nailed and modeled. The un-nailed control group and the four nailed model groups received finite element analysis comparison. The mechanical properties of the screws in each group were compared under the modified cortical bone trajectory technique by calculating the range of motion of the lumbar vertebrae, internal fixation system stress, L4-L5 vertebral body stress, and L4-L5 intervertebral disc stress.  RESULTS AND CONCLUSION: Under flexion, extension, lateral bending, and axial rotation working conditions, (1) the overall range of motion of the lumbar vertebrae was reduced by 14.16%, 23.75%, 8.44%, and 7.17% in the two-thirds group compared to the control group. The non-variable-diameter group was reduced by 14.45%, 23.97%, 8.52%, and 7.07%, respectively, compared with the control group. The three new variable-diameter screws had similar levels to the non- variable-diameter screws. (2) In the two-thirds group compared with the non-reducing screw group, the internal fixation system stress decreased by 3.94%, increased by 20.60%, increased by 1.16%, and decreased by 8.59%, respectively. In the one-half group compared with the non-reducing screw group, the internal fixation system stress increased by 2.06%, decreased by 0.05%, 0.14%, and 5.98%, respectively. In the one-third group compared with the non-reducing screw group, the internal fixation system stress increased by 4.16%, 13.96%, 5.07%, and decreased by 4.19%, respectively. (3) The vertebral body stresses in the four nailed model groups were elevated compared with the non-nailed group, and there was no significant increase in the three reducer screws group compared with the non-variable-diameter group. (4) The stress of the fixed segment of the intervertebral disc in the four nailed model groups was significantly reduced compared with the un-nailed group, and was basically the same in the three variable-diameter screw groups compared with the non-variable-diameter group. It is indicated that in the modified cortical bone trajectory technique, the new variable-diameter screws can provide a fixation effect that is not weaker than that of the non-variable-diameter screws.  Figures and Tables | References | Related Articles | Metrics

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Finite element simulation of scoliosis with muscle unit introduction: verification of correction effect under bidirectional load Wu Hongxu, Liu Xuanyu, Wang Taoyu, Wang Shiyao, Cheng Jingyi, Zhang Mingwen, Zhang Yinxia, Liu Zhihua, Wang Xiaojie 2026, 30 (9):  2172-2181.  doi: 10.12307/2026.116 Abstract ( 9 )   PDF (2076KB) ( 0 )   Save BACKGROUND: At present, conservative treatments for scoliosis mainly include physical therapy, brace correction, and traction. In clinical practice, as much traction as possible is usually used within the tolerance range of the patient, and as the tolerance increases, the traction will also increase. OBJECTIVE: To establish a three-dimensional finite element model of scoliosis, incorporating muscle units to enhance realism, and investigate the therapeutic efficacy of a scoliosis correction system with bidirectional (axial and lateral) corrective loads. By analyzing the interaction between axial traction and lateral pushing forces, the study explores how corrective forces influence the Cobb angle, providing a theoretical basis for optimizing individualized treatment plans. METHODS: Spinal CT scan data from a scoliosis patient aged 35 years old were used to construct a 3D finite element model using Mimics, Geomagic Wrap, and HyperMesh software, with muscle units integrated. Finite element analysis was performed via Abaqus. The therapeutic effects of axial traction and lateral pushing loads—applied individually and in combination—were evaluated. Additionally, the impact of periodic lateral loading on treatment efficacy was studied, and a mathematical model of the moments generated by the two loads was developed for computational analysis. RESULTS AND CONCLUSION: (1) When axial traction load combined with lateral push load, the correction rate of scoliosis treatment was 22% in the thoracic segment and 24% in the lumbar segment, respectively, which was better than the two effects alone, and the correction rate was further increased to 27% and 29% with the addition of periodic lateral load. (2) There was a certain relationship between the effect of the two kinds of loads and the Cobb angle. When the Cobb angle was less than 53.13°, the effect of the lateral load was better than that of the axial load. When the Cobb angle was more than 53.13°, the effect of the axial load was better than that of the lateral load, which provided a mechanical theoretical basis for the sequence of application of the two kinds of orthopedic forces. (3) These results provide theoretical support for the development of patient personalized treatment to ensure the safety and effectiveness of orthopedic forces. Figures and Tables | References | Related Articles | Metrics

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Three-dimensional finite element analysis of cervical spine biomechanical characteristics in a rat model of cervical vertigo Liu Jiafu, Ren Ruxia, Liao Zhouwei, Zhou Xiali, Wu Yihong, Zhang Shaoqun 2026, 30 (9):  2182-2190.  doi: 10.12307/2026.126 Abstract ( 7 )   PDF (2636KB) ( 3 )   Save BACKGROUND: Cervical vertigo is one of the common types of vertigo. Previous studies have mostly simulated cervical vertigo by establishing a rat model of cervical instability, but the specific biomechanical mechanisms leading to cervical vertigo remain unclear. OBJECTIVE: To investigate the biomechanical characteristics of the cervical instability model in cervical vertigo rats and reveal its pathogenic mechanisms. METHODS: Based on the three-dimensional CT data of the cervical spine from 8-week-old healthy rats, a normal three-dimensional geometric model of C2–C7 (including vertebrae, intervertebral discs, and ligaments) was constructed using Mimics software. The cervical vertigo model was created by removing the supraspinous ligament, interspinous ligament, and facet joint cartilage at C5–6. Ansys software was used to analyze the overall stress distribution, overall displacement of the cervical spine, and stress changes in the C5–6 intervertebral disc under various conditions such as loading, flexion, extension, rotation, and lateral bending.                RESULTS AND CONCLUSION: (1) Compared to the normal group, the cervical vertigo group exhibited increased maximum total displacement of the cervical spine across all loading conditions, with the largest increments observed during rotation (left rotation: +84%; right rotation: +233%). (2) Except for flexion, the cervical vertigo group showed elevated maximum stress in the cervical spine under all other conditions, peaking during rotation (left rotation: +102%; right rotation: +165%). (3) The C5–6 intervertebral disc stress in the cervical vertigo group was significantly higher than in the normal group under all conditions, with the most pronounced increases during rotation (left rotation: +312%; right rotation: +323%). (4) It is concluded that current cervical vertigo modeling method effectively reduces cervical stability, leading to abnormal stress concentration across the cervical spine, particularly at the C5–6 intervertebral disc during rotation. This study not only provides critical biomechanical evidence supporting the reliability of the rat cervical vertigo model but also elucidates the potential pathogenesis of “cervical instability–abnormal cervical stress concentration–cervical vertigo episodes.” Figures and Tables | References | Related Articles | Metrics

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Finite element analysis of tibial prosthesis loosening after fixed-bearing unicompartmental knee arthroplasty for osteoporosis Liu Wenlong, Dong Lei, Xiao Zhengzheng, Nie Yu 2026, 30 (9):  2191-2198.  doi: 10.12307/2026.541 Abstract ( 6 )   PDF (1644KB) ( 4 )   Save BACKGROUND: Osteoporosis is generally considered as one of the risk factors for tibial component loosening after unicompartmental knee arthroplasty. However, few finite element studies have investigated tibial component loosening after fixed-bearing unicompartmental knee arthroplasty in osteoporosis patients.  OBJECTIVE: To investigate the slip and stress characteristics around the prosthesis by finite element method after the intervention of cancellous bone slotting and reduction posterior slope under different bone mineral density.  METHODS: The three-dimensional model of the knee joint of a 61-year-old female patient with knee osteoarthritis was reconstructed by computed tomography. Subsequently, fixed-bearing unicompartmental knee arthroplasty surgery was performed on the three-dimensional model in the computer, and the intervention of tibial cancellous bone grooving and reducing the angle of retroversion was implemented. Then, the material parameters were assigned to the osteoporosis and non-osteoporosis, respectively. The finite element analysis method was used to verify whether tibial slotting and changing the tibial posterior tilt angle would affect the aseptic loosening rate of the prosthesis.   RESULTS AND CONCLUSION: (1) In the finite element analysis of fixed-bearing unicompartmental knee arthroplasty, the bone bearing capacity of the osteoporosis knee was weaker than that of the non-osteoporosis knee. (2) The tibial component with different bone mineral density was more prone to the anteroposterior slip than the medial and lateral slip. (3) The degree of cancellous bone slip was reduced after the transverse groove design, which could prevent the loosening of the prosthesis. (4) For the osteoporosis knee, the tibia with reduced posterior slope (6° to 4°) had a stronger ability to bear load, and the possibility of prosthesis loosening was reduced. (5) The scheme of reducing posterior slope and opening transverse groove at the same time had advantages in preventing postoperative prosthesis loosening, and this advantage was more significant in osteoporosis knees.  Figures and Tables | References | Related Articles | Metrics

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Finite element analysis of the force changes of the supraspinatus tendon and glenohumeral joint during the abduction and flexion of the humerus Zheng Wangyang, Fei Ji, Yang Di, Zhao Lang, Wang Lingli, Liu Peng, Li Haiyang 2026, 30 (9):  2199-2207.  doi: 10.12307/2026.098 Abstract ( 6 )   PDF (2053KB) ( 8 )   Save BACKGROUND: The shoulder joint is a complex and highly mobile joint in the human body. Its normal operation is crucial for daily life, but it is also prone to injuries. Diseases such as rotator cuff injuries, labral injuries, and dislocations are relatively common. Understanding the biomechanical characteristics of the shoulder joint is of great significance for the prevention and treatment of related diseases. Finite element analysis provides a powerful tool for such research. OBJECTIVE: To analyze the force changes of the supraspinatus tendon and glenohumeral joint during humeral abduction and flexion using finite element method. METHODS: A three-dimensional finite element model of the shoulder joint was constructed. The three-dimensional models of the humerus and scapula were extracted in Mimics software. They were processed and solidified in Geomagic software. In SolidWorks software, the models were assembled and models at different angles were established, and the supraspinatus tendon and articular cartilage were constructed. In Ansys software, material properties and contact relationships were set, and the stress changes of the supraspinatus tendon and articular cartilage were observed and analyzed. RESULTS AND CONCLUSION: (1) The type I acromion morphology did not induce subacromial impingement syndrome when the humeral abduction angle was ≤ 90°. (2) The stress of the supraspinatus tendon showed a non-linear increasing trend with the humeral abduction angle. (3) There was a significant positive correlation between the stress of the glenohumeral joint cartilage and the abduction/flexion angle. (4) The stress load of the articular cartilage in the abduction state was significantly higher than that in the flexion state (P < 0.01). (5) Through finite element analysis, this study for the first time revealed the biomechanical safety characteristics of the type I acromion within the abduction range of 0°-90°, and quantified the stress-angle dynamic relationship of the supraspinatus tendon and the glenohumeral joint. However, due to model simplification and static analysis, the conclusions need to be verified by multi-modal in vivo experiments. Nevertheless, this study has laid an important theoretical foundation for the intervention strategy of related diseases. Figures and Tables | References | Related Articles | Metrics

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Mechanical effects of Long’s traction orthopedic method on cervical functional units: quantitative analysis of biomechanical model of head and neck Cai Qirui, Dai Xiaowei, Zheng Xiaobin, Jian Sili, Lu Shaoping, Liu Texi, Liu Guoke, Lin Yuanfang 2026, 30 (9):  2208-2216.  doi: 10.12307/2026.535 Abstract ( 7 )   PDF (2642KB) ( 8 )   Save BACKGROUND: Long’s traction orthopedic method has demonstrated clear clinical efficacy in cervical spondylotic radiculopathy and is widely applied; however, its biomechanical mechanism of action has not been clearly reported.  OBJECTIVE: To explore the biomechanical basis for how Long’s traction orthopedic method improves cervical intervertebral foramen deformation using three-dimensional finite element analysis.  METHODS: Based on a previously developed and validated finite element model coupling the musculoskeletal system of the head and neck, the model was imported into LS-DYNA software to simulate classical cervical traction and three manipulative techniques of Long’s traction orthopedic method: the pushing technique, the pulling technique, and the shaking technique. C5 was designated as the target segment, with relevant boundary conditions set under a traction force of 200 N. Forward and downward leftward pulling forces, as well as left axial rotation torque, were sequentially applied to simulate the techniques. The relative displacement, angle, and lateral bending displacement of the cervical intervertebral foramen, direction of intervertebral disc displacement, and strain were recorded and analyzed.  RESULTS AND CONCLUSION: (1) The pushing technique produced the most significant effect on the relative displacement of the intervertebral foramen, with C5 displacement reaching up to 15.6 mm, resulting in an increased intervertebral foramen volume. Additionally, relative angle changes in the foramen were more pronounced, with a peak value of 22.9°. (2) In terms of relative displacement during lateral bending of the overall segment, the shaking technique was 2.4 times more effective than the pulling technique, while pushing technique and classical cervical traction showed minimal changes in lateral bending displacement. (3) In all orthopedic method, the direction of intervertebral disc displacement showed a forward tendency, with Y-axis displacements of 11.56 mm (pushing), 9.94 mm (pulling), and 7.73 mm (shaking), respectively. (4) The orthopedic method induced forward sliding strain in the intervertebral disc, which released the compressed intervertebral foramen volume in the posterior segments. (5) In comparison, classical cervical traction was less effective in achieving these changes and could not reach the same degree of alteration. (6) Therefore, Long’s traction orthopedic method is more effective than classical cervical traction in increasing the cervical intervertebral foramen gap and improving foramen deformation. Biomechanically, this is attributed to the increased relative displacement, angle, and lateral bending displacement of the cervical intervertebral foramen, as well as greater disc displacement and forward strain, thereby relieving nerve compression in the affected segments, alleviating symptoms, and achieving a positive therapeutic effect. Figures and Tables | References | Related Articles | Metrics

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Biomechanical differences between the new proximal femoral stable intramedullary nail and traditional intramedullary nail#br# Rao Jingcheng, Li Yuwan, Zheng Hongbing, Xu Zhi, Zhu Aixiang, Shi Ce, Wang Bing, Yang Chun, Kong Xiangru, Zhu Dawei 2026, 30 (9):  2217-2225.  doi: 10.12307/2026.620 Abstract ( 8 )   PDF (3116KB) ( 4 )   Save BACKGROUND: Intertrochanteric fractures of the femur are a common type of fracture, especially prevalent among the elderly. Traditional intramedullary nails used in treating such fractures exhibit certain biomechanical inadequacies that can lead to internal fixation failure. Therefore, developing a new type of intramedullary nail to improve fracture healing outcomes and stability is particularly important.  OBJECTIVE: To design and evaluate a novel proximal femoral stable intramedullary nail and compare its biomechanical performance with existing proximal femoral nail antirotation and InterTAN in order to enhance the treatment outcomes of intertrochanteric fractures. METHODS: The study employed computer-simulated experiments using three-dimensional finite element analysis to establish a geometric model of intertrochanteric fractures. Initially, CT scans were utilized to obtain CT data of the femur. Mimics Research and Geomagic Studio software were used to construct a three-dimensional model of the femur. Stable intramedullary nail CrossFix 6°, 7.5°, and 9° were designed and compared with proximal femoral nail antirotation and InterTAN. The biomechanical performance of each model was analyzed under conditions of vertical compression, anterior-posterior bending, and torsion, comparing the von Mises stress, maximum displacement and maximum torsion angle of the intramedullary nail and bone.  RESULTS AND CONCLUSION: (1) Under vertical compression, the stable intramedullary nail series exhibited lower proximal femur stress and femoral head displacement compared to proximal femoral nail antirotation and InterTAN, with stable intramedullary nail CrossFix 9° showing the best performance. (2) In anterior-posterior bending and torsion conditions, the stable intramedullary nail series also demonstrated lower stress and displacement, indicating good stability and anti-rotational properties. (3) The unique cross-screw design of the stable intramedullary nail series effectively distributed stress applied to the fracture site, reducing the risk of fatigue fractures caused by stress concentration. (4) The stable intramedullary nail demonstrates superior biomechanical performance compared to proximal femoral nail antirotation and InterTAN, with excellent structural stability. Although there is preliminary support for its effectiveness, clinical trials are necessary to verify its long-term efficacy and safety, thereby assessing its application value in actual treatments.  Figures and Tables | References | Related Articles | Metrics

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Biomechanical performance of short-segment screw fixation combined with expandable polyetheretherketone vertebral body replacement in osteoporotic vertebrae Chen Long, Wang Xiaozhen, Xi Jintao, Lu Qilin 2026, 30 (9):  2226-2235.  doi: 10.12307/2026.600 Abstract ( 7 )   PDF (1860KB) ( 2 )   Save BACKGROUND: Vertebral replacement can restore the stability of the anterior column of the spine and correct deformity, but the traditional expandable titanium alloy replacement has a large elastic modulus and imaging artifacts, which increases the risk of adjacent segment degeneration. In theory, polyetheretherketone is more suitable for osteoporotic patients because of its similar density to bone, radiolucency and intraoperative adaptability, but there is still a lack of sufficient evidence.   OBJECTIVE: To investigate the biomechanical performance of posterior short-segment screw fixation combined with a novel expandable polyetheretherketone vertebral body replacement in osteoporotic vertebrae using finite element analysis.   METHODS: Four finite element models of T12 vertebral body replacement were developed based on different screw fixation methods and vertebral body replacement materials. Model 1: Conventional pedicle screws through the fractured vertebra combined with an expandable titanium cage (M1). Model 2: Conventional pedicle screws through the fractured vertebra combined with a polyetheretherketone-vertebral body replacement (M2). Model 3: Cement-augmented pedicle screws across the fractured vertebra combined with a polyetheretherketone-vertebral body replacement (M3). Model 4: Cement-augmented pedicle screws through the fractured vertebra combined with a polyetheretherketone-vertebral body replacement (M4). The range of motion, maximum von Mises stress of the fixation system, and adjacent segment endplates in T11-L1 segments were compared among the four models under identical boundary conditions.   RESULTS AND CONCLUSION: (1) Comparing M1 and M2, the range of motion values of M2 under four motion states were higher than those of M1, but the differences were not significant. The maximum stress on the vertebral body replacement in M2 under the four motion states was reduced compared to M1. Additionally, M2 showed a decrease in the maximum stress on the adjacent segment endplates compared to M1. (2) Among M2, M3, and M4, the fixed segment’s maximum range of motion was lowest in M4. The maximum stresses on the screw-rod system and vertebral body replacement under the four motion states were also lowest in M4. The maximum stress on pedicle screws under four motion directions was significantly highest in M3. For the adjacent segment endplates, M4 had the lowest maximum stress across all directions. However, the differences among the three were not statistically significant. (3) In vertebral body replacement for osteoporotic vertebrae, the biomechanical performance of the expandable polyetheretherketone-vertebral body replacement is similar to that of the expandable expandable titanium cage and may perform better in reducing subsidence. Posterior short-segment screw fixation combined with the expandable polyetheretherketone-vertebral body replacement provides good stability, with cement-augmented pedicle screws through the fractured vertebra demonstrating the best biomechanical performance and the least impact on the fixation system and adjacent endplates. Figures and Tables | References | Related Articles | Metrics

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Influence of different depths and loads on knee joint mechanics and peripheral muscle force characteristics during squatting Yan Xiangning, Chen Lei, Chen Yonghuan, Wang Chao, Li Xiaosheng 2026, 30 (9):  2236-2247.  doi: 10.12307/2025.829 Abstract ( 3 )   PDF (1348KB) ( 0 )   Save BACKGROUND: There are many variations and techniques of squatting in sports, and different squatting methods will have different effects on knee mechanics. Existing research results lack a full discussion concerning the effects of different depths and loads on the mechanical changes of the knee joint during squatting.  OBJECTIVE: To investigate the knee biomechanical characteristics of three different depths (shallow, parallel and deep squat) under three loads: 85%, 50%, and 0% of 1 repetition maximum, in order to provide a scientific evidence for choosing a reasonable depth and load for squatting training. METHODS: Kinematic, kinetic, and electromyographic data from 15 male subjects taking squats with different squat depths and loads were synchronously collected using a high-speed video camera (Sony), a three-dimensional force platform (Kistler), and an electromyograph (Noraxon). Inverse kinetics, biomechanical musculoskeletal modeling, and optimization algorithms were used to compute knee joint mechanics and lower limb muscle group force. Lastly, a two-way analysis of variance was employed to analyze the differences between the different depths and load conditions.  RESULTS AND CONCLUSION: (1) The main effect of load on knee joint moment was significant (P < 0.01). The shallow, flat, and deep squats all had the smallest knee moments at 0% load. (2) The main effect of loading on tibiofemoral joint force, patellofemoral joint force, and cruciate ligament force was significant (P < 0.01). With the increase of squat depth, the curves of tibiofemoral joint force, patellofemoral joint force, and cruciate ligament force showed a bimodal trend. (3) The main effect of loading on quadriceps force, hamstring force, and gastrocnemius force was significant (P < 0.01). 50% loading had the greatest quadriceps force, and hamstring and gastrocnemius forces were greatest at 85% loading. With the increase of depth, the change of quadriceps and hamstring muscle force showed a bimodal trend, while the gastrocnemius muscle force showed a trend of decreasing and then increasing. (4) Various mechanical parameters of the knee joint increased with increased loading, but the difference between 50% and 85% loading was small. All three depths of squatting showed maximum patellofemoral joint force and quadriceps force at 50% loading. The posterior cruciate ligament force, hamstring force, and gastrocnemius muscle force all reached their maximum at 85% loading. The increase in squatting in depth had no significant effect on the posterior cruciate ligament force. When the aim was to maximize the development of the muscle strength for the weighted squat, the 50% loaded parallel squat is recommended, but consider that it results in greater joint and ligament forces. Figures and Tables | References | Related Articles | Metrics

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Fracture mapping and imaging analysis of triplane fracture of distal tibia in adolescents Wang Bokai, Wang Zhiqiang, Zhou Hongyan, Li Junran, Wu Yiheng, Zhao Hongbo 2026, 30 (9):  2248-2254.  doi: 10.12307/2025.984 Abstract ( 3 )   PDF (1816KB) ( 0 )   Save BACKGROUND: Because of its complex and unique spatial structure, the triplane fracture of the distal tibia only occurs in adolescents with epiphyseal closure, which is a great test for clinicians’ experience and understanding in the treatment. In recent years, fracture mapping technology has developed rapidly and has been widely used in trauma orthopedics.  OBJECTIVE: To draw a triplane fracture map of the distal tibia in adolescents by using fracture mapping technology, observe the shape, location, and frequency of the cross-sectional fracture line, and analyze the characteristics of the triplane fracture of the distal tibia.  METHODS: The medical records of 79 patients with triplane fractures of the distal tibia were retrospectively studied. The original CT image data were collected. The required two cross-sectional images were obtained by Mimics 21.0 software. The patient’s CT images were reset and fitted to the standard template in Photoshop 24.0 software, and all fracture lines were depicted and superimposed to generate a fracture map. The Matlab (r2023b) software was used to create a heat map to show the high-density and low-density fracture areas, and the distribution of fracture lines was analyzed. RESULTS AND CONCLUSION: (1) Among the 79 adolescent patients included in this study, 73% were male and 27% were female, with an average age of 12.8±1.5 years (range, 10-15 years). (2) The fracture line of metaphysis mainly concentrated in the posterior side. The fracture line of the articular surface showed obvious “Y” type characteristics. The fracture line of this plane could be subdivided into “Y” type (18%), transverse type (32%), anteromedial notch type (33%) and other types (17%). The zonal fracture map showed that there were significant differences in the number of fracture lines passing through different regions (P < 0.01). (3) The formation of the “Y” shaped fracture line on the articular surface may be related to the anterior and posterior ligaments of the lower tibiofibula. The results show that the fracture map can provide an intuitive visual framework for the triplane fracture of the distal tibia, and provide references for further image classification, internal fixation design, and screw placement. Figures and Tables | References | Related Articles | Metrics

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Biomechanical characteristics of volar locking plate only versus combined dorsal mini-plate fixation of distal radius fractures with dorsal ulnar fragment  Zhou Daobin, Wang Kehao, Xie Yang, Ning Rende 2026, 30 (9):  2255-2261.  doi: 10.12307/2026.503 Abstract ( 8 )   PDF (1024KB) ( 2 )   Save BACKGROUND: For many years, surgical treatment for intra-articular fractures of the distal radius has been widely recognized, but there is still controversy over which surgical approach can achieve better efficacy and maximize joint function recovery. Regardless of the chosen treatment method, the goal is anatomical reduction and stable internal fixation. Although palmar locking plate fixation has recently become the most commonly used surgical method, one of the main limitations of this fixation method is the inability to achieve sufficient stability of the ulnar dorsal fracture fragment. OBJECTIVE: To analyze the biomechanical characteristics of treating distal radius fractures with dorsal ulnar fragment with only volar locking plate fixation and combined dorsal mini-plate fixation, and to explore the optimal internal fixation methods for different fracture patterns of distal radius fractures with dorsal ulnar fragment. METHODS: Thirty radial bone specimens were produced using 3D printing technology to establish distal radius fracture models with dorsal ulnar fragment and divided into three groups. Group 1 established distal radius fracture models with a dorsal ulnar fragment not exceeding the Lister tubercle. Group 2 established distal radius fracture models with a dorsal ulnar fragment exceeding the Lister tubercle. Group 3 established distal radius fracture models with comminuted fractures with dorsal ulnar fragment. Each group of models was randomly fixed with either a simple palmar locking steel plate or a palmar locking steel plate combined with a dorsal mini steel plate. The prepared model was installed into a customized biomechanical fixture. Cyclic loading and failure loading experiments were conducted on each model in sequence. Biomechanical stability was observed.  RESULTS AND CONCLUSION: (1) In the cyclic loading experiment, all test models did not fail. Comparison of stiffness among different models: There was no significant difference in fixing method at the initial stage of group 1 (P > 0.05), but there was a significant difference in fixing method values at the 1 000th, 2 000th, and 3 000th cycles (P < 0.05). There was no significant difference in fixing method between each stage of group 2 (P > 0.05). There were significant differences in each stage of group 3 (P < 0.05). (2) In the failure load experiment, the elastic limits of each group of models were compared: there was a significant difference between group 1 and group 3 (P < 0.05). There was no significant difference in group 2 (P > 0.05). Comparison of failure loads among different models: There was a significant difference between group 1 and group 3 (P < 0.05). There was no significant difference in various fixing methods in group 2 (P > 0.05). (3) It is concluded that for comminuted distal radius fractures or distal radius fractures with a relatively small dorsal ulnar fragment not exceeding the Lister tubercle, the stiffness and axial compressive strength of volar locking plate combined with dorsal mini-plate fixation are superior to only volar locking plate fixation, which can provide stronger fixation in the early stages of fracture healing. For distal radius fractures with a larger dorsal ulnar fragment exceeding the Lister tubercle, the biomechanical stability of the two fixation methods is basically the same. Figures and Tables | References | Related Articles | Metrics

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MRI evaluation of nerve root subsidence sign affecting efficacy of percutaneous endoscopic decompression in lumbar spinal stenosis Wang Nan, Chen Shuang, Xi Zhipeng, Qian Yuzhang, Zhang Xiaoyu, Gu Jun, Kang Ran, Xie Lin 2026, 30 (9):  2262-2268.  doi: 10.12307/2026.502 Abstract ( 5 )   PDF (1214KB) ( 1 )   Save BACKGROUND: The nerve root sedimentation sign has improved the imaging understanding of lumbar spinal stenosis as a new assessment index for it, but controversy still exists as to whether the nerve root sedimentation sign affects the prognostic efficacy of total endoscopic lumbar spinal decompression surgery. OBJECTIVE: To investigate the effect of nerve root sedimentation sign on the efficacy of lumbar spinal stenosis treated by full endoscopic techniques.  METHODS: Clinical data of 69 patients with lumbar spinal stenosis who underwent full endoscopic lumbar decompression from September 2018 to September 2022 in Jiangsu Provincial Hospital of Integrated Traditional Chinese and Western Medicine were retrospectively analyzed. The patients were divided into positive group (n=45) and negative group (n=24) according to whether the cauda equina was sedated under MRI. The general data, visual analog scale scores for low back pain and leg pain, Oswestry disability index scores and Macnab efficacy ratings of the two groups were compared, and the changes in the sagittal diameter of the lumbar spinal canal, transverse diameter of the spinal canal, the area of the spinal canal, and the angle of anterior convexity of the lumbar spine were compared between the pre- and post-treatment periods. RESULTS AND CONCLUSION: (1) Postoperative visual analog scale scores and Oswestry disability index scores of the two groups were reduced compared with those of the preoperative period, and the differences were statistically significant (P < 0.05). Comparing the two groups, the scores of the positive group in terms of low back pain were significantly lower than those of the negative group in both the 1-week and the 1-year periods after treatment, and the differences were statistically significant (P < 0.05). (2) The area of the spinal canal, the sagittal diameter of the spinal canal, and the transverse diameter of the spinal canal were significantly enlarged after the operation in both groups compared with the preoperative period, and the difference was statistically significant (P < 0.05). (3) The lumbar anterior convexity angle was not significantly affected in both groups after surgery, and the difference was not statistically significant compared with the preoperative and postoperative periods (P > 0.05). (4) The 1-year postoperative efficacy of the patients was evaluated by MacNab: positive group: 30 cases were excellent, 11 cases were good, 3 cases were average, and 1 case was poor, with an excellent and good rate of 91%; negative group: 16 cases were excellent, 4 cases were good, 4 cases were average, with an excellent and good rate of 83%. No significant difference was detected between the two groups (P > 0.05). (5) The above results show that total endoscopic lumbar spinal canal decompression in the treatment of lumbar spinal stenosis has outstanding efficacy, which can achieve accurate decompression and can be well reflected on MRI, while the presence or absence of nerve root sedimentation sign has no obvious effect on the postoperative efficacy.  Figures and Tables | References | Related Articles | Metrics

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Cervical motion characteristics in patients with cervical spondylotic radiculopathy based on motion capture technology Li Zhifei, Han Bin, Liu Qiuli, Zhang Zhanming, Wei Haokai, Zuo Kuangshi, Zhang Yisheng 2026, 30 (9):  2286-2293.  doi: 10.12307/2026.543 Abstract ( 7 )   PDF (1305KB) ( 2 )   Save BACKGROUND: Motion capture technology can comprehensively and accurately analyze the three-dimensional structure angle of the cervical spine and obtain accurate data, which is helpful to understand the movement characteristics of the cervical spine in patients with cervical radiculopathy. It is of vital significance for guiding the prevention of cervical spondylotic radiculopathy, assisting cervical spondylotic radiculopathy diagnosis, formulating personalized treatment plans, and guiding rehabilitation training.  OBJECTIVE: To explore the cervical motion characteristics of patients with cervical spondylotic radiculopathy and reveal the pathogenesis of cervical spondylotic radiculopathy through motion capture technology.  METHODS: Five cervical spondylotic radiculopathy patients who visited the Orthopedics Department of First Affiliated Hospital of Guangxi University of Chinese Medicine from October 1, 2023 to March 1, 2024 were analyzed as the cervical spondylotic radiculopathy group. Five healthy individuals were selected as the healthy control group. The gender, age, head circumference, and body mass index of all subjects were recorded. The angle change process (trajectory) and motion range were captured during the six degrees of freedom of neck flexion, extension, left flexion, right flexion, left rotation, and right rotation of the research subjects using Inertial Measurement Unit sensors.  RESULTS AND CONCLUSION: (1) The cervical spondylotic radiculopathy group had significantly smaller changes in C2-C7 relative angles during forward flexion than the healthy control group (P < 0.01). The range of neck motion error in cervical spondylotic radiculopathy group was significantly larger than that in the healthy control group during right rotation (P < 0.01). The time for the cervical spine to reach its maximum range of flexion during forward flexion was longer than the time to return to normal position (P < 0.01). (2) The range of motion of the cervical spondylotic radiculopathy group was significantly lower than that of the healthy control group in terms of forward flexion and right rotation (P < 0.001). These findings indicate that patients with cervical spondylotic radiculopathy have degeneration of the muscles and nerves on the affected side during vertebral body movement, muscle strength and coordination abilities are reduced. The muscles and nerves on the healthy side will compensate for the deficiency of the affected side and overcontrol, which is consistent with the concept of “musculoskeletal imbalance.”  Figures and Tables | References | Related Articles | Metrics

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Evaluation parameters and specific region of C6 nerve oppression by uncinate process degeneration Li Sa, Sun Ning, Sun Zhaozhong, Feng Zhimeng, Li Xuedong 2026, 30 (9):  2294-2302.  doi: 10.12307/2026.064 Abstract ( 4 )   PDF (2296KB) ( 2 )   Save BACKGROUND: Degeneration of the uncinate process and the development of osteophytes are recognized as prevalent factors contributing to cervical intervertebral foramen stenosis in individuals suffering from cervical spondylotic radiculopathy. Nonetheless, there is a notable scarcity of research data, both domestically and internationally, regarding C6 cervical spondylotic radiculopathy induced by mutations in the C6 uncinate process. Furthermore, the current body of imaging data is insufficient to establish a definitive diagnostic protocol for identifying the specific region affected by cervical spondylotic radiculopathy due to uncinate process degeneration. OBJECTIVE: To delineate the spatial relationships between the uncinate process and adjacent anatomical structures using three-dimensional CT image reconstruction, to identify specific diagnostic regions within CT images for C6 nerve entrapment associated with uncinate process degeneration, and to guide key-hole surgical procedures aimed at decompressing the C6 nerve root canals. METHODS: A cohort of 56 patients presenting with C5/6 unilateral cervical spondylotic radiculopathy, each patient fulfilled the predefined inclusion criteria, was enrolled in the study. This group comprised 29 males and 27 females, ranging in age from 35 to 71 years. Cervical spine CT data were imported into Mimics 21.0 software to construct a three-dimensional model of the cervical spine. The following parameters at the C5/6 level were measured: (1) Measurement on the sagittal plane of the uncinate process situated within the most constricted segment of the cervical intervertebral foramen: The vertical distance from the uncinate process situated within the most constricted segment of the cervical intervertebral foramen to the transverse section of the lower edge of the C5 pedicle and the upper edge of the C6 pedicle (a, b); (2) measurement on the cross section of the uncinate process situated within the most constricted segment of the cervical intervertebral foramen: The horizontal distance from the uncinate process situated within the most constricted segment of the cervical intervertebral foramen to the sagittal plane where the lowest point of the posterior edge of the upper endplate is located (c); (3) the horizontal distance from the uncinate process situated within the most constricted segment of the cervical intervertebral foramen to the sagittal plane of the medial and lateral margin of the pedicle of C6 (d, e); (4) the narrowest distance of intervertebral foramen (f); (5) measurement on the cross section of the lowest point of the posterior edge of the C6 upper endplate: the left and right distance from the upper endplate to the sagittal plane of the medial edge of the left and right pedicle of C6 (g, h); (6) on the median sagittal plane, the line connecting the anterior and inferior edge of the C5 inferior endplate (the line of inferior edge of the vertebral body ) was established, and the parallel line of the line of inferior edge of the vertebral body (the inferior endplate line) was established through the highest point of the C5 lower endplate. The parallel line (uncinate process line) of the line of inferior edge of the vertebral body was established through the uncinate process situated within the most constricted segment of the cervical intervertebral foramen, and the location between the line of inferior edge of the vertebral body, the inferior endplate line and the uncinate process line was observed on the median sagittal plane; (7) observation of the morphological characteristics of intervertebral foramen on the sagittal plane of the uncinate process situated within the most constricted segment of the cervical intervertebral foramen. All patients underwent single-port split endoscopic key-hole surgery on the cervical spine under the guidance of the above imaging data. The clinical efficacy was evaluated by visual analog scale and Japanese Orthopaedic Association scores before operation and 1 month, 6 months and the last follow-up after operation. RESULTS AND CONCLUSION: (1) There was no significant difference in the related parameters between the two genders (P > 0.05). (2) There was no significant difference between the left side and the right side of a, b, c, d, e, f, g, and h (P > 0.05), and there was also no significant difference between g and h in the total sample (P > 0.05). (3) Visual analog scale score and Japanese Orthopaedic Association scores were improved at 1 month, 6 months, and the last follow-up after operation, and the difference was statistically significant (P < 0.05). (4) The region between the line of inferior edge of the vertebral body and the inferior endplate line was the absolute region and above the inferior endplate line was the region of above the inferior endplate line. The uncinate process region composed of the two regions was the specific region for the diagnosis of uncinate process degeneration by CT. (5) The intervertebral foramen region between the inner and outer edges of the sagittal pedicle included by the uncinate process region was a specific region in the diagnosis of cervical spondylotic radiculopathy. The uncinate process region with clinical symptoms and signs was accurate and reliable in the diagnosis of cervical spondylotic radiculopathy caused by uncinate process degeneration. (6) The uncinate process situated within the most constricted segment of the cervical intervertebral foramen was only the narrowest point of the intervertebral foramen, and the compression of the nerve root was often caused by the stenosis of the intervertebral foramen with the uncinate process at the uncinate process situated within the most constricted segment of the cervical intervertebral foramen as the center. (7) Different pathomorphological types of intervertebral foramen could be observed in the sagittal plane where the uncinate process situated within the most constricted segment of the cervical intervertebral foramen was located, and different types oppressed cervical nerve in different parts of intervertebral foramen. (8) Additional resection of uncinate process could be considered for grade 2 cervical intervertebral foramen stenosis; during the operation, the inferior margin of C5 pedicle and the upper, medial and lateral margin of C6 pedicle could be located and the uncinate process that was severely compressed cervical nerve can be removed. (9) Cervical spondylotic radiculopathy resulting from uncinate process degeneration warrants careful attention. The uncinate process region is particularly useful for CT diagnosis. Diagnosing cervical spondylotic radiculopathy caused by uncinate process degeneration using CT scans focused on this area, along with clinical signs and symptoms, is accurate and dependable, reducing the chance of missed or incorrect diagnoses. In cases of severe cervical nerve compression due to uncinate process degeneration, key-hole uncinate process resection may be considered. Figures and Tables | References | Related Articles | Metrics