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Abstract:Orthodontic biomechanics, through the integration of multiple disciplines, has made significant advancements in understanding tooth movement mechanisms, optimizing orthodontic techniques, and providing personalized treatment. Research indicates that three-dimensional finite element models accurately reveal the dynamic relationship between the stress distribution in periodontal tissues and bone remodeling, highlighting the critical role of light force control in ensuring treatment safety. Clear aligners, through low-friction elastic attachments (LFEH), collaborative anchorage strategies, and material mechanics optimization, significantly enhance the predictability of tooth movement, with LFEH design reducing lingual and buccal tilting stresses. The application of biologically active materials and smart archwires has significantly enhanced enamel resistance to demineralization and sustained light force release. Artificial intelligence technology is deeply integrated into the entire treatment process: dynamic prediction models based on deep learning optimize force application schemes, while real-time mechanical monitoring systems dynamically calibrate movement paths, promoting the precision of treatment. However, individual differences in biomechanical responses and complex movements remain key challenges. Future efforts should focus on integrating multimodal data to build intelligent diagnostic systems, developing mechanically responsive biomaterials and degradable anchorage devices, and deepening research on molecular-cell-tissue cross-scale mechanisms to achieve a leap from 'force-oriented' to 'biological response-oriented' precision orthodontics.

Abstract:With the advancement of socioeconomic development and clear Aligner technology, invisible orthodontics has become an important treatment approach for malocclusion. However, in extraction cases involving anterior tooth retraction, the limited three-dimensional force control of aligners often leads to lingual tipping of incisors, deepened overbite, and anchorage loss of posterior teeth, thereby increasing the complexity and uncertainty of orthodontic treatment. As an effective tool for simulating complex biomechanical behaviors, finite element analysis (FEA) enables quantitative assessment of tooth movement and stress distribution in the periodontium, providing theoretical support for optimizing aligner design. This review focuses on FEA studies of anterior tooth retraction using clear aligners in extraction cases, summarizes tooth movement characteristics, and discusses key influencing factors including Aligner parameters, movement patterns, attachment design, and auxiliary appliances. Finally, the future directions of FEA in dynamic simulation and personalized modeling are explored to support more predictable and effective clinical outcomes.

Abstract:Objective This study investigates the force distributions and movement patterns of the maxillary dentition during molar intrusion with clear aligners, aiming to provide a theoretical basis for optimizing clinical orthodontic treatment strategies. Methods A three-dimensional (3D) finite element model of the periodontal ligament-teeth-clear aligners complex was established to simulate different intrusion modes, including bilateral first molar intrusion, bilateral second molar intrusion, and simultaneous intrusion of bilateral first and second molars. The von Mises stress distribution characteristics and displacement patterns of each tooth under different intrusion conditions were systematically analyzed. Results Compared with simultaneous molar intrusion, the individual intrusion design resulted in greater intrusive movement (10.500–4.260 μm) accompanied by distal-lingual crown inclination (distal displacement: -7.690–-5.100 μm; buccal displacement: -20.500–6.750 μm). Anchorage teeth displayed a displacement trend opposite to that of the intruded molars. The anterior teeth demonstrated minimal displacement and low stress levels. During maxillary molar intrusion with clear aligners, the maximum equivalent stress in the periodontal ligaments occurred at the anchorage teeth mesial to the intruded molars, primarily concentrated in the apical region and the mesial aspect of the buccal cervical area. Conclusions A sequential intrusion strategy enhances vertical control efficiency compared to simultaneous intrusion. Unanticipated mesiodistal and buccolingual displacements in the posterior region necessitate the implementation of counteracting mechanisms in aligner design. In clinical practice, priority should be given to monitoring the risks of root resorption and bone remodeling effects in stress-concentrated zones (apical and buccal cervical regions) of anchorage teeth.

Abstract:Objective To investigate the biomechanical characteristics of the mandibular anterior teeth intrusion assisted by buccal mini-implants, so as to provide theoretical guidance for the clinical treatment of deep overbite and other conditions requiring intrusion of the mandibular anterior teeth. Methods A finite element model of implant screws, clear aligners (CAs) and mandibular complex including the mandibular dentition, periodontal ligament (PDL) and alveolar bone was constructed. The model was designed with 0.2 mm intrusion in the mandibular anterior teeth. Seven groups were set: without traction, 30 g, 50 g, 100 g, 150 g, 200 g, and 250 g force groups. The stress and displacement of the teeth as well as the related stress distributions of PDL and CAs in each group after loading were analyzed. Results Without traction and under different traction forces, the mandibular anterior teeth tended to be tipped and intruded. With the increase of traction force, the increasing trend was manifested in the vertical displacement and labial displacement of the mandibular anterior teeth. When the traction force reached 200 g, the vertical displacement showed a significant increase, the subsequent increase then showed a tendency to flatten. The ratio of the labial tipping displacement to the intrusive displacement of the mandibular anterior teeth showed a decreasing trend with the increase of traction force.Within a reasonable force range, increasing traction force led to greater bodily intrusion of the anterior teeth. When the traction force was less than 150 g, the mandibular posterior teeth exhibited a tendency of extrusion. When the traction force of more than 150 g was applied, it showed a tendency of intrusion. The PDL stress was concentrated on the labial and cervical surface of the anterior teeth. Conclusions Intrusion efficiency of the mandibular anterior teeth has been effectively improved with CAs assisted by buccal mini-implants. Moreover, the traction force of the mini-implants has a significant impact on the movement of the mandibular anterior teeth. Based on a comprehensive analysis of factors such as the displacement trend of the mandibular dentition and the PDL stress, the optimal force value for buccal traction of the mini-implants to intrude the mandibular anterior teeth can be selected as 150–200 g force.

Abstract:Objective To investigate the biomechanical characteristics of clear aligners combined with Class Ⅱ elastics during retraction of upper anterior teeth, and compare the differences between two traction methods. Methods A case with a molar distal relationship and extraction of four first premolars was selected. The finite element method was applied to analyze tooth displacement, force distribution, and periodontal ligament (PDL) stress during 0.2 mm en-masse retraction of the anterior teeth. Three working conditions were defined: En-masse retraction without elastics (Condition 1)?,?120 g Class Ⅱ elastics with aligner-cut hooks on upper canines and lower first molars (Condition 2), 120 g Class Ⅱ elastics with aligner windows and bonded buttons on upper canines and lower first molars (Condition 3). Results Class Ⅱ elastics significantly enhanced lingual movement of the upper anterior teeth and mesial movement of the lower posterior teeth, while reducing mesial movement of the upper posterior teeth and lingual movement of the lower anterior teeth. In the transverse direction, the forces exerted on the teeth in all three conditions were minimal. In the sagittal direction,?in Condition 2, the proximal force of the upper posterior teeth was effectively reduced by an average of 0.13 N, and the proximal force of the lower posterior teeth was increased by an average of 0.31 N. In Condition 3, the distal force of the upper canine teeth and the proximal force of the lower first molar were significantly increased by 0.40 N and 1.14 N, respectively. In the vertical direction, In condition 2, the average extrusive force of the upper teeth and the extrusive force of the lower molars were increased by 0.22 N and 0.20 N, respectively. In Condition 3, the upper canine extrusive force was increased by 0.91 N, while the lower molar intrusive force and the second molar extrusive force were reduced by 0.27 N and 0.25 N, respectively. The PDL stress distribution in the three groups was generally similar. In Condition 3, the maximum principal stress distribution area on the lower first molars expanded slightly, but the magnitude did not increase significantly. Conclusions Condition 2 optimized the lower posterior teeth mesialization through balanced force distribution and protected the upper posterior teeth anchorage. Condition 3 significantly increased extrusive and distal forces on the upper canines and mesial forces on the lower first molars but did not substantially elevate periodontal risks for these teeth.

Abstract:Objective To analyze the effects of different traction sites and directions on the maxilla and upper dentition when using clear aligners combined with protraction for the treatment of maxillary deficiency.Methods A three-dimensional (3D) finite element model including the zygomaticomaxillary complex, maxillary dentition, and clear aligners was constructed. The models were divided into Group 1 (traction hook at the distal of the lateral incisor) and Group 2 (traction hook at the distal of the canine). Each group was analyzed under four loading conditions with protraction angles of 0°, 10°, 20°, and 30° relative to the occlusal plane. A unilateral protraction force of 500 g was applied. The differences in stress distribution and displacement of the maxillary bone and dentition under different loading conditions were analyzed. Results When the protraction angle was 30°, both groups showed forward and downward displacement of the maxilla, while other angles resulted in counterclockwise rotation. Under the same protraction direction, the total displacement of the maxilla and displacements in all directions in Group 2 were greater than those in Group 1. The upper central incisors in Group 1 showed lingual displacement, which increased with the protraction angle. The maxillary dentition in Group 2 showed forward displacement, with the minimum total and sagittal displacements at a protraction angle of 30°. Stress concentration was mainly observed in the zygomaticomaxillary suture and anterior alveolar bone regions in both groups, decreasing as the protraction angle increased. Conclusions Clear aligners combined with protraction can be applied to skeletal Class III patients with mild maxillary deficiency. When the protraction site is located at the distal of the canine with a 30° downward and forward angle to the occlusal plane, the maxilla can achieve ideal forward and downward displacement with the minimum labial movement of the upper anterior teeth.

Abstract:Objective To investigate the effects of three types of twin-block (TB) appliances on the stress and displacement of anterior teeth, periodontal ligaments, and alveolar bone. Methods A three-dimensional (3D) finite element model was constructed, including maxillofacial bones, articular discs, teeth, and periodontal ligaments. Three types of twin-block appliances were designed: classic twin-block (classic-TB), twin-block with acrylic capping (capping-TB), and clear twin-block aligner (CTBA). All appliances had an inclination angle of 70°, and a masticatory force of 200 N was applied to their inclined planes. The finite element method was used to analyze the stress distribution and displacement differences of anterior teeth. Results All three types of TB appliances induced lingual tilting of maxillary anterior teeth and labial tilting of mandibular anterior teeth. The CTBA group showed the greatest lingual displacement and stress of maxillary anterior teeth, with a maximum stress of 30.6 MPa, while the mandibular anterior teeth in this group exhibited the smallest labial displacement (approximately 0.02 mm) and stress. Additionally, the CTBA group had the lowest compressive stress in mandibular anterior teeth, periodontal ligaments, and alveolar bone, whereas the classic-TB group had the highest. Conclusions In the treatment of Angle Class II malocclusion, classic-TB (with or without acrylic capping) causes labial inclination of mandibular anterior teeth. Compared with classic-TB, CTBA effectively reduces the compressive stress and displacement of mandibular anterior teeth, potentially minimizing adverse periodontal risks. However, attention should be paid to the lingual displacement of maxillary anterior teeth.

Abstract:Objective This study quantitatively analyzed the initial displacement and stress distribution of maxillary teeth and periodontal ligaments (PDLs) under different traction positions of Class Ⅱ elastics in the anterior region of fixed multibracket appliances, aiming to provide references for the optimal application of Class Ⅱ elastics. Methods A finite element model of the maxilla with Class Ⅱ elastics was established. Based on whether tooth extraction was performed and the traction positions of Class Ⅱ elastics in the maxillary anterior region, the models were divided into 4 groups and 8 working conditions. A 1.2 N load was applied between the maxillary anterior region and the tube of the mandibular first molar. The initial displacement of maxillary teeth and the von Mises stress of maxillary PDLs were analyzed. Results The finite element model of the maxilla with Class Ⅱ elastics was successfully constructed. Class Ⅱ elastics induced lingual inclination, eruption, and retraction of maxillary anterior teeth. Variations in the traction positions of Class Ⅱ elastics resulted in differences in the initial displacement of maxillary teeth and the von Mises stress of PDLs. The maximum von Mises stress of PDLs ranged from 5.8 to 12.2 kPa across all working conditions. Conclusions Different traction positions of Class Ⅱ elastics alter the torque, induce distinct deformation trends in the archwire, and thus affect tooth movement. Compared with attaching Class Ⅱ elastics to the maxillary canine bracket, attaching them to the hooks increases the tendency toward deep overbite, and this tendency is more pronounced in extraction models. For patients with Class Ⅱ, Division 1 malocclusion, anterior tooth protrusion, and a tendency toward open bite, applying Class Ⅱ elastics on the occlusal side of the hooks may be more beneficial in alleviating open bite and enhancing the smile arc. However, the actual efficacy requires clinical verification.

Abstract:Objective To establish a simplified simulation method of rocking-chair archwire (RCA), explore the biomechanical effect of RCA during anterior teeth retraction with sliding mechanics, and provide guidance for clinical treatment. Methods A standard 0.019×0.025 inch labial archwire was imported into ANSYS software and preloaded spring was used to simulate RCA at different angles to achieve parameterized modeling. A three-dimensional (3D) finite element model with labial straight wire appliance, teeth, periodontium and maxillary bone was established to analyze the displacement and force of anterior/posterior teeth under 1.5 N intra-arch traction combined with RCA at different angles. Results Preloading forces of 1.5, 3, 4.5, and 6 N in spring induced angles of approximately 5°, 10°, 15°, and 20° for RCA, demonstrating the flexibility and convenience of the parameterized modeling method. During intra-arch traction with increased angle of RCA, lingual crown displacement of the middle incisor gradually decreased, while the lateral incisor and canine showed decreased crown tipping and increased lingual root displacement; when the RCA angle was 20°, the lateral incisor and canine achieved almost bodily retraction. With the increase of RCA angle, premolars showed an extrusion tendency, while molars demonstrated distal crown tipping and intrusion tendency. As the RCA angle increased from 0° to 20°, intrusive force on the anterior teeth increased, and the moment-force ratio (M/F) at bracket level increased from 0 to near 9?mm. Conclusions RCA can effectively control the moving pattern of the maxillary anterior teeth and prevent their over-erection and extrusion during retraction with sliding mechanics. During intra-arch traction with rigid stainless steel archwire, RCA of 20° has sufficient torque control on the anterior teeth to achieve their En mass retraction.

Abstract:Objective To compare the differences in thickness and fitting accuracy between direct printed aligners (DPA) and conventional thermoformed aligners (TFA), and to provide experimental evidence for the clinical application of clear aligners (CAs). Methods Sixteen adult subjects with mild dental crowding and no significant caries or restorations were recruited. For each subject, CAs were fabricated using direct three-dimensional (3D) printing and conventional thermoforming methods. The CA thickness was measured at the labial/buccal and lingual surfaces of incisors, canines, and first molars using a high-precision electronic thickness gauge. Micro-CT scanning was employed to analyze the gap between the CAs and dental models, followed by statistical analyses. Results The overall mean thickness of the DPA group was (0.60±0.04) mm, significantly higher than that of the TFA group (0.48±0.06) mm (P<0.000 1), with superior thickness uniformity. The average gap between CAs and dental models in the DPA group was (0.29±0.08) mm, significantly smaller than that in the TFA group (0.31±0.16) mm (P<0.05), particularly at the incisal edges of incisors, buccal surfaces of canines, and occlusal surfaces of first molars. Conclusions Compared to conventional TFA, DPA demonstrates significant advantages in thickness uniformity and fitting accuracy, indicating that DPA has greater application potential in orthodontic clinical treatment.

Abstract:Objective To investigate the damage characteristics of peri-implant bones with varying densities under impact and occlusal forces using numerical simulation.Methods A finite element model of the microstructure of an implant and bones with different densities was established. Impact and occlusal forces were applied sequentially to the implant. The osteon damage threshold in the simulation was defined based on the bone damage strength at different strain rates. A user material subroutine was created for failure judgment using stress-based failure criteria, enabling the analysis of bone damage caused by impact and occlusal forces. Results No cortical bone damage was observed in bones of varying densities under impact force. Damage primarily occurred in the trabecular bone at the base of the implant, with the extent of damage worsening as bone density decreased. Additionally, the number of failed bone elements generated by the damage increased with reduced bone density. Bone tissues with pre-existing impact damage sustained secondary damage when subjected to occlusal force: the bonding interface between the implant and cortical bone was damaged, leading to implant displacement and fracture of peri-implant trabecular bone. The damage caused by occlusal force also worsened as bone density decreased. Conclusions The degree of damage from impact and occlusal forces is correlated with bone density, with damage worsening as bone density decreases. This underscores the protective role of cortical bone. The application of occlusal force exacerbates bone tissue damage, leading to implant displacement when the cortical bone is damaged. In clinical practice, patients with a history of impact damage should undergo thorough examination and evaluation. The occlusal force borne by damaged bones should be reduced; if necessary, the implant should be removed and reinserted after re-establishment of osseointegration.

Abstract:Objective To conduct preoperative simulations of three different osteotomy line design schemes under centric occlusion based on two distinct material assignment methods, evaluates biomechanical properties of the models, and explore which osteotomy line design schemes are more suitable for different types of mandibles. Methods Three types of mandibles were selected, and CT images were obtained for three-dimensional (3D) reconstruction. Material assignment was completed using the cortical/cancellous bone assignment method and the gray value assignment method. Osteotomy was simulated according to the three osteotomy line design schemes, followed by finite element analysis. Results In all simulation results of the mandibles, the maximum stress was 81.10 MPa, the maximum strain was 0.035 52, and the maximum displacement was 432.4 μm. The stress distributions obtained by the cortical/cancellous bone assignment method showed a larger stress distribution range than that that by the gray value assignment method, but the maximum stress, strain, and displacement were generally lower. For the outflare type and common type mandibles, Scheme 1 showed lower maximum stress, strain, and displacement under both material assignment methods, but no clearly suitable scheme was found for the retracted type. Conclusions The outflare type and common type mandibles are more suitable for adopting the osteotomy line design scheme of Scheme 1. For the retracted type, other mandibular angle osteotomy plastic surgery methods may be considered to ensure better biomechanical characteristics. Whether choosing the osteotomy line design scheme or the modeling material assignment method, it is necessary to make the final decision based on the specific analysis objectives and resource conditions.

Abstract:Objective To investigate changes in the microRNA expression profiles of apoptotic vesicles (apoVs) derived from bone marrow mesenchymal stem cells (BMSCs) under a simulated negative pressure environment, and to provide a theoretical basis for understanding the mechanism by which mechanical stress microenvironments influence the progression of osteoarthritis. Methods A negative pressure cellular environment was established using a pressure-loading system. Cell viability and apoptosis were assessed via the CCK-8 assay, Western blotting, and Annexin V-FITC/PI double staining. ApoVs were isolated by differential centrifugation and characterized using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blotting. Small RNA sequencing was performed using the HiSeq Single-End mode, and differential expression analysis of microRNAs was conducted using DESeq to screen for differentially expressed microRNAs. The differentially screened microRNAs were validated by real-time quantitative PCR. After treating BMSCs with inhibitors of these differentially expressed microRNAs, the effects of the screened microRNAs on BMSCs were detected. Results Compared to apoVs generated by BMSCs under STS chemical treatment, those produced under a -40 kPa pressure environment showed significantly upregulated miR-183-5p and downregulated miR-3473. GO and KEGG enrichment analyses revealed that these differentially expressed microRNAs affected cell activity and inflammatory responses through multiple signaling pathways. Inhibition of miR-183-5p and miR-3473 expression reduced the proliferative activity of BMSCs. After inhibiting miR-183-5p expression, the levels of inflammatory factors increased. Inhibition of miR-3473 expression did not alter the IL-6 expression level, but significantly increased the TNFα expression level. Conclusions MicroRNAs specifically expressed in BMSC-derived apoVs under negative pressure stimulation may act as critical mechanical signaling mediators, regulating inflammatory response processes to participate in the pathogenesis and progression of arthritis.

Abstract:Objective To elucidate the kinetic characteristics of viral replication and transcription, an in vitro model of viral replication and transcription was established. Utilizing single-molecule magnetic tweezers technology, the dynamic process of SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) during in vitro replication and transcription was investigated. Methods The force field of the single-molecule magnetic tweezer system was corrected using DNA fragments, followed by the construction of RNA fragments to explore the kinetics of RdRp replication and transcription in vitro. Results The force field calibration results were consistent with the worm-like chain model (WLC). The ssRNA strand was found to be approximately 0.3 μm longer than the dsRNA strand and could be stably extended under a 30 pN force field. The average synthesis rate of RdRp extension was determined to be 3.27 nt/s, with an average processivity of 886 nt. Conclusions By implementing force calibration in single-molecule magnetic tweezers, we achieved real-time tracking of RdRp kinetics during the full-cycle replication-transcription process (initiation, elongation, and termination) in vitro, thereby constructing a mechanistic model of RdRp-driven nucleic acid synthesis. This study provides a basis for further investigating the kinetics of viral RdRp in physiological processes including replication, transcription, and backtracking under varied in vitro environments using single-molecule magnetic tweezers, and establishes a single-molecule manipulation framework for evaluating the effects of therapeutic compounds on viral replication-transcription processes in vitro.

Abstract:Objective To investigate the effect of single osteochondral defect of the knee on pressure distributions in weight-bearing area of the medial femoral condyle, and further evaluate changes of the location of peak pressure on the medial condyle with the defect size changing. Methods Ten fresh porcine knee joints were fixed in extension position. First, mechanical loads were applied to the medial compartment of the normal porcine knee joint to determine the maximum contact pressure area. Then, rounded osteochondral defects with different diameter (in depth of 9 mm) were drilled at this area, respectively. The 100, 200, 300 N axial compression loads were applied to the medial compartment of each knee joint, and the strength and location of the peak contact pressure during loading were recorded. Results The peak pressure increased with defect size increasing, and the phenomenon of stress concentration appeared. The peak pressure was significantly higher in the defect with diameter exceeding 8.0 mm than that in the non-defect knee. The peak pressure showed a similar tendency to move closer to the defect rim as the defect size increased (the distance between the peak pressure position and the defect rim ,peak-to-rim distance, decreased). Conclusions In the single knee osteochondral defect model, when the diameter of the defect at the weight-bearing area was larger than 8.0 mm, the peak pressure on the uninjured site significantly increased, and the peak-to-rim distance significantly decreased, which implied 8.0 mm as a potential threshold for surgical intervention.

Abstract:Objective To study the effects of porous prothesis with radial gradient and homogenized structures on stress transmission in the tibia by using finite element method. Methods Based on the reverse engineering technology, the tibial model was constructed, and the bionic trabecular bone structure prosthesis with gradient change of pore edge diameter and the homogeneous bionic trabecular bone structure prosthesis were designed. The Vicon dynamic capture platform was used to obtain the human gait and the axial force of the tibia-femoral joint during flexion, which was imported into ANSYS Workbench as a boundary condition for mechanical performance analysis. Results In the case of proximal defect, the von Mises stress of the bone for prosthesis with radial gradient structure was increased by 3.68 MPa, and that in the case of distal defect was increased by 7.34 MPa. Compared with the homogenized prosthesis, the von Mises stress of the proximal and distal defects was decreased by 171 MPa and 190.4 MPa, respectively. Conclusions The stress of the radial gradient structure prosthesis diffuses from the outside to the middle high porosity area along the prosthesis, which can effectively transfer the tibial plateau load, reduce stress concentration of the prosthesis, improve bone stress and prolong service life of the prosthesis. This study provides a theoretical reference for clinical prosthesis replacement.

Abstract:Objective The biomechanical performance of Ilizarov fixator models with different configurations for humeral shaft defect was compared, so as to provide a biomechanical basis for selecting the appropriate circular external fixation structure for the clinical treatment of humeral shaft defects using Ilizarov technology. Methods Based on CT data of the humerus from a healthy volunteer, the external fixators with three configurations, namely, hybrid frame, semi-ring frame and 90° fan frame were established. The finite element method was used to simulate the displacement and stress distribution under different loading conditions, and the finite element results were validated by biomechanical tests. Results Finite element analysis results: in terms of displacement, under compression, tensile and torque conditions, the displacement of 90°fan model was smaller than that of hybrid and semi-ring models. In terms of stress, the 90°fan model had the smallest displacement under tensile condition. In compression and torque tests, the semi-annular model had the lowest stress. Biomechanical test results: the semi-ring model exhibited the smallest displacement under axial compression, but there was no significant difference between the three models (P> 0.05). Conclusions The semi-ring and 90° fan frames can achieve a similar stability as the traditional hybrid frame through the strategy of ‘reducing the ring and increasing the stem’. The unilateral structure of the 90° fan frame has the advantages of small size, light weight, and structural stability, as well as small impact on the shoulder and elbow joints, which makes it more valuable in clinical applications.

Abstract:Objective To compare the biomechanical characteristics of novel retrograde intramedullary nail, common femoral retrograde intramedullary nail, and medial femoral condyle locking plate for treating distal femur type A fractures by finite element analysis, and study the advantages of retrograde intramedullary nail on medial femoral condyle. Methods A novel retrograde intramedullary nail on medial femur condyle was designed. CT scan was performed on lower limb bones of a male volunteer, and a three-dimensional (3D) model of the femur was established. The model was then segmented to create models of distal femur type A2 and A3 fractures. The 3D models of internal fixator were established. The small and standard retrograde intramedullary nail on medial femoral condyle, common femoral retrograde intramedullary nail, locking plate on medial femoral condyle were used for internal fixation on A2 type fracture. A3 type fracture was fixed with one of the above internal fixators combined with lateral condylar plate respectively. The 600 N axial load and 4 N·m torsional load were applied to the models. The displacement and stress of femurs, the displacement and stress of internal fixators, the micro-momentum between the internal fixator and the bone, the relative displacement of the two fracture broken ends were observed in each group. Results Among the A2 and A3 type fractures under axial loads, the correponding standard group and corresponding standard combined group had the smallest peak displacement and peak stress of the femur and internal fixation. Among the A2 and A3 type fractures under torsional loads, the correponding standard group and corresponding standard combined group had the smallest peak displacement of the femur and internal fixation. The relative displacement of the two broken ends in the standard combined group was the smallest. Conclusions Compared with femoral medial condylar locking plate and common retrograde intramedullary nail, this novel retrograde intramedullary nail on medial femur condyle has a mechanical advantage of reducing stress concentration and reducing the risk of internal fixation failure, and it can be used alone for distal femur type A2 fracture, or in combination with the lateral condylar plate to fix distal femur type A3 fracture.

Abstract:Objective To evaluate the correlation of L4–5 multifidus muscle (MM) fat infiltration (FI) with lumbar range of motion (LROM) and quality of life in patients with degenerative spinal deformity (DSD). Methods Thirty patients with DSD were included. The Cobb angle, lumbar lordosis (LL), thoracic kyphosis (TK) and TK/LL were measured after the full-length spinal tablet was completed. Thirity-five healthy volunteers were included as the control group. The general conditions and history of underlying diseases were collected for both populations. FI of L4–5 MM was obtained by single-voxel MR spectroscopy (SV-MRS). The forward flexion, posterior extension, left/right lateral flexion LROM were measured. The lower back pain was assessed using visual analogue scale (VAS). The quality of life was assessed using Roland-Morris disability questionnaire (RDQ). Individual activity intensity was assessed using International Physical Activity Questionnaire (IPAQ). By comparing the difference in LROM, MM FI,RDQ scores between DSD group and control group, the correlation of RDQ scores in DSD group with MM FI, ROM, Cobb angle, LL, TK, and TK/LL were analyzed, respectively. Results The VAS score was higher in DSD group than that in control group (P<0.05). In terms of consistency, the DSD group had good forward flexion and posterior extension reliability, strong convex lateral flexion reliability and general concave lateral flexion reliability. The control group had good reliability of forward flexion and posterior extension, while the left/right lateral flexion reliability was general. There was no statistically significant difference in IPAQ score between two groups and FI of the left/right MM in the control group (P>0.05). Bilateral MM FI was negatively correlated with posterior extension in DSD group (r=-0.395), MM FI (convex side) was negatively correlated with VAS (r=-0.381), RDQ scores was negatively correlated with forward flexion and sagittal ROM, respectively (r=-0.441, -0.425), Cobb angle was positively correlated with posterior extension (r=0.372), TK was positively correlated with MM FI on the concave side (r=0.460) and negatively correlated with forward flexion and sagittal ROM (r=-0.406, -0.410), LL was positively correlated with FI on the concave side (r=0.412), TK/LL was negatively correlated with forward flexion, sagittal ROM and lateral flexion (convex side) (r=-0.424, -0.370, -0.576). Stepwise linear regression analysis indicated that the RDQ score=13. 070－flexion0.228+VAS1.900. Conclusions Patients with DSD showed a decreased LROM, an increased MM FI and a decreased RDQ score. Clinically, the LROM and paravertebral muscle degeneration should be evaluated comprehensively in DSD.

Abstract:Objective To determine the effect of limb dominance on landing biomechanics and lower limb functional outcomes in patients with anterior cruciate ligament reconstruction (ACLR). Methods Forty-nine participants were recruited and divided into the ACLR on dominant limb (ACLR-D) group, ACLR on nondominant limb (ACLR-ND) group and healthy control group. Single-leg jump landing, knee isometric muscle strength, Y balance, and single-leg hop distance were tested on both limbs of all participants. Kinematics and kinetics data during the single-leg jump landing were collected by an infrared motion capture system and a force platform, and knee joint muscle strength was collected using the IsoMed2000 isokinetic muscle strength testing system. Two-way mixed-design ANOVAs were used to observe the effects of limb and group on the outcomes of each test. Results The non-surgical limbs had greater knee valgus, knee external rotation angles and knee valgus moments in single-leg jump landing in the ACLR-D group compared with those in the ACLR-ND group, and the ACLR-D group had significantly smaller bilateral knee flexion angles than the control group. There were no differences in knee muscle strength, Y-balance composite scores and single-leg hop distance between ACLR-D and ACLR-ND groups, but the Y balance scores in ACLR-ND group were smaller than those in the control group. Conclusions Limb dominance has no effects on knee muscle strength, dynamic postural control, and single-leg hop function in ACLR patients. The non-surgical limbs of ACLR-D patients are at a higher risk of ACL injury due to the presence of greater knee valgus and external rotation angles and knee valgus moments.

Abstract:Objective To address the challenges in human-robot interaction control for lower limb rehabilitation exoskeletons by optimizing gait pattern design and compliance control strategies, thereby enhancing the safety, comfort, and precision of rehabilitation training. Methods Rhythmic dynamic movement primitives were utilized to generate personalized gait trajectories, combined with an admittance control strategy to design a trajectory tracking controller. This controller adjusted control parameters in real time to guide the user’s gait towards the desired trajectory, reduce interaction torque, improve gait consistency, and ensure safety and effectiveness during rehabilitation training. Results Walking experiments with three participants using the lower limb rehabilitation exoskeleton demonstrated that, compared to transparent mode, the trajectory tracking mode reduced the root mean square error (RMSE) of hip and knee joint angle trajectories from 7.24° and 13.25° to 3.01° and 4.76°, respectively. The mean absolute error (MAE) decreased from 6.35° and 11.17° to 2.54° and 3.50°, respectively. The absolute mean interaction torque decreased from 3.55 N·m and 3.42 N·m to 2.80 N·m and 1.86 N·m. These results validated that the trajectory tracking controller significantly improved gait consistency and comfort. Conclusions The application of rhythmic dynamic movement primitives combined with compliance control strategies in lower limb rehabilitation exoskeletons shows great potential. It effectively enhances the precision and comfort of rehabilitation training, providing patients with a safer and more personalized rehabilitation experience.

Abstract:Objective To address the personalized differences in motion gait between stroke patients and healthy older adults, as well as the issue of abnormal gait recognition, a deep learning fusion-based approach is proposed to effectively improve the accuracy of abnormal gait recognition. Methods A model fusing convolutional neural networks (CNN) and bidirectional long short-term memory networks (BiLSTM) was adopted, with the introduction of a residual network (ResNet). Unilateral ankle joint movement data at different walking speeds within a comfortable range were collected from healthy older adults and stroke patients. Signals from inertial sensors and electromyography sensors were used as inputs, while gait features were analyzed and gait differences between the two groups were compared. The effectiveness of the model was validated by comparing the classification performance of traditional deep learning models and CNN-ResNet-BiLSTM models with different layer combinations in terms of abnormal gait recognition accuracy. Results The CNN-ResNet-BiLSTM model, which introduced residual connectivity, performed excellently in abnormal gait recognition. Compared with traditional deep learning models such as the gated recurrent unit (GRU) and long short-term memory network (LSTM), its prediction accuracy was improved by 13.6% and 8.36%, respectively. Additionally, compared with other model combinations, this model achieved an overall accuracy of 97.78%. Conclusions The algorithm proposed in this study can be applied to stroke-related abnormal gait detection, providing technique support for the early diagnosis and precise monitoring of such diseases.

Abstract:Objective To investigate the effects of lower limb functional training on foot-ground contact area, plantar pressure and impulse in patients with diabetic foot, and provide theoretical and practical basis for the prevention and control of diabetic foot. Methods 100 subjects with diabetic foot aged 50 to 80 years old and 50 healthy subjects were included. The 100 subjects with diabetic foot were divided into a lower limb functional training group (HDG group), and a no-training positive control group (HCG group), each with 50 subjects, and 50 healthy subjects as a negative control group (NCG group) to compare the effects of the lower limb functional training interventions. The HDG group received the 12-week lower limb functional training intervention 4 times/week, 60 minutes/time. The NCG group and HCG group received routine care and normal life. Foot-ground contact area, plantar pressure and impulse metrics were tested and analyzed with the Intelligent Foot Detection Scanner. Results After the intervention, the foot-ground contact area at toe 1 (T1), metatarsal 1 (M1), mid foot (MF), heel medial (HM), and heel lateral (HL) region of the left and right foot in the HDG group was reduced, and the foot-ground contact area at toe 2–5 (T2–5), metatarsal 2–3 (M2–3) , metatarsal 4–5 (M4–5) , and mid foot (MF) region of the left and right foot were significantly increased. After the intervention, plantar load, peak pressure, mean pressure, and forefoot to forefoot load ratio were significantly reduced in the left and right foot of the HDG group. After the intervention, impulses at T1, M1, M2–3, M4–5, medial, and lateral MF region of the left and right foot in the HDG group were significantly decreased in, and impulses at T2–5, HM, and HL region of the left and right foot in the HDG group were significantly increased. Conclusions After functional training of the lower limbs, the abnormalities of plantar contact area in patients with diabetic foot were improved, the peak plantar pressure was reduced, the plantar pressure impulse was redistributed, and the occurrence of foot ulcers caused by localized overloading in gait was mitigated and delayed. This study can help to provide a reference for different rehabilitation and exercise methods of lower limbs for patients with diabetic foot.

Abstract:Objective To explore the peak moment characteristics of lower limb joints, as well as the contribution rate and compensation mechanism of lower limb joints when older adults with a history of falls cross obstacles at different paces. Methods Thirty healthy older adults and 30 eldely fallers were recruited. The Qualisys infrared high-speed motion capture system and the Kistler three-dimensional force platform were used to obtain the mechanical characteristic data of the older adults when they crossed an obstacle with a height of 15% of their height at three walking speeds (1.05, 1.41, 1.74 m/s). The data were then modeled and analyzed using Visual 3D software. Results As walking speed increased, the peak knee extension moment, peak ankle plantar flexion moment, and double peak value of hip flexion moment in healthy group all increased significantly (P<0.05). Compared with healthy group, the double peak values of hip flexion moment in faller group were significantly smaller than those in healthy group (P<0.05). During walking at moderate speed, the contribution rate of the left hip joint in faller group was significantly higher than that of healthy group (P=0.025)，while the contribution rate of the ankle joint was significantly lower (P=0.044). The margin of stability in the anterior-posterior direction at the moment of ground contact of the stance leg and the stride leg increased with walking speed (P=0.007, P=0.002). Conclusions Compared with healthy older adults, the elderly fallers have lower peak torque, peak ground reaction force, and dynamic stability in the anterior-posterior direction. As the walking speed increases, the mechanical parameters and the margin of stability of older adults increase significantly, and walking stability is improved. Compared with healthy older adults, elderly fallers usually rely more on the contribution of hip joint movements and reduce the involvement of ankle joints. It is recommended to incorporate fast walking exercises into the daily fall prevention exercise program for older adults, with combination of coordinated training of the hip, knee, and ankle joints.

Abstract:Objective The differences in biomechanical characteristics of the lower limbs between individuals with chronic ankle instability (CAI) and healthy individuals during unanticipated and anticipated jumping were compared, in order to provide practical references and ideas for the prevention and treatment of recurrent ankle sprains. Methods Thirty subjects were recruited, including 15 patients with CAI and 15 healthy volunteers. All subjects completed unanticipated and anticipated jumping tests in a random order, with a 1-week interval between the two tests. Kinematic and kinetic data of lower limbs were collected synchronously using Vicon infrared high-speed motion capture system and Kistler three-dimensional force platform. Results At the moment of touchdown, knee flexion angle was significantly greater during unanticipated jumping than that during anticipated jumping (P=0.009), while ankle eversion angle was notably lower (P=0.043). During the early landing phase, unanticipated jumping showed significantly greater peak hip flexion and abduction angles, as well as knee flexion (P=0.038, P=0.036, and P=0.04), while peak ankle dorsiflexion and eversion angles were significantly lower (P=0.001, P=0.01) compared to anticipated jumping. Additionally, peak hip abduction moment during unanticipated jumping was significantly higher in patients with CAI than that during anticipated jumping (P=0.028). Conclusions Unanticipated jumping reduced ankle dorsiflexion and eversion angles in individuals with CAI, putting the ankle in an open, sprain-prone position. Individuals with CAI compensated proximally by increasing hip flexion, abduction, knee flexion angles, and hip extension moment to stabilize the ankle.

Abstract:Objective Based on the finite element simulation analysis of the patient’s torso-spine model and combined with theoretical calculation data, a scoliosis orthosis was designed, and the effectiveness of the orthosis was verified through three-dimensional (3D) printing. Methods A patient with idiopathic scoliosis was chosen as the research object. Reverse engineering technology and computer-aided technology were used to establish the torso-spine model of the patient. The finite element method was used to analyze the model, and the optimal position and magnitude of the corrective force were determined by combining literature theory calculation. Based on this, an orthosis was designed. To verify the orthopedic effect, the patient’s X-rays before and after wearing the orthosis were compared and evaluated, and the patient was followed up 6 months later. Results The optimal position and magnitude of the initial corrective force were determined through theoretical calculations and finite element simulations. Specifically, a 62.95 N corrective force applied to the L3 vertebral body and the left posterior region corresponding to the upper and lower intervertebral discs in the patient’s lateral curvature segment of the spine to achieve the optimal orthopedic effect. On this basis, the orthosis was designed, followed by relevant experimental tests before and after wearing the designed orthosis. By comparing X-ray images of the patient before and after wearing the orthosis and combining them with follow-up data six months later, the optimized design of the orthosis met the expected clinical requirements for orthopedic effects. Conclusions The design of orthosis needs to be personalized according to the specific situation of patients with scoliosis. This study takes a patient with idiopathic scoliosis as the research object, providing new ideas and methods for the design of orthosis for patients with idiopathic scoliosis.

Abstract:Objective Based on statistical parametric mapping (SPM), to analyze the variability characteristics of lower limb in females with generalized joint hypermobility (GJH) during drop jump. Methods Fifteen females with GJH (GJH group) were recruited based on the Beighton scores, and 15 healthy females (control group) were matched. Kinematic and kinetic data were synchronously collected using the Qualisys infrared motion capture system and Kistler three-dimensional (3D) force platform. Joint angles and torques were computed using OpenSim. Custom Matlab scripts were used to calculate the standard deviation curves of joint angles, and SPM was applied to analyze differences in movement variability between the two groups during the eccentric, coupling, and concentric phases of drop jumps. The maximum joint flexion angles and torques (mean and standard deviation) were calculated to support the findings, and effect sizes were evaluated using Cohen's d. Results Significant differences were observed between the two groups during various phases of drop jumps. In all statistically significant periods, the GJH group exhibited higher joint angle standard deviations compared to the control group (P<0.05). Differences were primarily concentrated in joint flexion movements. During the coupling phase at different heights, the standard deviation of knee joint flexion angles in GJH group consistently exceeded that of control group (P<0.001). Discrete variables showed significant differences in the standard deviation of the maximum knee flexion angles at different heights: At 30 cm, P=0.001, Cohen's d=2.520; at 40 cm, P=0.014, Cohen's d=1.739; and at 50 cm, P=0.005, Cohen's d=1.768. No significant group differences were found in the mean values or standard deviations of the maximum joint flexion angles and torques. Conclusions Females with GJH exhibit higher movement variability during drop jumps compared to healthy females, particularly in knee flexion movements during the coupling phase. Excessive variability reflects insufficient motor control, reducing their ability to resist external disturbances and leading to high-risk movement patterns (e.g., excessive flexion or knee valgus).

Abstract:Objective To investigate the kinematic patterns of gate-turning techniques in sitting alpine skiing at the Winter Paralympic Games and their impact on skiing performance. Methods Using drone footage and inertial sensor technology, kinematic data were collected from 11 alpine sit-skiers preparing for the Winter Paralympics. Key technical indicators such as turning radius, skiing speed, and trajectory length were analyzed for their relationship with skiing performance. Results The minimum turning radius during gate turns was (15.80±3.55) m, and turning radius showed a significant positive correlation with skiing time (r=0.40, P=0.02) and trajectory length (r=0.88, P<0.01). The maximum skiing speed was (16.92±1.60) m/s, which was strongly negatively correlated with total skiing time (P<0.01). Exit speed was also significantly positively correlated with total skiing distance (P<0.05). Additionally, single-gate technical characteristics (such as turning radius and speed variation), were strongly reflective of overall skiing performance. Conclusions Optimizing turning radius and minimizing speed loss are critical for improving skiing efficiency. Single-gate kinematic analysis provides a scientific basis for overall technique optimization and offers valuable guidance for training and competition strategy design.

Abstract:Objective To explore the impact of different moving patterns during the dip-coating process on thickness distributions of polymer heart valves. Methods Based on the volume of fluid (VOF) multiphase flow model, the Eulerian wall-film (EWF) model, and dynamic mesh technology, the dip-coating manufacturing process of polymer heart valves were numerically simulated. The effects of vertical, horizontal, and circular moving patterns on flow characteristics of the surface impregnation liquid and liquid film distributions under self-rotation conditions of the models were mainly studied. Subsequently, seven identical test points were set on each valve leaflet to collect thickness data, and the coefficient of variation? was calculated to evaluate the uniformity of the liquid film thickness. Given that the vertical and horizontal pattern had fewer moving planes, limiting the optimization space, the circular pattern (45°) with richer moving planes was selected as the basis for optimization，and comparative analysis of numerical simulation was conducted. Results In the vertical pattern, the peak coefficient of variation (CV) was 0.461 3; in the horizontal pattern, the CV was 0.060 8; and in the circular pattern, the CV at 30°, 45° and 60° were 0.457 5, 0.272 8, and 0.255 6, respectively. After optimization, the CV for the circular pattern (45°) decreased to 0.052 5, representing an 80.7% reduction compared to the pre-optimization value. Conclusions The moving patterns significantly affect the uniformity of dip-coating thickness distributions. The horizontal pattern demonstrates the best uniformity, while the vertical pattern shows the poorest uniformity. The CV for the circular pattern decreases as the angle increases, with its uniformity is between that of the vertical and horizontal patterns. Optimization of moving pattern parameters based on simulation results has improved the thickness uniformity.

Abstract:Objective To develop a quantitative methodology for assessing the aortic media damage induced by stent-graft, and study the influence of various stent oversizing ratios (ORs) on damage of the aortic media. Methods Based on experimetal data from uniaxial tensile test on human aortic dissection, the material parameters of aortic wall’s constitutive equation were determined, including damage parameters. A finite element model was constructed to simulate the deployment process of the stent-graft in blood vessel. Damage factor was determined to analyze the stress distribution and the resultant damage within aortic media at different ORs of stent-graft. Results The distribution of damage factor and von Mises stress was basically consistent, with both peaking at the large curvature side near the aortic arch. Additionally, stress concentration was observed in distal anchoring region of the aortic wall. An increment in OR was correlated with a proportional increase in both peak values. At ORs of 10%, 15% and 20%, the maimum von Mises stresses were 469, 480 and 580 kPa, respectively, with increments of 2.3% and 20.8%. Correspondingly, the maximum damage factors were 0.01, 0.011 and 0.014, with an elevation of 10% and 27.3%. Conclusions An increment in OR is associated with a pronounced increase in peak value of the damage factor and the rate of increase, indicating a more severe impact on the aortic media. The distribution of the damage factor aligns closely with that of the von Mises stress, with both exhibiting peak values at the large curvature side of aortic arch. This correlation underscores the damage factor’s efficacy as a reliable indicator of the aortic media’s integrity and can accurately reflect the degree of medial layer injury in the aortic wall, thereby providing a theoretical basis for the subsequent assessment of endovascular interventional treatment risks through damage factor analysis.

Abstract:Objective To investigate the influence of oxygen supply flow rate in high-flow nasal cannula (HFNC) oxygen therapy on pressure distributions in the upper airway. Methods A three-dimensional (3D) model of the upper airway was reconstructed using CT images from an adult male, and then coupled with a high-flow nasal cannula model to establish a coupled model of the nasal cannula and the upper airway. Subsequently, a physical model of this upper airway, which was combined with a head model, artificial lungs, and a monitoring system was created by 3D printing technology to form a physical simulation platform in vitro. Computational and physical simulations were carried out respectively to determine the air pressure at typical locations in the upper airway under different oxygen supply flow rates. Results Pressures at typical upper airway locations obtained by computational and physical simulations turned out to be in good agreement; both peak inspirational pressure (PIP) and positive end-expiratory pressure (PEEP) increased quadratically with the increase of oxygen supply flow rate; and the air pressure distribution was more uniform in the laryngeal cross-section as compared to the nasal part of the upper airway. Conclusion This study may provide a theoretical support for optimization of the setting of oxygen suppy flow rate and the selection of PEEP effect assessment position in the clinical application of HFNC oxygen therapy.

Abstract:Orthodontic treatment is the primary method for correcting malocclusion. However, with the continuous increase in the number of patients, the shortage of orthodontists and the lack of standardized diagnosis and treatment have become increasingly prominent, resulting in difficulties in patients' access to care and variability in treatment quality. Traditional orthodontic diagnosis and treatment heavily rely on doctors' experience, which is highly subjective and inefficient, and thus cannot meet the growing demand for precise and standardized medical care. The strengths of artificial intelligence (AI) in data processing, pattern recognition, and intelligent decision-making offer new technological pathways to address these issues. In recent years, AI-based diagnostic and therapeutic systems have shown great potential in improving efficiency in orthodontics and optimizing the consistency of treatment outcomes. This article systematically reviews the advances in the application of AI technology in clinical orthodontic diagnosis and treatment, focusing on its innovative practices in intelligent data acquisition, automated imaging analysis, personalized treatment planning, efficacy prediction modeling, telemedicine, and digital file management, aiming to provide a theoretical basis for promoting the intelligent and standardized development of orthodontic diagnosis and treatment.

Abstract:Cellular mechanical transduction is the process by which cells perceive mechanical signals and transform them into chemical ones. Crucial cellular mechanosensors include PIEZO, TRPV4, and integrins. These sensors can modulate specific pathophysiological processes, such as fibrosis, tumor development, as well as cell proliferation, differentiation, and movement. Recent researches indicate that PIEZO, TRPV4, and integrins play an important role in various types of cancer pain, such as bone cancer pain, by detecting mechanical stimuli, which subsequently activate internal signaling pathways. This review summarizes advancements of PIEZO, TRPV4, and interegrins in cancer pain researches, aiming to lay a foundation for developing new therapeutic drugs that target cellular mechanical transduction for treating cancer pain.

Abstract:Tensile stimulation plays a crucial role in regulating tissue structure and function. Due to the limitations of in vivo studies, engineered tension tissues (ETTs) based on biomaterials and tissue engineering technologies have gradually become a research hotspot. Specifically, microscale-engineered tension tissues (μETTs) based on flexible microstructures overcome many limitations of traditional ETTs, thanks to their controllable mechanical constraints and precise mechanical characterization and stimulation capabilities. This has led to their widespread application in disease research, drug screening, and toxicologic studies. This review summarizes the materials and fabrication methods of flexible microstructures, analyzes their biomechanical roles in μETTs, provides an overview of research progress in myocardial, lung, and skeletal muscle μETTs, discusses mechanical modeling and analysis methods during the remodeling of μETTs, and looks ahead to the future development of this field.

Abstract:The pelvis, as a critical structure connecting the spine and lower limbs, not only supports the upper body but also plays a vital role in lower limb movement and force transmission. Its complex morphology and function have long been a focus of researches. However, the significant individual variations in pelvic morphology present challenges in studying the relationship between shape and function. Statistical shape model (SSM), as an effective method for quantifying and describing morphological variations, has become a key tool in exploring the morphology-function relationship of the pelvis. This review summarizes the progress of SSM applications in biomechanical studies of pelvic morphology and function, highlighting its role in uncovering morphological features and their impacts on biomechanics, and discusses future development directions. Through a comprehensive analysis of existing literature, this study aims to provide valuable insights and references for clinicians, biomechanics researchers, and medical device designers.

Abstract:Chronic non-specific lower back pain (CNLBP) is one of the most common symptoms in clinical lower back pain, which is prone to recurrence and shows a trend towards younger age. Patients with CNLBP typically experience local pain, reduced joint mobility and balance dysfunction. In depth analysis of the relevant factors and intervention methods that cause balance dysfunction in CNLBP patients can reveal the biological (mechanical) mechanisms of balance dysfunction in patients with CNLBP and provide references and basis for the subsequent improvement of CNLBP intervention methods. This review summarizes the research status of the impact of CNLBP on patients’ balance function and disease intervention methods from several aspects, including balance dysfunction in patients with CNLBP, damage to the motor and nervous system, and intervention methods for the disease. The aim is to provide references for the subsequent research on the pathogenesis and intervention methods of CNLBP.