The lumbar intervertebral disc exhibits a complex physiological structure with interactions between various segments, and its components are extremely complex. The material properties of different components in the lumbar intervertebral disc, especially the water content (undergoing dynamic change as influenced by age, degeneration, mechanical loading, and proteoglycan content) - critically determine its mechanical properties. When the lumbar intervertebral disc is under continuous pressure, water seeps out, and after the pressure is removed, water re-infiltrates. This dynamic fluid exchange process directly affects the mechanical properties of the lumbar intervertebral disc, while previous isotropic modeling methods have been unable to accurately reflect such solid-liquid phase behaviors. To explore the load-bearing mechanism of the lumbar intervertebral disc and establish a more realistic mechanical model of the lumbar intervertebral disc, this study developed a solid-liquid biphasic, fiber-reinforced finite element model. This model was used to simulate the four movements of the human lumbar spine in daily life, namely flexion, extension, axial rotation, and lateral bending. The fluid pressure, effective solid stress, and liquid pressure-bearing ratio of the annulus fibrosus and nucleus pulposus of different lumbar intervertebral discs were compared and analyzed under the movements. Under all the movements, the fluid pressure distribution was closer to the nucleus pulposus, while the effective solid stress distribution was more concentrated in the outer annulus fibrosus. In terms of fluid pressure, the maximum fluid pressure of the lumbar intervertebral disc during lateral bending was 1.95 MPa, significantly higher than the maximum fluid pressure under other movements. Meanwhile, the maximum effective solid stress of the lumbar intervertebral disc during flexion was 2.43 MPa, markedly higher than the maximum effective solid stress under other movements. Overall, the liquid pressure-bearing ratio under axial rotation was smaller than that under other movements. Based on the solid-liquid biphasic modeling method, this study more accurately revealed the dominant role of the liquid phase in the daily load-bearing process of the lumbar intervertebral disc and the solid-phase mechanical mechanism of the annulus fibrosus load-bearing, and more effectively predicted the solid-liquid phase co-load-bearing mechanism of the lumbar intervertebral disc in daily life.
Humans ; Finite Element Analysis ; Intervertebral Disc/physiology* ; Lumbar Vertebrae/physiology* ; Weight-Bearing/physiology* ; Biomechanical Phenomena ; Stress, Mechanical ; Computer Simulation ; Models, Biological

OBJECTIVE: To analyze the effectiveness of three internal fixation methods, namely hollow screw combined with Kirschner wire tension band, hollow screw combined with anchor nail, and modified 1/3 tubular steel plate, in the treatment of avulsion fracture of tibial tubercle (AFTT) in adolescents. METHODS: Between January 2018 and September 2023, 19 adolescent AFTT patients who met the selection criteria were admitted. According to different internal fixation methods, patients were divided into group A (8 cases, hollow screw combined with Kirschner wire tension band), group B (6 cases, hollow screw combined with anchor nail), and group C (5 cases, modified 1/3 tubular steel plate). There was no significant difference in the baseline data of age, gender, side, cause of injury, Ogden classification, and time from injury to operation among the three groups ( P>0.05). The range of motion (ROM), weight-bearing time, normal activity time of knee joint, and the hospital for special surgery (HSS) score at last follow-up were recorded and compared among the three groups. Recorded whether the fracture was displaced, whether the fracture line was blurred at 1 month after operation, whether there was epiphyseal dysplasia, and whether there was incision infection and other complications. RESULTS: There was no significant difference in hospital stay between the groups ( P>0.05). All patients were followed up 10-24 months, with an average of 14.3 months; there was no significant difference between the groups ( P>0.05). All the incisions healed well without soft tissue irritation or fracture nonunion, and no limb shortening deformity or epiphyseal dysplasia was found during follow-up. At 1 month after operation, the knee joint ROM and hospitalization expenses in group A were better than those in groups B and C, the fracture healing time, knee joint weight-bearing time, and normal activity time of knee joint were better than those in group C, and the hospitalization expenses in group C were better than those in group B, with significant differences ( P<0.05); there was no significant difference in the other indicators between the groups ( P>0.05). In group A, the fracture line was blurred 1 month postoperatively, the fracture ends were in close contact, and there was no fracture displacement; in groups B and C, the fracture line was clear in 2 cases, and 1 case in group C had slight fracture displacement; except for 1 case in group B, there was no fracture split in the other two groups. There was no significant difference in the incidences of blur of fracture line, fracture displacement, and intraoperative bone split between the groups at 1 month after operation ( P>0.05). At last follow-up, the HSS scores of knee joints in the three groups were excellent and good, and there was no significant difference between the groups ( P>0.05). CONCLUSION Hollow screw combined with Kirschner wire tension band technique is effective in treating adolescent AFTT, which has the advantages of stabilizing fracture, accelerating fracture healing and rehabilitation, early feasible knee joint functional exercise, and reducing hospitalization expenses.
Humans ; Tibial Fractures/surgery* ; Adolescent ; Male ; Fracture Fixation, Internal/instrumentation* ; Female ; Fractures, Avulsion/surgery* ; Bone Wires ; Bone Screws ; Bone Plates ; Treatment Outcome ; Range of Motion, Articular ; Bone Nails ; Weight-Bearing ; Fracture Healing

OBJECTIVE: To investigate the impact of bone mass and volume of low-density zones beneath the tibial plateau on the maximum von Mises stresses experienced by the cartilage and meniscus in the knee joint. METHODS: The study included one healthy adult volunteer, from whom CT scans were obtained, and one patient diagnosed with knee osteoarthrisis (KOA), for whom X-ray films were acquired. A static model of the knee joint featuring a low-density zone was established based on a normal knee model. In the finite element analysis, axial loads of 1 000 N and 1 800 N were applied to the weight-bearing region of the upper surface of the femoral head for model validation and subsequent finite element studies, respectively. The maximum von Mises stresses in the femoral cartilage, as well as the medial and lateral tibial cartilage and menisci, were observed, and the stress percentage of the medial and lateral components were concurrently analyzed. Additionally, HE staining, as well as alkaline magenta staining, were performed on the pathological specimens of patients with KOA in various low-density regions. RESULTS: The results of model validation indicated that the model was consistent with normal anatomical structures and correlated with previous calculations documented in the literature. Static analysis revealed that the maximum von Mises stress in the medial component of the normal knee was the lowest and increased with the advancement of the hypointensity zone. In contrast, the lateral component exhibited an opposing trend, with the maximum von Mises stress in the lateral component being the highest and decreasing as the hypointensity zone progressed. Additionally, the medial component experienced an increasing proportion of stress within the overall knee joint. HE staining demonstrated that the chondrocyte layer progressively deteriorated and may even disappear as the hypointensity zone expanded. Furthermore, alkaline magenta staining indicated that the severity of microfractures in the trabecular bone increased concurrently with the expansion of the hypointensity zone. CONCLUSION The presence of subtalar plateau low-density zone may aggravate joint degeneration. In clinical practice, it is necessary to pay attention to the changes in the subtalar plateau low-density zone and actively take effective measures to strengthen the bone status of the subtalar plateau low-density zone and restore the complete biomechanical function of the knee joint, in order to slow down or reverse the progression of osteoarthritis.
Humans ; Finite Element Analysis ; Knee Joint/physiology* ; Tibia/anatomy & histology* ; Cartilage, Articular/physiology* ; Menisci, Tibial/physiopathology* ; Tomography, X-Ray Computed ; Osteoarthritis, Knee/diagnostic imaging* ; Weight-Bearing ; Bone Density ; Adult ; Stress, Mechanical ; Male ; Middle Aged ; Biomechanical Phenomena ; Female

OBJECTIVE: To investigate the load distribution on the more painful and less painful limbs in patients with mild-to-moderate and severe bilateral knee osteoarthritis (KOA) and explore the compensatory mechanisms in both limbs among bilateral KOA patients with different severity levels. METHODS: A total of 113 participants were enrolled between July 2022 and September 2023. This cohort comprised 43 patients with mild-to-moderate bilateral KOA (Kellgren-Lawrence grade 2-3), 43 patients with severe bilateral KOA (Kellgren-Lawrence grade 4), and 27 healthy volunteers (healthy control group). The visual analogue scale (VAS) score for pain, the Hospital for Special Surgery (HSS) score, passive knee range of motion (ROM), and hip-knee-ankle angle (HKA) were used to assess walking pain intensity, joint function, and lower limb alignment in KOA patients, respectively. Motion trajectories of reflective markers and ground reaction force data during walking were captured using a gait analysis system. Musculoskeletal modeling was then employed to calculate biomechanical parameters, including the peak knee adduction moment (KAM), KAM impulse, peak joint contact force (JCF), and peak medial/lateral contact forces (MCF/LCF). Statistical analyses were performed to compare differences in clinical and gait parameters between bilateral limbs. Additionally, one-dimensional statistical parametric mapping was utilized to analyze temporal gait data. RESULTS: Mild-to-moderate KOA patients showed the significantly higher HSS score (67.7±7.9) than severe KOA patients (51.9±8.9; t=8.747, P<0.001). The more painful limb in all KOA patients exhibited significantly greater HKA and higher VAS scores compared to the less painful limb ( P<0.05). While bilateral knee ROM did not differ significantly in mild-to-moderate KOA patients ( P>0.05), the severe KOA patients had significantly reduced ROM in the more painful limb versus the less painful limb ( P<0.05). Healthy controls showed no significant bilateral difference in any biomechanical parameters ( P>0.05). All KOA patients demonstrated longer stance time on the less painful limb ( P<0.05). Critically, severe KOA patients exhibited significantly higher peak KAM, KAM impulse, and peak MCF in the more painful limb ( P<0.05), while mild-to-moderate KOA patients showed the opposite pattern with lower peak KAM and KAM impulse in the more painful limb ( P<0.05) and a similar trend for peak MCF. CONCLUSION Patients with mild-to-moderate KOA effectively reduce load on the more painful limb through compensatory mechanisms in the less painful limb. Conversely, severe bilateral varus deformities in advanced KOA patients nullify compensatory capacity in the less painful limb, paradoxically increasing load on the more painful limb. This dichotomy necessitates personalized management strategies tailored to disease severity.
Humans ; Osteoarthritis, Knee/physiopathology* ; Range of Motion, Articular ; Male ; Female ; Middle Aged ; Biomechanical Phenomena ; Knee Joint/physiopathology* ; Pain Measurement ; Severity of Illness Index ; Aged ; Gait/physiology* ; Walking/physiology* ; Case-Control Studies ; Adult ; Weight-Bearing

OBJECTIVE: To investigate the effectiveness of applying a standardized rehabilitation process in correction of adult clubfoot with the Ilizarov technique. METHODS: Thirty-eight adult patients who underwent orthopedic treatment with Ilizarov technique for clubfoot between August 2022 and December 2024 were retrospectively analyzed. The patients were divided into a study group and a control group with 19 cases in each group according to the different rehabilitation management processes and methods. The differences in baseline data such as gender, age, side, and preoperative Holden walking function grading between the two groups were not significant ( P>0.05). In both groups, most of the clubfoot deformities were surgically corrected first, and the residual deformities were corrected by dynamic slow retraction with Ilizarov ring-type external fixation frame. The study group adopted standardized rehabilitation process management mode, including preoperative lower limb muscle strength training, postoperative pain and swelling management, weight-bearing management, gait and lower limb stability training. The control group adopted the conventional postoperative rehabilitation management mode. The occurrence of complications was recorded, including pin tract infection, ankle stiffness and pain, and deformity recurrence. Holden walking function grading was used to evaluate the walking ability of the patients. Clinical efficacy was evaluated by the QIN Sihe Deformity Correction Disability Repair and Functional Reconstruction Postoperative Efficacy Evaluation Scale. Patient satisfaction was evaluated by Likert score. RESULTS: Patients in both groups successfully completed surgery and rehabilitation and were followed up. The follow-up time ranged from 8 to 29 months, with a mean of 18.5 months. Among them, the follow-up time was (18.8±5.5) months in the study group and (18.2±5.7) months in the control group, and the difference between groups was not significant ( t=0.316, P=0.754). The postoperative incidences of pin tract infection, ankle stiffness and pain, and deformity recurrence in the study group were 10.53%, 5.26%, and 5.26%, respectively, and in the control group were 21.05%, 36.84%, and 15.79%, respectively. And the difference between groups in the incidence of ankle stiffness and pain was significant ( P=0.042). At last follow-up, both groups showed an improvement in Holden walking function grading compared to preoperative levels ( P<0.05), and the grading of the study group was significantly higher than that of the control group ( P=0.006). According to the QIN Sihe Deformity Correction Disability Repair and Functional Reconstruction Postoperative Efficacy Evaluation Scale, the grade difference between groups was not significant ( P=0.089), and the excellent and good rates of clinical efficacy in study group and control group were 89.47% (17/19) and 73.68% (14/19), respectively. Patient satisfaction in study group was significantly better than that in control group ( P=0.036). CONCLUSION Standardized rehabilitation process can effectively promote the postoperative functional recovery of adult clubfoot treated with Ilizarov technique, reduce the risk of complications and improve effectiveness.
Humans ; Ilizarov Technique/rehabilitation* ; Clubfoot/rehabilitation* ; Male ; Female ; Retrospective Studies ; Adult ; Treatment Outcome ; Young Adult ; Weight-Bearing ; Adolescent

OBJECTIVE: To determine the impact of the lower limb weight bearing line ratio (WBLR) on motor function recovery after high tibial osteotomy (HTO). METHODS: A retrospective analysis was conducted on 55 patients with unilateral compartment knee osteoarthritis who underwent open-wedge HTO between August 2020 and October 2023 and met the selection criteria. Based on the postoperative Lysholm score, patients were divided into two groups: the good knee function group (Lysholm score≥90, group A) and the poor knee function group (Lysholm score<90, group B). Lysholm score, American Knee Society (AKS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and visual analogue scale (VAS) score for pain were compared between the two groups. Univariate analysis was performed on baseline data including gender, age, body mass index (BMI), affected side, disease duration, Kellgren-Lawrence grade, and radiographic parameters [preoperative and postoperative medial proximal tibial angle, lateral distal femoral angle, femoral-tibial angle, hip-knee-ankle angle (HKA), WBLR, posterior tibial slope angle, and joint line convergence angle] to identify factors influencing functional recovery. Multivariate logistic regression analysis was further used to identify independent factors. Additionally, receiver operating characteristic (ROC) curve analysis was employed to determine the optimal cut-off value of postoperative WBLR for predicting motor function recovery, and the area under curve (AUC) was calculated to assess diagnostic performance. RESULTS: All 55 patients were followed up 10-14 months (mean, 11.8 months). According to the postoperative Lysholm score, there were 30 patients in group A and 25 in group B. All postoperative clinical scores in group A were significantly better than those in group B ( P<0.05). Univariate analysis indicated that age, BMI, postoperative HKA, and postoperative WBLR were influencing factors for motor function recovery ( P<0.1). Further multivariate logistic regression analysis identified a postoperative WBLR≤55.5% as an independent factor influencing motor function recovery ( P<0.05). ROC curve analysis yielded an AUC of 0.788 and determined the optimal postoperative WBLR cut-off value for predicting motor function recovery to be 55.5% ( P<0.001). CONCLUSION A postoperative WBLR of 55.5% is associated with optimal motor function recovery after HTO.
Humans ; Male ; Female ; Osteotomy/methods* ; Retrospective Studies ; Tibia/surgery* ; Recovery of Function ; Middle Aged ; Osteoarthritis, Knee/physiopathology* ; Weight-Bearing ; Knee Joint/surgery* ; Lower Extremity ; Aged ; Adult ; Treatment Outcome

Large bone defects in load-bearing bone can result from tumor resection, osteomyelitis, trauma, and other factors. Although bone has the intrinsic potential to self-repair and regenerate, the repair of large bone defects which exceed a certain critical size remains a substantial clinical challenge. Traditionally, repair methods involve using autologous or allogeneic bone tissue to replace the lost bone tissue at defect sites, and autogenous bone grafting remains the "gold standard" treatment. However, the application of traditional bone grafts is limited by drawbacks such as the quantity of extractable bone, donor-site morbidities, and the risk of rejection. In recent years, the clinical demand for alternatives to traditional bone grafts has promoted the development of novel bone-grafting substitutes. In addition to osteoconductivity and osteoinductivity, optimal mechanical properties have recently been the focus of efforts to improve the treatment success of novel bone-grafting alternatives in load-bearing bone defects, but most biomaterial synthetic scaffolds cannot provide sufficient mechanical strength. A fundamental challenge is to find an appropriate balance between mechanical and tissue-regeneration requirements. In this review, the use of traditional bone grafts in load-bearing bone defects, as well as their advantages and disadvantages, is summarized and reviewed. Furthermore, we highlight recent development strategies for novel bone grafts appropriate for load-bearing bone defects based on substance, structural, and functional bionics to provide ideas and directions for future research.
Humans ; Bone Transplantation/methods* ; Weight-Bearing ; Bone Regeneration ; Bone Substitutes ; Bone and Bones ; Animals ; Tissue Scaffolds

OBJECTIVE: To establish a finite element model of the knee joint based on coronal plane alignment of the knee (CPAK) typing method, and analyze the biomechanical characteristics of different types of knee joints. METHODS: The finite element models of the knee joint were established based on CT scan data of 6 healthy volunteers. There were 5 males and 1 female with an average age of 24.2 years (range, 23-25 years). There were 3 left knees and 3 right knees. According to the CPAK typing method, the knees were rated as types Ⅰ to Ⅵ. Under the same material properties, boundary conditions, and axial loading, biomechanical simulations were performed on the finite element model of the knee joint. Based on the Von Mises stress nephogram and displacement nephogram, the peak stresses of the meniscus, femoral cartilage, and tibial cartilage, and the displacement of the meniscus were compared among different types of knee joints. RESULTS: The constructed finite element model of the knee joint was verified to be effective, and the stress and displacement results were consistent with previous literature. Under the axial load of 1 000 N, the stress nephogram showed that the stress distribution of the medial and lateral meniscus and tibial cartilage of CPAK type Ⅲ knee joint was the most uneven. The peak stresses of the lateral meniscus and tibial cartilage were 9.969 6 MPa and 2.602 7 MPa, which were 173% and 165% of the medial side, respectively. The difference of peak stress between the medial and lateral femoral cartilage was the largest in type Ⅳ knee joint, and the medial was 221% of the lateral. The displacement nephogram showed that the displacement of the medial meniscus was greater than that of the lateral meniscus except for types Ⅲ and Ⅵ knee joints. The difference between medial and lateral meniscus displacement of type Ⅲ knee joint was the largest, the lateral was 170% of the medial. CONCLUSION In the same type of joint line obliquity (JLO), the medial and lateral stress distribution of the knee was more uniform in varus and neutral positions than in valgus position. At the same time, the distal vertex of JLO subgroup can help to reduce the uneven medial and lateral stress distribution of varus knee, but increase the uneven distribution of valgus knee.
Humans ; Finite Element Analysis ; Knee Joint/diagnostic imaging* ; Female ; Biomechanical Phenomena ; Adult ; Male ; Young Adult ; Stress, Mechanical ; Weight-Bearing/physiology* ; Computer Simulation ; Tomography, X-Ray Computed/methods* ; Cartilage, Articular/physiology* ; Range of Motion, Articular ; Menisci, Tibial/anatomy & histology* ; Tibia/anatomy & histology* ; Meniscus/diagnostic imaging* ; Femur/diagnostic imaging* ; Models, Biological

OBJECTIVE: To investigate ideal screw implant angle in reconstruction of tibiofibular syndesmosis injury by using a biomechanical test. METHODS: A total of 24 ankle specimens from adult cadavers were used as the tibiofibular syndesmosis injury model. According to the angle of screw placement, the tibiofibular syndesmosis injury models were randomly divided into groups A (0°), B (10°-15°), C (20°-25°), and D (30°-35°), and the screws were placed at a level 2 cm proximal to the ankle joint. The displacement of fibula was measured by biomechanical testing machine at neutral, dorsiflexion (10°), plantar flexion (15°), varus (10°), and valgus (15°) positions, with axial load of 0-700 N (pressure separation test). The displacement of fibula was also measured at neutral position by applying 0-5 N·m torque load during internal and external rotation (torsional separation test). RESULTS: In the pressure separation test, group C exhibited the smallest displacement under different positions and load conditions. At neutral position, significant differences were observed ( P<0.05) between group A and group C under load of 300-700 N, as well as between group B and group C under all load conditions. At dorsiflexion position, significant differences were observed ( P<0.05) between group A and group C under load of 500-700 N, as well as between groups B, D and group C under all load conditions, and the displacements under all load conditions were significantly smaller in group A than in group B ( P<0.05). At plantar flexion position, significant differences were observed ( P<0.05) between group D and group C under all load conditions. At valgus position, significant differences were observed ( P<0.05) between group A and group C under load of 400-700 N, as well as between groups B, D and group C under all load conditions. In the torsional separation test, group C exhibited the smallest displacement and group B had the largest displacement under different load conditions. During internal rotation, significant differences were observed ( P<0.05) between group B and group C under all load conditions, as well as between group D and group C at load of 3-5 N·m. During external rotation, significant differences were observed between groups B, D and group C under all load conditions ( P<0.05). No significant difference was detected between groups at the remaining load conditions ( P>0.05). CONCLUSION The ideal screw implant angle in reconstruction of tibiofibular syndesmosis injury was 20°-25°, which has a small displacement of fibula.
Humans ; Bone Screws ; Biomechanical Phenomena ; Fibula/injuries* ; Fracture Fixation, Internal/methods* ; Adult ; Ankle Joint/surgery* ; Ankle Injuries/surgery* ; Tibia/surgery* ; Male ; Range of Motion, Articular ; Weight-Bearing ; Female ; Cadaver ; Plastic Surgery Procedures/methods*

OBJECTIVE: To explore weight-bearing stability of Pilon fracture fixed by external fixator. METHODS: Six ankle bone models (right side) and 4 pairs (8 ankle cadaver specimens) were selected. Pilon fracture model was prepared by using the preset osteotomy line based on Ruedi Allgower Pilon fracture type. Pilon fracture model was built by using a minimally invasive osteotomy. After ankle bone model and cadaver specimen model were fixed with external fixator, axial load was carried out on mechanical loading machine. After ankle bone model and cadaver specimen model were fixed with external fixator, axial load was carried out on mechanical loading machine. Axial loads of 150, 300 and 450 N were applied to ankle bone model, and displacements of fibula fracture blocks, lateral tibia fracture blocks and medial tibia fracture blocks in three-dimensional space (X, Y and Z axes) were recorded by dynamic capture instrument. Axial loads of 300, 600 and 900 N were applied to ankle cadaver model fixed by external fixator. X-ray films of Pilon fracture cadaver model fixed by external fixator under different loading conditions were taken. The anterior tibial angle, tibial malleolar point angle, talus shift value, talus tilt angle, lateral malleolar shift value, lateral malleolar shift value, medial malleolar separation shift value and articular surface step displacement value were measured under different loads by digimizer software. RESULTS: After 150, 300 and 450 N axial loads were applied to Pilon fracture models fixed by external fixator, no loosening or fracture of external fixator was observed, and no loosening, fracture or irreversible plastic deformation of Kirschner needle were observed. The displacement values of fibular fracture pieces on X-axis(around) were 0.032 (-0.022, 0.269), 0.061 (-0.002, 0.427), 0.212(-0.016, 1.223) mm, and the displacement values on Y-axis(above and below) were 0.002(-0.031, 0.103), 0.051(-1.133, 0.376), 0.128 (-1.394, 0.516) mm, and displacement values on Z-axis (front and rear) were -0.003 (-0.130, 0.171), 0.137 (-0.076, 0.433), 0.030(-0.487, 0.478) mm;the displacement values of lateral tibial fractures on X-axis were 0.000(-0.108, 0.027), 0.083(-0.364, 0.050), -0.121(-0.289, 0.165) mm, and displacement values on Y-axis were -0.009(-0.200, 0.025), -0.179(-0.710, 0.084), -0.257(-0.799, 0.027) mm, and displacement values on Z-axis were 0.112(-0.024, 0.256), 0.157(-0.068, 0.293), -0.210(-0.035, 0.430) mm;the displacement values of medial tibial fracture block on X-axis were -0.010(-0.060, 0.013), -0.165(-0.289, 0.056), -0.181(-0.395, 0.013) mm, and the displacement values on Y-axis were -0.036(-0.156, 0.007), -0.104(-0.269, 0.178), -0.245(-0.380, -0.011) mm, and displacement values on Z-axis were -0.005(-0.372, 0.189), -0.012 (-1.774, 0.380), 0.200 (-1.963, -0.540) mm. After 300, 600 and 900 N axial loads were applied to Pilon fracture cadaverous models fixed with external fixators, there were no significant difference in anterior tibial angles, angles of malleolar points of tibia, oblique angles of talus, fracture steps, shift values of talus, lateral shift values of lateral malleolus, lateral shift values of medial malleolus, lateral shift values of medial malleolus between under different loading conditions and those without loading (P>0.05). No loosening or fracture of external fixator as a whole, loosening, fracture or irreversible deformation of Kirschner needle at the local fixed fracture end occurred. CONCLUSION The early weight-bearing external fixator could maintain stability of fracture end and ankle joint, and the maximum weight is not more than 300 N. In clinical practical application, material characteristics of the implant and type of fracture should be selected.
Humans ; Weight-Bearing ; Biomechanical Phenomena ; External Fixators ; Tibial Fractures/physiopathology* ; Fracture Fixation/instrumentation* ; Male