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28 November 2021, Volume 25 Issue 33 Previous Issue    Next Issue

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Cervical spondylosis with osteoporosis treated by the new pedicle fixation system through the anterior cervical approach with three-dimensional printing technology: three-dimensional finite element analysis Yang Jiujie, Wang Tao, Li Zhi, Yang Lifeng, Tian Ye, Bi Zheng, Zeng Yaling 2021, 25 (33):  5249-5253.  doi: 10.12307/2021.309 Abstract ( 467 )   PDF (1319KB) ( 229 )   Save BACKGROUND: In osteoporosis patients, the stability of cervical spine after internal fixation is poor; the fracture healing process is slow; and the risk of re-fracture at the same site and other sites is significantly increased. Therefore, it is necessary to design a new method of anterior internal fixation to reduce complications and surgical revision rate.   OBJECTIVE: To design a new fixation system for the treatment of cervical spondylosis with osteoporosis through the anterior pedicle approach using three-dimensional (3D) finite element analysis and 3D printing technology, which is beneficial to improve the stability of the patient’s cervical spine after surgery. METHODS:  3D CT data of 15 healthy cervical spine patients and 15 osteoporosis patients who were examined in the Department of Orthopedics, Affiliated Central Hospital of Shenyang Medical College from December 2017 to December 2019 were collected. The cervical spine models of 30 patients were constructed by 3D printing technology. A new nail plate internal fixation system was designed based on the pedicle positioning guide. 3D models were subjected to the vertebral pedicle fixation through the anterior approach guided by the localizer under external conditions. The prepared postoperative models were connected to the computer for finite element analysis and biomechanical analysis, and the best nail plate internal fixation system was designed based on the analysis results.   RESULTS AND CONCLUSION: (1) 3D printing technology was used to successfully construct the cervical spine models of osteoporosis patients, as well as the anterior vertebral pedicle fixation and positioning guide and the anterior vertebral pedicle fixation nail plate system. (2) Finite element biomechanics analysis results showed that the bone mass of patients with severe osteoporosis was significantly higher than that of normal bone by torsional displacement and rotation angle. The addition of screws did not significantly improve the torsional deformation of the anterioposterior bending and the left and right bending. The addition of screws had a significant improvement in the deformation of the axial torsional load. (3) The results indicated that the trial designed a vertebral pedicle internal fixation nail plate system for the anterior cervical approach using 3D printing technology, confirming that 3D printing technology can successfully assist the cervical spine through anterior pedicle fixation for cervical spondylosis combined with osteoporosis. Figures and Tables | References | Related Articles | Metrics

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Mechanical difference between anterior approach and anterior combined with posterior approach in the treatment of acetabular both-column fractures Gu Jinshan, Yang Chaohui, Li Shuwei 2021, 25 (33):  5254-5258.  doi: 10.12307/2021.310 Abstract ( 448 )   PDF (1459KB) ( 188 )   Save BACKGROUND: Surgery is the gold standard for the treatment of both-column acetabular fractures with large displacement, but the surgical treatment for both-column acetabular fractures is controversial and there is no consensus.   OBJECTIVE: The finite element model of acetabular both-column internal fixation was established by using the finite element method to analyze and compare the difference of mechanical distribution between anterior approach and anterior combined with posterior approach in the treatment of acetabular both-column fractures, and to provide new ideas for clinical treatment from the perspective of mechanics. METHODS:  An adult male was selected to undergo pelvic CT scan. The CT scan data of pelvic acetabulum were imported into Mimics, Geomagics and Hypermesh software for processing. Acetabular both-column fracture model and finite element models of single fixed anterior acetabular both-column fractures and anterior combined with posterior approach in the treatment of acetabular both-column fractures were established in the ABAQUS. The biomechanical differences of the internal fixation system for acetabular both-column fractures under two different internal fixation methods were compared.   RESULTS AND CONCLUSION: (1) There was no significant difference in the amount of acetabular strain displacement between the two types of acetabular both-column fracture internal fixation models. (2) In the model of acetabular both-column fracture with single anterior fixation, the maximum stress was concentrated in the anterior acetabular column, the top of the acetabulum and the quadripartite area. (3) In the model of acetabular both-column fracture fixed by anterior combined with posterior approach, the stress was evenly distributed; the maximum stress was concentrated at the top of the acetabulum, and the stress in the quadripartite area was significantly reduced. (4) The maximum stress of femoral neck in the model of acetabular both-column fracture fixed by a single anterior approach was greater than that in the model of acetabular both-column fracture fixed by a combined anterior and posterior approach. (5) The results indicate that in the acetabular both-column fracture model with a single anterior fixation, no additional stress was observed in the posterior column, but the stress was more concentrated in the quadrisquare zone and the neck of the femur, and more than in the model with combined anterior and posterior approach. Thus, the additional posterior fixation of the posterior acetabular column is not necessary for the stabilization of the acetabular both-column fracture by anterior fixation. However, for the elderly patients with traumatic femoral head necrosis tendency, lower limb line deformity, osteoporosis or extreme obesity, the combination of anterior and posterior approach is preferred. Figures and Tables | References | Related Articles | Metrics

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Finite element analysis of reconstruction of sagittal balance in ankylosing kyphosis with vertebral column resection Xie Jiang, Guo Huili, Li Hui, Dai Jie, Zhu Xu 2021, 25 (33):  5259-5264.  doi: 10.12307/2021.311 Abstract ( 498 )   PDF (1781KB) ( 251 )   Save BACKGROUND: In the past, the correction of ankylosing kyphosis often focused on the correction of local deformities, ignoring the reconstruction of sagittal balance.   OBJECTIVE: To establish a three-dimensional finite element model of ankylosing spondylitis kyphosis by using computer-aided software, design a personalized osteotomy scheme based on the reconstruction of sagittal balance of spine by hilum hip axis method, simulate the operation of vertebral column resection (VCR), calculate and analyze its biomechanical characteristics, and compare with two kinds of sagittal balance models without reconstruction. METHODS:  CT data of an inpatient from the Sixth Affiliated Hospital of Xinjiang Medical University were collected. According to 301 classification, kyphosis was identified as IIIA. The CT data were imported into computer modeling software to establish a three-dimensional finite element model of ankylosing kyphosis. Three different surgical models were designed, which were VCR30°, VCR32.2° and VCR40°, in which VCR32.2° was used to measure the pre osteotomy angle of L3, which was 32.2° using the measurement method of hilum hip axis. In addition, two non-reconstructed spinal sagittal plane balance models were constructed, in which VCR30° was set as the osteotomy angle 30° and VCR40° was set as the osteotomy angle 40° to simulate VCR in the three models. The spinal displacement, screw rod system, titanium cage and osteotomy surface of the three models were calculated by finite element method.   RESULTS AND CONCLUSION: (1) The order of total displacement and displacement of 24 vertebral bodies was VCR40° > VCR30° > VCR32.2°; VCR40° was significantly higher than VCR32.2°; VCR30° and VCR32.2° had no significant displacement difference due to the small difference of osteotomy angle. (2) The stress distribution trend of pedicle screw, titanium rod, titanium cage and osteotomy contact surface: no matter titanium rod or titanium cage, VCR40° was higher than the other two models and the average, and the difference was significant. VCR32.3° had the smallest stress in the three models, and was lower than the average value. The equivalent stress distribution of each segment was uniform, and there was no stress concentration. (3) Results confirmed that reconstruction of sagittal balance of spine based on hilum hip axis method can increase postoperative spinal stability, and lower stress distribution of internal fixation, which is a reasonable and scientific surgical design. Figures and Tables | References | Related Articles | Metrics

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Effect of zoledronic acid on bone mineral density and bone metabolism markers in elderly patients with osteoporotic intertrochanteric fracture after hip arthroplasty: 2-year follow-up Qiu Wei, Lian Xingye 2021, 25 (33):  5265-5272.  doi: 10.12307/2021.312 Abstract ( 451 )   PDF (2672KB) ( 369 )   Save BACKGROUND: In recent years, artificial joint arthroplasty has achieved good results in the surgical treatment of intertrochanteric fractures. Due to the presence of osteoporosis, postoperative loosening and subsidence of implant, periprosthetic fracture and other conditions have become one of serious postoperative complications. In addition to surgical treatment, senile osteoporotic fracture should be combined with anti-osteoporosis drugs to reduce the risk of recurrent fracture or implant loosening.   OBJECTIVE: To study the clinical significance of anti-osteoporosis treatment in elderly patients with intertrochanteric fracture after artificial hip arthroplasty. METHODS:  Forty-six elderly female patients with osteoporotic intertrochanteric fractures who underwent artificial femoral head replacement were included and were divided into two groups according to the treatment plan. Twenty-two patients in the treatment group were treated with zoledronic acid (once a year, a total of three infusions), and regularly orally taken calcitriol and caltrate D for anti-osteoporosis treatment. Twenty-four patients in the control group were regularly orally taken calcitriol and caltrate D for anti-osteoporosis treatment, with the absence of zoledronic acid. Bone mineral density and bone metabolism markers were measured before treatment and 6, 12 and 24 months after treatment. Serum osteocalcin was selected as bone formation marker, and tartrate resistant acid-base phosphatase-5b was selected as bone absorption marker. Dual-energy X-ray absorptiometry was used to detect bone mineral density, and ELISA was used to detect bone metabolism.   RESULTS AND CONCLUSION: (1) After treatment, the bone mineral density of the two groups increased in different degrees, and bone mineral density was better in the treatment group than that in the control group 1 year after treatment (P < 0.05). (2) Bone formation markers (osteocalcin) increased temporarily after injury, and gradually increased in the treatment group after 6 months; the difference was statistically significant (P < 0.05). The control group maintained at a certain level after 6 months. The difference between the two groups was statistically significant after 6 months (P < 0.05). (3) Bone resorption markers (tartrate resistant acid-base phosphatase-5b) increased after injury, and gradually decreased in the treatment group; the difference was statistically significant (P < 0.05). The decrease was not significant in the control group after treatment, and the difference was not significant (P > 0.05). The difference between the two groups was statistically significant 12 and 24 months after treatment (P < 0.05). (4) It is concluded that zoledronic acid can further assist in the anti-osteoporosis treatment of elderly patients with intertrochanteric fracture after hip arthroplasty, which plays an important role in improving bone mineral density, promoting bone formation and inhibiting bone resorption. Figures and Tables | References | Related Articles | Metrics

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Finite element analysis of stress and displacement of Lenke 3 adolescent idiopathic scoliosis thoracolumbar spine Wu Chao, Gao Mingjie, Wang Jianzhong, Zhang Yunfeng, Yu Jinghong, Cai Yongqiang, Wang Haiyan, He Yujie, Tong Ling, Li Jiawei, Gao Shang, Wang Xing, Wu Min, Li Zhijun, Li Xiaohe 2021, 25 (33):  5273-5280.  doi: 10.12307/2021.313 Abstract ( 574 )   PDF (1539KB) ( 249 )   Save BACKGROUND: Juvenile idiopathic scoliosis causes changes in spine structure, and the stress of the scoliosis spine changes accordingly. The thoracic and lumbar vertebrae bear most of the stress load throughout the spine. Thus, this study simulates and analyzes the biomechanical characteristics of the thoracolumbar spine under different working conditions, which is very meaningful for the study of the etiology of the disease.   OBJECTIVE: To establish a Lenke type 3 three-dimensional digital model of adolescent idiopathic scoliosis, to simulate and analyze the stress and displacement characteristics of scoliosis under six working conditions. METHODS: A case of adolescent patient with idiopathic scoliosis and double main curvature deformity was selected to undergo spine CT scan. The scanned Dicom format CT data were imported into Mimics software. According to the CT gray scale, the corresponding tissues were distinguished and stl or cloud point cloud format was exported. After denoising, paving, smoothing and other processing, the processed image was transferred to Hypermesh software for meshing. Specific material properties were given to the vertebral body and surrounding tissues. A three-dimensional finite element model of adolescent idiopathic scoliosis was established to simulate the role of spinal ligaments. Finally, the mechanical analysis was performed in Abaqus & Ansys software.   RESULTS AND CONCLUSION: (1) During flexion and extension, lateral flexion and rotation, the stress of vertebral body in lateral curvature (T6 and T12 vertebral body), thoracolumbar junction and lumbar vertebrae was larger, and the stress of facet joint and pedicle was larger than that of other parts. The stress from the apex to the end decreased gradually. (2) When lateral flexion and rotation motion, the stress at the concave part of the spine (T6-7 at the left margin, T10-11, and L3-4 at the right margin) was greater. (3) Three-dimensional finite element model of chest-waist segment of Lenke 3 adolescent idiopathic scoliosis patients was successfully established. The simulation analysis showed that the stress and displacement of the vertebral body and intervertebral disc of adolescent idiopathic scoliosis at different positions under different loading conditions changed accordingly. The results of the study may provide global and regional quantitative indicators for the three-dimensional scoliosis correction, and provide a digital model for clinical device orthopedics and brace treatment. Figures and Tables | References | Related Articles | Metrics

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Biomechanical characteristics of children with different body weights during vertical jump Ji Zhongqiu, Li Jiahui, Zhao Panchao, Jiang Guiping 2021, 25 (33):  5281-5287.  doi: 10.12307/2021.314 Abstract ( 505 )   PDF (1313KB) ( 230 )   Save BACKGROUND:  Overweight and obesity are becoming more and more common in young children. Studies have shown that excessive body mass affects the fundamental movement competence of young children. However, there are fewer studies using biomechanical methods for analysis, and there is a lack of researches on using simulation to analyze the muscle force during exercise.   OBJECTIVE: To analyze the kinematics, dynamics and lower limb muscle strength of children of different weights during vertical jump using sports biomechanics research methods, and compare the differences in these data. METHODS:  Totally 52 children aged 4-5 years old were selected from a kindergarten in Beijing using a random sampling method. According to the body mass index, they were divided into a normal body mass group (n=20), an overweight group (n=16) and an obesity group (n=16). The BTS three-dimensional infrared motion capture system, the Kistler three-dimensional force plate and the VIXTA video analysis system were used to synchronously collect the kinematics and dynamics data of the children during the vertical jump. AnyBody7.1.2 simulation modeling software was used to calculate the lower limb muscle strength indicators.   RESULTS AND CONCLUSION: (1) The vertical jump height and knee changes in the normal body mass group were higher than those in the overweight group and the obesity group (P < 0.05 , P < 0.01). The minimum knee flexion and the trunk angle were greater in the normal body mass group than those of the obesity group (P < 0.05). (2) The soleus lateralis, gastrocnemius lateralis, and gluteus medius anterior in the normal body mass group were smaller than those in the overweight group (P < 0.05). (3) The soleus lateralis, gastrocnemius lateralis, peroneus longus, inferior funicle of vastus medialis, and anterior funicle of gluteus medius in normal body mass group were smaller than those in the obesity group (P < 0.05). (4) The semitendinosus and the anterior funicle of gluteus minimus in the normal body mass group were larger than those in the obesity group (P < 0.05). The inferior and superior of gemellus and obturator internus in the normal body mass group were larger than those in the overweight group (P < 0.05). (5) Peroneal brevis muscle was larger in the obesity group than that in the normal body mass group (P < 0.05) and overweight group (P < 0.05). (6) Posterior funicle of gluteus minimus was smaller in the obesity group than that in the normal group (P < 0.05) and overweight group (P < 0.05). (7) The results showed that the vertical jump height of overweight and obese children was lower than that of normal-weight children of the same age, and showed the kinematic characteristics of the initial vertical jump stage. During the landing stage, overweight and obese children have greater ground reaction forces in the front and rear and left and right directions. The main muscles that children use when they complete the vertical jump are the soleus lateralis, the gastrocnemius lateralis, the peroneus brevis, the peroneus longus, and the quadriceps, gluteus medius, gluteus maximus muscle, and adductor magnus muscles. The normalized muscle strength of the quadriceps femoris and the active hip joint of the overweight and obese children was lower than that of the normal weight children of the same age. Figures and Tables | References | Related Articles | Metrics

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Three-dimensional finite element analysis of the biomechanics of the posterior segment of lumbar facet arthroplasty with different sizes Yu Yang, Xie Yizhou, Shi Yin, Wu Weidong, Gu Dangwei, Fan Xiaohong 2021, 25 (33):  5288-5293.  doi: 10.12307/2021.315 Abstract ( 388 )   PDF (1434KB) ( 114 )   Save BACKGROUND: Percutaneous lumbar endoscopy is in full swing in China and even in the world. Transforaminal lateral approach is one of the most commonly used approaches in percutaneous lumbar endoscopic surgery, but the biomechanical effects of the relevant segments are rarely reported.   OBJECTIVE: To investigate the biomechanical effects of different sizes (7.5 mm, 10 mm, 15 mm) of facet arthroplasty on related segments of lumbar spine by three-dimensional finite element simulation. METHODS:  A three-dimensional finite element model of L3-L5 was established to verify its effectiveness. The arthroplasty of L4/5 lumbar vertebrae in percutaneous endoscopic surgery was simulated. The angle between the needle and the horizontal plane and the coronal plane was taken as the puncture target, and the base of L5 superior articular process was taken as the puncture target. According to the puncture path, the circular saw with the diameter of 7.5 mm, 10 mm and 15 mm was made respectively, so as to obtain three-dimensional finite element model formed at different diameters of the base of L5 superior articular process. The normal model, 7.5 mm, 10 mm and 15 mm diameter forming finite element models were loaded in six directions to calculate the von Mises stress extremum and range of motion of the operating segments (L4/5) and adjacent segments (L3/4) of the three models under six states of flexion, extension, left flexion, right flexion, left rotation and right rotation. Relevant comparative studies were conducted to determine the effect of different sizes of facet arthroplasty on the biomechanical stability of lumbar spine.   RESULTS AND CONCLUSION: (1) The effect on the operating segment (L4/5): The maximum stress of L4/5 disc with 15 mm diameter of L5 superior articular process was significantly increased under six working conditions of flexion, extension, left-right lateral bending and left-right rotation compared with that of 7.5 mm and 10 mm diameter of L4/5. The maximum stress of L4/5 disc with 15 mm diameter of L5 superior articular process was increased by 110%, 95% and 97% respectively. The range of motion of L4/5 segment of L5 with 15 mm diameter was greater than that of 7.5 mm and 10 mm diameter, which increased by 8.6%, 21.8%, 8.9%, 17.6%, 35.7% and 21.4% respectively. (2) Effect on adjacent segment (L3/4): The maximum stress of adjacent segment L3/4 disc with 15 mm diameter of L5 superior articular process increased compared with 7.5 mm and 10 mm diameter of L5 superior articular process in six working conditions, in which flexion was the most obvious, and the maximum stress of L3/4 disc increased by 29.3% compared with normal model. The range of motion of adjacent segment L3/4 of different sizes (7.5 mm, 10 mm, 15 mm) of zygapoplasty in flexion, extension, left-right lateral bending and left-right rotation was not significantly increased compared with normal model. (3) It is concluded that compared with 7.5 mm and 10 mm in diameter, 15 mm in diameter has a greater mechanical effect on the operating segment, and even has a corresponding effect on the stress of adjacent segments. Figures and Tables | References | Related Articles | Metrics

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Foot posture and gait in adolescent idiopathic scoliosis patients: three-dimensional morphological analysis and biomechanics evaluation Zhu Feilong, Zhang Ming, Wu Yu, Wang Bin, Guo Xiaoqi, Cao Jiangang, Zhu Qian, Chen Wei 2021, 25 (33):  5294-5300.  doi: 10.12307/2021.316 Abstract ( 911 )   PDF (1648KB) ( 336 )   Save BACKGROUND: The current studies of walking performance in adolescent idiopathic scoliosis patients lack comparison among groups with different severity levels and have ignored the impact of foot posture on walking.   OBJECTIVE: To explore the differences in foot posture and walking performance of patients with mild, moderate, and severe adolescent idiopathic scoliosis compared with healthy peers and provide scientific basis for the function assessment and rehabilitation in the future. METHODS:  A total of 96 subjects were included in the study, including 64 adolescent idiopathic scoliosis patients and 32 healthy voluntary adolescents as the healthy group. Adolescent idiopathic scoliosis patients were subdivided into mild, moderate, and severe grades according to the Cobb angle, including 18 mild cases, 32 moderate cases and 14 severe cases. An experienced physiotherapist assessed a subject's foot posture according to the Foot Posture Index. A 3D foot morphology scanner was used to scan for morphological parameters of the foot and GaitScan instrument for gait and plantar pressure data collection. Comparative analysis was conducted between mild, moderate, and severe adolescent idiopathic scoliosis patients and healthy adolescents, and the characteristics of foot posture, balance, gait, and plantar pressure distribution were summarized.   RESULTS AND CONCLUSION: (1) In terms of foot morphology and posture, the foot arch index of the moderate and severe adolescent idiopathic scoliosis groups was significantly higher than the healthy group, and the foot posture index of the severe adolescent idiopathic scoliosis group was significantly higher than the healthy group (P < 0.05). (2) Regarding gait parameters, the severe adolescent idiopathic scoliosis group had advanced loading response, and a delayed terminal stance as compared with the healthy group (P < 0.05). The walking speed of the moderate and severe adolescent idiopathic scoliosis group was slower than the healthy group, and the center of pressure excursion index increased significantly (P < 0.05). (3) Regarding plantar pressure distribution, the pressure percentages of the medial and lateral heel of the severe adolescent idiopathic scoliosis groups were significantly higher and lower than the healthy group (P < 0.05). The percentage of the first metatarsal pressure in the severe adolescent idiopathic scoliosis group was significantly higher than the healthy group, and the percentage of the third, fourth and fifth metatarsal pressure was significantly lower than the healthy group (P < 0.05). (4) For the static balance, the load ratio of the forefoot of severe adolescent idiopathic scoliosis patients was significantly lower than the rear foot, and the load ratio of the left foot was significantly lower than the right foot (P < 0.05). (5) It is concluded that the walking efficiency and stability of patients with moderate to severe adolescent idiopathic scoliosis decreased significantly. Future studies on walking of adolescent idiopathic scoliosis patients should consider foot posture as an accompanied factor, because foot posture may affect walking performance. Figures and Tables | References | Related Articles | Metrics

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Biomechanical finite element analysis of lateral displacement of the cage after oblique lumbar interbody fusion Lü Jie, Wang Yongfeng, Yuan Jie, Xu Zhaojian, Qin Yichuan, Hao Jiaqi 2021, 25 (33):  5301-5306.  doi: 10.12307/2021.317 Abstract ( 402 )   PDF (1340KB) ( 205 )   Save BACKGROUND: Oblique lateral interbody fusion is an effective method for the current clinical treatment of lumbar degenerative diseases. However, the treatment for postoperative lateral displacement of the cage has not been determined yet. Therefore, using finite element analysis to analyze the biomechanics of different conditions after oblique lateral interbody fusion has become a choice for more and more researchers.   OBJECTIVE: To evaluate the effect of lateral displacement of cage on the lumbar biomechanics after oblique lateral interbody fusion with finite element analysis, and to provide biomechanical basis for the treatment of this condition. METHODS:  A healthy male was selected to undergo lumbar CT scanning, and the scanning data were obtained. The three-dimensional finite element model of L3-L5 was established by Mimics, Geomagic, SolidWorks and ANSYS Workbench software, and was set as normal control group. Oblique lateral interbody fusion Stand alone fixation group (SA) and oblique lateral interbody fusion with bilateral pedicle screws fixation group (BPS) were established. According to the degree of Cage displacement, the SA group was divided into five groups: the cage non-displaced model (SA0), the midpoint of the right edge of the cage shifted to the right 1/8 point (SA1), 2/8 point (SA2), 3/8 point (SA3), and 4/8 point (SA4) of the transverse diameter of the upper endplate of L5. On the basis of SA grouping, the models with bilateral pedicle screws were BPS0, BPS1, BPS2, BPS3 and BPS4, respectively. The same loading conditions were applied to different models to simulate the flexion, extension, lateral flexion and rotation of the spine. The range of motion of the lumbar spine and the stress peak of the cage and screw-rod system were observed under different working conditions.   RESULTS AND CONCLUSION: (1) The range of motion of SA0, SA1 and SA2 was lower than that of normal control group in different motion states, while the range of motion of SA3 and SA4 was greater than that of normal control group in extension and right flexion states. (2) Under different conditions, the range of motion and the peak stress of the cage in the SA group and the BPS group were increased with the increase of the lateral distance of the cage. (3) When the cage was in the same position, the activity and the peak stress of the cage in all states in the BPS group were lower than that in the SA group. (4) In each state, the peak stress of the screw and rod system in the BPS group was BPS0 < BPS1 < BPS2 < BPS3 < BPS4. (5) It is concluded that when the left side of the cage was displaced after oblique lateral interbody fusion stand alone, the range of motion of the lumbar spine and the stress peak of the cage in various states were gradually increased with the increase of the displacement distance, showing a tendency of spinal instability. On this basis, combined with bilateral pedicle screw fixation, better biomechanical stability of the lumbar spine can be obtained. Figures and Tables | References | Related Articles | Metrics

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Biomechanical characteristics of bone cement reduction for V-type calcaneal fractures Zhang Wen, Chen Liang, Jiang Zhenhuan 2021, 25 (33):  5307-5311.  doi: 10.12307/2021.318 Abstract ( 536 )   PDF (1854KB) ( 167 )   Save BACKGROUND: Bone cement has good strength and fixation, which can effectively play the role of fracture reduction.  OBJECTIVE: For V-type calcaneal fractures, the reduction was treated by implanting different volumes of polymethyl methacrylate bone cement, and the effect of different volumes of bone cement reduction on calcaneal fractures was analyzed by finite element method. METHODS: A CT image of the foot and ankle of a normal male youth was selected to establish a three-dimensional finite element model of the calcaneal bone with physiological status. By simulating the clinical V-type calcaneal fractures, the model was cut to form a V-type calcaneal fractures. To simulate the clinical surgical reduction method for the fracture model, 2, 3 and 4 mL bone cement of different volumes were injected, respectively, to complete the establishment of the postoperative finite element model for the three groups. By applying the same load and constraint to the three groups of models, the maximum stress distribution and maximum deformation of the three groups of models under various load conditions were observed through finite element analysis and calculation.  RESULTS AND CONCLUSION: Under the action of vertical load of 700 N, the deformation and stress distribution of the overall model (including cancellous bone, cortical bone and bone cement) increased with the increase of the volume of bone cement. Among them, the volume of 4 mL bone cement showed the largest stress on the cancellous bone, cortical bone and bone cement, with peak stresses reaching 8.04, 136.96 and 10.15 MPa respectively. It is concluded that with the injection of bone cement, the stiffness of cancellous bone, cortical bone and bone cement all increased. As the volume of bone cement increases, the stress increase of cortical bone decreases and the increase of cancellous bone increases. Figures and Tables | References | Related Articles | Metrics

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Comparison of one-stage bilateral total hip arthroplasty between SuperPATH approach and posterolateral approach based on enhanced recovery after surgery Zhang Weicheng, Li Rongqun, Wu Mingzhou, Zheng Kai, sun houyi, Zhang Lianfang, Zhou Jun, Xu Yaozeng 2021, 25 (33):  5312-5317.  doi: 10.12307/2021.319 Abstract ( 366 )   PDF (1281KB) ( 267 )   Save BACKGROUND: With the gradual deepening of the concept of enhanced recovery after surgery, orthopedists have put forward higher requirements for the efficacy of total hip replacement. The traditional posterolateral surgical approach is traumatic, with slow postoperative recovery. Minimally invasive total hip replacement surgery provides a new option for orthopedic surgeons.   OBJECTIVE: To compare the clinical effects of Supercapsular Percutaneously-Assisted Total Hip (SuperPATH) approach and conventional posterolateral approach for one-stage bilateral total hip arthroplasty. METHODS:  A retrospective study was conducted on 25 patients (50 hips) with one-stage bilateral total hip arthroplasty in the First Affiliated Hospital of Soochow University from April 2016 to April 2018. In terms of surgical approach conducted, 12 patients (24 hips) had total hip arthroplasty performed by SuperPATH approach, while remaining 13 patients (26 hips) underwent total hip arthroplasty with posterolateral approach. The length of incision, operation time, intraoperative blood loss, postoperative blood transfusion, hemoglobin difference, and length of stay were compared between the two groups. Harris score (pain, function, deformity, range of motion), visual analogue scale score and complications were compared between the two groups after surgery. The differences in abduction angle, anteversion angle, and length of both lower limbs were compared between the two groups.   RESULTS AND CONCLUSION: (1) All the patients entered in the enhanced recovery after surgery management process during the perioperative period. Totally 25 patients had operation performed smoothly. (2) Comparison of the related indexes of the two sets of approaches showed that SuperPATH approach group had smaller surgical incision, less postoperative blood transfusion, and less hemoglobin difference compared with the posterolateral approach group (P < 0.05). However, operation time was longer in the SuperPATH approach group (255.17±38.57) minutes than that in the posterolateral approach group (188.15±30.84) minutes (P < 0.01). (3) The Harris score of SuperPATH approach group at 3 and 7 days after operation was significantly higher than that in the posterolateral approach group (P < 0.05). The visual analogue scale score at 1 and 3 days after operation was significantly lower in SuperPATH approach group compared to the posterolateral approach group (P < 0.05). (4) There was no statistically significant difference in the length of lower limps, anteversion and abduction angle of the acetabular prosthesis (P > 0.05). (5) The results show that under the guidance of the concept of enhanced recovery after surgery, SuperPATH minimally invasive in phase I bilateral total hip arthroplasty was safe and effective, with advantages of shorter incision length, less postoperative blood transfusion, less recessive blood loss, faster hip function recovery and less pain. Figures and Tables | References | Related Articles | Metrics

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Medium- and long-term assessment of lateral compartment and patellofemoral compartment osteoarthritis after medial unicompartmental knee arthroplasty with Oxford mobile-bearing Qiao Renqiu, Yin Li, Zhang Yi, Wang Haitao, Xia Peige, Kong Zhiheng 2021, 25 (33):  5318-5323.  doi: 10.12307/2021.320 Abstract ( 442 )   PDF (1175KB) ( 209 )   Save BACKGROUND: Unicompartmental knee arthroplasty has attracted more and more attention because of its advantages, such as less trauma, faster recovery, less cost and better proprioception. However, there are few studies on the medium- and long-term development of lateral compartment and patellofemoral compartment osteoarthritis after mobile-bearing medial unicompartmental knee arthroplasty.   OBJECTIVE: To evaluate the progression of posterolateral and patellofemoral osteoarthritis with mobile-bearing medial unicompartmental knee arthroplasty. METHODS:  Totally 95 patients who underwent mobile-bearing medial unicompartmental knee arthroplasty in the Department of Orthopedics of First Affiliated Hospital of Zhengzhou University from January 2011 to January 2016 were retrospectively analyzed. Lateral compartment osteoarthritis was assessed by Kellgren-Lawrence classification based on preoperative and final follow-up knee radiographs; there were advanced group (n=32) and non-advanced group (n=63). Patellofemoral compartment osteoarthritis was assessed by Kellgren-Lawrence classification; there were advanced group (n=41) and non-advanced group (n=54). Imaging and clinical features were compared in the advanced group and non-advanced group to analyze the relationship between the postoperative effect and the progression of lateral and patellofemoral compartment osteoarthritis.   RESULTS AND CONCLUSION: (1) During final follow-up, compared with the non-advanced group, Hospital for Special Surgery scores were lower in the advanced group after lateral compartment osteoarthritis (P < 0.05); however, the visual analogue scale score and forgotten joint score were higher (P < 0.05). (2) The incidence of osteoarthritis progression in the lateral compartment (33.7%) was less than that in the patellofemoral compartment (43.2%) after mobile-bearing medial Unicompartmental knee arthroplasty. There was no significant correlation between the progression of lateral compartment osteoarthritis and the progression of patellofemoral compartment osteoarthritis (P > 0.05). (3) After 5-10 years follow-up, there were no complications such as infection, polyethylene gasket dislocation or periprosthetic fracture. (4) The medium and long-term outcomes of the mobile-bearing medial unicompartmental knee arthroplasty were mainly affected by the progression of lateral compartment osteoarthritis, but not by the patellofemoral compartment. Figures and Tables | References | Related Articles | Metrics

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Diagnostic value of D-dimer, erythrocyte sedimentation rate and C-reactive protein in deep vein thrombosis of lower extremity after hip and knee arthroplasty Fan Xinchao, Bao Wenjuan, Zhang Kai, Sun Xilong, Huang Teng, Gao Bo, Zhai Jinshuai, Zhou Yibin, Qiu Changmao, Li Wenyi, Li Xicheng 2021, 25 (33):  5324-5328.  doi: 10.12307/2021.321 Abstract ( 440 )   PDF (1026KB) ( 173 )   Save BACKGROUND: Lower extremity deep vein thrombosis is a common complication after hip and knee arthroplasty. There are many introductions about its influencing factors, but there are few introductions about the thresholds of influencing factors.   OBJECTIVE: To investigate the diagnostic value of D-dimer, erythrocyte sedimentation rate and C-reactive protein in deep vein thrombosis of lower limbs after hip and knee arthroplasty. METHODS:  The clinical data of 216 patients who underwent hip and knee arthroplasty in Hebei Provincial People’s Hospital from January 2018 to November 2020 were retrospectively analyzed, including 77 cases of total knee arthroplasty, 31 cases of unicondylar arthroplasty, 35 cases of total hip arthroplasty, and 73 cases of hemiarthroplasty of the hip. Color Doppler ultrasonography of deep veins in both lower extremities was performed on the first day after surgery, and the diagnosis of deep vein thrombosis in lower extremities was confirmed by more than two attending physicians. Among them, there were 86 patients with lower extremity deep vein thrombosis and 130 patients without deep vein thrombosis. The rates of deep vein thrombosis in lower limbs were compared. According to the criteria of age, gender and replacement type, 86 patients without lower extremity deep vein thrombosis after surgery were selected as the control group using PSM propensity score matching method. The levels of plasma D-dimer, albumin and hemoglobin in 172 patients (86 patients in the thrombosis group and 86 patients in the control group) were compared, and the diagnostic efficacy of each index in the diagnosis of lower extremity deep vein thrombosis after hip and knee arthroplasty was analyzed by ROC curve.   RESULTS AND CONCLUSION: (1) Compared with the control group, the D-dimer level of 172 patients in thrombus group was increased (P < 0.05). (2) The sensitivity and specificity of D-dimer for the diagnosis of deep vein thrombosis of lower extremity after hip arthroplasty were 71.8% and 74.1%. The time sensitivity and specificity of prothrombin were 66.7% and 66.7% respectively. The sensitivity and specificity of erythrocyte sedimentation rate were 61.5% and 70.4%. The sensitivity and specificity of C-reactive protein level were 94.9% and 33.3% respectively. The age sensitivity was 71.8% and the specificity was 100%. (3) The sensitivity and specificity of D-dimer for the diagnosis of deep venous thrombosis of lower extremity after knee arthroplasty were 78.7% and 44.1%, respectively. (4) The above data confirmed that the sensitivity of D-dimer level indicators in the diagnosis of deep vein thrombosis of lower extremities after knee replacement was higher, while the sensitivity and specificity of prothrombin time, erythrocyte sedimentation rate, C-reactive protein level and age in the diagnosis of deep vein thrombosis of lower extremities after hip arthroplasty were higher. Figures and Tables | References | Related Articles | Metrics

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Effect of muscle flap in limb salvage operation of tumor type prosthesis of proximal tibia Gao Yuan, Xia Tienan, Liu Jinxin, Shang Guanning 2021, 25 (33):  5329-5334.  doi: 10.12307/2021.322 Abstract ( 377 )   PDF (1362KB) ( 156 )   Save BACKGROUND: The prosthesis replacement with tumors of the proximal tibia will lead to complications such as local prosthesis exposure and infection. The transfer of the medial gastrocnemius muscle flap to cover the surface of the tibial prosthesis can effectively reduce the risk of postoperative complications. However, in the replacement of the long-segment proximal tibia prosthesis, the transfer of the gastrocnemius muscle flap to cover the tibia is only used. The area of the prosthesis is limited, and it needs to be reconstructed with other repair methods.   OBJECTIVE: To investigate the clinical effect of applying gastrocnemius muscle flap and soleus muscle flap to repair the soft tissue defect after tibial prosthesis replacement. METHODS:  From March 2017 to June 2020, 17 patients with proximal tibia malignant bone tumor admitted to the Shengjing Hospital of China Medical University. All tumors were treated by tumor segment resection and tumor knee prosthesis replacement. The medial gastrocnemius muscle flap alone was used to reconstruct the anterior tibial soft tissue defect, when the difference between the length of the tibia prosthesis and the maximum width of the gastrocnemius muscle flap was less than or equal to the maximum width of the gastrocnemius muscle flap. The medial gastrocnemius muscle flap combined with the soleus muscle flap could effectively cover the tibial prosthesis without tension, when the difference between the length of the tibia prosthesis and the maximum width of the gastrocnemius muscle flap was greater than the maximum width of the gastrocnemius muscle flap. Patients were followed up regularly after surgery, and lower limb function was evaluated by the Musculoskeletal Tumor Society scoring system.   RESULTS AND CONCLUSION: (1) All 17 patients were followed up, with a mean of (17.5±9.8) months. (2) The incisions were healing by first intention in all patients without infection, skin flap necrosis and other complications. One patient with osteosarcoma underwent amputation due to periprosthesis infection after chemotherapy one year after knee prosthesis replacement, and there was no case of revision of tumor prosthesis, metastasis or death. (3) Musculoskeletal tumor society score was averagely 24 points, of which 10 cases were excellent, 2 cases were good and 5 cases were fair. The knee flexion angle was (84.76±12.88)°. (4) Above data confirmed that during limb salvage treatment of tumor prosthesis of proximal tibia, gastrocnemius muscle flap and soleus muscle flap were selected to repair soft tissue defects according to the difference between the length of tibia prosthesis and the maximum width of gastrocnemius muscle flap, which could fully cover the prosthesis surface without tension and effectively reduce local complications. Figures and Tables | References | Related Articles | Metrics

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Which is more suitable for conversion to hip arthroplasty after failure of dynamic hip screws or proximal femoral nail anti-rotation for stable intertrochanteric fractures in the elderly? Zhang Tianyi, Mao Kaige, Dong Wei, Li Lixin, Kong Fanlin, Zhu Jun, Fan Guofeng 2021, 25 (33):  5335-5340.  doi: 10.12307/2021.323 Abstract ( 426 )   PDF (1228KB) ( 140 )   Save BACKGROUND: The prognosis of dynamic hip screws versus proximal rotation-proof intramedullary nailing for the treatment of intertrochanteric fractures has been discussed previously. However, there is a lack of comparative long-term prognostic studies on the conversion to hip arthroplasty after failure of internal fixation with both procedures.   OBJECTIVE: To compare the long-term clinical outcomes after conversion to hip arthroplasty following failed treatment of stable intertrochanteric fractures with dynamic hip screws versus proximal femoral nail anti-rotation. METHODS:  Between January 2012 and April 2017, data of 102 elderly patients treated at Hebei Petro China Center Hospital were retrospectively analyzed. Fifty of these patients were included in the dynamic hip screws group, which was the group converted to treatment with conversion to hip arthroplasty after failure of dynamic hip screw for stable femoral intertrochanteric fractures, and 52 in the proximal femoral nail anti-rotation group, which was the group converted to treatment with conversion to hip arthroplasty after failure of proximal femoral nail anti-rotation for stable femoral intertrochanteric fractures. Clinical indicators (Harris score) and imaging results at least 3 years after surgery were compared between the two groups.   RESULTS AND CONCLUSION: (1) The surgery was completed successfully in both groups, and no nerve or vascular injury occurred intraoperatively in either group. (2) There were no significant differences between the two groups in terms of age, gender, cause of internal fixation failure, ASA grading, mode of fixation of the femur, follow-up time and fracture typing of the intertrochanteric fracture of the femur (P > 0.05). (3) There was no significant difference in the Harris score of the hip joint before and after each follow-up between the two groups of patients (P > 0.05). (4) The overall postoperative complication rate was 48.0% (24/50) in the dynamic hip screws group compared to 21.2% (11/52) in the proximal femoral nail anti-rotation group, with a statistically significant difference between the two groups (P < 0.05). The incidence of orthopedic complications was 32.0% (16/50) in the dynamic hip screws group compared to 13.7% (7/52) in the proximal femoral nail anti-rotation group at the time of final follow-up, with a statistically significant difference between the two groups (P=0.025). (9) Nine postoperative periprosthetic fractures were noted in the dynamic hip screws group compared to two in the proximal femoral nail anti-rotation group, with a statistically significant difference between the two groups (P=0.021). (6) Above results confirm that conversion to hip arthroplasty after failed dynamic hip screws treatment has a higher orthopedic complication rate than conversion to hip arthroplasty after failed proximal femoral nail anti-rotation, especially periprosthetic fractures. Thus, conversion to hip arthroplasty is more suitable for treatment after failed internal fixation in proximal femoral nail anti-rotation than after failed internal fixation in dynamic hip screws. Figures and Tables | References | Related Articles | Metrics

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Double-rows technique with suture anchors in eight patients with fracture of distal patellar pole: reliable initial fixation Chen Yu, Yu Zhongxiang, Kuang Yong, Wang Shuqiang, Cai Yuwei, Fang Lei, Xu Shengming 2021, 25 (33):  5341-5344.  doi: 10.12307/2021.324 Abstract ( 488 )   PDF (2619KB) ( 586 )   Save BACKGROUND: Fracture of distal patellar pole is a special type of patellar fracture. Because of the comminuted inferior pole of patella without enough holding force, the commonly used techniques of patellar fracture are not applicable. There is no gold standard surgical treatment for fracture of distal patellar pole.   OBJECTIVE: To investigate the clinical effects of the double-rows technique with suture anchors in fixation of fracture of distal patellar pole. METHODS:  A retrospective study was conducted in eight patients with fracture of distal patellar pole in Shuguang Hospital Affiliated to Shanghai University of Chinese Traditional Medicine who underwent double-rows technique with suture anchors from May 2017 to May 2019. Systematic knee joint function exercise was performed in all patients, and joint function evaluation was regularly followed up. The range of motion was compared between the healthy side and postoperative joint.   RESULTS AND CONCLUSION: (1) All eight patients were followed up for 16-28 months, with an average of 19.5 months. (2) The incisions of all patients healed in stage I, without complications such as infection, loosening of anchor or pain of knee. Three months later, X-ray films showed bone healing in all patients. (3) At 12 months after operation, Bostman patellar fracture function score was (28.5±1.5); the knee joint injury and osteoarthritis curative effect score was (93.6±4.4); the excellent and good rate was 100%. (4) From 3 months after operation (3, 6, 12 months), the active flexion angle of the affected side was not significantly different from that of the healthy side (P > 0.05). (5) It is concluded that the double-rows technique with suture anchors can provide good initial fixation strength for the fracture of distal patellar pole. It has the advantages of good reduction effect, reliable fixation, no need for secondary surgery to remove internal fixation, less interference to soft tissue and early functional exercise. Figures and Tables | References | Related Articles | Metrics

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Modified open-door laminoplasty with preserved posterior cervical musculo-ligamentous complex in the treatment of cervical spondylotic myelopathy: neurological function and axial symptoms Zhao Lingtong, Hu Bing 2021, 25 (33):  5345-5350.  doi: 10.12307/2021.325 Abstract ( 426 )   PDF (1147KB) ( 239 )   Save BACKGROUND: Cervical spondylotic myelopathy causes spinal canal stenosis and spinal cord dysfunction through direct or indirect compression of the spinal cord or surrounding blood vessels. Posterior cervical laminoplasty for cervical spondylotic myelopathy is effective and widely used in clinical practice.   OBJECTIVE: To evaluate the repair effect of modified open-door laminoplasty with preserved posterior cervical musculo-ligamentous complex in the treatment of cervical spondylotic myelopathy. METHODS:  Medical record data of 126 patients with cervical spondylotic myelopathy from Tianyou Hospital Affiliated to Wuhan University of Science & Technology from June 2015 to July 2018 were retrospectively analyzed. They were assigned to two groups according to the surgical program. The 72 patients in the modified group received modified open-door laminoplasty with preserved posterior cervical musculo-ligamentous complex. The 54 patients in the control group received traditional vertebral plate keratoplasty. Baseline data, operation time, intraoperative blood loss, cervical curvature index, range of motion, and posterior cervical volume were compared between the two groups. Japanese Orthopaedic Association Scores, visual analogue scale scores, and Neck disability index were recorded before surgery, 24 months after surgery, and during final follow-up. The incidence of complications was recorded after surgery.   RESULTS AND CONCLUSION: (1) The last follow-up showed that the cervical curvature rate, range of motion, and cervical curvature index in the modified group were better than those in the control group (P < 0.01). (2) Compared with the control group, visual analogue scale score and Neck disability index were significantly lower in the modified group (P < 0.01). (3) The body volume on the hinge side in the modified group was not significantly different from that before surgery, but it was significantly increased compared with the control group (P < 0.01). (4) In addition, the incidence of axial symptoms in the modified group was significantly lower than that in the control group (6% vs. 22%), and the difference was statistically significant (P < 0.05). (5) It is suggested that modified open-door laminoplasty with posterior cervical musculo-ligamentous complex is an effective method for the treatment of cervical spondylotic myelopathy. The patient’s neurological function recovered well, and the curvature and range of motion of cervical vertebra were well maintained. Moreover, it reduced the incidence of postoperative axial symptoms compared to traditional open-door laminoplasty. Figures and Tables | References | Related Articles | Metrics

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Serum inflammatory mediators and oxidative stress in patients with type C distal radius fractures treated with external fixator combined with mid-frequency pulse therapy Li Jia, Fu Tingting, Ma Yuanchen, Liu Xiangqian, Chen Min 2021, 25 (33):  5351-5355.  doi: 10.12307/2021.326 Abstract ( 299 )   PDF (1197KB) ( 193 )   Save BACKGROUND: Type C distal radius fractures are often treated with external fixation. However, some patients still have undesirable symptoms such as delayed fracture healing and slow growth of callus. How to promote fracture healing and recovery of wrist joint function after surgery is of great significance.   OBJECTIVE: To investigate the effect of mid-frequency pulse therapy combined with external fixator on type C distal radius fracture and its influence on oxidative stress and inflammatory mediators. METHODS:  Clinical data of 86 patients with type C distal radius fracture admitted in Guangdong Provincial People’s Hospital from January to December 2018 were analyzed retrospectively. Patients were divided into two groups according to different treatment methods: external fixation group (n=41 cases) and combined group (mid-frequency pulse therapy combined with external fixation treatment, n=45 cases). The clinical effect of different treatment methods was observed, and the changes of serum inflammatory mediators and oxidative stress indexes before and 4 weeks after treatment were compared between the two groups.   RESULTS AND CONCLUSION: (1) The quantitative score of callus in the combined group was higher than that in the external fixation group, and the visual analogue scale score and Gartland-Werley score were lower than that in the external fixation group (P < 0.05). (2) At 4 weeks after treatment, malondialdehyde and advanced oxidation protein product levels decreased, and the level in the combined group was lower than that in the external fixation group (P < 0.05). The level of antioxidant glutathione peroxidase and superoxide dismutase levels increased; the level in the combined group was higher than that in the external fixation group (P < 0.05). (3) At 4 weeks after treatment, the levels of C-reactive protein, interleukin-6, and interleukin-1 β in the serum of the two groups were significantly lower than those before treatment (P < 0.05), and the levels in the combined group were lower than those in the external fixation group (P < 0.05). (4) It is concluded that mid-frequency pulse therapy combined with external fixator can promote the healing of type C distal radius fracture and the functional recovery of wrist joint, reduce postoperative inflammation and oxidative stress. Figures and Tables | References | Related Articles | Metrics

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Evaluation of regional characteristics and structural, functional stability of C2-C7 articular process based on Micro-CT observation Hu Zhe, Zhao Haiyan, Zhang Shaojie, Cai Yongqiang, Wang Xing, Qu Xingyue, Ma Yuan, Li Zhijun 2021, 25 (33):  5356-5361.  doi: 10.12307/2021.327 Abstract ( 454 )   PDF (1365KB) ( 145 )   Save BACKGROUND: Cervical spine joints are important structures involved in cervical spine movements, and are also one of the important causes of cervical spondylosis and cervical-derived disease. Quantifying the spatial distribution of the trabecular structure of the cervical articular bone is very important for the early diagnosis of skeletal diseases and potential fracture risks.   OBJECTIVE: To explore the difference of biomechanics between bone cement augmented and common proximal femoral nail antirotation in the treatment of type AO31-A3.3 intertrochanteric fracture. METHODS:  A total of 144 specimens of cervical articular process. Each joint was divided into four regions of interest: superior anterior, superior posterior, inferior anterior, and posterior inferior. A sample with a volume of 5 mm×5 mm×5 mm was scanned by Micro-CT. The microstructure of each sample was calculated, and the characteristics of the microstructure changes in the articular process regions were summarized to reveal the structure and strength predominant areas and weak areas of the articular processes, and the safety and stability of the cervical spine were evaluated.   RESULTS AND CONCLUSION: (1) There were significant differences in bone volume fraction (BV/TV), bone surface/bone volume (BS/BV), and trabecular separation (Tb.Sp) between different areas of the articular process. Partial Eta was 5.5%, 4.8% and 4.3%, respectively (Eta% is the percentage of variables influencing each other; the larger the value, the greater the influence). Among them, the BV/TV value had the largest difference between articular processes. (2) Significant differences were detected in C2-C7 vertebral sequence in BV/TV, trabecular number (Tb.N), BS/BV, trabecular thickness (Tb.Th), Tb.Sp, and trabecular bone pattern factor (Tb.Pf) values. Among them, the Eta of Tb.N was the largest, which indicated that the difference of Tb.N between different vertebral sequences was the largest. (3) There was a significant difference in Tb.Th between the left and right sides. The partial Eta was 2.0%. The left side of C2-C7 had a larger BV/TV value than the right articular process. The largest area was the superior anterior area, and the smallest area was concentrated in C7. (4) The maximum value of TB.N was mainly concentrated in the superior anterior and superior posterior areas, and the minimum value was concentrated in the posterior inferior area. C2-C5 declined; C5-C6 rose; and then C6-C7 dropped significantly. (5) The overall change trend of BS/BV was opposite to BV/TV. The maximum value was mainly concentrated in the superior posterior area, and the minimum value was mainly concentrated in the superior anterior area. (6) The left side C2 of Tb.Th was larger than the right side. The change of superior posterior > superior anterior > inferior anterior > posterior inferior was similar to that of BV/TV. The largest area was concentrated in the superior anterior area and the value of the C5 articular process peaked; and the changes on the left and right sides were similar. (7) The maximum and minimum values of Tb.Sp were mainly concentrated in the superior posterior and superior anterior regions (indicating that the bone structure was suitable for function and had obvious anisotropy). (8) The maximum and minimum values of Tb.Pf were mostly concentrated at the C7 and C5 levels. (9) The microstructure and mechanical properties of C2-C7 cervical vertebrae had different contributions to cervical vertebra motion. The larger the microstructure parameters BV/TV, Tb.N, and Tb.Th, which were positively related to bone mass, which meant the better the bone mass in this area, the better the stress load capacity; and it was less likely to be damaged because it belonged to the structural performance advantage area. Otherwise, the microstructure parameters BS/BV, Tb.Sp, and Tb.Pf, which were inversely related to bone mass, had larger values and the worse the load stress capacity, the higher the risk of damage in this area. Figures and Tables | References | Related Articles | Metrics

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Biomechanical stability of oblique lateral lumbar fusion and internal fixation Hou Kunpeng, Zhao Quanlai, Wu Tianliang, Xiao Liang, Liu Chen, Xu Hongguang 2021, 25 (33):  5362-5368.  doi: 10.12307/2021.328 Abstract ( 400 )   PDF (1068KB) ( 154 )   Save BACKGROUND: The oblique lateral approach interbody fusion is used more and more clinically. There are more and more biomechanical studies on the oblique lateral approach interbody fusion and internal fixation. OBJECTIVE: To summarize the research progress of the biomechanics of the oblique lateral approach interbody fusion and internal fixation in recent years so as to provide important reference value for the clinical application of the oblique lateral approach interbody fusion for the treatment of lumbar degenerative diseases. METHODS: In CNKI, Wanfang, PubMed, and Web of Science databases, “oblique lateral interbody fusion, oblique and anterior lumbar interbody fusion, finite element analysis, biomechanics, lumbar interbody fusion” were selected as the key words, and 45 articles were finally included for review.  RESULTS AND CONCLUSION: (1) There are few studies on the biomechanics of oblique lateral approach interbody fusion, mainly including the comparison of lumbar interbody fusion with other approaches, stability comparison of different internal fixation methods, postoperative adjacent segmental degeneration, different types of fusion apparatus and so on. (2) The biomechanical stability of the oblique lateral approach is not significantly different from that of the lateral approach, which is better than other approaches. (3) Oblique lateral approach interbody fusion combined with bilateral pedicle screw fixation has the best biomechanical stability, and it is recommended that clinicians apply this technique as the first choice for oblique lateral approach interbody fusion. (4) Comparative studies of biomechanics between oblique lateral approach interbody fusion and anterior approach interbody fusion are insufficient, and there are few clinical outcomes comparisons, and further research is needed. Figures and Tables | References | Related Articles | Metrics

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Biomechanical properties of fixation methods for clavicle fractures Sun Yitong, Nie Weizhi 2021, 25 (33):  5369-5373.  doi: 10.12307/2021.329 Abstract ( 527 )   PDF (1009KB) ( 166 )   Save BACKGROUND: Clavicle fractures are a relatively common type of fractures, which are usually caused by falls. Scholars in and outside China have conducted numerous studies addressing the types, treatments and biomechanical characteristics of clavicle fractures. With the continuous development of science and technology and the maturity of therapeutic measures, there are more and more options for the treatment and fixation of clavicle fractures. Both conservative treatment and surgical treatment have the advantages and disadvantages. OBJECTIVE: To summarize the current research progress regarding clavicle fracture fixation methods and biomechanical properties in and outside China, so as to guide the selection of appropriate methods for clavicle fractures in the clinic. METHODS: A computer search of relevant articles published from 2010 to 2020 in Wanfang, CNKI, PubMed, Embase, and Web of Science was conducted. Chinese search terms were “clavicle fracture, fixation method, biomechanics, conservative treatment”. English search terms were “clavicle, fixation, biomechanics”. According to the inclusion criteria, 38 relevant articles were finally included for summary.  RESULTS AND CONCLUSION:  For clavicle fractures, both conservative and surgical treatments have their limitations. Taken together, clinically, the best therapeutic method should be selected according to the patient’s age, fracture nature, fracture degree, fracture location, and evaluation of postoperative exercise. It is not only necessary to restore the normal biomechanical and anatomical relationship of the clavicle, but also to maintain the beauty and stability of the fixation as much as possible. Figures and Tables | Related Articles | Metrics

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Application of total femoral arthroplasty in limb salvage reconstruction Qu Zhaopeng, Rong Jiesheng 2021, 25 (33):  5374-5380.  doi: 10.12307/2021.330 Abstract ( 404 )   PDF (1128KB) ( 135 )   Save BACKGROUND: Attribute to the increasing development of tissue engineering, patients who were forced to abandon their limbs due to disease in the past are now more likely to choose limb salvage reconstruction to save limb function. Among them, the clinical application of total femoral arthroplasty is the specific embodiment of tissue engineering in limb salvage reconstruction technology. OBJECTIVE: To summarize and analyze the application methods of total femoral arthroplasty in limb salvage reconstruction in recent years. METHODS: The authoritative databases such as PubMed and CNKI were searched for the literature related to total femoral arthroplasty. After reading the full text, surgical indications, surgical treatment strategies, and common postoperative complications were systematically reviewed.  RESULTS AND CONCLUSION: (1) Artificial total femoral arthroplasty is a reconstruction technique suitable for poor bone status or severe bone defect, with beautiful appearance and preservation of lower limb function. It is a reconstruction surgery superior to traditional limb salvage surgery. (2) There is no consensus on surgical indications, but most scholars believe that neoplastic diseases, recurrent pathological fractures and difficult revision surgery are the main surgical indications. (3) Hip instability and infection are common complications of total femoral arthroplasty, and poor soft tissue conditions are one of the main causes of the above complications. (4) Reconstruction of double/triple head combined with abductor muscle group can effectively prevent hip instability; prolonging the use time of antibiotics is currently the main means to prevent and treat postoperative infection after total femoral arthroplasty, but the effect is poor. (5) Total femoral arthroplasty is a limb salvage reconstruction technique that has gradually emerged in recent years. Unlike lesioning surgery and traditional reconstruction surgery, it has the advantages of beautiful appearance and preservation of lower limb function. (6) At present, the sample size of total femoral arthroplasty is small; the follow-up time is short; and the relevant case reports are relatively isolated. There is no relevant large-sample randomized controlled trial and meta-analysis, which causes some difficulty in formulating the corresponding consensus and guidelines. (7) Hip instability and infection are the main causes of surgical failure. The poor soft tissue conditions of these patients are often associated with multiple bacterial colonization. The combined use of daptomycin in the treatment of methicillin-resistant Staphylococcus aureus colonization has a good effect. Figures and Tables | References | Related Articles | Metrics

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Participation and regulation of long-chain non-coding RNA on pathogenesis of avascular necrosis of the femoral head Wang Chuan, Peng Wuxun 2021, 25 (33):  5381-5387.  doi: 10.12307/2021.331 Abstract ( 445 )   PDF (1175KB) ( 286 )   Save BACKGROUND: The incidence of avascular necrosis of the femoral head is high, and it usually occurs in young and middle-aged people. Most of the patients with osteonecrosis have progressed to the middle and late stage when they come to see a doctor, and joint replacement may be the most effective treatment. However, the prosthesis has a certain service life, and if young patients undergo joint replacement, they may need to undergo one or more revision at a later stage. Early diagnosis, using simple methods to block the progression of osteonecrosis and avoiding the collapse of the femoral head are the goals of diagnosis and treatment of avascular necrosis of the femoral head. Therefore, it is of great practical significance to explore its pathogenesis and find new effective non-operative treatment. OBJECTIVE: To explore the effect and pathogenesis of long-chain non-coding RNA on avascular necrosis of the femoral head, and to provide new ideas and methods for the treatment of avascular necrosis of the femoral head. METHODS: The computer was used to search the relevant articles in PubMed database from 2011 to 2021. Abstract retrieval was used to search. Finally, articles were systematically summarized and analyzed. The role of long-chain non-coding RNA in regulating avascular necrosis of the femoral head and the new progress in the pathogenesis of avascular necrosis of the femoral head were systematically summarized and expounded.  RESULTS AND CONCLUSION: A total of 47 articles were finally included. (1) There are many theories about the pathogenesis of avascular necrosis of the femoral head, all of which are more or less related to long-chain non-coding RNA. At present, the mainstream concept is related to bone marrow mesenchymal stem cells, brain microvascular endothelial cells apoptosis, abnormal differentiation, fat metabolism disorder, insufficient blood supply and gene polymorphism. (2) Regarding the role of long-chain non-coding RNA in the pathogenesis of avascular necrosis of the femoral head, there are still many problems to be solved. For example, the pathogenesis of avascular necrosis of the femoral head associated with long-chain non-coding RNA is still not very clear, the mechanism of long-chain non-coding RNA in bone microvascular endothelial cells of avascular necrosis of the femoral head on apoptosis and how the gene polymorphism in avascular necrosis of the femoral head regulates long-chain non-coding RNA. (3) Therefore, the study on the role of long-chain non-coding RNA in the pathogenesis of avascular necrosis of the femoral head is helpful to provide new ideas and methods for the clinical treatment of avascular necrosis of the femoral head. Figures and Tables | References | Related Articles | Metrics

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Clinical application and progress of computer assisted navigation system in total knee arthroplasty Zhang Tao, Liang Chunyu, Zhang Dingding, Bai Xiaosong, Shen Xiaoyang 2021, 25 (33):  5388-5394.  doi: 10.12307/2021.332 Abstract ( 584 )   PDF (1094KB) ( 270 )   Save BACKGROUND: With the introduction and development of computer assisted navigation system technology, its application in total knee arthroplasty is more common than before but not widely popular, and clinicians have different opinions on the application of computer assisted navigation system in total knee arthroplasty. OBJECTIVE: To review the research progress of total knee arthroplasty with computer assisted navigation system at home and abroad, and to make prospects for the current and future development of computer assisted navigation system. METHODS: Literature related to computer assisted navigation system and total knee arthroplasty published from 2015 to 2020 was searched through CNKI and PubMed. The classification, advantages and disadvantages, clinical efficacy, adaptive population, latest development and progress in other total knee arthroplasty were reviewed by summarizing and analyzing the literature.  RESULTS AND CONCLUSION: (1) As computer assisted navigation system can accurately reconstruct lower limb power line. Good soft tissue balance accurately placed the prosthesis at the same time, also reduced the incidence of thrombosis and bleeding. (2) However, physicians with rich experience in total knee arthroplasty but inexperience in navigation could increase the operation time and expenses during navigation assisted total knee arthroplasty, even cause complications such as fractures and infections. (3) The inexperienced physicians performing total knee arthroplasty could achieve good clinical effect and learn the traditional operation method. (4) Applying computer assisted navigation system in appropriate patients has unexpected effects, which can also help researchers to obtain relevant data and effect analysis intuitively. (5) To sum up, computer assisted navigation system has a broader application prospect in the future. Figures and Tables | References | Related Articles | Metrics

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Medial pivot versus posterior stabilized prostheses for total knee arthroplasty: a meta-analysis Gu Mingxi, Zhu Yunong, Tian Fengde, An Ning, Wang Changcheng, Guo Lin 2021, 25 (33):  5395-5403.  doi: 10.12307/2021.333 Abstract ( 609 )   PDF (2380KB) ( 169 )   Save OBJECTIVE: Medial pivot and posterior stabilized prostheses are still controversial in terms of clinical outcomes after total knee arthroplasty. The aim of this study was to compare the differences in the main clinical outcome measures after surgery between the two groups of prostheses using meta-analysis.  METHODS: PubMed, Medline, Cochrane Library, and China National Knowledge Infrastructure were searched for studies comparing the efficacy of medial pivot prosthesis and posterior stabilized prosthesis for total knee arthroplasty. The search period was from the date of database establishment to September 2020. Two researchers independently searched the literature and extracted the data. The quality of randomized controlled trials was evaluated using the Cochrane Collaboration's tool for assessing the risk of bias of randomized controlled trials. The quality of non-randomized controlled clinical trials was assessed using the NOS scale. RevMan 5.3 software was used for statistical analysis. RESULTS: Finally, 18 controlled clinical trials were included, totally 3 025 knees for total knee arthroplasty. Meta-analysis results showed that compared with the selection of posterior stable prosthesis in total knee arthroplasty, the use of medial pivot prosthesis improved the Knee Society Score (MD=0.81, 95%CI:0.36−1.86, P=0.02). Radiographic results showed that the femoral crown inclination angle α of the medial pivot prosthesis was more in line with the optimal anatomical angle between the two groups of prostheses (MD=−0.80, 95%CI: −1.49 to −0.11, P=0.02). Medial pivot prosthesis had a lower incidence of overall postoperative complications (MD=−0.56, 95%CI: 0.34−0.97, P=0.03), while there were no significant differences in the postoperative range of motion, Knee Society Functional score, Oxford Knee scores, Hospital for Special Surgery knee Score, Western Ontario and McMaster Universities Osteoarthritis Index, Forgotten Joint Score, and revision rate.   CONCLUSION: Compared with the selection of posterior stable prosthesis, the improvement of KSS score after total knee arthroplasty using medial pivot prosthesis has lower incidence rate of overall complications, better vectorial stability and more physiological function anatomy. This meta-analysis is based on limited data, still has some limitations, and more and higher quality studies are needed to verify the results. Figures and Tables | References | Related Articles | Metrics

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Network meta-analysis of different drugs for the treatment of ankylosing spondylitis Jia Hongsheng, Li Xianlin, Cai Lei, Zhang Chongfeng, Chen Zuchuang, Zhang Ye 2021, 25 (33):  5404-5412.  doi: 10.12307/2021.334 Abstract ( 708 )   PDF (2318KB) ( 157 )   Save OBJECTIVE: Clinical studies have found that sulfasalazine, etanercept, Yisaipu (recombinant human tumor necrosis factor receptor type II antibody fusion protein for injection), thalidomide and other drugs can significantly improve the symptoms and quality of life of patients with ankylosing spondylitis, but there is no evaluation system. This article systematically evaluated the difference of clinical efficacy and safety of different drugs in the treatment of ankylosing spondylitis.  METHODS: Computer was used to search CNKI, Wanfang Database, VIP, SinoMed China Biomedical Literature Service System, PubMed, Cochrane Library and Web of Science. The articles of randomized controlled trials of different drugs for ankylosing spondylitis from inception to September 30, 2020 were collected. EndNote software was used to screen the literature. Cochrane system evaluation and RevMan 5.3 were used to evaluate the quality of the included literature. Network meta-analysis was performed with Stata 14.2. RESULTS:  A total of 29 randomized controlled trials were included in this study, including 21 high-risk articles and 8 low-risk articles. The control group was treated with sulfasalazine, Yisaipu and thalidomide, while the observation group was treated with Yisaipu, etanercept, thalidomide, sulfasalazine combined with Yisaipu, thalidomide combined with Yisaipu, thalidomide combined with sulfasalazine and etanercept combined with sulfasalazine. The network meta-analysis results showed that the total clinical effective rates were as follows: treatment with Yisaipu combined with thalidomide (OR=0.07, 95%CI:0.03-0.17, P < 0.05),  treatment with Yisaipu (OR=0.23, 95%CI:0.13-0.40, P < 0.05) and treatment with Yisaipu combined with sulfasalazine (OR=0.18, 95%CI:0.10-0.33, P < 0.05) were better than sulfasalazine treatment. The overall effective rate was ranked as: Yisaipu + thalidomide treatment (97.0%) > sulfasalazine + Yisaipu treatment (67.7%) > thalidomide + sulfasalazine treatment (60.0%) > Yisaipu treatment (52.2%) > etanercept + sulfasalazine treatment (47.9%) > etanercept treatment (45.4%) > thalidomide treatment (29.7%) > sulfasalazine treatment (0.2%). (2) The incidence of adverse reactions induced by Yisaipu (OR=0.21, 95%CI:0.05-0.81, P < 0.05) and thalidomide (OR=0.32, 95%CI:0.17-0.61, P < 0.05) was lower than that induced by sulfasalazine. The incidence of adverse reactions from high to low was: etanercept (91.8%) > sulfasalazine (84.8%) > etanercept combined with sulfasalazine (58.8%) > sulfasalazine + Yisaipu (44.5%) > Yisaipu + thalidomide (32.3%) > thalidomide (24.9%) > Yisaipu (12.9%).   CONCLUSION: Based on the results of 29 randomized controlled trials of different drugs in the treatment of ankylosing spondylitis, in terms of improving clinical efficacy and reducing adverse reactions, Yisaipu combined with thalidomide can be used as the first choice of drug treatment, while Yisaipu alone can be used as the secondary choice of drug treatment. Figures and Tables | References | Related Articles | Metrics