Comparison of posterolateral approach and combined approach in treatment of Mason type 2B posterior malleolar fracture / 中国修复重建外科杂志

OBJECTIVE@#To compare the effectiveness between the posterolateral approach and the posterolateral combined posteromedial approaches in the treatment of Mason type 2B posterior malleolar fracture.@*METHODS@#A retrospective analysis was performed on the clinical data of 79 patients with posterior ankle fracture who met the selection criteria between January 2015 and January 2022. There were 62 cases of Mason 2B Pilon subtype and 17 cases of avulsion subtype. Among Mason 2B Pilon subtype patients, 35 were treated with posterolateral approach (group A), 27 patients were treated with combined approach (group B). There was no significant difference in gender, age, injured side, cause of injury, time from injury to operation, preoperative hospital stay, preoperative visualanalogue scale (VAS) score, and intraoperative internal fixation between the two groups ( P>0.05). All patients with Mason 2B avulsion subtype were treated by posterolateral approach, including 7 males and 10 females, aged from 25 to 68 years, with an average of 46.1 years. The operation time, intraoperative blood loss, postoperative hospital stay, and complications were recorded. The reduction quality was evaluated by Ovadia deals radiographic score, and the ankle function and pain were evaluated by VAS score, American Orthopaedic Foot and Ankle Society (AOFAS) score, and ankle range of motion.@*RESULTS@#Mason 2B Pilon subtype: There was no significant difference in operation time, intraoperative blood loss, postoperative hospital stay, and follow-up time between the two groups ( P>0.05). The radiological evaluation of Ovadia deals in group A was significantly worse than that in group B ( P<0.05). The VAS score in the two groups significantly improved at each time point after operation, and the VAS score and AOFAS score further improved with the extension of time after operation, and the differences were significant ( P<0.05). Except that the AOFAS score of group A was significantly lower than that of group B at last follow-up ( P<0.05), there was no significant difference in VAS score and AOFAS score between the two groups at other time points ( P>0.05). At last follow-up, the ankle range of motion in group A was significantly less than that in group B ( P<0.05). There was no significant difference in the incidence of sural nerve injury, deep tissue infection, limitation of toe movement, and traumatic ankle arthritis between the two groups ( P>0.05). Mason 2B avulsion subtype: The operation time was (119.47±20.61) minutes and the intraoperative blood loss was 50 (35, 55) mL. Seventeen patients were followed up 13-25 months, with an average of 18 months. The Ovadia deals score was excellent in 10 cases, good in 6 cases, and poor in 1 case at 1 week after operation, and the excellent and good rate was 94.1%. All fractures healed in 8-18 weeks with an average of 12.35 weeks. There were 1 case of sural nerve injury and 3 cases of traumatic ankle arthritis after operation. No deep tissue infection or limitation of toe movement occurred. The VAS score decreased significantly and AOFAS score increased significantly with time, and the differences were significant between different time points before and after operation ( P<0.05). The ankle range of motion at last follow-up was (56.71±2.47)°.@*CONCLUSION@#Compared with the posterolateral approach, the combined approach is a better choice for the treatment of Mason 2B Pilon subtype. If the posteromedial bone block does not affect the reduction of the medial malleolus, the posterolateral approach can achieve good effectiveness for Mason 2B avulsion subtype.

Management of tibia deformity with fixator assisted nailing technique / 中华骨科杂志

Objective@#To discuss the result of treating tibia deformity with fixator assisted nailing technique (FAN).@*Methods@#A total of 5 patients with 7 limbs of tibial deformity-were treated with FAN technique. Etiology: 2 patients with bilateral tibial deformity suffered from Ricket's disease, 2 patients were malunion after tibial fracture, 1 patient was congenital pseudoarthrosis of tibia. This is a retrospective study. The unilateral external fixator was mounted on the medial side of tibia, and thenthe minimal invasive osteotomy was performed. After the deformity was corrected, the intramedullary nail was inserted to fix the tibia. None of the patients need bone autograft. The pre-operation and post-operation medial proximal tibia angle (MPTA), mechanical axis deviation (MAD) and range of motion (ROM) were measured and analyzed.@*Results@#All the 5 patients were followed-up for 12-60 months (average 32 months). The osteotomy site united in 3-5 months (average 4.5 months) post-operatively. According to Paley’s imaging scores, 4 patients were excellent and 1 patient was good. According to Paley's functional result scores, 5 patients were excellent; according to Paley’s bone results evaluation, 4 patients were excellent and 1 patient was good. We achieved desired post-operative MAD (from medial 15 mm-lateral 10 mm) in 6 limbs. The MPTA in 7 limbs was corrected to normal (84°-90°). The ROM was not significantly changed before and after operation. The average ROM of knee before operation was 125°(120°-135°), and average postoperative ROM was 120°(115°-130°), No deep infection or neurovascular injury occurred. All patients were satisfied with the method and results of the operation.@*Conclusion@#FAN technique combines the advantage of external fixation and intramedullary nail, and it is a good method to treat tibial deformity, the patient should be carefully evaluated and selected for applying this technique.

Management of tibia deformity with fixator assisted nailing technique / 中华骨科杂志

To discuss the result of treating tibia deformity with fixator assisted nailing technique (FAN). Methods A total of 5 patients with 7 limbs of tibial deformity?were treated with FAN technique. Etiology: 2 patients with bilater?al tibial deformity suffered from Ricket's disease, 2 patients were malunion after tibial fracture, 1 patient was congenital pseudoar?throsis of tibia. This is a retrospective study. The unilateral external fixator was mounted on the medial side of tibia, and thenthe minimal invasive osteotomy was performed. After the deformity was corrected, the intramedullary nail was inserted to fix the tibia. None of the patients need bone autograft. The pre?operation and post?operation medial proximal tibia angle (MPTA), mechanical axis deviation (MAD) and range of motion (ROM) were measured and analyzed. Results All the 5 patients were followed?up for 12-60 months (average 32 months). The osteotomy site united in 3-5 months (average 4.5 months) post?operatively. According to Paley’s imaging scores, 4 patients were excellent and 1 patient was good. According to Paley's functional result scores, 5 patients were excellent; according to Paley’s bone results evaluation , 4 patients were excellent and 1 patient was good. We achieved de?sired post?operative MAD (from medial 15 mm-lateral 10 mm) in 6 limbs. The MPTA in 7 limbs was corrected to normal (84°-90°). The ROM was not significantly changed before and after operation. The average ROM of knee before operation was 125° (120°-135°),and average postoperative ROM was 120°(115°-130°),No deep infection or neurovascular injury occurred. All pa?tients were satisfied with the method and results of the operation. Conclusion FAN technique combines the advantage of exter?nal fixation and intramedullary nail, and it is a good method to treat tibial deformity, the patient should be carefully evaluated and selected for applying this technique.

Biomechanical effects of intervertebral disc degeneration on the cervical spine:a finite element analysis / 中国组织工程研究

BACKGROUND: The biomechanics of cervical spine is complicated. It is an important way to select the appropriate biomechanical model and research method so as to explore the diagnosis and evaluation mechanism of cervical spine injury and prognosis judgement.OBJECTIVE: To discuss the alternation of cervical biomechanics after the degeneration of cervical disc and the influence of degeneration on cervical stability.METHODS: (1) A three-dimensional finite element model of cervical spine was established from the CT scan images of cervical spine of a healthy male volunteer, Solid-Works2015, HyperMesh and ANSYS11.0. We created a cervical three-dimensional finite element model. To simulate the degenerative disc by modified the mechanical characters and height of the disc model, we observed the biomechanics of the impact on the cervical spine (the range and the stress on intervertabral disc).RESULTS AND CONCLUSION: (1) The entire model with a total of 97705 nodes and 372896 elements. Ligament and joint capsule were also constructed. Face to face contact element was used in the facet joint, with complete structure and high accuracy of measurement of spatial structure. (2) The range of motion of cervical spine increased during degeneration compared with normal cervical segments (P < 0.05). (3) Intervertebral disc degeneration caused angle increase at disc and motion segment. Osteophyte formed on vertebral edge. Intervertebral disc degeneration caused cervical instability. Simultaneously, instability increased the disc degeneration.

Perpendicular double-locking plating system for the internal fixation of type C distal humerus fractures through two kinds of postcubital approaches / 中国组织工程研究

BACKGROUND: Distal humerus fracture is often comminuted, and is difficult to receive reduction and fixation due to its special anatomical structure. Choosing which surgical approach is still a controversy.OBJECTIVE: To compare and analyze the curative efficacy of the perpendicular double-locking plating system for the internal fixation of type C distal humerus fractures through two kinds of postcubital approaches.METHODS: Thirty-two cases of type C distal humerus fractures were enrolled and divided into groups A (osteotomy of olecranon approach) and B (tricep anconeus flap approach). There was no significant difference in the baseline data between two groups. The operation time, intraoperative blood loss, hospital stay, healing time,postoperative follow-up and complications were recorded and analyzed. The patients were followed up at 2 weeks, 1, 3,6, 12, and 18 months. The healing time and complications were recorded according to radiographs and physical examinations. The Mayo Elbow Performance Score was used to determine the elbow function at 1 year postoperatively.RESULTS AND CONCLUSION: (1) The group A had a longer operation time and more intraoperative blood loss than those in the group B (P 0.05). (3) These results suggest that the articular surface of the distal humerus fracture is displayed well through two approaches, and the perpendicular double-locking plating system for the internal fixation of type C distal humerus fractures is rational. Noticeably, the tricep anconeus flap approach dose little damage to the muscle, while the osteotomy of olecranon approach obtains better elbow function and less complications.

Biomechanical research on different pairs of lumbar laminectomy with finite element analysis / 生物医学工程学杂志

The finite element model of the intact lumbar spine (L1-L5) was set up to study the biomechanical changes of three different pairs of the lumbar laminectomy. The three-dimensional finite elements model of L1-L5 vertebrae structure was constructed by the combination of self-compiled software and Hyper Mesh. The finite element model was compared with the experimental data in vitro. The finite element model was modified of stenosis at L3-L4 and L4-L5 with the same boundary conditions and physical loads to study the motion and loading in the annulus changes at the surgical site as a result of surgical alteration. The study suggested that the removal of posterior lumbar spinal elements for the treatment of stenosis at L3-L4 and L4-L5 produced a graded increase in motion at the surgical site, with the greatest changes occurring in flexion-extension and axial rotation and that during lateral bending the amount of resection was only slightly affected. The data showed that for flexion-extension and axial rotation the increases in motion were correlated to the extent of posterior element removal. It is necessary to retain the greatest degree of posterior lumbar structures in thorough decompression, which can further reduce the postoperative intervertebral disc, facet degeneration.

Acqusition of full-length gene for rabbit osteoprotegerin / 生物医学工程学杂志

This paper is to show a way of acqusition of the variable region gene of rabbit osteoprotegerin (OPG) and to analyse series. Total RNA was extracted from rabbit tibia, transcripted reversely into cDNA with random primers. The variable region of the OPG gene ampliflied using 5'RACE. Sequencing was confirmed by agarose gel electrophoresis and sequencing analysis. Full length of OPG gene was 1540bp that encoding 400 amino acids. It shared 89% identity with human OPG in whole amino acid sequence and about 85% with rattus norvegicus and other mammal. The OPG sequence of rabbit was obtained by 5'RACE, which could provide a good basis for OPG functional study.

Quantitative study of bone growth and remodeling adaptation model in rapid-growing rats / 中国组织工程研究

BACKGROUND: At present, bone remodeling biological model study usually applys finite element method combing with computer technique to simulate and predict bone quantity or bone structure. In this study the author integrate inversion method with animal experiment to establish a quantification bone remodeling biological model of in vivo bone tissue in real stress environment.OBJECTIVE: To set up a quantification biological model of bone growth and remodeling adaptation, which integrates animal experiments, parameter inversion identification of mathematical functions, and technique of computer simulation. DESIGN, TIME AND SETTING: The experiment was accomplished in Animal Experiment Center of Dalian Medical University in October 2002.MATERIALS: 60 female Sprague Dawley mice of 6-week old were used in this study. Challenger double-energy X ray bone density device was provided from DMS Company, France. Sensation l6 CT machine was provided from Germany Siemens Company.METHODS: 60 mice were randomly divided into two groups: i 5 animals were in normal control groups. 45 in experiment groups. By designing a new animal experiment, we investigate the effects of stress environments on bone growth and remodeling of rapid growing rats and gather the bone mineral density (BMD) of proximal femur in the same interval for the unknown parameters (B and K) inversion of bone growth and remodeling equation to create the femur three-dimension geometrical model based on CT images. MAIN OUTCOMING MEASURES: Body weight of animal, bone density and CT imagine of proximal femur. RESULTS: Body mass in the experiment group and control group was increased with the rat growing; BMD in the control group and overloading group was also increased with the rat growing; but BMD in the unloading group was decreased in the fifth week. Inversion and experimental data showed that parameter B was rapidly decreased as compared to time, and it was closed to zero in the 10th week. Parameter K was rapidly increased as compared to time. and it was gradually increased from the 5th to the 10th weeks, moreover, it was closed to the horizontal line after 10 weeks. This predicted that rapid growth was over, and bone reconstitution and absorption came into another balance cycle. CONCLUSION: The thought and method used in the model creating in.this paper provide clue and reference to establish human model of bone growth and remodeling.

Quantification study of bone adaptive model based on experiment of rapid-growing rats in different stress environment / 生物医学工程学杂志

Presented is a method to set up a quantification model of bone growing and remodeling adaptation, which integrates animal experiments, parameter identification of mathematical functions and technique of computer simulation. By designing a new animal experiment, we investigate the effects of growing and remodeling of the rat femurs in different stress environments, gather the bone mineral density (BMD) of proximal femur in the same interval for the unknown parameter (B and K) inversion of bone growing and remodeling equation and create the femur three-dimensional geometrical model based on CT images. The model in this paper can not only numerically measure the relation between outer stimulus and the femur BMD variation of rapid growing rats, but also predict the growth trend of rat femur under different stress environments in its whole lifecycle. The thought and method of creating the model in this paper can be used for reference to modeling human bone growth and remodeling.

A theoretical model study of open section effect on the mechanical properties of long bone / 生物医学工程学杂志

The mechanical model of femur mid-diaphysis with a rectangular open section in the exterior cortex was developed and a finite element method was adopted in calculating and analysing the changes of torsional stiffness and the stress distribution when the dimension of the open section altered. It showed that the open section with a length of 1 OD (femur mid-diaphysis diameter) had little influence on the femur torsional stiffness or stress distribution. The torsional stiffness decreased most dramatically as the length increased from 2 to 4 OD. Shear stress peaked at the center of the open section. This conclusion provides an important theoretical ground for the operative methods and the dimension control of an open section in clinical orthopaedics.

Effect of low stress environment on bone density and geome-morphology of rat femur / 生物医学工程学杂志

6-week old rats were subjected to sciatic nerve resection and the right hindlimbs were then under a low stress environment. Bone mineral density (BMD) of different regions and geome-morphological parameters of femurs were measured. The results showed that the increase in the diameter, subperiosteal area and bone mineral density of femurs were suppressed obviously under low stress environment. But the sensitivity of BMD of different regions of the femur to the low stress environment was different. The suppression of the increase in femoral BMD was composed of an early impairment in the gain of BMD at the femoral metaphysis, which is rich in trabecular bone, and a sustained reduction in the gain of BMD at the femoral diaphysis, which is rich in cortical bone. The results of geome-morphology suggested that the early reduction in the increase of BMD at the metaphysis was due to an enhancement of bone resorption, whereas the suppression of gain in cortical bone mass and size is the result of a sustained reduction of periosteal bone formation.

Biomechanical test study of rat femurs growing under different stress environment / 生物医学工程学杂志

By creating two kinds of stress environment in the same animal model, we performed a three-point bending test and a compressing test on the rat femurs growing under different stress conditions to characterize the effect of stress on bone mechanical properties. The right hindlimbs were subjected to sciatic nerve resection to become cripple and were used as unloading group; the left hindlimbs bore excess load and made up the overloading group; the normal rats were used as control group. The animals were encouraged to exercise for half an hour everyday in the morning, noon and evening. The experiment observation finished in four weeks. The biomechanical parameters of femur diaphyses were measured. The experiment results showed that stress environment may change several mechanical parameters of rat femurs. This study indicated that bone tissues can adapt to its stress environment by changing its mechanical properties. The experimental model in this article is practical and reliable.