Kinematics of the Ortho-SUV Frame Using as a Novel External Fixator for Orthopedic Surgery

The Ortho-SUV frame,a novel external fixator,can effectively treat limb deformities and fractures.Its kinematics is used when it is necessary to achieve bone movements with high precision.In this work,the kinematics model of the Ortho-SUV frame is established by six pose parameters,and its forward and inverse solutions are given.There is no need to solve nonlinear high-coupling equations with trigonometric functions in this solution method due to its special structure.By numerical examples and simulated orthopedic experiment of tibial fracture,the correctness and accuracy of the kinematics model and its solutions are verified.Besides,on the basis of kinematics analysis,the position workspace and orientation workspace of the Ortho-SUV frame are simulated in Matlab,which can help surgeons choose suitable device dimensions.The kinematics analysis provides a theoretical basis for the Ortho-SUV frame to be used in orthopedic treatment.

Management of Tibial Metaphyseal Fractures by Hybrid External Fixator

Introduction: The Hybrid External Fixator combines the advantages of the monolateral pin fixators and the circular Ilizarov wire fixators. Principle of early motion has been touted as the functional savior of major intra articular injuries in application of hybrid external fixation. Materials & Methodology: 48 patients were considered for the study with tibial fractures admitted in Mamata General Hospital from May 2011 to May 2013. Results: The union and functional outcome of hybrid external fixator in simple and complex proximal and distal metaphyseal fractures of tibia in adults was evaluated at our centre. The fractures of the proximal tibia united with an average of 13.3 weeks (12 - 16 weeks). The fractures of the distal tibia united with an average of 14.42 weeks (13 - 22 weeks) with minimal complications. Conclusion: Our study shows high satisfaction rate after fixation, provides adequate stability and allows early motion of the joint. It is also effective in extra articular fractures occurring within 5 cm of the joint as the IM nails often do not provide enough stability and plating requires extensive soft tissue dissection.

Cartilage Repair by Joint Distraction and Motion Using an External Fixator for Massive Cartilage Defect

The objective of the present study was to investigate our novel methods for the repair of massive cartilage defects by joint distraction and motion using an external fixator. In this study, we used a rabbit model of massive articular cartilage defect in order to evaluate the effectiveness of using joint distraction and motion with a ring-type external fixator. This external fixator has a hinged joint with a center of rotation along the femoral transepicondylar axis, which allows the knee joint to freely flex and extend. Mesenchymal cells from bone marrow, induced by spongialization, were differentiated into mature chondrocytes and formed hyaline-like cartilage as a result of joint distraction and movement. The transplantation of autologous cells expanded from bone-marrow-derived mesenchymal cells, concentrated autologous bone marrow aspirate, and concentrated autologous peripheral blood cells were all effective in promoting cartilage repair. The quality of the cartilage after long-term joint distraction for 6 months was inferior to that after 12 weeks. In general, weight bearing on the regenerated cartilage promoted cartilage repair, although this effect differed based on when gradual weight bearing was begun. Specifically, gradual weight bearing beginning at 9 weeks produced superior results to that beginning at 6 weeks. Our methods provide an optimal environment for cartilage regeneration.

Memory alloy embracing fixator in treatment of multiple fractured ribs and flail chest

BACKGROUND： With the development of internal fixation materials, simple operation with internal fixation has become a tendency. Ni-Ti shape memory alloy embracing fixator has such advantages as slight injury, easy operation, security, reliable fixation, and better histocompatibility. The present study was to explore curative effect and postoperative results of Ti-Ni shape memory alloy embracing ？ xator in patients with multiple fractured ribs and ？ ail chest.METHODS： The curative effect and long-term follow-up results were observed after internal ？ xation with a shape memory alloy embracing ？ xator in patients with multiple fractured ribs and ？ ail chest from January 2006 to December 2009.RESULTS： All patients were cured with an average hospital stay of 10.31±3.14 days. Post-operative pain was less severe than preoperative pain （P=0.02）.The rate of postoperative complications such as atelectasis, pulmonary infection, etc was 17.65%. There were fewer long-term complications and less in？ uence on daily work and life.CONCLUSIONS： It is practical to perform an operation for fracture of multiple ribs using a Ti-Ni shape memory alloy embracing ？ xator. The ？ xator, which is less traumatic, simple, safe, and reliable, has a good-histocompatibility and fewer postoperative complications.

Internal fixator vs external fixator in the management of unstable pelvic ring injuries:A prospective comparative cohort study

BACKGROUND Reconstruction of the pelvic ring anatomy in unstable anterior pelvic ring injuries is a significant step to reduce the mortality rate associated with these injuries efficiently.There is a debate on using either an anterior subcutaneous pelvis internal fixator(INFIX)or an anterior supra-acetabular external fixator(EXFIX)to manage an unstable anterior pelvic ring fracture.AIM To compare the functional and radiological outcomes and complications of INFIX vs EXFIX in managing unstable pelvic ring injuries.METHODS A prospective cohort study included 54 patients with unstable pelvic ring fractures.The patients were divided into two groups;the INFIX group,in which 30 cases were fixed by INFIX,and the EXFIX group,in which 24 patients were treated by EXFIX.The average age in the EXFIX group was 31.17 years(16-57 years),while in the INFIX group,it was 34.5 years(17-53 years).The study included 20(66.7%)males and 10(33.3%)females in the INFIX group and 10(41.7%)males and 14(58.3%)females in the EXFIX group.The radiological outcomes were evaluated using Matta and Tornetta's score,and the functional outcomes using the Majeed score.RESULTS The results revealed a statistically significant difference between both groups(P=0.013)regarding radiological outcomes,according to Matta and Tornetta's score in favor of the INFIX group.Sitting,standing,and walking abilities were measured at a 3-mo follow-up visit using Majeed score modules.It was significantly better among the INFIX group than the EXFIX group in all three modules.At the final follow-up,both groups had no statistically significant difference according to the Majeed score;92.35 in the INFIX group and 90.99 in the EXFIX group(P=0.513).A lower surgical site infection rate was noticed in the INFIX group(P=0.007).CONCLUSION Anterior subcutaneous pelvis INFIX is associated with better radiological outcomes and a lower infection rate than anterior supra-acetabular EXFIX in managing patients with unstable anterior pelvic ring fractures.

Proximal tibial osteotomy for genu varum:Radiological evaluation of deformity correction with a plate vs external fixator

BACKGROUND High tibial osteotomy(HTO)is a well-known procedure for the correction of knee varus.The purpose of this study was to compare the radiological results and accuracy of deformity correction performed using two different techniques:acute opening wedge correction using a plate and gradual correction with a monolateral external fixator.AIM To compare of the radiological results of two different techniques:acute opening wedge correction(a plate and screw)and gradual correction(external fixator).METHODS A total of 43 patients with plates and 36 patients with external fixators were included.All patients had moderate uniplanar varus deformities.We measured radiographic parameters,including the mechanical axis deviation(MAD),medial proximal tibial angle(MPTA),Caton-Deschamps Index(CDI),posterior proximal tibial angle,and joint line obliquity angle(JLOA).The accuracy of MAD correction was calculated based on a correction goal of neutral or overcorrection for medial compartment arthritis.RESULTS Demographics including age,body mass index,sex,and preoperative deformities were similar between the groups.The MAD significantly improved from 23.6 mm medial to the midline(SD=8.2 mm)to 6.9 mm lateral to the midline(SD=5.4 mm)(P<0.001).The accuracy of MAD correction did not differ between the groups and was 96.1%(SD=8.1%)in the plate group and 98.2%(SD=5.2%)in the external fixator group(P=0.18).The MPTA significantly improved from 83.9°(SD=2.9°)to 90.9°(SD=3.3°)(P<0.001),and the change was similar between the groups.Differences were noted in patella height,with a CDI change of-19.2%(SD=13.7%)and 3.1%(SD=8.0%)for the plate and external fixator groups,respectively(P<0.001).The change in JLOA was 1.6 degrees(SD=1.1 degrees)and 0.9 degrees(SD=0.9 degrees)for the plate and external fixator groups,respectively(P=0.04).CONCLUSION Reliable correction of moderate varus alignment was achieved with both the acute opening wedge technique with a plate and the gradual monolateral external fixator technique.The patellar height decreased with the open wedge plate technique.Joint line obliquity decreased to a greater degree with the open wedge plate technique,perhaps as a result of medial collateral ligament release.The appropriate technique should be selected based on surgeon and patient preferences;however,external fixation may be a better choice when the preservation of patellar height is deemed important.

Biomechanical Study on Osteotomized Tibias Fixed with Unilateral Adjustable External Fixator

Five fresh tibias removed from 30-40 years old dead males were osteotomized at one-third supra-medium segment and then fixed by an unilateral adjustable external fixator (UAEF) to be used as a model of external fixation of tibial fracture. For each loading test under different configurations of UAEF, the ratio of the force-displacement was used to determine its stiffness value. The weakest mode of the UAEF device is in AP bending. Under each mode of compression,distraction , anteroposterial and lateral bending and torsion loading , increasing the pin number or pin diameter or pin separation, and/or reduction of pin group separation can significantly increase the stiffness values of UAEF (P<0.01). These data revealed that UAEF is suitable for the external fixation of tibial fracture.

HYBRID EXTERNAL FIXATOR FOR THE TREATMENT OF UNICAMERAL BONE CYSTS WITH PATHOLOGICAL FRACTURE IN THE PROXIMAL HUMERUS

Objective: Unicameral bone cyst is a nonneoplasticbone lesion characterized by its tenacity and risk ofrecurrence. Pathological fracture is common and is often the presenting symptom. The objective of the present study was to evaluate the results of hybrid external fixator for thetreatment of a unicameral bone cyst with a pathologicalfracture. Methods: Hybrid external fixator for thetreatment of a unicameral bone cyst was performed intwelve patients. These patients presented with a pathological fracture and were managed immediately with hybridexternal fixator, of whom four had been managedconservatively at other clinics before they were referred toour department. The cyst was located in the proximalhumerus in all patients. The mean age of the patients at the time of surgery was 8.7 years, and the mean duration offollow-up was 32.6 months. Radiographic evaluation wasperformed according to the criteria of Capanna et al., andthe cyst was classified as completely healed, healed withresidual radiolucency (osteolysis), recurred, or having noresponse. Results: The healing period ranged from three to eight months. Eight cysts healed completely, and threehealed with residual radiolucent areas visible onradiographs. There was recurrence of one cyst that hadhealed with residual radiolucency. All of the cysts in thepresent study responded to treatment. A modulation ofhybrid external fixator was necessary in three patients, asthe bars had become too short after bone growth or the pins had been loose. No major complications were observed.Conclusion: Hybrid external fixator provides earlystability, which allows early mobilization and thus obviates the need for a plaster cast. This method of treatment alsoallows for an early return to normal activity.

改良Masquelet技术联合Ilizarov Mini-Fixator治疗掌指骨大段骨缺损的临床疗效

目的探讨改良Masquelet技术联合Ilizarov Mini-Fixator外固定治疗掌指骨大段骨缺损的可行性、临床应用及疗效分析。方法回顾性分析2019年11月-2021年10月符合手术适应证的掌指骨大段骨缺损17例患者的病历资料,均行改良Masquelet技术联合Ilizarov Mini-Fixator外固定治疗。⑴创伤性骨缺损:一期急诊行“地毯式”清创及相应修复手术,抗生素聚甲基丙烯酸甲酯(Polymethylmethacyrlate,PMMA)填充骨缺损,皮肤软组织缺损者同时给予骨水泥覆盖;二期:行带蒂皮瓣或植皮修复皮肤缺损创面,伤口愈合6~8周后去除骨水泥行自体骨移植联合Ilizarov Mini-Fixator外固定治疗;⑵感染性骨缺损:一期彻底清创、PMMA填充骨缺损,皮肤软组织缺损或皮肤软组织条件较差者给予彻底清创修复创面;二期方案同创伤性骨缺损。术后均给予预防或控制感染、观察患指(肢)及皮瓣血运等对症处理,均早期(2周)进行功能康复训练。结果17例术后随访5~29个月,移植骨均愈合,平均愈合时间11.9周(10.5~14.0周),术后均未出现伤口感染及皮瓣坏死等并发症。16例伤口均甲级愈合,1例延期愈合,移植骨愈合优良率为82.35%。根据随访结果,骨折愈合康复结束后手部功能评估:优5例,良8例,可4例,优良率为70.47%。均实现保指(肢)的目的,部分患者获得较好的手功能。结论应用改良Masquelet技术联合Ilizarov Mini-Fixator治疗掌指骨创伤性及感染性大段骨缺损的方法疗效可靠,具有操作简单、经济实用、损伤小,且移植骨愈合率高、愈合快、并发症及风险小等优点。可早期进行功能训练,有助于恢复手的外观及功能。

Treatment of Resistant Clubfoot with Soft Tissue Release and Alkhooly External Fixator

After the first research with this technique done by the first author, ten operations on the foot and ankle were performed on five patients (two boys and three girls) suffering from severe club foot deformity all with bilateral foot affection. Their ages ranged from five to fourteen years. All of them were treated by soft tissue release, skin flap (rotational flap), supplemented with Alkhooly external fixator. The follow up period ranged from two to seven years. The results according to Mittal (1987) [1] were excellent in eight feet (80%) and good in two feet (20%).

A BIOMECHANICAL ANALYSIS OF UNILATERAL HOOKED-SULCATED EXTERNAL FIXATOR ON OSTEOMINED TIBIA

Four tibiae removed from 30-40 years males, who died of accidents in less than 12 hours, were os- teomized at medium part. Then these tibiae were fixed by an unilateral hooked-sulcated external fixator (UHSEF), and the bone-fixator system was used as a model of external fixation of tibial fracture. The axial compression, distraction, torsion, antero-posterior and lateral bending rigidly and the strain of the pins were determined in this system. Based on the results, we found that compared with the configuration of four paralled pins, the rigidity of the fan-like configuraton didn’t decrease significantly if the angle between lateral and medium pins was less than 45’. But the reverse was true when the frame separation increased from 5 to 8 cm. What’ more, the pin strain decreased if the rigidity of the system was improved. These data provided a theoretical basis of biomechanics for the improvement of UHSEF.

Microfluidic-oriented synthesis of enriched iridium nanodots/carbon architecture for robust electrocatalytic nitrogen fixation

Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-products.However,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic efficiency.Herein,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon architecture.Owing to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption capacity.As a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH solution.Moreover,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) solution.The microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.

Finite Element Analysis Study of Prototype of a Novel Intramedullary Injectable Bioresorbable Polymer Fixator versus a Volar Plate for Surgical Treatment of Distal Radius Fractures

Complications and shortcomings of volar plating, which is very widely used for surgical treatment of distal radius fractures, are well known. Thus, there is scope for alternative innovative surgical methods. In the present work, we used the finite element analysis method to compare the biomechanical performance of a model of a construct comprising a simulated distal radius fracture considered fixated using a notional intramedullary injectable bioresorbable polymer-bioresorbable balloon osteosynthesis system (“fixator”) versus using a commercially-available volar locking plate (VP). The biomechanical parameters determined were longitudinal stiffness and factor of safety under each of the applied loads.?For the fixator model, 1) each of the biomechanical parameters was markedly influenced by fracture gap fill ratio (FGFR) (defined as the proportion of the volume of the fracture gap that is considered occupied by the expanded polymer-filled balloon)?but not by modulus of elasticity assigned to the polymer;2) with FGFR = 100%, stiffness was comparable to that of the Ti-6Al-4V alloy VP construct model;and 3) stiffness was within the range of literature values for stiffness of constructs comprising simulated fractures in fresh cadaveric distal radii fixated using metal volar locking plate. These results suggest that the fixator may be an alternative modality to metal volar plating and, as such, deserves further evaluation.

Dynamic External Fixator Combined with Volar Locking Plate Fixation for the Treatment of AO Type C3 Distal Radius Fractures

Background: AO type C3 distal radius fracture (DRF) is the most difficult-to-treat fracture type because of a tendency to shorten and collapse. The purpose of this study is to investigate the clinical and radiographic outcomes of comminuted intra-articular DRFs treated with a dynamic external fixator combined with a volar locking plate (VLP). Methods: Eleven patients (mean age, 61 years) with comminuted intra-articular DRFs were treated with a dynamic type of external fixator combined with a VLP. Following reduction and fixation with a VLP, the dynamic external fixator was applied and the distal ball joint of the fixator was aligned with the lunate-capitate line. The ball joint was unlocked approximately 2 weeks after surgery to allow wrist mobilization. The fixator was removed 3 - 6 weeks (mean, 5 weeks) after surgery. Consequently, clinical and radiographic assessments were carried out at the final follow-up. Results: At the final follow-up, the mean range values of wrist extension and flexion were 76&deg;and 64&deg;, respectively. Compared with the contralateral side, the mean grip strength was 84%. The mean Modified Mayo Wrist Score and the Disabilities of the Arm, Shoulder and Hand score were 88 and 9, respectively. No significant differences in the radiographic parameters exist between after surgery and final follow-up. Conclusions: This study indicated that the dynamic wrist fixator combined with a VLP is effective for the treatment of AO type C3 DRFs.

In vitro performance of a biodegradable zinc alloy adjustable-loop cortical suspension fixation for anterior cruciate ligament reconstruction

Anterior cruciate ligament(ACL)injuries of the knee are one of the most common and serious athletic injuries.The widely used cortical suspension fixation buttons for ligament reconstruction are permanent implants,particularly those made from conventional steel or titanium alloys.In this study,a biodegradable Zn-0.45Mn-0.2Mg(ZMM42)alloy with the yield strength of 300.4 MPa and tensile strength of 329.8 MPa was prepared through hot extrusion.The use of zinc alloys in the preparation of cortical suspension fixation buttons was proposed for the first time.After 35 d of immersion in simulated body fluids,the ZMM42 alloy fixation buttons were degraded at a rate of 44μm/a,and the fixation strength was retained(379.55 N)in the traction loops.Simultaneously,the ZMM42 alloy fixation buttons exhibited an increase in MC3T3-E1 cell viability and high antibacterial activity against Escherichia coli and Staphylococcus aureus.These results reveal the potential of biodegradable zinc alloys for use as ligament reconstruction materials and for developing diverse zinc alloy cortical suspension fixation devices.

Increased dependence on nitrogen-fixation of a native legume in competition with an invasive plant

Suppression of roots and/or their symbiotic microorganisms,such as mycorrhizal fungi and rhizobia,is an effective way for alien plants to outcompete native plants.However,little is known about how invasive and native plants interact with the quantity and activity of nutrient-acquisition agents.Here a pot experiment was conducted with monoculture and mixed plantings of an invasive plant,Xanthium strumarium,and a common native legume,Glycine max.We measured traits related to root and nodule quantity and activity and mycorrhizal colonization.Compared to the monoculture,fine root quantity(biomass,surface area)and activity(root nitrogen(N)concentration,acid phosphatase activity)of G.max decreased in mixed plantings;nodule quantity(biomass)decreased by 45%,while nodule activity in Nfixing via rhizobium increased by 106%;mycorrhizal colonization was unaffected.Contribution of N fixation to leaf N content in G.max increased in the mixed plantings,and this increase was attributed to a decrease in the rhizosphere soil N of G.max in the mixed plantings.Increased root quantity and activity,along with a higher mycorrhizal association was observed in X.strumarium in the mixed compared to monoculture.Together,the invasive plant did not directly scavenge N from nodule-fixed N,but rather depleted the rhizosphere soil N of the legume,thereby stimulating the activity of N-fixation and increasing the dependence of the native legume on this N source.The quantity-activity framework holds promise for future studies on how native legumes respond to alien plant invasions.

Application of lesser trochanteric reduction fixator in the treatment of unstable intertrochanteric fractures

BACKGROUND Closed reduction and internal fixation with intramedullary nails has been widely accepted for treating intertrochanteric fractures.AIM To focus on how to avoid displacement of the lesser trochanter in unstable intertrochanteric fractures.METHODS We developed a lesser trochanteric reduction fixator for treating intertrochanteric fractures through fixing the lesser trochanter by combining the loop plate through the fixator after reduction by the reducer.Five patients with intertrochanteric fractures treated with the newly developed lesser trochanteric reduction fixator and loop plate combined with intramedullary nails,and 20 patients with intertrochanteric fractures treated with simple intramedullary nails were selected from December 2020 to March 2021.RESULTS The postoperative Harris hip score was significantly higher in patients treated with the lesser trochanteric reduction fixator than in patients treated without the lesser trochanteric reduction fixator,which indicated that this lesser trochanteric reduction fixator had a positive impact on rehabilitation of the hip joint after surgery and could significantly improve the quality of life of patients.CONCLUSION We fully realize the significance of trochanteric reduction and fixation,namely,reconstruction of structures under pressure,in the treatment of intertrochanteric fractures.As long as the general condition of patients is favorable and they are willing to undergo surgery,fixation of the main fracture end should be performed and the lesser trochanter should be reduced and fixed at the same time.

The damage control in tibial pilon open fractures with a new external fixator delta frame

Objective: To evaluate the effectiveness of the damage control, in emergency to treat the open tibial pilon fractures with Dolphix? External Fixator Frame(CITIEFFE?, Calderara di Reno, Bologna, Italy). Methods: From January 2017 to August 2017, at the Department of Orthopedics and Traumatology of Vito Fazzi Hospital Lecce, we treated 23 open tibial pilon fractures with Dolphix? External Fixator Frame(CITIEFFE?, Calderara di Reno, Bologna, Italy). The evaluation criteria of the case series were: the time needed to assemble the external fixator;the time taked to treat the ankle associated lesions;the time of skin healing;the ankle alignment;the subjective/objective Ovadia and Beals score;and complications. The Endpoint assessment was set at the days of the definitive surgery. Results: The results in terms of alignment, biomechanical stability of the frame, healing of soft tissue, complications were as good as the objective and subjective results according Ovadia and Beals score. Conclusion:Pilon fractures are complex and often present complications;the damage control treatment, in emergency, with Dolphix? External Fixator Frame(CITIEFFE?, Calderara di Reno, Bologna, Italy) permits a stable osteotaxis with minimal soft tissue damage and permit the repair of muscles, blood vessels and nerves with a stable bone and the soft tissue healing with vaccum therapy.

浅谈引进型可调垫铁——Fixator固定器

在汽轮发电机组的汽轮机及发电机安装工作中,台板支撑大多数采用的是直接斜垫铁支撑,当斜垫铁灌浆后,就只能使用垫片调整间隙及标高,给设备的标高、水平度再次调整带来许多不便。随着科学技术的发展,旧式的安装工艺已无法满足大型汽轮发电机组设备安装的需要。现本文介绍一种国外引进的新型的可调垫铁装置——Fixator固定器,阐述其安装方法及注意事项,为今后设备安装提供借鉴。

Stress Analysis of the Sarafix External Fixator Design

A stress analysis of the Sarafix external fixator design was performed using finite element analysis （FEA） and experimental tensometric measurements. The study was conducted at one of the Sarafix fixator configurations that have a clinical application in the treatment of tibia fractures. The intensity of principal and yon Mises stresses generated at two measuring points （MP） on the fixator connecting rod were monitored and analyzed during the testing on axial compression on the fixator design and its finite element model （FEM）. The 3D geometrical and FEM model of the fixator was formed using the computer aided design/computer aided engineering （CAD/CAE） software system CATIA. Verification of the results for the dominant principal stresses obtained from FEA was carried out through tensometric measurements. The measuring chain consisted of strain gauges connected into two Wheatstone half-bridges, digital measuring amplifier system and a computer with software for acquisition and monitoring of measurement results. A quite good agreement was observed between the results obtained on the basis of FEA and results of experimental tensometric analysis,