External Fixation System Research Articles

The Ilizarov Technique: A Dynamic Solution for Orthopaedic Challenges.

The Ilizarov technique is one of the most important tools that is currently employed in bone reconstruction surgeries. Its inception dates back to the mid-20th century and involves various bone reconstruction methodologies implemented using a circular external fixator system devised by G. A. Ilizarov. The key advantages of this approach include the generation of viable new bone via distraction osteogenesis, high union rates, and the functional utilization of the limb during the treatment process. The exploration of distraction osteogenesis phenomenon triggered by tensile stress with the Ilizarov device served as a catalyst for progress in bone reconstruction surgery. Subsequently, the original technique has been utilized alongside several adaptations resulting from the introduction of novel fixation tools and methods of their application, such as hexapod external fixators and motorized intramedullary lengthening nails. It is crucial to possess a precise comprehension of the Ilizarov principles of deformity correction in order to effectively utilize this fixation system. In this article, we will discuss the history of Ilizarov frame, the basic sciences behind it, the mechanical principles governing its use, and the clinical application of the fixation system in our daily practice.

Clinical Utility of Integrant’s FrameIt

This paper explores Integrant’s FrameIt, a novel external fixator based on the Taylor Spatial Frame (TSF). The TSF, invented by Dr. Charles Taylor, offers significant advantages over traditional Ilizarov frames in treating complex bone deformities and fractures. FrameIt leverages the TSF’s ability for precise six-axis adjustments and computer-assisted planning to achieve faster correction times and improved patient outcomes. The paper delves into the TSF’s background, highlighting its development as a solution to the limitations of the Ilizarov frame. It emphasizes the TSF’s reliance on principles from projective geometry, the Chasles’ Theorem and the Stewart Platform to achieve its superior accuracy. Furthermore, the paper explores the factors impacting the TSF’s success. It analyzes the influence of: Available and Emerging Technologies: The paper stresses the importance of utilizing advancements enhancing the TSF’s design and functionality Historical and Cultural Factors: The paper acknowledges the historical context that led to the development of external fixation systems, with the Ilizarov frame paving the way for the TSF Economic Factors: The paper discusses the economic considerations surrounding the TSF’s adoption, including equipment costs, procedures and aftercare. It highlights the limitations imposed by high costs on accessibility for some patients In conclusion, the paper positions Integrant’s FrameIt as a promising advancement in bone deformity correction. By building upon the TSF’s foundation and addressing economic barriers, FrameIt has the potential to revolutionize patient care in this field.

Limb Salvage by Means of Hindfoot Arthrodesis Utilizing Bulk Allograft and External Fixation.

Retrospective Review. 18 months. Rearfoot and Ankle Reconstruction. Level 4 Retrospective Review. A retrospective review was performed of 6 patients who had undergone limb salvage procedures between January 2016 and April 2019. Patients underwent surgery due to severe limb-threatening diagnosis including Charcot and/or osteomyelitis. Salvage arthrodesis was performed with bulk femoral head allograft incorporation using a hexapod external fixation system. The external fixation was retained for an average of 16 weeks. All patients were followed for a postoperative period of 16 months. Successful rearfoot arthrodesis and limb salvage was achieved in ⅚ (83%) of patients. This review demonstrates that limb salvage and arthrodesis are possible using femoral head allograft incorporation by external fixation alone. The involved patients had resolution of the osteomyelitis and Charcot deformity, salvage arthrodesis of the rearfoot and avoidance of a major limb amputation. IV.

Finite element analysis of modified Slongo's external fixation in the treatment of supracondylar humeral fractures in older children.

Older children over 8 years old are at higher risk of elbow joint stiffness after treatment of supracondylar humeral fractures. The objective of this study was to improve the Slongo's external fixation system for treating supracondylar humeral fractures in older children. This would be achieved by increasing fixation strength and providing a theoretical basis through finite element analysis and mechanical testing. A 13-year-old female patient with a history of previous fracture was selected for CT data processing to create a three-dimensional model of the distal humerus fracture. Two internal fixation models were established, using the Slongo's external fixation method with Kirschner wire (Group A) and modifying the Slongo's external fixation (Kirschner wire tail fixation) (Group B). The fracture models were then subjected to mechanical loading analysis using Finite Element Analysis Abaqus 6.14 software to simulate separation, internal rotation, and torsion loads. A PVC humeral bone model was used to create a supracondylar fracture model, and the A and B internal fixation methods were applied separately. The anterior-posterior and torsional stresses were measured using the Bose Electroforce3510 testing system, followed by a comparative analysis. The finite element simulation results showed that under the same tensile, torsion, and inversion forces, the osteotomy model fixed with Kirschner wire at the distal end in Group B exhibited smaller tensile stress and deformation compared to the unfixed osteotomy model in Group A. This indicated that the fixation strength of Group B was superior to that of Group A. According to the test results of the Bose Electroforce3510 testing system, a simple linear regression analysis was conducted using SPSS software. The K values of rotation angle-torque tests and front and rear displacement-stress tests were calculated for Groups A and B, with Group B showing higher values than Group A. The results of this study supported the significantly enhanced biomechanical reliability and stability of fracture fixation in Group B, which utilized the modified Slongo's external fixation (Kirschner wire tail fixation). This optimized method provides a new choice for the clinical treatment of supracondylar humeral fractures in older children, backed by both clinical evidence and theoretical basis.

Design, Engineering Analysis, and Fabrication of a Prototype Electromechanical Finger Fixator Control System

This paper investigates a new external fixator system for treating finger contractures. This innovative system is electric and user-friendly, providing precise readings of the angles of diseased finger joints. Accurate measurements of the angles of the diseased finger joints can assist therapists and patients during rehabilitation procedures. The fixator consists of ten parts assembled using polyether-ether-ketone (PEEK) for the plastic components and stainless steel for the metal components. The design model was engineered, drawn, and analyzed using SolidWorks Computer-Aided Design software. The verification process utilizes finite element analysis to demonstrate that the maximum stress was lower than the yield strength of the chosen materials. As a result, the new device design is robust and stable enough to withstand the anticipated loading conditions of human fingers. Subsequently, a prototype was fabricated using advanced additive manufacturing technology, specifically fused deposition modeling (FDM). The proposed fixator is simple to control, reliable, easy to use, and reproducible. It enables device users to exercise their finger joints throughout the day without requiring the assistance of specialists.

The management of metacarpal and phalangeal fractures of hand by K-wires and Joshi’s external stabilization system

Background: Hand injuries are quite common and affect 15% of people who go to the emergency room. The metacarpals and phalanges are the two bones that fracture most frequently, with a prevalence of between 10 and 15%. Use of K-wires with an external fixation system, such as Joshi's external stabilization system (JESS), is optional. According to the ligamentotaxis theory, JESS functions. Aim was to evaluate the clinical and radiological outcome of metacarpal and phalangeal fractures using k wires and jess. Methods: This prospective study was conducted in post graduate department of orthopaedics SKIMS medical college Bemina, on 40 patients with metacarpal and phalangeal fractures managed by Kirschner wires (K-wires) and JESS. The collected data was analyzed with the help of statistical package for social science (SPSS), version 21 Results: In present study the most of the study subjects were in the age group of 28-37 years (40%), there was male predominance with the male to female ratio 2.5:1, majority of the study subjects were labourer (38%), right side was involved most commonly (62%), the major cause of fracture was road traffic accident (58%) and most (96%) of the study subjects were operated within 24 hours of the injury. Conclusions: The study concluded that augmentation of JESS over K-wires provides a stable skeletal environment with early tissue healing and immediate active and passive mobilization of the uninjured adjacent joints and also provides rotational stability as the majority of the study subjects achieved excellent functional outcome.

Tibial fractures treated with mono-lateral fixation: Principles of design and application.

This paper presents the outcome of a data review of patients treated with the IOS external fixation system at the Royal Stoke University Hospital: a fixation designed to meet four requirements for external fixation proposed in this paper. Demographic data and outcome were collected and assessed. From 69 initial patients, 64 patients (55 males and 9 females) had an average age of 35.9 years. The mean time to union was 127 days. There were no incidences of malunion, or refracture post fixation removal attributable to the treatment method. In addition, in this cohort, there was no incidence of pin tract infection resulting in osteomyelitis. Of all the factors assessed the only factor to have any significant effect on healing was smoking: an average delay of 31 days. An examination of RUST (radiographic union score tibia) and modified RUST scores illustrated a potential false negative of up to 80%. Hence, this study cannot support the use of either scoring system to diagnose fracture healing. IOS external fixation was shown to be an effective method for the treatment of unstable tibial fractures. The reduction at fixation removal was shown to be very good. There was no incidence of osteomyelitis. It is, therefore, suggested that appropriately used external fixation is a viable alternative to intramedullary nailing if designed and surgically applied using four design principles outlined in this paper. Furthermore, it is proposed that external fixation be designed and applied to meet these four principles.

Evaluation of distal femur fractures in cats by hybrid external fixator

In this study, clinical and radiological findings obtained from the treatment of distal femur fractures in cats with hybrid external fixator were evaluated. A total of 10 cats of different ages, breeds and genders with clinically diagnosed femur fractures were used as research material. In the study, hybrid external fixators consisting of circular and linear fixators were used as osteosynthesis material. Closed reduction and external fixation methods were used in 2 cases diagnosed with closed fractures, while limited open reduction and external fixation methods were used in 8 cases diagnosed with open fractures or excessive dislocations. In the radiological examination findings, it was determined that fracture consolidation started on the post-operative 7th day in 9 cases and on the 10th day in 1 case, respectively. Fracture healing was completed in 4 weeks in 2 cases, in 5 weeks in 2 cases, and in 6 weeks in 6 cases (osseous callus was detected). Fixators were removed one week after healing was completed in all patients. In the study, soft tissue complications such as edema in the extremities in 3 cases, mild pin infection in 3 cases and open wounds in 4 cases were determined. However, it was observed that these complications did not adversely affect the recovery time. As a result, with the data obtained from the study, it was concluded that the distal femur fractures in cats of the age and weight scales examined in the study can be successfully treated with the hybrid external fixator system.

Tie-Cross Acrylic External Skeletal Fixator: Technique and 13 cases

This study aims to describe a novel design of an acrylic external skeletal fixator system for stabilizing epiphyseal/metaphyseal fractures with or without articular involvement and evaluate its efficiency in 13 cases. Client-owned five cats and eight dogs with epiphyseal/metaphyseal fractures were included in this study. Cross pins with or without a transcortical pin were included in "J" shaped acrylic ESF, and this novel technique was called the Tie-cross ESF. The functional use of the extremity was evaluated, and the joint range of motion was assessed and compared with the contralateral side. Radiographs were evaluated for bone healing and possible complications. The time of the first use of the extremities changed from the day of surgery to the second day. Fracture healing occurred in 35-69 days, and ESFs were removed. No persistent lameness was observed, and total functional recovery was provided in all cases. Fixation of epiphyseal and metaphyseal fractures can be challenging, especially when it involves the articular surface. Including cross-pins in an acrylic ESF (Tie-cross ESF) is useful and can be considered an alternative technique for the stabilization of these fractures. This technique encourages the patient to use the extremity during the fracture healing and enables joint functions; therefore, additional physical therapy will not be necessary.

Complex rigid foot deformity correction with hexapod external fixator system.

Complex rigid foot deformities include three-plane deformities and usually presents with poor soft tissue coverage. In the last decades, gradual correction with computer-assisted fixator became an appropriate option for the treatment rigid foot deformities. This study aims to report our experience about treatment of complex foot deformities using Smart Correction fixator system®. We retrospectively analyzed 13 complex rigid foot deformities of ten consecutive patients treated with Smart Correction fixator system® from 2016 to 2020. Primary outcomes were classified as good, fair, and poor according to previously determined criteria. The outcomes were also assessed with The Manchester-Oxford Foot Questionnaire (MOXFQ). Non-parametric analysis (Wilcoxon test) for continuous variables and the Fisher's exact test for categorical variables were used. Plantigrade foot was achieved in all patients after correction program. Supramalleolar osteotomy was applied in nine feet, midfoot osteotomy was applied in two feet, hindfoot osteotomy was required in one foot, and only soft tissue distraction performed in two feet. Two patients had recurrent deformity managed by further acute corrections. The mean MOXFQ scores improved from 72.7 preoperatively to 24.8 at last follow-up. Present study shows that SCF the reliable option for the treatment of complex foot deformities, which also facilitates three-plane correction and concomitant lengthening with gradual soft tissue balance.

Calibration of force sensor

The paper deals with the issue of calibration of an analogue force sensor with a voltage output. For measurement, the force sensor uses a deformation member with a tensometric bridge and a measuring amplifier. This measuring chain must be used for force measurement, but the measurement uncertainty of this measuring chain is not known. Force sensors are planned for use in intelligent traumatological external fixation systems.

Design and Development of a Novel 3-D Printed External Fixation Device for Fracture Stabilization

BackgroundAn external fixator is an orthopaedic device used to stabilize long bone fractures after high energy trauma. These devices are external to the body and fixed to metal pins going into non-injured areas of bone. They serve a mechanical function to maintain length, prevent bending, and resist torque forces about the fracture area. The purpose of this manuscript is to describe a design and prototyping process creating a low-cost entirely 3-D printed external fixator for fracture stabilization of extremity fractures. The secondary objective of this manuscript is to facilitate future advancements, modifications, and innovations in this area of 3-D printing in medicine.MethodsThis manuscript describes the computer aided design process using desktop fused deposition modeling to create a 3-D printed external fixator system designed for fracture stabilization. The device was created using the orthopaedic goals for fracture stabilization with external fixation. However, special modifications and considerations had to be accounted for given the limitations of desktop fused deposition modeling and 3-D printing with plastic polymers.ResultsThe presented device accomplishes the goals of creating a construct that can be attached to 5.0 mm metal pins, allows for modularity in placement orientations, and facilitates adjustable lengths for fracture care. Furthermore, the device provides length stability, prevention of bending, and resists torque forces. The device can be printed on a desktop 3-D printer using standard low-cost polylactic acid filament. The print time is less than two days and can be completed on one print bed platform.ConclusionsThe presented device is a potential alternative for fracture stabilization. The concept of a desktop 3-D printed external fixator design and method of production allows for numerous diverse applications. This includes assisting areas with remote or limited access to advanced medical care and large-scale natural disasters or global conflicts where large volumes of fractures exceed the local medical supply chain capabilities. The presented device creates a foundation for future devices and innovations in this fracture care space. Further research is needed on mechanical testing and clinical outcomes with this design and initiative in fracture care before clinical application.

Accuracy of the hexapod external fixator in treating tibial angular deformities with or without limb length discrepancy: a retrospective study.

Hexapod external fixator systems allow simultaneous deformity correction in multiple planes as well as limb lengthening. The aim of this study is to evaluate the accuracy of a hexapod frame (smart correction frame) in different types of tibial deformities requiring correction with or without lengthening. A total of 54 tibial angular deformities and limb length discrepancies operated with a hexapod frame between January 2015 and January 2021 were classified into four groups: "Group A (n = 13): only lengthening," "Group B (n = 14): lengthening and uniplanar correction," "Group C (n = 16): only uniplanar correction," and "Group D (n = 11): biplanar correction." The accuracy of angular deformity correction/lengthening was calculated by dividing the actual correction/lengthening achieved after frame removal by the preoperative planned lengthening/correction. The lengthening accuracy in Group A and Group B was 96.3 ± 7.1% and 95.7 ± 5.9%, respectively (P = 0.685). The angular deformity correction accuracy was 85.1 ± 9.9% for Group B, 85.2 ± 13.9% for Group C, and 80.2 ± 18.4% for Group D (P = 0.852). A revision program was performed in six cases (1 in Group B, 1 in Group C, and 4 in Group D) for full correction of the deformities. The accuracy of tibial lengthening is high with the hexapod frame and is minimally affected by simultaneous deformity correction; however, the accuracy of angular correction slightly reduces as the deformity becomes more complex. Surgeons should be aware that reprogramming may be required after complex deformity correction.

Simultaneous tibio-talar fusion and tibial lengthening for end-stage ankle arthritis.

Arthrodesis of the ankle joint is an accepted treatment option in patients with end-stage ankle arthritis. The goal is to achieve fusion between the tibia and the talus, thereby stabilizing the joint and alleviating pain. There might be associated limb length discrepancy, especially in post-traumatic and post-infectious cases. These patients require limb lengthening and arthrodesis. The purpose of this study is to report our experience with simultaneous ankle arthrodesis and lengthening using external fixation in adolescent and young adult patients. This retrospective case series included all patients treated in our hospital by concomitant ankle arthrodesis and tibial lengthening procedures on the same limb, using ring external fixation system. All surgeries included distal tibial joint surface resection and the talar dome, thereby correcting any associated deformity at the ankle. The arthrodesis was fixed and compressed using ring external fixator. A concurrent proximal tibial osteotomy was done, and limb lengthening, or bone transport was performed. Eight patients operated between the years 2012-2020 were included in this study. Median patient age was 20.4years (range 4-62years), 50% women. Median limb lengthening was 20mm (range 10-55mm), and median final leg length discrepancy (LLD) was 7.5mm (range 1-72mm). The most common complication recorded was pin tract infection, which resolved with empiric antibiotics in all cases. Based on our experience, combined arthrodesis and proximal tibial lengthening is efficient solution that provides stable ankle and restores length of the tibia even in complex and challenging situations.

Metatarsal Gradual Lengthening for Brachymetatarsia Using a Mini-rail External Fixator System.

To describe the surgical technique for gradual lengthening of the metatarsal using the Orthofix MiniRail System (Orthofix Medical Inc., Lewisville, TX, USA). Brachymetatarsia refers to the shortening of the metatarsal bone. When indicated, metatarsal lengthening is performed to treat this deformity. A dorsal approach to the short metatarsal is performed, protecting the neurovascular structures and the extensor tendons. The most proximal wire or screw is inserted first, followed by the most distal wire or screw. The distal wire or screw should not be inserted in the metatarsal head. The middle wires or screws are inserted thereafter. All wires or screws should be placed perpendicular to the anatomic axis of the bone. Once the MiniRail lengthener is assembled, a 1.6 mm K-wire is inserted from the tip of the toe into the metatarsal head, blocking the motion of the metatarsophalangeal joint and avoiding joint subluxation during lengthening. The osteotomy is then performed perpendicular to the metatarsal shaft, in between the middle two wires and screws. The surgical technique for gradual lengthening of the metatarsal using the Orthofix MiniRail System was described in detail with accompanying step-by-step intraoperative clinical and fluoroscopic images. This surgical technique of metatarsal lengthening is simple and effective. An understanding of the surgical technique of gradual lengthening of the metatarsal bone is important when treating shorting deformities of more than 1 cm. Marwan Y, Abu Dalu K, Bernstein M, et al. Metatarsal Gradual Lengthening for Brachymetatarsia Using a Mini-rail External Fixator System. Strategies Trauma Limb Reconstr 2022;17(3):184-188.

Correction of all deformities in a single planned session with the application of a spider frame fixator

Objectives. This study aimed to demonstrate the simultaneous correction of all deformities with the Spider Frame computer-assisted external fixation system, to determine the characteristics of the application technique, and to evaluate its effectiveness, complications and results. Materials and Methods. The evaluation was performed on 22 patients treated with a spider frame between 2012 and 2014. The lengthening amount, union status and bone angles were evaluated radiologically on the pre and postoperative orthoroentgenograms. In the preoperative evaluation, the Paley difficulty scale was used; the postoperative bone and functional results were evaluated according to the Paley criteria. The external fixator index and distraction index were evaluated. Results. The mean score of the Paley difficulty scale applied preoperatively, was 4.5 (range, 1-10). The mean duration of the fixator was 199 days (range, 104-300 days). The mean external fixator index was 105.3 day/cm (range, 38-300 day/cm). The mean distraction index was 11.4 day/cm (range, 7-22 day/cm). According to the Paley criteria, excellent and good results were obtained in 75% and moderate results in 25% of cases involving the femur. In the tibia cases, excellent and good functional results were obtained in 83.3% and excellent and good bone results in 91.6% patients. Conclusion. In cases of deformity, acute fracture and nonunion, the computer-assisted external fixator system (spider frame® ) without any modification provides single-stage correction by allowing postoperative intervention to the deformity. It is a new generation external fixator system which has shown successful functional results, and can therefore be considered for use.

Outcomes of two circular external fixation systems in the definitive treatment of acute tibial fracture related infections

IntroductionAcute tibial fracture-related infection (FRI) is one of the most feared and challenging complications after a tibial fracture. The most appropriate treatment in this scenario is far from a resolved topic. Circular external fixators (CEFs) offer multiplanar control and minimize soft tissue injury using temporary implants far from the infected area. This study aimed to investigate the outcomes of two different types of CEFs (Ilizarov and hexapod) in the treatment of a series of acute tibial FRIs. Material and MethodsA retrospective study at two specialized limb reconstruction centres identified all patients with an acute tibial FRI (≤4 weeks after index procedure) definitively treated with a CEF from January 2015 to December 2020. Primary outcomes: fracture healing and infection eradication rate with a minimum FU of 12 months after frame removal. Secondary outcomes: to investigate the differences between the two types of circular frames regarding final post-treatment deformity magnitude. ResultsWe included 31 patients with acute tibial FRIs: 18 treated with hexapod-type and 13 with Ilizarov-type CEFs. Average age was 45.5±16.56 years. Fracture healing and infection eradication were achieved in all patients (31/31) after a mean follow-up of 24.7 months (range 12.1-55.3). Patients treated with an Ilizarov-type fixator presented shorter time to fracture union (5.5±2.2 months vs. 9.2±6.0 months; p-value 0.021) and shorter duration of external fixation (p-value 0.001). Regarding residual post-treatment deformity, the hexapod system presented significantly less residual coronal translation deformity (p-value 0.034) and better callus quality. Fixator-related complications were similar when comparing the two groups. No significant differences were seen in pain (p-value 0.25), RTW rate (35% vs. 45%; p-value 0.7) or functionality (p-value 0.4). ConclusionsDefinitive circular external fixation is an excellent treatment for acute tibial FRI. Both Ilizarov and hexapod systems offer a very high rate of fracture healing and infection eradication. Although both presented very low radiological post-operative residual deformity, the hexapod system showed less residual coronal translation deformity and better callus quality.

Outcomes of a Mini External Fixator System for the Treatment of Unstable Periphyseal Hand Fractures.

Background: Most unstable hand fractures in children are treated by closed methods. If osteosynthesis is required, Kirschner (K)-wires are commonly used, though they carry a risk of injury to the physis. We have been using a mini external fixator system (MEFS) for the treatment of unstable periphyseal fractures of the hand. The aim of this study is to describe the application and report the outcomes of MEFS for the treatment of periphyseal fractures of the hand. Methods: We retrospectively reviewed all the patients with periphyseal fracture of the hand treated with MEFS from March 2010 to December 2019. Data with regard to age, sex, hand dominance, digit and bone injured, mechanism of injury, medical records and related radiographs were collected. Salter-Harris classification was used to classify epiphyseal fractures and the Al-Qattan classification for categorising neck fractures. Range of motion and residual deformity of the affected fingers were evaluated during follow-up and at 3 months postoperatively. Results: Fourteen periphyseal unstable fractures were treated using closed reduction and MEFS. Only one patient with a fracture of the neck of the proximal phalanx of the little finger required revision surgery. No patient had pin site infection or pin loosening and the device was well tolerated by all patients. All fractures united and all the patients recovered a full range of motion at final follow-up. Conclusions: The MEFS is a reasonable alternative for unstable periphyseal fractures with good outcomes and avoids the risk of iatrogenic physeal injury from K-wire fixation. Level of Evidence: Level IV (Therapeutic).

Focus on stability: biomechanical evaluation of external fixation technique versus locking plate osteosynthesis in 3-part proximal humeral fractures.

The purpose of this study was to investigate the primary stability and displacement tendencies of an external fixation system in 2 different configurations in comparison to locking plate fixation in a 3-part proximal humeral fracture model. Twenty-one fresh-frozen human cadaveric proximal humeral specimens were divided into 3 groups of 7 stripped specimens. An unstable3-part fracture of the proximal humerus was set. Construct A consisted of the Galaxy Fixation Shoulder System, with fixation in accordance with the manufacturer's recommended technique (3 pairs of threaded wires). Construct B was fixed with an additional pair of threaded wires according to the recommendations of Gumina etal (4 pairs of threaded wires). The remaining 7 specimens were fixed with a locking plate. By use of an optical motion capture system, relative motion at the fracture site and failure load were evaluated during a cyclic loading protocol. Plate osteosynthesis showed the highest cyclic load to failure (895±239 N; range, 597-1135 N), followed by construct B (692 ± 121 N; range, 432-788 N) and construct A (350 ± 190 N; range, 139-615 N). Statistically significant differences were found between plating and construct A (P < .001), between plating and construct B (P = .031), and between construct B and construct A (P = .013). Relative motion at the fracture site, in terms of change in distance during cyclic loading, was lowest with construct B measured at the peak load of 395 N after 11 steps (1.73 ± 1.98 mm; range, 0.53-5.96 mm) and highest with construct A (8.46 ± 10.67 mm; range, 2.26-20.79 mm). Angular change measured at the peak load after 11 steps was lowest with construct B (1.19° ± 0.36°; range, 0.59°-1.7°) and highest with construct A (2.44° ± 1.63°; range, 0.77°-4.04°). Statistically significant differences were found between construct A and construct B and between construct A and plating at various steps of cyclic loading. In this biomechanical study of unstable3-part proximal humeral fractures, locking plate osteosynthesis demonstrated the highest possible load application. External fixator application with 8 threaded wires (construct B) revealed the least relative motion at the fracture site, without a statistically significant difference compared with locking plates. It therefore represents another valid technique for treatment regarding primary stability. The use of external fixator application with 6 threaded wires (construct A) resulted in the lowest stability and the highest rates of displacement.

A biomechanical study: Comparison of three different implant options in high Tibial osteotomy

BackgroundMany implant options could be preferable for fixation after osteotomy in varus knee medial compartment arthrosis. Due to usage characteristics, it is important to compare the biomechanical properties of them. For this purpose, we aimed to examine three different implant types biomechanically in our study. MethodsOvine tibiae undergoing medial open-wedge high tibial osteotomy were fixed in vitro with three different implants using an angular wedge plate, a metal block plate and an external fixator system. The fixed ovine tibiae were subjected to axial tensile, axial loading and three-point bending tests in a test machine. All biomechanical tests were repeated five times, the maximum and minimum values were ignored, and the average values of the remaining three test results were taken into account. The test results were interpreted after converted into force-elongation curves in Trapezium-X software. FindingsBiomechanical test results revealed some differences between implant types. While the metal block plate had the highest axial tensile strength value, it was the fixation group showing the lowest strength in axial load tests. The used fixator system was the highest strength in axial load tests and the lowest strength in axial tensile tests. InterpretationConsidering the clinically significant forces related to the biomechanical stability of the three different implants used for high tibial osteotomy, the fixator system would appear to be slightly superior, although it should be noted that torsional forces, as well as parameters that could change in living tissue, might affect the results.