Smooth Wires Research Articles

Irrigant flow in the root canal during ultrasonic activation: A numerical fluid-structure interaction model and its validation.

AimThe aim of the study was (a) to develop a three‐dimensional numerical model combining the oscillation of a tapered ultrasonic file and the induced irrigant flow along with their two‐way interaction in the confinement of a root canal. (b) To validate this model through comparison with experiments and theoretical (analytical) solutions of the flow.MethodologyTwo partial numerical models, one for the oscillation of the ultrasonic file and another one for the irrigant flow inside the root canal around the file, were created and coupled in order to take into account the two‐way coupled fluid–structure interaction. Simulations were carried out for ultrasonic K‐files and for smooth wires driven at four different amplitudes in air or inside an irrigant‐filled straight root canal. The oscillation pattern of the K‐files was determined experimentally by Scanning Laser Vibrometry, and the flow pattern inside an artificial root canal was analysed using high‐speed imaging together with Particle Image Velocimetry. Analytical solutions were obtained from an earlier study. Numerical, experimental and analytical results were compared to assess the validity of the model.ResultsThe comparison of the oscillation amplitude and node location of the ultrasonic files and of the irrigant flow field showed a close agreement between the simulations, experiments and theoretical solutions.ConclusionsThe model is able to predict reliably the file oscillation and irrigant flow inside root canals during ultrasonic activation under similar conditions.

Лечение пациента с открытым переломом плечевой кости с обширным дефектом костной ткани с использованием костной пластики (случай из практики)

Introduction Treatment of a patient with an open comminuted humerus fracture and an extensive bone defect is challenging and associated with high risk of a poor outcome, infection resulting from skin and soft tissue injury and considerable bone transport. The objective of the study is to demonstrate the experience with an open comminuted humerus fracture and an extensive bone defect treated with staged use of transosseous fixation with rod-andwire device, autologous fibula graft and internal wiring. Material and methods We report a case of an open humerus fracture and an extensive bone defect treated with a bone replacement technique and followed up to 4 years. Results and discussion The limb was temporarily fixed with external fixation device extrafocally using wires and rods. A 24 cm autograft was harvested from the fibula. Osteosynthesis of the humerus and autografting were produced with the graft fixed using smooth wires and external fixation was provided using wires and rods. With consolidation of the humerus achieved, the external fixation device was dismantled and transosseous wires removed. Anatomical length of the segment was restored. Conclusion Combined techniques and technical means of external fixation, autologous graft, internal fixation with smooth wires facilitated complete restoration of the injured limb avoiding complications with a good clinical outcome.

Compression of A Midfoot Osteotomy Using A Circular External Fixator: What is the Ideal Pin Configuration?

Category:Midfoot/Forefoot; Diabetes; TraumaIntroduction/Purpose:Foot and ankle deformity correction through midfoot osteotomy can be implemented in a wide variety of clinical situations. Use of a circular ring fixator for osteotomy fixation is particularly useful for patients with poor soft tissue envelopes and/or active infection as can occur in diabetes and Charcot arthropathy. The foot pins in a ring fixator can be configured to apply compression at the osteotomy site. However, the optimal pin configuration and force has yet to be determined. The purpose of this study was to quantify compressive forces achieved across midfoot osteotomies with various wire configurations in a circular ring fixator construct.Methods:Nine through-knee amputation cadavers were stabilized with a standard circular external fixation carbon frame. A midfoot osteotomy through the transverse tarsal joint was performed using an oscillating saw. A 4mm bone wedge was removed from the osteotomy site for placement of a Tekscan pressure sensor. A two-ring frame was applied in the standard fashion and three parallel 1.8mm smooth wires were placed parallel to each other through the foot distal to the osteotomy: wire #1 proximally through the cuneiforms, wire #2 through the base of the metatarsals, wire #3 through the metatarsal shafts. After baseline pressure readings, wires were sequentially attached (wire #1 alone, wire #1-2, wire #1-3) to the ring fixator and tensioned to 90kg. Pressure readings were recorded at the osteotomy site for each sequential wire tensioning both at the hole location where the wire naturally crossed, 'neutral', and again at one hole 'proximal' (e.g., toward the osteotomy).Results:Average compressive load at neutral hole positioning for wire #1 was 382 N. The addition of wire #2 increased the compressive load to 439 N on average. The addition of wire #3 decreased compressive force to 372 N. Similar trends were seen in proximal hole positioning where average compressive force increased following tensioning of wire #2 from 580 N to 600 N but compressive force decreased on wire #3 addition to 425 N. Therefore, tensioning forefoot thin wires in the proximal hole position increases compressive forces by 50% compared to neutral position, and adding a second wire increased compressive force by up to 15% compared to a single forefoot wire.Conclusion:In a circular frame midfoot fusion model, the greatest compressive force was achieved with two wires tensioned in the proximal hole position. The addition of a third wire led to force decrease likely due to off-axis forces that may distract the osteotomy site given the difficulty of passing all wires perfectly parallel in all planes. Ideal positioning and tensioning of forefoot pins may optimize construct stability and compression and improve healing of the midfoot osteotomy.

Determinación de la longitud de transferencia de alambres con distintos grados de corrosión en elementos pretensados de hormigón

En elementos pretensados de hormigón, la adherencia entre el acero y el hormigón puede verse deteriorada por diferentes motivos, siendo uno de los más recurrentes el daño inducido por procesos de corrosión. El parámetro fundamental para caracterizar las propiedades adherentes existentes entre el acero pretensado y el hormigón es la longitud de transferencia. Este artículo compara los resultados experimentales obtenidos en ensayos sobre elementos pretensados tipo viga con las predicciones arrojadas por un modelo analítico, basado en la teoría de cilindros de pared gruesa y en la fisuración cohesiva del hormigón, desarrollado para analizar los procesos de degradación de la adherencia motivados por la corrosión en alambres lisos e indentados y su influencia en el comportamiento de elementos pretensados de hormigón.

Highly transparent, conducting, body-attachable metallized fibers as a flexible and stretchable film

Core–shell-structured silver-electroplated nickel microfibers were fabricated via electrospinning and subsequent electroplating for applications including transparent conductive films (TCFs) and heaters. Fabrication protocol generated self-fused junctions at the intersections of overlapping micro-nanofibers. This reduced contact resistance between wires, yielding remarkably high electrical conductivity, which is highly desirable for the aforementioned applications. A very low sheet resistance of less than 0.2 Ω sq−1 with a high transmittance of over 92% was achieved in these structures. A cactus-like morphology of silver-plated microfibers, which dramatically increases surface-to-volume (S/V) ratio and should produce electric field concentration at silver nanowire tips, was also demonstrated. This unique surface morphology could be promising for energy and environmental applications that require large interfacial areas and electric field concentration, but yielded lower transmittance than smooth wires. These cactus-like microfibers were further coated with Cu and Pt to produce hierarchically-structured multimetallic microfibers. The low-resistivity transparent silver micro-nanofiber films exhibited good heating and mechanical properties, as demonstrated in bending and stretching tests. A record high temperature of 209 °C was achieved with a transparent heater based on the Ag microfibers.

Identification and preparation of stable water dispersions of protein - Carbon nanotube hybrids and efficient design of new functional materials

Carbon nanotubes, CNTs, and proteins could not be more chemically and physically distant. CNTs are hardly soluble and strongly hydrophobic. They are smooth wires, mechanically strong, with electronic properties that make them unique. Many proteins are water soluble and hydrophilic. They are highly corrugated and elastic. They can recognize a target molecule with high selectivity and sensitivity and can have catalytic activity. Integration of the remarkably different features of CNTs and proteins would create a new class of multifunctional materials. The conundrum to solve lies in how to best match proteins and CNTs. High-throughput virtual screening is used to predict the ability of 1207 proteins to recognize carbon tubes with a well-defined 1.3 nm diameter. The propensity for formation of protein-CNT hybrids is ranked. Experiments carried out in this work validated the computational results and show that the identified proteins are able to bind and disperse in water the selected CNTs. The highest scoring proteins are further examined in detail to identify general rules for binding and discussed for a variety of practical applications.

Geometrical size effect in the fatigue life predictions of aluminum wires with micro holes using methods of the critical distance

Recent research has shown that fretting fatigue is the main cause of fatigue failure in electrical transmission lines, and this phenomenon can be modeled as a stress concentration problem. The present study investigates the expected fatigue life of aluminum alloy 6201-T81 wires with micro holes, used in cables for transmission lines. The expected fatigue life of wires with micro holes is calculated based on the Theory of Critical Distances (TCD), where the characteristic size of the material (LM) varies with the number of cycles to failure (Nf), establishing an LM (Nf) relation. To calibrate this relation, two S-N calibration curves were plotted with fully reversed uniaxial fatigue tests carried out on smooth wires (unnotched) and wires with a sharp notch. Experimental σ-N curves were constructed for different types of holes to validate and evaluate fatigue life prediction results of wires with micro holes, more precisely: (i) two through holes (TH), with diameters of 0.5 and 0.7 mm, and (ii) two types of blind holes (BH), with diameters and depths of 0.1 × 0.1 mm and 0.7 × 0.7 mm, respectively.The LM - Nf relation, based on the concepts of TCD, associated with the maximum principal stress as parameter to assess fatigue damage, was an effective methodology for fatigue life prediction of aluminum alloy 6201-T81 wires with micro holes.

A new near-surface-mounted anchorage system of shape memory alloys for local strengthening

Shape memory alloys (SMAs) are increasingly used as local reinforcements to control deformation and crack development of reinforced concrete members. This paper presented a new near-surface-mounted strengthening approach, in which the bond performance between SMAs and cement mortar is concerned. To ensure a reliable anchorage of smooth SMA wires embedded in cement mortar, three types of anchors, i.e. the U-shaped stirrups (AU), the block anchors with the flat head bolts (AF), and the block anchor with the hex socket bolts (AH), were suggested. The tensile and recovery tests were firstly undertaken to verify the anchorage performance between smooth SMA wires and the anchors. Then the bond performance of anchored SMA wires embedded in cement mortar was studied by pull-out tests. The results showed that the proposed AH anchor could ensure a reliable anchorage between smooth SMA wires and cement mortar within a short embedded length.

Screw fixation for supracondylar humerus fractures in children: a report of seventeen cases.

Supracondylar fractures in the pediatric population are common. For years, K-wires have been the preferred method of surgical fixation. However, fixation with K-wires alone may lead to multiple complications. This study reports the results of surgical care of supracondylar humerus fractures using screw fixation with K-wires or screw fixation alone. This study retrospectively reviewed all patients with supracondylar humerus fractures treated with screw fixation between 2007 and 2013. Patients treated only with smooth wires, or having a displaced medial epicondyle, or presenting with lateral condyle fractures were excluded from the study. Flynn's criteria were used to determine the outcome. Seventeen patients who met inclusion criteria formed the study group. All patients were followed until union, resolution of complications, and return to preinjury activity level. Satisfactory outcome was reported in 70.6% of patients with less than 15° loss of either flexion or extension. Mean time to union was 6.5weeks (range 3.3-12.1weeks). Screw fixation alone had a shorter mean time to union (5.5weeks) than compared screw fixation with K-wires group (6.9weeks). Full range of motion following surgical invention was associated with Flynn's criteria (p value = 0.044). Screw fixation for pediatric supracondylar fractures is a viable option to achieve healing and early motion in highly unstable fractures as well as fractures which require (1) increased stability, (2) maintenance of stability during wound checks in the immediate postoperative period and after discontinuation of the cast, or (3) if further exploration like associated vascular injury is warranted.

Continuously Grooved Stent Struts for Enhanced Endothelial Cell Seeding

PurposeImplantation of pre-endothelialized stents could enhance cellular recovery of a damaged vessel wall provided attached cells remain viable, functional and are present in sufficient numbers after deployment. The purpose of this study was to evaluate the feasibility of grooved stainless steel (SS) stents as a primary endothelial cell (EC) carrier with potentially enhanced EC protection upon stent deployment.Materials and MethodsAttachment and behavior of enzymatically harvested human adult venous ECs seeded onto gelatin-coated vascular stents were evaluated in an in vitro setting. Smooth and grooved SS stents and smooth nitinol stents were studied.ResultsAll cells expressed EC markers vWF and CD31. Using rotational seeding for a period of 16–24 h, ECs attached firmly to the stents with sufficient coverage to form a confluent EC monolayer. The grooved SS wire design was found to enable attachment of three times the number of cells compared to smooth wires. This also resulted in an increased number of cells remaining on the stent after deployment and after pulsatile flow of 180 ml/min for 24 h, which did not result in additional EC detachment.ConclusionsThe grooved stent provides a potential percutaneous means to deliver sufficient numbers of viable and functional cells to a vessel segment during vascular intervention. The grooves were found to offer a favorable surface for EC attachment and protection during stent deployment in an in vitro setting.

Improvement of Hydrogen Bubbles Detaching from the Tool Surface in Micro Wire Electrochemical Machining by Applying Surface Microstructures

Wire electrochemical micromachining (WEMM) has increasingly come to be recognized as a flexible and effective method for producing planar contour microfeatures. The machining performance of WEMM is significantly influenced by the mass transport rate in the machining gap. Recently, it has been found that the use of a wire electrode with surface microstructures further increases the mass transport rate. Nevertheless, the mechanism through which the microstructures on the wire surface affect the flow field in the machining gap has been poorly understood. In this paper, a simplified mathematical model taking account of the velocity slippage caused by hydrogen bubbles attached to the axially traveling wire surface is first established. The effects on the flow field distribution in the machining gap of surface hydrophilicity and microstructures on the wire surface are theoretically analyzed. The results show that the microstructures facilitate rapid detachment of hydrogen bubbles from the wire surface, resulting in a reduction in velocity slippage and increasing the mass transport rate. A series of comparative experiments on WEMM using both smooth wires and microstructured wires prepared by laser direct scanning machining are conducted. The results are in accordance with the theoretical analysis.

Uncontrolled Removal of Dentin during In Vitro Ultrasonic Irrigant Activation in Curved Root Canals

IntroductionThe aim of this study was to examine the effect of file type and activation time on the uncontrolled removal of dentin during in vitro ultrasonic irrigant activation in prepared curved root canals. MethodsSeventy-two curved mesial root canals of human mandibular molars were prepared to size 35/.04 taper. The specimens were randomly allocated to 4 groups (n = 18). Two milliliters of 2% sodium hypochlorite were delivered 3 times to each root canal, and the irrigant was ultrasonically activated every time for 10 seconds at 35% power either by a ultrasonic K-file (group A), an Irrisafe file (Acteon Satelec, Merignac, France) (group B), or a smooth wire (group C). The same specimens also received further activation continuously for another 30 seconds. No activation took place in group D. Specimens were scanned by micro–computed tomographic imaging before and after preparation and after the first and second activation period. Scans were coregistered and segmented, and the amount of dentin removed during activation was quantified by morphological operations. Results were analyzed by nonparametric statistical tests (α = 0.05). ResultsDefects with a maximum depth of 0.18 mm were identified. Both the type of file and activation time affected the removal of dentin (P ≤ .002 and P ≤ .031, respectively). K-files removed more dentin than Irrisafe files and smooth wires in the coronal and middle third. All files removed comparable amounts in the apical third. ConclusionsAll 3 types of files may result in uncontrolled removal of dentin. A longer activation time may increase this effect.

Porous Gold Nanowires: Plasmonic Response and Surface‐Enhanced Infrared Absorption

Because of its extended surface area porous gold is of potential interest for surface‐enhanced spectroscopy methods. Optical properties of porous and smooth gold nanowires of similar diameter are analyzed with infrared spectroscopy and modeled with finite‐difference time‐domain simulations. By electrochemical deposition in ion‐track etched polymer smooth gold and gold–silver alloy nanowires are synthesized. Porous gold nanowires are subsequently obtained by dealloying. The porosity clearly affects important plasmonic characteristics, resulting in a strong redshift of the resonant wavelength, and significant line broadening, which can be convincingly explained by effective Drude parameters related to a lowered average electron density and a higher electron scattering in the porous gold, respectively. Finally, the sensing performance of porous wires is tested by surface‐enhanced infrared absorption. The measurements show a similar vibrational signal contrast for smooth and porous wires. This is explained by simulations which reveal that the nanowire near‐field modeled with bulk gold data is higher and thus accordingly the vibrational signal is enhanced compared to nanowires modeled with the effective Drude parameters of porous gold. This means that the advantages offered by the larger surface of porous wires are counterbalanced by lower near‐field strength.

Which Proximal Humerus Fractures Should Be Pinned? Treatment in Skeletally Immature Patients.

Most proximal humerus fractures in skeletally immature individuals are treated nonoperatively with excellent functional results. Extensive remodeling of the proximal humerus and the wide arc of motion of the glenohumeral joint accommodate a large degree of fracture displacement and angulation. The treatment of severely displaced fractures and/or severely angulated fractures continues to be debated. Older patients and those with significantly displaced fractures may benefit from surgery because of their inability to remodel displacement and angulation during their limited remaining growth. The decision to treat a proximal humerus fracture in a skeletally immature patient operatively versus nonoperatively is dependent on the following 3 factors: displacement, bone age, and capacity to remodel. There is an increasing trend toward treating severely displaced and severely angulated fractures surgically, especially in older patients and adolescents. Smooth wires, percutaneous threaded wires, cannulated screws, and retrograde elastic stable intramedullary nailing are acceptable options for fixation.

Characterization of tensile and shear loading on indented PC-strand cable bolts

The tensile and shear strength of intrinsic bolting support systems has always been a major concern of designers. A comprehensive laboratory testing program was designed to evaluate the tensile and shear strength of individual wires and completely wound PC-strand cables. PC-strand cables with smooth wires and the recent anchorage enhancement innovation of indentation were evaluated and compared. The testing protocol detailed in ISO Standard 15630 utilizes a mandrel system that was investigated at 3 different diameters which alters the wire to mandrel ratio from 2:1 to 9:1. The results demonstrate that the difference between smooth and indented wires is statistically insignificant when larger diameter mandrels are used, and that indentation does not adversely affect strand properties and performance. Insight into the shearing mechanism and evaluation techniques are discussed with the introduction of triaxial loading to describe the PC-strand tensile and shearing mechanisms. Another important result indicates that the shear strength of PC-strand cable bolting systems has a greater shear strength value than traditional steel bar bolting systems.

Phonon-engineered thermal transport in Si wires with constant and periodically modulated cross-sections: A crossover between nano- and microscale regimes

The transition between nanoscale and microscale thermal transport regime at room temperature in silicon wires with constant and periodically modulated cross-section is theoretically investigated. Extrapolating the calculated thermal conductivity from the nano- to micrometer range, we find the characteristic dimensions of the wires where a crossover between nanoscale and microscale thermal transport occurs. This crossover is observed in both generic (smooth) and cross-section-modulated wires. In case of smooth silicon wires, we reveal a strong dependence of the crossing point position on the boundary roughness. For silicon wires with weak boundary roughness, the crossover occurs at cross-sections ∼60 nm × 300 nm, while for very rough boundaries it occurs at cross-sections ∼150 nm × 750 nm. In case of the periodically modulated wires, the crossover between nano- and microscale regimes occurs at typical cross-sections ∼120 nm × 120 nm of the narrow segment, and it is almost independent of boundary roughness. A strong distinction from the case of smooth wires is attributed (i) to the different trends at the nanometer scale, wherefrom the extrapolation was performed, and (ii) to the different phonon–boundary scattering due to the specific geometry. For modulated silicon wires, the influence of modulation thickness, modulation length, and cross-sectional area on the phonon thermal conductivity at the room temperature is analyzed. A possibility of thermal transport engineering in cross-section-modulated wires by resizing them is revealed in both nano- and microscale regimes. The presented results pave the way towards a better understanding of thermal transport reduction in Si nanowires with engineered diameter modulations and shed light on the crossover between nano- and microscale regimes of thermal transport.

Tensile test and interface retention forces between wires and composites in lingual fixed retainers.

In daily orthodontic clinical practice retention is very important, and lingual retainers are part of this challenge. The failure of lingual retainers may be due to many factors. The aim of this study was to assess the retention forces and mechanical behavior of different types of wires matched with different kinds of composites in lingual retainers. A tensile test was performed on cylindrical composite test specimens bonded to orthodontic wires. The specimens were constructed using four different wires: a straight wire (Remanium .016×.022″ Dentaurum), two round twisted wires (Penta One .0215″ Masel, Gold Penta Twisted .0215″ Gold N'braces) and a rectangular braided wire (D-Rect .016×.022″ Ormco); and three composites: two micro-hybrids (Micro-Hybrid Enamel Plus HFO Micerium, and Micro-Hybrid SDR U Dentsply) and a micro-nano-filled composite (Micro-Nano-Filled Transbond LR 3M). The test was performed at a speed of 10mm/min on an Inström device. The wire was fixed with a clamp. The results showed that the bonding between wires and composites in lingual fixed retainers seemed to be lowest for rectangular smooth wires and increased in round twisted and rectangular twisted wires where the bonding was so strong that the maximum tension/bond strength was greater than the ultimate tensile strength of the wire. The highest values were in rectangular twisted wires. Concerning the composites, hybrid composites had the lowest interface bonding values and broke very quickly, while the nano- and micro-composites tolerated stronger forces and displayed higher bonding values. The best results were observed with the golden twisted wire and reached 21.46 MPa with the Transbond composite. With the rectangular braided wire the retention forces were so high that the Enamel Plus composite fractured when the load exceeded 154.6 N/MPa. When the same wire was combined with the Transbond LR either the wire or the composite broke when the force exceeded 240 N. The results of this study show that, when selecting a lingual retainer in daily clinical practice, not only must the patient's compliance and dependability be considered but also the mechanical properties and composition of different combinations of composites and wires.

Fog collecting biomimetic surfaces: Influence of microstructure and wettability

We analyzed the fog collection efficiency of three different sets of samples: replica (with and without microstructures), copper wire (smooth and microgrooved) and polyolefin mesh (hydrophilic, superhydrophilic and hydrophobic). The collection efficiency of the samples was compared in each set separately to investigate the influence of microstructures and/or the wettability of the surfaces on fog collection. Based on the controlled experimental conditions chosen here large differences in the efficiency were found. We found that microstructured plant replica samples collected 2–3 times higher amounts of water than that of unstructured (smooth) samples. Copper wire samples showed similar results. Moreover, microgrooved wires had a faster dripping of water droplets than that of smooth wires. The superhydrophilic mesh tested here was proved more efficient than any other mesh samples with different wettability. The amount of collected fog by superhydrophilic mesh was about 5 times higher than that of hydrophilic (untreated) mesh and was about 2 times higher than that of hydrophobic mesh.

Kirschner wire infections in pediatric orthopaedic surgery.

Few studies have described the presentation, bacteriology, risk factors, and complications of Kirschner wire infections in pediatrics. The purpose of this study is to describe these factors to better understand, prevent, and treat infectious complications of smooth wires. A retrospective review was performed to identify all patients (birth to 16 y) who were hospitalized for Kirschner wire infection from 1995 to 2012. Presentation, hospital course, bacteriology, outcomes, and complications were recorded. A management algorithm was developed from the experience. Kirschner wire infections were present in 12 patients: 5 supracondylar fractures, 3 lateral humeral condylar fractures, a distal tibia physeal fracture, a great toe open fracture, a distal radius fracture, and an elective osteotomy for hallux valgus. The patients presented with cellulitis in 3 cases, soft-tissue abscess in 4 cases, osteomyelitis in 4 cases, and 1 case of toxic shock syndrome. A history of missed appointments or wet dressing was present in 60% of cases. Reoperation was required in 5 patients with abscess, septic arthritis, or osteomyelitis. Methicillin-sensitive Staphylococcus aureus (MSSA) was the most common pathogen followed by Pseudomonas aeruginosa. Methicillin-resistant S. aureus was not seen. Complications were present in 5 patients and included: loss of range of motion, joint destruction, wound breakdown, catheter migration, and toxic shock syndrome. Infected Kirschner wires are rare and may be maintained in a nonunited bone if the infection is superficial. Infections in this series commonly had a history of missed appointments and wet dressings, which suggests that improved postoperative education may reduce the risk. Osteomyelitis was often preceded by pin-site drainage and failed oral antibiotic therapy. MSSA and Pseudomonas were most commonly cultured and should be considered when empiric antibiotic therapy is necessary. Prognostic level IV.

Effect of asymmetrical configuration of pins in the TSF external fixator used for tibial lengthening in a pediatric population.

The Taylor Spatial Frame (TSF) is a relatively new circular external fixator linked with a computer program used in limb reconstruction surgery. It is routinely used in our unit (Royal Manchester Children's Hospital) for pediatric tibial lengthening. The case notes and radiographs of 17 children who underwent 18 tibial lengthenings were reviewed. The TSF was attached to the tibia using a hybrid fixation method in the safe zone with two 1.8 mm tensioned smooth wires and 2 anteriorly placed hydroxyapatite-coated pins. Mechanical compression testing of our TSF construct was performed and compared with a double-ring Ilizarov frame construct fixed with only tensioned wires. Out of the 18 tibiae lengthened 14 (77.8%) had a significant anterior angulation (>10 degrees) at the end of the distraction period that was corrected with a residual TSF program, with no known long-term consequences. The mechanical tests showed that the Ilizarov frame showed a more symmetrical distribution of loading in compression when compared with the TSF. With increasing load the TSF had the tendency to angulate anteriorly, that is, the apex of the angulation was pointing toward the 2 pins. The problem of anterior angulation observed in our clinical and mechanical studies is due to instability of the fixation of the proximal part of the frame. Surgical techniques that can improve the stability of the proximal fixation and promote symmetrical loading are discussed.