Straight Plate Research Articles

45° helical plates are a valid alternative to straight plates for treatment of proximal humeral shaft fractures.

Helical plates used for proximal humeral shaft fracture fixation avoid the radial nerve distally as compared to straight plates. To investigate in a human cadaveric model the biomechanical competence of straight lateral plates versus 45° helical plates used for fixation of proximal comminuted humeral shaft fractures, eight pairs of human cadaveric humeri were instrumented using either a long straight PHILOS plate (Group 1) or a 45° helical plate (Group 2) for treatment of an unstable proximal humeral shaft fracture. All specimens were tested under non-destructive quasi-static loading in axial compression, internal and external rotation, and bending in four directions. Subsequently, progressively increasing cyclic loading in internal rotation was applied until failure and interfragmentary movements were monitored by motion tracking. Axial displacement (mm) was 3.13 ± 0.31 in Group 1 and 2.60 ± 0.42 in Group 2, p = 0.015. Flexion/extension deformation (°) in Group 1 and Group 2 was 0.56 ± 0.42 and 0.43 ± 0.23, p = 0.551. Varus/valgus deformation (°) was 6.39 ± 0.44 in Group 1 and 5.13 ± 0.87 in Group 2, p = 0.012. Shear (mm) and torsional (°) displacement were 5.36 ± 0.76 and 17.75 ± 1.06 in Group 1, and 5.03 ± 0.46 and 16.79 ± 1.36 in Group 2, p ≥ 0.090. Cycles to catastrophic failure were 10000 ± 1401 in Group 1 and 9082 ± 1933 in Group 2, p = 0.708. From a biomechanical perspective, 45° helical plating is associated with lower axial and varus/valgus displacement under axial loading and demonstrates comparable resistance to failure versus straight plating. Therefore, 45° helical plates can be considered as a valid alternative to straight plates for treatment of proximal humeral shaft fractures.

Computational fluid dynamics analysis of flat plate type solar collector under different fin variables to enhance air-based heat transfer

Purpose This study begins by outlining the core principles of how flat plate solar collectors (FPSC) operate and the underlying mechanisms of heat transfer. It underscores the pivotal role of fin patterns in enhancing convective heat transfer. Design/methodology/approach The primary objective is to examine the impact of diverse fin patterns on the thermal performance of FPSCs. The study involves the development of a 3D-CFD model for FPSC using the computational fluid dynamics (CFD) software ANSYS FLUENT. The analysis is conducted for variable mass flow rates (mf) ranging from 0.01 to 0.05 kg/s with an interval of 0.02 kg/s. Each flow rate is assessed for three distinct fin patterns: straight plate fins, V-shaped fins and wavy fins. Recognizing the variation in solar radiation intensity throughout the day, the analysis is executed at six different time points ranging 10:00 a.m. to 03.00 p.m. with a time interval of 1.00 h. Findings It is observed that the wavy fin pattern with a mass flow rate of 0.01 kg/s exhibited the highest outlet temperature, showing a significant temperature difference of 12.4 K at noon. Conversely, the V-shaped fin pattern with a mf of 0.05 kg/s has the lowest temperature difference value, measuring only 3 K. The analysis included the calculation of thermal efficiency for each case, revealing that the V-shaped fin pattern at a mf of 0.05 kg/s and a sun radiation intensity of 885.42 W/m2 achieved the maximum instantaneous thermal efficiency (ηth) of 34.7%. The study records the outlet air temperature for all of these combinations and presents the data graphically in the paper. Originality/value The findings of the simulations indicate that the thermal performance that is ηth and maximum temperature of outlet air of FPSCs can be improved through the utilization of variable fin patterns.

Assessment of the trapezoidal miniplate with posterior extension for open management of condylar fractures: Can it be used instead of straight miniplates?

AbstractObjectiveThis study comparatively measures and evaluates the strength of five plating techniques for mandibular condylar fracture fixation when linear loading is applied.Materials and MethodsThe investigators designed and implemented a cross‐sectional in vitro study. The sample was composed of 60 polyurethane mandibles for the mechanical tests. For the photoelastic test, 10 photoelastic mandibles were used. The predictor variable is the plating technique, and it was categorized as groups G2P‐2.0: two 4‐hole 2.0 mm straight plates, G1TP‐2.0: 4‐hole 2.0 mm trapezoidal plate; G1TPPE‐2.0: 4‐hole 2.0 mm trapezoidal plate with posterior extension; G1TP‐1.5: 4‐hole 1.5 mm trapezoidal plate and G1TPPE‐1.5: 4‐hole 1.5 mm trapezoidal plate with posterior extension. The outcome variable is the strength of the plating techniques that was evaluated with the loading test: peak/ending load and peak/ending displacement measures collected. The photoelastic test was used to detect tension distribution throughout the structure helping to understand the material's behaviour. Values of the loading test were analysed using SAS (SAS Institute, Cary, NC, EUA). A p <0.5 (p = 0.05) was considered significant and means were compared using the Tukey test.ResultsThe results indicated that the fixation with two plates presented a higher resistance in the anteroposterior direction and fixation with a trapezoidal plate with posterior extension is more resistant towards mediolateral. The photoelastic analysis showed that the strain lines were best distributed when trapezoidal plates were used.ConclusionAccording to the results, the posterior extension of the trapezoidal plates increased the strength of the fixation system, and the use of trapezoidal plates with or without posterior extension was favourable to a more balanced stress distribution. However, clinical studies must be done to confirm the biomechanical findings.

Kinematic analysis of engagement and bending capabilities of a point-of-care, incremental skeletal fixation plate bending system

The current standard of care for skeletal reconstruction surgery is to join skeletal disunions with fixation plates and these plates are most commonly fit to bones through manual bending. The bending procedure is often performed in the surgical operating theatre with specialized pliers or, if available, lengthy pre-operative bending to fit a 3D printed skeletal model prepared on computer as part of a virtual surgical plan. Manual bending of fixation plates by eye or to a model can take considerable time. Repetitive bending at a single location can result in work hardening that increases the subsequent risk of fatigue failure. However, incremental forming systems may provide a solution to automatically bend fixation plates accurately, rapidly, and as little at any one location as possible. This paper is an investigation of the kinematics and manipulability of two versions of an incremental fixture plate bending system for Point of Care Manufacturing (POCM) of craniomaxillofacial (CMF) skeletal fixation hardware. The Automatic Plate Bender (APB) v1 is a minimal POCM system that is designed for simple straight plates with a constant incremental pitch. The APB v2 is a more complex POCM that is designed to accommodate a larger variety of standard plates. Kinematic and manipulability analysis demonstrate the engagement and bend classes that each system can accomplish, and identifies a critical singularity in the APB v2 mechanism. The paper concludes with two case studies in which a path planning algorithm uses a manipulability analysis to avoid singularities during incremental bending.

Study of a novel capacitive pressure sensor using spiral comb electrodes

Abstract For traditional capacitive pressure sensors, high nonlinearity and poor sensitivity greatly limited their sensing applications. Hence, an innovative design of capacitors based on spiral comb electrodes is proposed for high-sensitivity pressure detection in this work. Compared to traditional capacitive pressure sensors with straight plate comb electrodes, the proposed sensor with the spiral comb electrodes increases the overlap areas of electrodes sufficiently, the pressure sensitivity can thus be greatly improved. Moreover, the capacitance variation of the proposed sensor is dominated by the change of the overlap area of the electrodes rather than the electrode's distance, the linearity can also thus be improved to higher than 0.99. Theoretical analysis and COMSOL-based finite element simulation have been implemented for principle verification and performance optimization. Simulation results show that the proposed design has a mechanical sensitivity of 1.5 ×10-4 m/Pa, capacitive sensitivity of 1.10 aF/Pa, and nonlinear error of 3.63%, respectively, at the pressure range from 0 to 30 kPa. An equivalent experiment has been further carried out for verification. Experimental results also show that both the sensitivity and linearity of capacitive pressure sensors with spiral comb electrodes are higher than those with straight comb electrodes. This work not only provides a new avenue for capacitor design, but also can be applied to high-sensitivity pressure detection.

Optimal Plate Choice for High-Neck Mandibular Condyle Fracture: A Mechanistic Analysis of 16 Options

(1) Background: Mandibular fractures are common, with the condylar process being a frequent site of injury, accounting for 25–45% of cases. This research aims to assess the mechanical suitability of various plates for high-neck condyle fractures. (2) Methods: Polyurethane models mimicking high-neck condyle fractures were utilized in this study. Sixteen distinct plate designs, constructed from titanium sheets, were tested. The figures underwent force assessments on a durability testing apparatus, and the relationship between used force and fracture movement was documented. (3) Results: For high-neck breaking, the two straight plates emerged as the most effective, aligning with established osteosynthesis standards. The second-best plate exhibited nearly half the strength of the gold standard. (4) Conclusions: In response to the aim of this study, considering the mechanical aspects, the double plain plate stands out as the optimal choice for osteosynthesis in cases of high-neck fractures of the mandibular condylar process. In addition, the authors propose the Mechanical Excellence Factor (MEF) as a superior metric for appraising a plate’s mechanical force, surpassing the conventional Plate Design Factor (PDF).

Helical Plating Compared with Straight Plating and Nailing for Treatment of Proximal Third Humeral Shaft Fractures-A Biomechanical Study.

Background and Objectives: The surgical treatment of proximal humeral shaft fractures usually considers application of either long straight plates or intramedullary nails. By being able to spare the rotator cuff and avoid the radial nerve distally, the implementation of helical plates might overcome the downsides of common fixation methods. The aims of the current study were (1) to explore the biomechanical competence of different plate designs and (2) to compare their performance versus the alternative treatment option of using intramedullary nails. Materials and Methods: Twenty-four artificial humeri were assigned to the following four groups for simulation of an unstable proximal humeral shaft fracture and instrumentation: Group 1 (Straight-PHILOS), Group 2 (MULTILOC-Nail), Group 3 (45°-Helical-PHILOS), and Group 4 (90°-Helical-PHILOS). All specimens underwent non-destructive, quasi-static biomechanical testing under loading in axial compression, torsion in internal/external rotation, and pure bending in four directions, accompanied by motion tracking. Results: Axial stiffness/displacement in Group 2 was significantly higher/smaller than in all other groups (p ≤ 0.010). Torsional displacement in Group 2 was significantly bigger than in all other groups (p ≤ 0.017). Significantly smaller coronal plane displacement was identified in Group 2 versus all other groups (p < 0.001) and in Group 4 versus Group 1 (p = 0.022). Significantly bigger sagittal plane displacement was detected in Group 4 versus all other groups (p ≤ 0.024) and in Group 1 versus Group 2 (p < 0.001). Conclusions: Intramedullary nails demonstrated higher axial stiffness and smaller axial interfragmentary movements compared with all investigated plate designs. However, they were associated with bigger torsional movements at the fracture site. Although 90°-helical plates revealed bigger interfragmentary movements in the sagittal plane, they demonstrated improved resistance against displacements in the coronal plane when compared with straight lateral plates. In addition, 45°-helical plates manifested similar biomechanical competence to straight plates and may be considered a valid alternative to the latter from a biomechanical standpoint.

Which of the 37 Plates Is the Most Mechanically Appropriate for a Low-Neck Fracture of the Mandibular Condyle? A Strength Testing.

(1) Background: The mandible is the most frequently injured component of the facial skeleton, with 25-45% of mandibular fractures involving the condylar process. This study aims to mechanically compare which plates are most suitable for use in low-neck fractures of the condyle. (2) Methods: Polyurethane mandibular models with simulated low-neck fractures were tested using 37 distinct plate designs. These plates were fabricated from 1 mm thick, grade 23 titanium sheets. The models were then subjected to force tests on a strength machine, and the correlation between applied force and fracture displacement was recorded. (3) Results: For low-neck fractures, XCP side-dedicated 3+5 and ACP-T plates demonstrated strength comparable to that of two straight plates, the current gold standard in osteosynthesis. (4) Conclusions: The Mechanical Excellence Factor (MEF) introduced by the authors provides a more accurate metric for theoretically predicting a plate's mechanical strength compared to the Plate Design Factor (PDF). Eight plate characteristics were utilized to calculate the MEF. Employing the MEF allows for rapid, preliminary validation before undertaking strength tests. Furthermore, the findings of this study can guide the selection of the most durable plate designs for subsequent fatigue testing.

Medial helical versus straight lateral plating of distal femoral fractures—a biomechanical comparative study

BackgroundDistal femoral fractures are commonly treated with lateral straight plates. However, the lateral approach may not always be desirable, and 180°-helical plates may be an alternative. AimTo investigate the biomechanical competence of 180°-helical plating versus standard straight lateral plating of unstable fractures at the distal femur. MethodsTwelve left artificial femora were instrumented with a 15-hole Locking Compression Plate–Distal Femur, using either 180°-helical plates (group 1) or conventional straight lateral plates (group 2). An unstable distal femoral fracture AO/OTA 33-A3.3 was simulated. All specimens were biomechanically tested under quasi-static and progressively increasing combined cyclic axial and torsional loading in internal rotation until failure. FindingsInitial axial stiffness (N/mm) was significantly higher in group 1 (185.6 ± 50.1) compared to group 2 (56.0 ± 14.4), p < 0.001. Group 1 demonstrated significantly higher initial interfragmentary flexion (°) and significantly lower initial varus/valgus deformation (°) under 500 N static axial compression versus group 2 (2.76 ± 1.02 versus 0.87 ± 0.77 and 4.08 ± 1.49 versus 6.60 ± 0.47), p ≤ 0.005. Shear displacement (mm) under 6 Nm static torsion was significantly higher in group 1 versus group 2 in both internal (1.23 ± 0.28 versus 0.40 ± 0.42) and external (1.21 ± 0.40 versus 0.57 ± 0.33) rotation, p ≤ 0.013. Cycles to failure and failure load (N) (clinical/catastrophic) were significantly higher in group 1 (12,484 ± 2116/13,752 ± 1518 and 1748.4 ± 211.6/1875.2 ± 151.8) compared to group 2 (7853 ± 1262/9727 ± 836 and 1285.3 ± 126.2/1472.7 ± 83.6), p ≤ 0.001. InterpretationAlthough 180°-helical plating using a pre-contoured standard straight lateral plate was associated with higher shear and flexion movements, it demonstrated improved initial axial stability and resistance against varus/valgus deformation compared to straight lateral plating. Moreover, the helical plates were associated with significantly higher endurance to failure. From a biomechanical perspective, 180°-helical plating may be considered as a valuable alternative to standard straight lateral plating of unstable distal femoral fractures.

Mechanical evaluation of different sagittal osteotomy fixation techniques used in minimally invasive surgery

Minimally invasive orthognathic surgery has advantages such as faster recovery, less paresthesia, and lower morbidity in the immediate postoperative period. However, there is no consensus regarding which fixation method is safer. The aim of the present study is to compare different methods of fixation of the short sagittal osteotomy like the Cordier G modification performed in minimally invasive surgery. An in vitro study was performed, consisting of 54 standardized polyurethane synthetic hemimandibles with Short sagittal osteotomy divided into 6 groups comprising 09 hemimandibles each. The groups consisted of bicortical screws, 4-hole straight plates, 0.8 mm and 1.0 mm thick curved plates, and 0.8 mm thick double Y and 1.0 mm thick double Y plates. All groups are System 2.0 and trademark Artfix®. The loading test was carried out, at a speed of 1mm/min, with a 50 Kgf load note for progressive load application on the system. Peak load (Kgf) and peak displacement (mm) were evaluated. Greater load resistance was found in the groups that received bicortical screws and 0.8mm and 1.0mm thick double Y plates.

Evaluation of the Relationship of Screw Pullout and Plate Fracutre in Fixation of Mandible Condyle Fractures: A Mechanistic Study.

The mandible is the most injured part of the facial skeleton, and 25-40% of mandibular fractures involve the condyle process. The aim of this study is to answer the question of the relationship between screw pullout and/or plate fracture during osteosynthesis. We tested polyurethane models of mandibles whose condylar process was cut (simulating a fracture) and fused using plates and screws. A total of 672 plates were tested. A total of 25.6% of them were fractured during the test, with most being fractures of the base of the condyle. More screws (81.97%) are pulled out from the ramus than from the condyle-69.15%. The gold standard in the osteosynthesis of condylar fractures is two straight plates. Other than these, there is no one-size-fits-all plate for every type of fracture. Plates fixed with fewer screws (smaller plates used in higher-lying fractures) are more likely to result in screw pullout. On the other hand, in plates fixed with more screws, plate fracture is more common.

Translated article] The use of an anatomical implant compared to a straight LCP decreases extraction in posterior humeral MIPO

PurposePosterior MIPO approach in the humerus has been described by using a 4.5mm LCP plate. Although straight plates have shown good results, they have not been designed to adapt to the distal humeral metaphysis. The goal of the study was to test the null hypothesis that there is no difference in hardware removal after posterior MIPO with either a straight or a pre-contoured plate. MethodsPatients older than 18 years, who had suffered mid-distal humeral shaft fracture, were treated by a posterior MIPO technique with a locking plate and had a minimum of 12-month follow-up were retrospectively included. Patients were separated into: group 1 (LCP 4.5mm straight plate); and group 2 (3.5mm anatomically shaped plate). Clinical and radiological evaluations were performed in the postoperative period. Patient-reported outcomes and the need of hardware removal because of pain were assessed. ResultsSixty-seven patients fulfilled the inclusion criteria. Twenty-seven patients in group 1 and 40 in group 2. No patient was lost to follow-up. There were no statistical differences between in patient reported outcomes measures. All the fractures healed. Within group 1, 18% (95%CI: 6–38%) of the patients required implant removal while in group 2 this incidence was 0% (95%CI: 0–9%) (P 0.009). ConclusionThese results suggest that the use of a 4.5mm LCP compared to an anatomical 3.5mm LCP in posterior MIPO of the humerus generates greater discomfort and therefore leads to a 18% increase in the risk of implant removal.

Сравнительный анализ репозиционных возможностей ортопедического гексапода Орто-СУВ и его минимизированной («педиатрической») версии (экспериментальное исследование)

Introduction Currently, orthopedic hexapods have been effectively used for long bone, foot and large joint deformity correction in both adults and children. Previous studies demonstrated the superiority of the reduction capabilities of the orthopedic hexapod Ortho-SUV Frame (OSF) in comparison with other designs of external fixation devices. However, the reduction capabilities of the minimized version of this hexapod (minimized Ortho-SUV Frame, OSFm) have not been studied yet. Purpose To identify the reduction capabilities of OSFm compared to OSF. Materials and methods The bench test was performed using plastic models of the tibia osteotomized at the middle third of the shaft. One-ring modules were used to fix each of the bone fragments. In the first series of the experiment, the reduction capabilities of OSFm with a standard strut size and in the second series OSF with a short strut size were studied. In each series of experiments, three groups were studied depending on the method of fixing the struts to the rings: directly to the ring, using straight plates, and using Z-shaped plates. Reduction capabilities were assessed by the maximum displacement of the distal bone fragment relative to the proximal one in distraction, translation, angulation, and rotation. Results The magnitude of the maximum distraction of OSF and OSFm with fixation of the struts directly to the rings and with the use of straight plates is the same (p &gt; 0.05). With Z-plates, OSFm outperforms OSF by 27.3 %. OSFm surpasses OSF by 2.8-29.3 % in terms of the planar-parallel movement. OSFm surpasses OSF by 29.6-55.4% in terms of angular movement capabilities. The study of rotational movement found that OSFm exceeds the capabilities of OSF by 20.3-41.3%. Conclusion The findings obtained indicate that OSFm, in comparison with OSF, has better deformity correction capabilities.

Distal femur fractures management and evolution in the last century.

The purpose of this historical review is to illustrate the progression and evolution of treatment for distal femur fractures. Scientific literature was searched for descriptions of treatment for distal femur fractures to provide an in-depth overview of the topic, with emphasis on the evolution of surgical constructs used to treat these fractures. Prior to the 1950s, distal femur fractures were treated nonoperatively, resulting in considerable morbidity, limb deformity, and limited function. As principles of surgical intervention for fractures emerged in the 1950s, surgeons developed conventional straight plates to better stabilize distal femur fractures. Angle blade plates and dynamic condylar screws emerged out of this scaffolding to prevent post-treatment varus collapse. Meanwhile, intramedullary nails, and later, in the 1990s, locking screws, were introduced to minimize soft tissue disruption. Treatment failure led to the development of locking compression plates with the advantage of accommodating either locking or nonlocking screws. Despite this advancement, the rare but significant incidence of nonunion has not been eliminated, leading to the recognition of the biomechanical environment as important for prevention and the development of active plating techniques. Emphasis for the surgical treatment of distal femur fractures has incrementally progressed over time, with initial focus on complete stabilization of the fracture while the biological environment surrounding the fracture was ignored. Techniques slowly evolved to minimize soft tissue disruption, allow more ease of implant placement at the fracture site, and attend to the systemic health of the patient, while simultaneously ensuring appropriate fracture fixation. Through this dynamic process, the desired results of complete fracture healing and maximization of functional outcomes have emerged.

HELICAL PLATING VERSUS STRAIGHT PLATING AND INTRAMEDULLARY NAILING OF PROXIMAL THIRD HUMERAL SHAFT FRACTURES: A BIOMECHANICAL COMPARATIVE STUDY

Proximal humeral shaft fractures are commonly treated with long straight plates or intramedullary nails. Helical plates might overcome the downsides of these techniques as they are able to avoid the radial nerve distally. The aim of this study was to investigate in an artificial bone model: (1) the biomechanical competence of different plate designs and (2) to compare them against the alternative treatment option of intramedullary nails.Twenty-four artificial humeri were assigned in 4 groups and instrumented as follows: group1 (straight 10-hole-PHILOS), group2 (MULTILOCK-nail), group3 (45°-helical-PHILOS) and group4 (90°-helical-PHILOS). An unstable proximal humeral shaft fracture was simulated. Specimens were tested under quasi-static loading in axial compression, internal/external rotation and bending in 4 directions monitored by optical motion tracking.Axial displacement (mm) was significantly lower in group2 (0.1±0.1) compared to all other groups (1: 3.7±0.6; 3: 3.8±0.8; 4: 3.5±0.4), p&lt;0.001. Varus stiffness in group2 (0.8±0.1) was significantly higher compared to groups1+3, p≤0.013 (1: 0.7±0.1; 3: 0.7±0.1; 4: 0.8±0.1). Varus bending (°) was significantly lower in group2 compared to all other groups (p&lt;0.001) and group4 to group1, p=0.022. Flexion stiffness in group1 was significantly higher compared to groups2+4 (p≤0,03) and group4 to group1, p≤0,029 (1: 0.8±0.1; 2: 0.7±0.1; 3: 0.7±0.1; 4: 0.6±0.1). Flexion bending (°) in group4 was higher compared to all other groups (p≤0.024) and lower in group2 compared to groups1+4, p≤0.024. Torsional stiffness remained non significantly different, p≥0.086. Torsional deformation in group2 was significantly higher compared to all other groups, p≤0.017. Shear displacement remained non significantly different, p≥0.112.From a biomechanical perspective, helical plating with 45° and 90° may be considered as a valid alternative fixation technique to standard straight plating of proximal third humeral fractures. Intramedullary nails demonstrated higher axial and bending stiffness as well as lower fracture gap movements during axial loading compared to all plate designs. However, despite similar torsional stiffness they were associated with higher torsional movements during internal/external rotation as compared to all investigated plate designs.

ANATOMICAL ANALYSIS OF DIFFERENT HELICAL PLATE DESIGNS FOR PROXIMAL HUMERAL SHAFT FRACTURE FIXATION

Helical plates are preferably used for proximal humeral shaft fracture fixation and potentially avoid radial nerve irritation as compared to straight plates. Aims:(1) to investigate the safety of applying different long plate designs (straight, 45°-, 90°-helical and ALPS) in MIPO-technique to the humerus. (2) to assess and compare their distances to adjacent anatomical structures at risk.MIPO was performed in 16 human cadaveric humeri using either a straight plate (group1), a 45°-helical (group2), a 90°-helical (group3) or an ALPS (group4). Using CT-angiography, distances between brachial arteries and plates were evaluated. Following, all specimens were dissected, and distances to the axillary, radial and musculocutaneous nerve were evaluated.None of the specimens demonstrated injuries of the anatomical structures at risk after MIPO with all investigated plate designs. Closest overall distance (mm(range)) between each plate and the radial nerve was 1(1-3) in group1, 7(2-11) in group2, 14(7-25) in group3 and 6(3-8) in group4. It was significantly longer in group3 and significantly shorter in group1 as compared to all other groups, p&lt;0.001. Closest overall distance (mm(range)) between each plate and the musculocutaneous nerve was 16(8-28) in group1, 11(7-18) in group2, 3(2-4) in group3 and 6(3-8) in group4. It was significantly longer in group1 and significantly shorter in group3 as compared to all other groups, p&lt;0.001. Closest overall distance (mm(range)) between each plate and the brachial artery was 21(18-23) in group1, 7(6-7) in group2, 4(3-5) in group3 and 7(6-7) in group4. It was significantly longer in group1 and significantly shorter in group3 as compared to all other groups, p&lt;0.021.MIPO with 45°- and 90°-helical plates as well as ALPS is safely feasible and showed a significant greater distance to the radial nerve compared to straight plates. However, distances remain low, and attention must be paid to the musculocutaneous nerve and the brachial artery when MIPO is used with ALPS, 45°- and 90°-helical implants. Anterior parts of the deltoid insertion will be detached using 90°-helical and ALPS implants in MIPO-technique.

ANATOMICAL ANALYSIS OF DIFFERENT HELICAL PLATE DESIGNS FOR DISTAL FEMORAL FRACTURE FIXATION

Helical plates potentially bypass the medial neurovascular structures of the thigh. Recently, two plate designs (90°- and 180°-helix) proved similar biomechanically behaviour compared to straight plates. Aims of this study were: (1) Feasibility of MIPO-technique with 90°- and 180°-helical plates on the femur, (2) Assessment of distances to adjacent anatomical structures at risk, (3) Comparison of these distances to using medial straight plates instead, (4) Correlation of measurements performed in anatomic dissection with CT-angiography.MIPO was performed in ten cadaveric femoral pairs using either a 90°-helical 14-hole-LCP (Group1) or a 180°-helical 15-hole-LCP-DF (Group2). CT angiography was used to evaluate the distances between the plates and the femoral arteries as well as the distances between the plates and the perforators. Subsequently, the specimens were dissected, and the distances were determined again manually. Finally, all helical plates were removed, and all measurements were repeated after application of straight medial plates (Group3).Closest overall distances between plates and femoral arteries were 15 mm (11 − 19 mm) in Group1, 22 mm (15 − 24 mm) in Group2 and 6 mm (1 − 8 mm) in Group3 with a significant difference between Group1 and Group3 (p &lt; 0.001). Distances to the nearest perforators were 24 mm (15 − 32 mm) in Group1 and 2 mm (1 − 4 mm) in Group2. Measurement techniques (visual after surgery and CT-angiography) demonstrated a strong correlation of r2 = 0.972 (p &lt; 0.01).MIPO with 90°- and 180°-helical plates is feasible and safe. Attention must be paid to the medial neurovascular structures with 90°-helical implants and to the proximal perforators with 180°-helical implants. Helical implants can avoid medial neurovascular structures compared to straight plates although care must be taken during their distal insertion. Measurements during anatomical dissection correlate with CT-angiography.

HELICAL VERSUS STRAIGHT PLATING OF PROXIMAL THIRD HUMERAL SHAFT FRACTURES - A BIOMECHANICAL STUDY

Proximal humeral shaft fractures are commonly treated with long straight locking plates endangering the radial nerve distally. The aim of this study was to investigate the biomechanical competence in a human cadaveric bone model of 90°-helical PHILOS plates versus conventional straight PHILOS plates in proximal third comminuted humeral shaft fractures.Eight pairs of humeral cadaveric humeri were instrumented using either a long 90°-helical plate (group1) or a straight long PHILOS plate (group2). An unstable proximal humeral shaft fracture was simulated by means of an osteotomy maintaining a gap of 5cm. All specimens were tested under quasi-static loading in axial compression, internal and external rotation as well as bending in 4 directions. Subsequently, progressively increasing internal rotational loading until failure was applied and interfragmentary movements were monitored by means of optical motion tracking.Flexion/extension deformation (°) in group1 was (2.00±1.77) and (0.88±1.12) in group2, p=0.003. Varus/valgus deformation (°) was (6.14±1.58) in group1 and (6.16±0.73) in group2, p=0.976. Shear (mm) and displacement (°) under torsional load were (1.40±0.63 and 8.96±0.46) in group1 and (1.12±0.61 and 9.02±0.48) in group2, p≥0.390. However, during cyclic testing shear and torsional displacements and torsion were both significantly higher in group 1, p≤0.038. Cycles to catastrophic failure were (9960±1967) in group1 and (9234±1566) in group2, p=0.24.Although 90°-helical plating was associated with improved resistance against varus/valgus deformation, it demonstrated lower resistance to flexion/extension and internal rotation as well as higher flexion/extension, torsional and shear movements compared to straight plates. From a biomechanical perspective, 90°-helical plates performed inferior compared to straight plates and alternative helical plate designs with lower twist should be investigated in future paired cadaveric studies.

Pengaruh pulse current terhadap kekuatan bending implan micro-plate hasil dari proses edm die-sinking

Micro-plate implants are jaw implants in the form of straight plates. The need for micro-plate implants in Indonesia is quite high. Current micro-plate implants are fabricated using two machining processes, namely Wire Electrical Discharge Machining (wire-EDM) and micro-milling. These two processes are one of the reasons why the price of micro-plate implants in the market is expensive. One way to lower the price of implants is to shorten the implant manufacturing process. This research develops a process for manufacturing micro-plate implants using the EDM die-sinking process. The main objective of this study was to investigate the effect of pulse current on the bending strength of micro-plate implants resulting from the EDM die-sinking process. The micro-plate implant material uses commercially pure titanium (CP-Ti) with a thickness of 400 μm. The implant manufacturing process uses a pulse current of 6, 9 and 13 A. The electrode material uses graphite. The results showed that the bending strength of micro-plate implants increased with an increase in pulse current. In addition, the increase in pulse current also causes the micro-plate implant to become soft. This is indicated by the elongation value of the micro-plate implant which increases as the pulse current increases.

La utilización de un implante anatómico comparado a una LCP recta disminuye su extracción en la osteosíntesis percutánea posterior del húmero

PurposePosterior MIPO approach in the humerus has been described by using a 4.5mm LCP plate. Although straight plates have shown good results, they have not been designed to adapt to the distal humeral metaphysis. The goal of the study was to test the null hypothesis that there is no difference in hardware removal after posterior MIPO with either a straight or a pre-contoured plate. MethodsPatients older than 18 years, who had suffered mid-distal humeral shaft fracture, were treated by a posterior MIPO technique with a locking plate and had a minimum of 12-month follow-up were retrospectively included. Patients were separated into: group 1 (LCP 4.5mm straight plate); and group 2 (3.5mm anatomically shaped plate). Clinical and radiological evaluation were performed in the postoperative period. Patient-reported outcomes and the need of hardware removal because of pain were assessed. ResultsSixty-seven patients fulfilled the inclusion criteria. Twenty-seven patients in group 1 and 40 in group 2. No patient was lost to follow-up. There were no statistical differences between in patient reported outcomes measures. All the fractures healed. Within group 1, 18% (95%CI: 6-38%) of the patients required implant removal while in group 2 this incidence was 0% (95%CI: 0-9%) (P 0.009). ConclusionThese results suggest that the use of a 4.5mm LCP compared to an anatomical 3.5mm LCP in posterior MIPO of the humerus generates greater discomfort and therefore leads to a 18% increase in the risk of implant removal.