Effect of plate orientation on apparent thickness of mineral plates by transmission electron microscopy.

PURPOSE: Transmission electron microscopy (TEM) is widely used to study the ultrastructure of bone. The mineral of bone occurs as polycrystalline mineral plates about 3 to 6 nm in thickness. A problem in using TEM to make quantitative analyses of bone is that the orientation of the plates with respect to the plane of the section being imaged is expected to affect their apparent thickness. The purpose of this study was to test if this was true, if the apparent thickness of plates changed substantially as a result of tilt of the section. METHODS: We prepared TEM sections of samples of cortical human bone by ion beam milling, orienting one section parallel to the collagen fibril axes and one perpendicular to them. We obtained TEM bright field and HAADF images of these sections, tilting the sections up to ± 20° at 2° intervals and measuring the apparent thickness of individual mineral platelets at each angle of tilt. RESULTS: Thickness appears to double as section is tilted ± 20°. True thickness of plates is determined by tilting the section along an axis parallel to the plate orientation and determining the minimum apparent thickness. However, as plates are tilted away from minimum-thickness orientation, they become less well-resolved, disappearing when tilted more than 20°. We therefore also measured apparent thickness of only the darkest (most electron scattering) plate images in an untilted section and obtained the same average thickness as that obtained by tilting. CONCLUSION: We conclude that tilting of the section is not necessary to obtain an accurate measurement of the thickness of mineral plates.

Cement-augmented locked plate fixation proximal humerus fractures in elderly patient: a systematic review and meta-analysis.

BACKGROUND: This systemic review and meta-analysis aimed to evaluate the clinical outcomes of proximal humeral fracture in elderly patient fixation using locked plate with or without cement augmentation. METHODS: The databases of PubMed, Embase, and Cochrane Library were searched in August 2023 for literature comparing the clinical outcomes of patients with PHFs treated with locked plate alone and locked plate augmented with cement. Data describing study design; level of evidence; inclusion criteria; demographic information; final follow-up; revision rate; implant failure rate; avascular necrosis rate; total complication rate; constant score; and disability of arm, shoulder, and hand (DASH) score were collected. RESULTS: Eight studies (one randomized-controlled trial and seven observational studies), involving 664 patients, were identified. Compared with locked plates alone, using cement-augmented locked plates reduced the implant failure rate (odds ratio (OR) = 0.19; 95% confidence interval (CI) 0.10-0.39; P < 0.0001) and total complication rate (OR = 0.45; 95% CI 0.29-0.69; P = 0.0002) and improved DASH scores (mean difference (MD) = 2.99; 95% CI 1.00-4.98; P = 0.003). However, there was no significant difference in clinical outcomes, including revision rate, avascular necrosis rate, and constant score. CONCLUSION: In this review and meta-analysis, fixation of the PHFs in elderly patients using locked plates with or without cement augmentation has no significant difference in revision rate, but the implant failure and total complication rates may be lesser on using the cement-augmented locked plate for fixation than on using a locked plate alone. Good results are expected for most patients treated with this technique. TRIAL REGISTRATION: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)21 guidelines were followed to conduct this systematic review and meta-analysis and was registered as a protocol in PROSPERO (CRD42022318798).

Making developmental sense of the senses, their origin and function.

The primary senses-touch, taste, sight, smell, and hearing-connect animals with their environments and with one another. Aside from the eyes, the primary sense organs of vertebrates and the peripheral sensory pathways that relay their inputs arise from two transient stem cell populations: the neural crest and the cranial placodes. In this chapter we consider the senses from historical and cultural perspectives, and discuss the senses as biological faculties. We begin with the embryonic origin of the neural crest and cranial placodes from within the neural plate border of the ectodermal germ layer. Then, we describe the major chemical (i.e. olfactory and gustatory) and mechanical (i.e. vestibulo-auditory and somatosensory) senses, with an emphasis on the developmental interactions between neural crest and cranial placodes that shape their structures and functions.

Enhanced fabrication of size-controllable chitosan-genipin nanoparticles using orifice-induced hydrodynamic cavitation: Process optimization and performance evaluation.

Chitosan nanoparticles (NPs) possess great potential in biomedical fields. Orifice-induced hydrodynamic cavitation (HC) has been used for the enhancement of fabrication of size-controllable genipin-crosslinked chitosan (chitosan-genipin) NPs based on the emulsion cross-linking (ECLK). Experiments have been performed using various plate geometries, chitosan molecular weight and under different operational parameters such as inlet pressure (1-3.5 bar), outlet pressure (0-1.5 bar) and cross-linking temperature (40-70 °C). Orifice plate geometry was a crucial factor affecting the properties of NPs, and the optimized geometry of orifice plate was with single hole of 3.0 mm diameter. The size of NPs with polydispersity index of 0.359 was 312.6 nm at an optimized inlet pressure of 3.0 bar, and the maximum production yield reached 84.82 %. Chitosan with too high or too low initial molecular weight (e.g., chitosan oligosaccharide) was not applicable for producing ultra-fine and narrow-distributed NPs. There existed a non-linear monotonically-increasing relationship between cavitation number (Cv) and chitosan NP size. Scanning electron microscopy (SEM) test indicated that the prepared NPs were discrete with spherical shape. The study demonstrated the superiority of HC in reducing particle size and size distribution of NPs, and the energy efficiency of orifice type HC-processed ECLK was two orders of magnitude than that of ultrasonic horn or high shear homogenization-processed ECLK. In vitro drug-release studies showed that the fabricated NPs had great potential as a drug delivery system. The observations of this study can offer strong support for HC to enhance the fabrication of size-controllable chitosan-genipin NPs.

Functional outcomes and complications of plate fixation for midshaft clavicle fractures by type and location: a systematic review and meta-analysis.

Background: Various plate types are used in the surgical treatment of displaced midshaft clavicle fractures. These plates can be positioned in different locations on the clavicle, although no studies to date have elucidated optimal plate type and location of fixation. This systematic review compares the functional outcomes and complications in the management of displaced midshaft clavicle fractures using plate fixation by stratifying by both plate type and location. Methods: A systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted to identify all papers reporting functional outcomes, union rates, and/or complications using plates for the management of midshaft clavicle fractures. Multiple databases and trial registries were searched from inception until March 2022. A meta-analysis was conducted for functional outcomes and type of complication, stratified by plate type (locking, compression, or reconstruction) and location (superior or anteroinferior). Pooled estimates of functional outcome scores and incidence of complications were calculated using a random effects model. Risk of bias and quality were assessed using the risk of bias version 2 and ROBINS-I (Risk Of Bias In Non-randomised Studies - of Interventions) tools. The confidence in estimates were rated and described according to the recommendations of the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) working group. Results: Forty-five studies were included in the systematic review and 43 were included in the meta-analysis. Depending on plate type and location, pooled Constant-Murley Scores ranged from 89.23 to 93.48 at 12 months. Nonunion rates were 3% (95% confidence interval [CI] 1-6) for superior locking plates (GRADE Low). Rates of any complication (nonunion, hardware failure, hardware irritation, wound dehiscence, keloid, superficial infection, deep infection, delayed union, malunion, and/or persistent pain) by plate type and location ranged from 3% to 17% (GRADE Very Low to Moderate). Superior compression plates had the highest incidence of any complications (17% [95% CI 5-44], GRADE Very Low), while anterior inferior compression plates had the lowest incidence of any complication (3% [95% CI 0-15], GRADE Very Low). Hardware irritation was the most reported individual complication for superior locking plates and superior compression plates, 11% (95% CI 7-17, GRADE Low) and 11% (95% CI 3-33, GRADE Very Low), respectively. Conclusion: Although most studies were of low quality, studies reporting functional outcomes generally showed good functional results and similar incidence of any complication regardless of plate type and location. There is no evidence of a plate and location combination to optimize patient functional outcomes or complications. We were unable to reliably evaluate union rates or individual complications for most plate types stratified by location.

Intramedullary Plate Fixation and Viable Bone Allografting in a Complex Intra-articular Distal Radius Fracture Nonunion: A Case Report.

In this report, we detail a 69-year-old female who sustained a comminuted intra-articular left distal radius fracture that failed to heal with bridge plate fixation. Given the patient's poor subchondral bone stock and refusal of bone autograft, we designed a construct using a dorsal spanning plate and an intramedullary fragment-specific plate as a volarly placed strut in combination with viable bone allograft and cancellous bone chips to treat this nonunion. This case demonstrates an option for distal radius non-union treatment and highlights the importance of ingenuity that orthopedic surgeons should demonstrate when trying to accommodate patients' wishes.

Topology optimization of the flat steel shear wall based on the volume constraint and strain energy assumptions under the seismic loading conditions.

In structural engineering systems, shear walls are two-dimensional vertical elements designed to endure lateral forces acting in-plane, most frequently seismic and wind loads. Shear walls come in a variety of materials and are typically found in high-rise structures. Because steel shear walls are lighter, more ductile, and stronger than other concrete shear walls, they are advised for usage in steel constructions. It is important to remember that the steel shear wall has an infill plate, which can be produced in a variety of forms. The critical zones in flat steel shear walls are the joints and corners where the infill plate and frame meet. The flat infill plate can be modified to improve the strength and weight performance of the steel shear walls. One of these procedures is Topology Optimization (TO) and this method can reduce the weight and also, increase the strength against the cyclic loading sequences. In the current research paper, the TO of the infill steel plate was considered based on the two methods of volume constraint and maximization of strain energy. Four different volumes (i.e., 60%, 70%, 80%, and 90%) were assumed for the mentioned element in the steel shear wall. The obtained results revealed that the topology configuration of CCSSW with 90% volume constraint presented the highest seismic loading performance. The cumulated energy for this type of SSW was around 700 kJ while it was around 600 kJ for other topology optimization configurations.

Comparing the modified socket-shield technique with the conventional immediate implantation technique in the anterior dentition: A 5-year retrospective clinical study.

AIMS: The aim of this retrospective clinical study was to compare the 5-year radiological and clinical outcomes of patients undergoing immediate implantation with or without the modified socket-shield technique. MATERIALS AND METHODS: Patients who underwent anterior tooth replacement via the modified socket-shield technique (MSST) or the conventional immediate implantation technique (CIIT) between 2016 and 2017 were included. The labial bone thickness was assessed at different measurement levels (0, 2, 4 and 6 mm apical to the implant shoulder (IS)) postoperatively (T1), 6 months postoperatively (T2) and 5 years postoperatively (T3). The pink aesthetic score (PES) was evaluated before surgery (T0) and at T2 and T3. Implant success, complications and patient satisfaction were evaluated at every visit. RESULTS: Thirty-six patients (18 in the MSST group) underwent follow-up for 5 years, with no cases of implant failure. Two cases of exposure were detected in the MSST group, but there were no significant effects on hard or soft tissue. Patients in the MSST group showed less and more stable bone resorption than did those in the CIIT group at any measurement level and any time. A higher PES was achieved in the MSST group. Patient satisfaction was similar in both groups. CONCLUSIONS: The MSST is a reliable immediate implantation method because of its ability to preserve the alveolar bone and provide superior recovery of aesthetics.

[Is the 95°blade plate still important in the treatment of proximal femoral pseudarthrosis?] / Hat die 95°-Winkelplatte bei der Behandlung von proximalen Femurpseudarthrosen noch einen Stellenwert?

Due to demographic changes, fractures and subsequently delayed fracture healing as well as pseudarthrosis of the proximal femur are on the increase. In the acute fracture situation, a load-stable treatment with an intramedullary implant (cephalomedullary nail) is generally sought. To date, there is no uniform consensus on the optimal treatment for complicated cases. The aim of this study was to evaluate the clinical and radiological outcome after revision of pseudarthrosis using a 95° blade plate in aseptic proximal femoral pseudarthrosis and to identify the specifications of blade plate treatment.The retrospective study design was used to evaluate data, some of which were prospectively collected. The study period covered January 2010 to December 2020 and 22 patients (10 women, 12 men) with an average age of 59 years were included in this single-center study. All patients showed pseudarthrosis after a femoral fracture type AO 31 A1-A3 or proximal femoral fracture type AO 32 A-C. Clinical and radiological follow-up were performed after 3, 6 and 12 months. Functional outcomes were assessed using the modified Harris hip score (mHHS), the numerical rating scale (NRS) and the short form health survey (SF-12).The postoperative radiological results after reosteosynthesis using a blade plate showed good results and 86.4% of the patient population were healed during the observation period. Pseudarthrosis persisted in four patients and was surgically revised.The functional results showed good results on average, albeit with a high dispersion of 17-91 points in the mHHS. The SF-12 averaged 42.6 (±10.4) points and the psychological score 49.4 (±9.6) points. The postoperative pain level was low both at rest and under stress.It was shown that reosteosynthesis with a blade plate is a surgically demanding but effective treatment option with a low potential for infection and safe bone consolidation, especially for the correction of high-grade axial deviation or varus malalignment.

Optimizing hook implantation angle of the clavicular hook plate: a cadaveric study.

PURPOSE: While Clavicle hook plates have demonstrated favorable results regarding bone and shoulder function, their design can potentially lead to complications due to pressure concentration at the plate's tip. This study aims to investigate the impact of different hook implantation angles on the contact surface area between the hook plate and acromion, with the goal of minimizing mismatch and maximizing contact surface area. METHODS: Twenty soft shoulder cadavers were included in the study, and the contact surface area of the hook plate was measured in different positions based on the hook implantation angle. RESULTS: The results showed variations in compatibility, width, and length of the contact surface area depending on the hook implantation angle and the medial or lateral row placement. The lateral row generally demonstrated superior compatibility (84.0% vs 46.67%, p-value < 0.001), with a broader contact area (3.55 ± 0.08 mm vs 3.09 ± 0.10 mm, p-value = 0.004) and a longer contact area (7.36 ± 0.19 mm vs 5.10 ± 0.23 mm, p-value < 0.001) at specific angles. A detailed analysis of the lateral position revealed that the zero angle of implantation resulted in the greatest contact surface area, measuring 3.91 ± 0.70 mm in width (p value = 0.083) and 8.85 ± 1.24 mm in length (p value < 0.001). CONCLUSION: Placing the hook laterally and at the zero position according to the hook implantation angle can maximize contact surface area, may reduce stress concentration, and minimize complications in hook plate fixation. Further research and consideration of anatomical variations are warranted to refine the placement technique and enhance patient outcomes. LEVEL OF EVIDENCE: Level V evidence.

Locking Attachment Plate for the Surgical Treatment of Periprosthetic and Periimplant Fractures: Long-Term Follow-Up.

Objectives: The surgical management of periprosthetic fractures (PPF) and periimplant fractures (PIF) can be challenging. The locking attachment plate (LAP) was proposed in recent years for the osteosynthesis of such fractures. The aim of this study was to assess the experience of a third-level hospital with LAP for the treatment of PPF and PIF, and analyse the clinical outcomes. Methods: Data were prospectively collected and analysed from all patients whose PPF/PIF was treated surgically with LAP in a third-level hospital from June 2018 to June 2022. All fractures were postoperative low-energy femur fractures. The minimum follow-up period was six months. Results: Thirty-eight patients (31 women) met the eligibility criteria. The mean age was 86.3 years. The median time until surgery was 4 days. A mean of 3.61 screws were used for each LAP. The mean femur plate length was 14 holes, and the mean working length 7.1 holes. The median hospital stay was nine days. The mean follow-up was 19.56 months. At one month, 12 patients tolerated partial weight-bearing. Five patients walked independently indoors. One patient had died and seven patients were readmitted. At six months, six more patients had died. Fifteen patients tolerated full weight-bearing (FWB). Nine patients walked independently indoors, six outdoors. Twenty-five patients reached fracture consolidation without malalignment. Nine patients were readmitted. At 12 months, another patient had died. Seventeen patients tolerated FWB. Eleven patients walked independently indoors, six outdoors. Twenty-five patients achieved fracture consolidation without malalignment. Five patients were readmitted. Fourteen patients crossed the two-year postoperative threshold. All achieved fracture consolidation. Two patients passed the 4-year postoperative milestone. Conclusion: The clinical results of patients whose PPF or PIF was treated with the LAP are promising. This fixation method is a viable option to be considered when planning surgery for such fractures.

Embryology of the fat-tailed dunnart (Sminthopsis crassicaudata): A marsupial model for comparative mammalian developmental and evolutionary biology.

BACKGROUND: Marsupials are a diverse and unique group of mammals, but remain underutilized in developmental biology studies, hindering our understanding of mammalian diversity. This study focuses on establishing the fat-tailed dunnart (Sminthopsis crassicaudata) as an emerging laboratory model, providing reproductive monitoring methods and a detailed atlas of its embryonic development. RESULTS: We monitored the reproductive cycles of female dunnarts and established methods to confirm pregnancy and generate timed embryos. With this, we characterized dunnart embryo development from cleavage to birth, and provided detailed descriptions of its organogenesis and heterochronic growth patterns. Drawing stage-matched comparisons with other species, we highlight the dunnarts accelerated craniofacial and limb development, characteristic of marsupials. CONCLUSIONS: The fat-tailed dunnart is an exceptional marsupial model for developmental studies, where our detailed practices for reproductive monitoring and embryo collection enhance its accessibility in other laboratories. The accelerated developmental patterns observed in the Dunnart provide a valuable system for investigating molecular mechanisms underlying heterochrony. This study not only contributes to our understanding of marsupial development but also equips the scientific community with new resources for addressing biodiversity challenges and developing effective conservation strategies in marsupials.

Use of a novel three-dimensional anatomical plating system for treatment of caudal mandibular fractures in cats: 13 cases (2019-2023).

CASE SERIES SUMMARY: A total of 13 cases of cats with a caudal mandibular fracture treated with a novel surgical technique using the Ramus Anatomical Plate system were reviewed. Preoperative, immediate postoperative and a minimum of 8 weeks postoperative CT images were required as inclusion criteria. The outcome and complications were determined from clinical data and radiographic follow-up examinations. All cases achieved adequate anatomical reduction, resulting in a functional and atraumatic occlusion postoperatively. No intraoperative complications were reported. Time to voluntary food intake was in the range of 1-25 days. No evidence of disruptions to the implants or screw loosening was observed in the 8-week postoperative CT imaging, with radiographic evidence of complete osseous union in all fractures. The most common postoperative complication was swelling at the surgical site. Two cats had postoperative exophthalmos due to retrobulbar haemorrhage, and one cat exhibited partial wound dehiscence 5 days postoperatively, which resolved with medical management. Longer-term complications included intraoral plate exposure in one cat, which required plate removal 10 months postoperatively. RELEVANCE AND NOVEL INFORMATION: In this case series, rigid internal fixation of caudal mandibular fractures using the Ramus Anatomical Plate osteosynthesis system was associated with a minimal complication rate, and satisfactory radiographic and clinical outcomes. The reported outcomes of this novel technique are favourable when compared with previous techniques described for the management of these fracture types.

Accuracy of Modern Intraocular Lens Formulas in Highly Myopic Eyes Implanted with Plate-Haptic Intraocular Lenses.

PURPOSE: To evaluate the predictive accuracy of modern intraocular lens (IOL) formulas and axial length (AL) adjusted traditional IOL formulas, including Wang-Koch and Cooke-modified AL (CMAL) method, in long eyes with plate-haptic IOLs, and to compare refractive prediction error variances with C-loop IOLs. DESIGN: Retrospective consecutive case series study. METHODS: Data from 391 eyes with Zeiss 509M and 302 eyes with Alcon SN6CWS implants in highly myopic patients, following cataract surgery from January 2019 to November 2023, were collected. One eye per patient was selected. Predictive outcomes of 15 modern formulas (Barrett Universal II (BU II), Cooke K6 (K6), Emmetropia Verifying Optical (EVO) 2.0, Hoffer-QST, Kane, Karmona, Ladas AI, Naeser 2, Olsen, Pearl-DGS, Radial Basis Function (RBF) 3.0, T2, VRF-G, Zhu-Lu, and Z-Calc) and 4 traditional IOL formulas (Haigis, Hoffer Q, Holladay 1, and SRK/T) with AL adjusted methods, were evaluated. The mean prediction error, mean absolute prediction error (MAE), root-mean-square absolute prediction error (RMSAE) and the proportions of eyes with PEs within ±0.25 Diopter (D), ±0.50 D, ±0.75 D and ±1.00 D were analyzed. Top 10 RMSAE-ranked formulas underwent further subgroup analysis based on AL, anterior chamber depth (ACD), and keratometry (K). RESULTS: For the 509M group, RMSAE ranking for the top 10 IOL formulas were the RBF 3.0 (0.432), Zhu-Lu (0.436), Olsen (0.436), EVO 2.0 (0.437), Pearl-DGS (0.447), K6 (0.452), VRF-G (0.454), Naeser 2 (0.464), Haigis-CMAL (0.465) and Karmona (0.477). Karmona and Naeser 2 showed poorer performance in the extremely long AL and steep K subgroups, respectively (p≤0.042). Haigis-CMAL accuracy was significantly lower in shallow ACD and flat K subgroups (p≤0.045). The SN6CWS group showed significantly lower MAE and RMSAE compared to the 509M group for the BU II, EVO 2.0, Hoffer-QST, Kane, Pearl-DGS, and Zhu-Lu formulas (p≤0.024). CONCLUSIONS: In long eyes with plate-haptic IOLs, RBF 3.0 performed best, closely followed by Zhu-Lu, Olsen, and EVO 2.0; Karmona and Naeser 2 are discouraged for extreme AL and steep K conditions, respectively; Haigis-CMAL is not suggested for shallow ACD and flat K cases. Refractive outcomes in eyes implanted with a C-loop design IOL were more accurate than for those implanted with a plate-haptic design, for most tested formulas.

Dedicated locking plate reduces non-union risk in open ankle fusion in obese patients.

INTRODUCTION: Obesity is a growing public health concern. In ankle osteoarthritis, non-conservative treatment in advanced stages consists in ankle fusion, or else total ankle replacement, for which obesity is a relative contraindication. One of main complications of ankle fusion is non-union. Devascularization, obesity and fixation material are all factors involved in postoperative non-union, and have to be taken into account in surgical strategy for reliable results. The objective of this study was to compare the rate of ankle non-union in obese patients using quadruple screwing or a dedicated locking plate. The hypothesis was that the locking plate limits the risk of non-union in this population. METHODS: All patients were obese (BMI > 30kg/m²) and presented ankle osteoarthritis with > 10° intra-articular deformity. The approach and joint preparation were performed via an anteromedial approach. Group S was composed of 32 patients, operated on by quadruple screwing; group P comprised 10 patients operated on using a dedicated locking plate. The main endpoint was a significant difference in the rate of non-union between the 2 groups. The secondary endpoint was improvement in pre- and 6-month post-operative AOFAS score. RESULTS: Group S presented 31% non-union (10/32) and group P 0% (0/10) (p<0.05). Postoperative AOFAS score was significantly higher in group P: 67.8 ± 10.4 [range, 40 - 92] vs 83.1 ± 8.0 [range, 64 - 92] (p<0.05). CONCLUSION: The dedicated anterior locking plate is a technique of choice for ankle fusion in obese patients with intra-articular deformity > 10°, to limit the risk of non-union. LEVEL OF EVIDENCE: IV; retrospective study.

Investigating the stretch-shortening cycle fatigue response to a high-intensity stressful phase of training in collegiate men's basketball.

Introduction: While using force-plate derived measures of vertical jump performance, reflective of stretch-shortening-cycle (SSC) efficiency is common practice in sport science, there is limited evidence as to which tests and measures may be most sensitive toward neuromuscular fatigue. The aim of this study was to explore the SSC fatigue response to a one-week high-intensity fatiguing phase of training in National Collegiate Athletic Association (NCAA) Division-I basketball players. Methods: The study timeline consisted of three weeks of baseline measures, one week of high-intensity training, and two weeks of follow-up testing. Countermovement jumps (CMJ) and 10-5 hop tests were performed at baseline, as well as at two time-points during, and three time-points following the fatiguing training period, allowing for performance-comparisons with baseline. Results: Compared to the weekly training sum at baseline, during the high intensity training phase, athletes were exposed to very large increases in selected external load metrics (ES = 1.44-3.16), suggesting that athletes experienced fatigue acutely, as well as potential longer lasting reductions in performance. Vertical jump data suggested that in the CMJ, traditional metrics such as jump height, as well as metrics reflecting kinetic outputs and movement strategies, were sensitive to the stark increase in high-intensity training exposure. The 10-5 hop test suggested a fatigue-induced loss of tolerance to ground impact reflected by performance reductions in metrics related to jump height and reactive strength qualities. Discussion: These findings emphasize that when monitoring neuromuscular fatigue, variables and assessments may not be looked at individually, but rather as part of a more global monitoring approach.

Biomechanical analysis of plate versus K-wire fixation for metacarpal shaft fractures with wedge-shaped bone defects.

BACKGROUND: Metacarpal shaft fracture is a common type of hand fracture. Numerous studies have explored fixing transverse fractures in the midshaft of the metacarpal bone. However, this section of the metacarpal bone is often susceptible to high-energy injury, resulting in comminuted fracture or bone loss. In such cases, wedge-shaped bone defects can develop in the metacarpal shaft, increasing the difficulty of performing fracture fixation. Notably, the research on this type of fracture fixation is limited. This study compared the abilities of four fixation methods to fix metacarpal shaft fractures with wedge-shaped bone defects. METHODS: In total, 28 artificial metacarpal bones were used. To create wedge-shaped bone defects, an electric saw was used to create metacarpal shaft fractures at the midshaft of each bone. The artificial metacarpal bones were then divided into four groups for fixation. The bones in the first group were fixed with a dorsal locked plate (DP group), those in the second group were fixed with a volar locked plate (VP group), and those in the third group were fixed by combining dorsal and volar locked plates (DP + VP group), and those in the fourth group were fixed with two K-wires (2 K group). Cantilever bending tests were conducted using a material testing machine to measure yielding force and stiffness. The four groups' fixation capabilities were then assessed through analysis of variance and Tukey's test. RESULTS: The DP + VP group (164.1±44.0 N) achieved a significantly higher yielding force relative to the 2 K group (50.7 ± 8.9 N); the DP group (13.6 ± 3.0 N) and VP group (12.3 ± 1.0 N) did not differ significantly in terms of yielding force, with both achieving lower yielding forces relative to the DP + VP group and 2 K group. The DP + VP group (19.8±6.3 N/mm) achieved the highest level of stiffness, and the other three groups did not differ significantly in terms of stiffness (2 K group, 5.4 ± 1.1 N/mm; DP group, 4.0 ± 0.9 N/mm; VP group, 3.9 ± 1.9 N/mm). CONCLUSIONS: The fixation method involving the combined use of dorsal and volar locked plates (DP + VP group) resulted in optimal outcomes with respect to fixing metacarpal shaft fractures with volar wedge bone defects.

A comparative study of volar locking-plate fixation with corticocancellous and pure cancellous bone grafts for scaphoid nonunion with dorsal intercalated segmental instability secondary to scaphoid humpback deformity.

INTRODUCTION: Bone grafts for scaphoid nonunion with deformity include cortcicocancellous or pure cancellous bone grafts. This study compared the outcomes between two types of bone grafts when employing a volar locking-plate in patients with scaphoid nonunion with dorsal intercalated segmental instability (DISI). PATIENTS AND METHODS: This retrospective study included 34 patients with scaphoid nonunion and DISI due to humpback deformity treated between March 2017 and January 2022. Two types of bone grafts were obtained from iliac crest. Twenty of the corticocancellous (CC) group underwent a wedge-shaped graft, while 14 patients of the pure cancellous (C-only) group received graft chips. In both groups, a 1.5-mm anatomically pre-contoured locking plate was used for fixation. Radiographic evaluations included the union rate and carpal alignment including scapholunate angle (SLA), radiolunate angle (RLA), intrascaphoid angle (ISA) and scaphoid height to length ratio (HLR). Clinical assessments encompassed wrist range-of-motion, grip strength, and patient-reported outcomes. RESULTS: Nineteen of the 20 patients in the CC group and 12 of the 14 patients in the C-only group respectively, achieving osseous union. The mean follow-up period in CC group was 14.7 (range, 12 ∼ 24) months and that in C-only group was 12.6 (range, 12 ∼ 15) months. Postoperatively, there were no significant intergroup differences of radiographic parameters including SLA (CC; 49.9° ± 6.7° vs. C-only; 48.9° ± 3.5°, P = 0.676), RLA (1.7° ± 6.4° vs. 2.4° ± 3.3°, P = 0.74), ISA (36° ± 7.5° vs. 36.6° ± 12.2°, P = 0.881), and HLR (0.54 ± 0.09 vs. 0.53 ± 0.05, P = 0.587). Clinical outcomes, including the flexion-extension arc (137° ± 30° vs. 158° ± 33°, P = 0.122), grip strength (93.4 % ± 15.4% vs. 99.5 % ± 16.7 %, P = 0.39), Quick Disabilities of the Arm, Shoulder, and Hand scores (11.2 ± 8.3 vs. 12.5 ± 7.7, P = 0.74) and Mayo Wrist Scores (81.2 ± 13.1 vs. 89 ± 11.4, P = 0.242) also showed no significant intergroup differences. CONCLUSIONS: Volar locking-plate fixation with pure cancellous bone grafts achieved outcomes comparable to those achieved with corticocancellous bone grafts in scaphoid nonunion with deformity, possibly due to the biomechanical advantages of the volar plate to provide structural supports.

What to Expect? Use of Supplemental Fixation With a Concomitant Dorsal Spanning Plate for Complex Intraarticular Distal Radius Fractures.

BACKGROUND: The dorsal spanning plate (DSP) is a versatile implant suitable for bridging severely comminuted intraarticular distal radius fractures [AO (Arbeitsgemeinschaft für Osteosynthesefragen) 23-C.1-C.3]. It may be used alone or with supplemental fixation such as a volar locking plate (VLP) or fragment-specific fixation (FSF). Outcomes following DSP fixation with additional implants have not been specifically evaluated. METHODS: We retrospectively reviewed consecutive patients who underwent internal fixation of a distal radius fracture by a single surgeon from 2017 to 2021. Patients were grouped according to implants used: DSP only, DSP + FSF, and DSP + VLP. Preoperative variables, treatment times, and wrist range of motion (ROM) were assessed. Functional wrist ROM was defined as minimum 80° combined flexion and extension. RESULTS: One hundred fifty-two patients underwent surgery for wrist fracture, 33 of them were treated with a DSP: 8 DSP only, 6 DSP + VLP, and 19 DSP + FSF. Falls from height greater than 10 ft accounted for 52% of injuries, most of which were treated with a DSP + FSF. Treatment times and ROM were similar between subgroups. Wrist ROM did not improve significantly beyond 4 weeks following DSP removal. Overall, DSP patients recovered a mean wrist ROM of 85° (range 0°-130°) within a median 26 weeks total treatment period (range 12-68 weeks). CONCLUSION: Regardless of the construct used, if the distal radius articular surface is well reduced and other principles of fracture fixation are applied, most patients treated with a DSP can expect to regain functional wrist ROM. LEVEL OF EVIDENCE: Level IV-Retrospective review of prospectively collected data.

Elastic Stable Intramedullary Nailing Versus Plate Internal Fixation for Pediatric Diaphyseal Femur Fractures: A Systematic Review and Meta-analysis.

Background: Elastic stable intramedullary nailing (ESIN) and plates are currently the main internal fixation for treating Pediatric Diaphyseal Femur Fractures (PDFF), and the optimal choice of internal fixation is controversial. The purpose of this meta-analysis is to compare the surgical outcomes and complications of the two fixation methods. Materials and Methods: MEDLINE, Embase, and the Cochrane Library were systematically searched for studies published up to March, 2023, that compared ESIN and plate fixation techniques for treating PDFF. Pooled analysis identified differences in surgical outcomes between ESIN and plate, mainly regarding surgical outcomes and postoperative complications, such as time at surgery, fracture healing time, blood loss and related complications. Results: We included 10 studies with 775 patients with PDFF in our review. Of these, 428 and 347 were treated with ESIN and Plate, respectively. In terms of postoperative complications, ESIN led to a shorter surgery time [MD = - 28.93, 95% CI (- 52.88 to - 4.98), P < 0.05], less blood loss [MD = - 66.94, 95% CI (- 87.79 to - 46.10), P < 0.001] and more fracture healing time [MD = 2.65, 95% CI (1.22-4.07), P < 0.001]. In terms of postoperative complications, ESIN led to fewer fections (RR = 0.77, 95% CI 0.37, 1.60, P = 0.48), fewer angulation deformities (RR = 0.80, 95% CI 0.35, 1.83, P = 0.60) and more prominent implants (RR = 3.36, 95% CI 1.88, 6.01, P < 0.001), more delayed unions (RR = 4.06, 95% CI 0.71, 23.06, P = 0.11). Conclusions: ESIN and Plate have similar rates of complications besides a prominent implant rate, while ESIN has a shorter period of operation and less intraoperative bleeding. Although both options are suitable, the results of this study support the use of ESIN rather than plates in the treatment of PDFF in terms of complication rates. In clinical applications, surgeons should choose the appropriate treatment method according to the actual situation.