Search Results (57)

This study focuses on the numerical solution and dynamics analysis of fractional governing equations related to double-layer nanoplates based on the shifted Legendre polynomials algorithm. Firstly, the fractional governing equations of the complicated mechanical behavior for bilayer nanoplates are constructed by combining the Fractional Kelvin–Voigt (FKV) model with the Caputo fractional derivative and the theory of nonlocal elasticity. Then, the shifted Legendre polynomial is used to approximate the displacement function, and the governing equations are transformed into algebraic equations to facilitate the numerical solution in the time domain. Moreover, the systematic convergence analysis is carried out to verify the convergence of the ternary displacement function and its fractional derivatives in the equation, ensuring the rigor of the mathematical model. Finally, a dimensionless numerical example is given to verify the feasibility of the proposed algorithm, and the effects of material parameters on plate displacement are analyzed for double-layer plates with different materials. Full article

Background: Displaced proximal humerus fractures (PHFs) in adults represent a common orthopedic challenge, especially in elderly patients with compromised bone quality. Intramedullary nails (IM) and locking plates (LP) are the most widely used fixation techniques, though the literature remains inconclusive regarding their comparative efficacy. Methods: This retrospective cohort study included 187 patients (mean age: 65.4 years) treated surgically for Neer ≥ 2-part proximal humerus fractures at a single tertiary referral center between 2018 and 2023. Patients underwent either IM nailing or LP fixation. Baseline characteristics included age, sex, smoking status, ASA score, trauma mechanism, and bone quality (assessed by the Deltoid Tuberosity Index). Functional outcomes (DASH and Constant–Murley scores), range of motion (ROM), radiographic healing, and complications were evaluated at 1, 3, 6, and 12 months postoperatively. Results were stratified by fracture type (two-, three-, and four-part fractures) and treatment group. Results: At 12 months, no statistically significant differences were found between groups in terms of DASH (p = 0.484) or Constant–Murley scores (p = 0.057). ROM recovery was comparable across all time points. Stratified analysis showed similar outcomes across fracture types. Age, smoking, and bone quality did not significantly influence clinical results. The overall complication rate was 11.8%, with no significant difference between groups. Avascular necrosis and hardware-related issues occurred predominantly in four-part fractures. Conclusions: Both intramedullary nailing and locking plate fixation provided comparable short-term outcomes for displaced PHFs. Functional recovery appeared more dependent on fracture complexity than on the choice of implant. Surgical technique should therefore be selected based on fracture morphology, patient characteristics, and surgeon experience. Full article

Background/Objectives: Distal radius fractures (DRFs) are among the most common fractures in the elderly, with increasing incidence due to population aging. Recent evidence questions the benefits of operative treatment, particularly in elderly patients. The present study aimed to assess post-traumatic osteoarthritis (OA) and patient-reported outcome measures (PROMs) after a minimum of two years of follow-up of the previously published VOLCON randomized controlled trial (RCT), which compared operative and non-operative treatments of unstable DRFs in patients aged ≥ 65 years. Methods: This study presents a minimum two-year follow-up of a single-center, assessor-blinded RCT. A total of 100 patients with unstable DRFs were randomized to either operative treatment with volar locking plating or non-operative treatment with cast immobilization. The primary outcome was post-traumatic OA, assessed using the Knirk and Jupiter classification. Secondary outcomes included PROMs (Quick Disabilities of the Arm, Shoulder, and Hand (Quick-DASH)) and Patient-Rated Wrist/Hand Evaluation (PRWHE), complications, pain, grip strength, and range of motion (ROM). Statistical analyses were performed using two-way ANOVA. Results: After a median follow-up of 3.0 years, 60 patients (28 non-operative and 32 operative) were available for analysis. There was no significant difference in OA between the groups (p = 0.57). PROMs (Quick-DASH, PRWHE), pain, grip strength, and ROM were time-dependent (p < 0.001) but not treatment-dependent. Complications were more frequent in the operative group, including hardware-related issues requiring reoperation. Conclusions: At a minimum of two years of follow-up, no correlation was found between treatment choice and post-traumatic OA. Functional outcomes were similar between groups, suggesting that non-operative treatment remains a viable option for elderly patients with unstable DRFs. Full article

Metal additive manufacturing has emerged as a revolutionary technology for the fabrication of high-complexity components. However, this technique presents unique challenges related to the structural integrity and final strength of the parts produced due to inherent defects, such as porosity, cracks, and geometric deviations. These defects significantly impact the fatigue life of the material by acting as stress concentrators that accelerate failure under cyclic loading. On the one hand, this type of model is very complicated in its approach, since, even with encouraging results, the complexity of the calculation with these variables makes it difficult to obtain a simple result that allows for a generalized interpretation. On the other hand, using more familiar methods, it is possible to qualitatively guess the behavior that helps obtain results with better applicability, even at limited levels of precision. This paper presents a simplified finite element method combined with a statistical approach to model the presence of porosity in metal components produced by additive manufacturing. The proposed model considers a two-dimensional square plate subjected to tensile stress, with randomly introduced defects characterized by size, shape, and orientation. The percentage of porosity that affects each aspect determines the adjustment of the mechanical properties of finite elements. A series of simulations were performed to generate multiple models with random defect distributions to estimate maximum stress values. This approach demonstrates that complex models are not always necessary for a preliminary practical estimate of the effects of new manufacturing techniques. Furthermore, it demonstrates the potential for the extension of frugal computational techniques, which aim to minimize computational and experimental costs in the engineering field. The article discusses future research directions, particularly those related to potential business applications, including commercial uses. This follows a discussion of the existing limitations of this study. Full article

The Fokas method (also known as the unified transform method) is used to investigate acoustic scattering by thin, infinite grating by extending the methodology to apply to spatially periodic domains. Infinite grating is used to model a perforated screen, a material of interest in aeroacoustics and noise reduction. Once the method is established, its numerical results are verified against the Wiener–Hopf (WH) technique, which has solved the problem only for a special case. A key benefit of the novel approach is that the scatterer, modelled as an infinitely repeating unit cell consisting of a thin, rigid plate, can take any length. This is in contrast to the WH method, where the plate length is restricted to half the width of the unit cell (for this method, no such restriction exists). The numerical method is an over-sampled collocation method of the integral equation resulting from applying the Fokas method: the global relation. The only increase in complexity in adapting the Fokas method to more complicated cell geometries is a higher number of terms in the global relation. The proportion of energy transmitted and reflected by the grating structure is assessed for varying incident wave angles, frequencies, and plate lengths. Full article

Background: Congenital craniovertebral junction anomalies (CCVJAs) encompass a diverse range of conditions characterized by distorted anatomy and significant variation in the pathways of neurovascular structures. This study aims to assess the safety and feasibility of tailoring posterior fixation for CCVJAs through intraoperative CT-based navigation. Methods: An in-depth retrospective analysis was conducted on eight patients diagnosed with CCVJAs (excluding Arnold–Chiari malformation). These patients underwent posterior fixation/arthrodesis facilitated by intraoperative CT-based navigation. The analysis included an examination of the fixation strategies, complication rates, length of stay, post-operative complications, and success of arthrodesis. Additionally, a comprehensive literature review was undertaken to contextualize and compare our findings. Results: Patients undergoing CVJ posterior fixation with intraoperative CT-based navigation exhibited a flawless record, devoid of complications related to the damage to neurovascular structures, as well as any instances of screw misposition, pullout, or breakage (0 out of 36 total screws). Furthermore, the entire cohort demonstrated a 100% arthrodesis rate. None of the patients required treatment with an occipital plate. Conclusions: The incorporation of intraoperative CT-based navigation proves to be an invaluable asset in executing CVJ posterior fixation within the context of CCVJAs. This technology facilitates the customization of posterior constructs, a crucial adaptation required to navigate the anatomical challenges posed by these anomalies. The secure placement of screws into the occipital condyles, made possible by navigation, has proven highly effective in achieving CVJ fixation, obviating the need for an occipital plate. This technological leap represents a significant advancement, enhancing the safety, precision, and overall outcomes for patients undergoing this surgical procedure, while concurrently reducing the necessity for more invasive and morbid interventions. Full article

Continuous advancements in technology have made it possible to integrate clear aligner therapy (CAT) with orthognathic surgery. This case report presents a novel, individually-planned workflow, combining CAT with a surgery-first orthognathic approach (SFOA) in collaborating with engineers for an in-house production of surgical guides and customized titanium plates. The patient was evaluated subjectively, using the Oral Health-Related Quality of Life-14 (OHIP-14) questionnaire and Orthognathic Quality of Life questionnaire (OQLQ), and objectively with the Peer Assessment Rating (PAR) index. The patient displayed the planned occlusal relationship with no report of discomfort in the temporomandibular joint (TMJ) or post-surgical complications. The surgical and occlusal outcomes have remained consistent and stable after debonding. A decreased score was reported in both questionnaires and the PAR after treatment, thereby indicating improvements in both subjective and objective evaluations. This case report demonstrates that with proper individual planning, satisfactory subjective and objective outcomes can be achieved when combining SFOA with CAT. Full article

Background: Minimally invasive plate osteosynthesis (MIPO) for clavicular shaft fracture yields favorable functional outcomes and results in less surgery-related soft tissue injury than other techniques. Anterior chest and shoulder skin numbness, a common complication after open reduction and plate fixation, is related to injury to the supraclavicular nerves. We propose MIPO combined with a mini-open approach without fluoroscopy for nerve preservation to minimize the risk of postoperative numbness compared with traditional open plating without nerve preservation. Methods: A total of 59 patients were retrospectively identified, with a follow-up period of 6 months. Thirty-two patients underwent MIPO with mini-open and nerve preservation technique (MIPO group), and 27 patients underwent traditional open plating without nerve preservation (open group). Constant–Murley shoulder outcome score, operation time, wound length, skin numbness, and number of implant removals were compared between the groups. Results: The MIPO group had significantly lower rates of anterior chest and shoulder skin numbness than the open group (MIPO: 12.5% vs. open: 55.6%; p < 0.001). Operation time was significantly longer in the MIPO group than in the open group (MIPO: 109.38 ± 18.83 vs. open: 81.48 ± 18.85; p < 0.001). Wound length was significantly shorter in the MIPO group than in the open group (MIPO: 4.73 ± 0.79 vs. open: 9.76 ± 1.64; p < 0.001). Both groups had similarly excellent Constant–Murley shoulder scores. There were significantly fewer implant removals in the MIPO group than in the open group (MIPO: 6.3% vs. open: 25.9%; p = 0.036). Neither group experienced any infection, implant failure, or nonunion. Conclusions: Our technique combining MIPO with the mini-open approach and supraclavicular nerve preservation yields a lower incidence of skin numbness than traditional open plating without nerve preservation. Full article

Background/Objectives: Various bone substitutes have been recommended to augment the horizontal gap following immediate implantation. The purpose of this study was to compare the effectiveness of an autogenous mineralized dentin graft or a deproteinized bovine bone in horizontal gap augmentation following immediate implant placement in the maxillary anterior region. Methods: A total of 110 patients underwent tooth extraction followed by immediate implant placement. The patients were divided into two groups. The first group received an autogenous mineralized dentin graft (the test group) while the second group received a deproteinized bovine bone (the control group) to augment the horizontal gap. Preoperative (T0), immediate postoperative (T1), and 1-year postoperative (T2) cone beam computed tomography scans were taken from all the patients. Linear measurements were recorded 1 mm (R1) and 5 mm (R2) points apical to the implant platform at both T1 and T2 time intervals. Pink Esthetic Scores and prosthetic complications were evaluated as well. Results: There were 57 patients with a mean age of 45.42 ± 9.86 (range 24–63 years) selected as the test group and 53 patients with a mean age of 40.28 ± 11.69 (range 20–63 years) as the control group. The mean reduction in the buccal bone plate at R1 was 6.39 ± 3.78% in the test group and 6.99 ± 5.01% in the control group (p > 0.05). The mean reduction in the buccal bone plate at R2 was 5.46 ± 4.98% in the test group and 6.77 ± 7.60% in the control group (p < 0.05). The PES and prosthetic-related complications were shown to be negligible between the groups (p > 0.05). Conclusions: The efficiency of using an autogenous mineralized dentin graft for horizontal gap augmentation showed similar results in comparison to using a deproteinized bovine bone in relation to buccolingual socket reduction following immediate implantation. Full article

Background: The surgical treatment of bony non-unions is traditionally performed with additional bone grafts when atrophic and/or stronger implants when hypertrophic. In the case of the clavicle shaft, however, in our experience, a more controversial method where no additional bone graft is needed leads to equally good consolidation rates, independent of the non-union morphology. This method requires the meticulous anatomical reconstruction of the initial fracture and fixation according to the AO principle of relative stability. Methods: A retrospective review following the STROBE guidelines was performed on a consecutive cohort of all patients who received surgical treatment of a midshaft clavicle non-union at the Medical Center of the University of Freiburg between January 2003 and December 2023. Patients were identified using a retrospective systematical query in the Hospital Information System (HIS) using the International Statistical Classification of Diseases and Related Health Problems Version 10 (ICD-10) codes of the German Diagnosis Related Groups (G-DRG). Two groups were formed to compare the consolidation rates of patients who received additional bone grafting from the iliac crest with those of patients who did not. A 3.5 mm reconstruction LCP plate was used in all patients. Consolidation rates were evaluated using follow-up radiographs and outcomes after material removal with a mean follow-up of 31.5 ± 44.3 months (range 0–196). Results: Final data included 50 patients, predominantly male (29:21); age: 46.0 ± 13.0 years, BMI 26.1 ± 3.7. Autologous bone grafts from the iliac crest were used in 38.0% (n = 19), while no bone addition was used in 62.0% (n = 30). Six patients were lost to follow-up. Radiological consolidation was documented after a mean of 15.1 ± 8.0 months for the remaining 44 patients. Consolidation rates were 94.4% (n = 17) in patients for whom additional bone grafting was used and 96.2% (n = 25) in patients for whom no graft was used. There was no relevant difference in the percentage of atrophic or hypertrophic non-unions between both groups (p = 0.2425). Differences between groups in the rate of consolidation were not significant (p = 0.7890). The complication rate was low, with 4.5% (n = 2). Conclusions: Independent of the non-union morphology, non-unions of the clavicle midshaft can be treated successfully with 3.5 mm locking reconstruction plates without the use of additional bone grafting in most cases. Full article

Study Design: Prospective and retrospective studies. Objective: The aim of this study was to evaluate the clinical effects and accuracy of three-dimensionally (3D)-printed patient-specific surgical plates used for mandibular defect reconstruction. Methods: This study included patients who underwent mandibular defect reconstruction with vascularized autogenous bone grafts between January 2012 and August 2021. They were divided into experimental (fixation with 3D-printed surgical plates) and control (fixation with conventional surgical plates) groups. Flap survival rate, postoperative complications and patient self-evaluated facial appearance were compared. Mandibular reconstruction accuracy evaluation included postoperative position deviation of the whole mandible, transplanted bone graft, lower mandibular border, mandibular condyle, and mandibular angle on the reconstructed side compared to baseline. Results: This study included 20 patients (14 males, six females; age, 39.45 ± 11.69 years), ten each in the experimental and control groups. The mean follow-up was 16 ± 22.05 (range, 6–99) months. All procedures were successful, no plate-related complications (breakage, loosening, or exposure of the surgical plates) were reported, and all patients were satisfied. The groups were statistically similar in th e position deviation of the whole mandible, transplanted bone graft, mandibular condyle, and mandibular angle, but the position and morphology of the lower mandibular border on the reconstructed side in the experimental group were better than those in the control group (p = 0.016). Conclusions: 3D-printed patient-specific surgical plates could be applied in mandibular reconstruction safely and effectively, simplifying the surgical procedure, shortening the preoperative preparation times, achieving satisfactory outcomes, and improving the clinical effects and accuracy of individualized mandibular reconstruction. Full article

Background and Objectives: Stable fixation is essential for successful healing after medial open wedge high tibial osteotomy (MOWHTO) to minimize the risk of non-union and correction loss. In Asians, potential complications such as D-hole screw osteotomy plane violation (D-hole violation) and inadequate plate fitting arise due to improper plate size. This study aimed to evaluate the risk factors for D-hole violation and compare the conventional anatomic (CA) plate with an individualized anatomic (IA) plate in MOWHTO procedures. Materials and Methods: A simulation study on D-hole violation using the CA plate was conducted, involving preoperative radiographs and CT scans of 64 lower extremities from 47 MOWHTO patients. Additionally, a randomized controlled study compared CA and IA plates in MOWHTO procedures with 34 patients (17 in the CA plate group; 18 in the IA plate group). Patient demographics, patient-reported outcome measures (PROMs), and radiological measures were analyzed. Results: In the simulation study, the rates of D-hole violation ranged from 20.3% to 59.4%, with an increase observed as the plate was distalized from 5 mm to 10 mm away from the joint line. Short stature was identified as an independent risk factor for D-hole violation (p < 0.001), with a cutoff value of 155.3 cm. In the randomized controlled study, no significant difference in PROMs and D-hole violation was observed between the CA plate and IA plate groups. However, the IA plate group showed better plate fitting compared to the CA plate group (p = 0.041). Conclusions: This study identified a high risk of D-hole screw osteotomy plane violations in MOWHTO procedures, particularly when the plate is positioned more distally and in individuals with a stature below 155.3 cm. It also revealed that individualized plates provide better tibial fitting compared to conventional anatomic plates, particularly in Asian populations where tibial morphology tends to be shorter than in Western populations. Therefore, evaluating patient stature and selecting tailored plates are essential to optimize plate positioning and minimize plate-related complications in MOWHTO procedures. Full article

Maxillofacial fractures are a prevalent occurrence, and the widespread use of miniplates to stabilize and secure these fractures during surgery is common. However, the post-surgical fate of these miniplates remains a subject of contention among surgeons. Some advocate for their removal, while others suggest leaving them in place. This study aims to perform an extensive meta-analysis of pertinent studies to ascertain the destiny of miniplates employed in maxillofacial surgery and discuss the consequences of either their extraction or retention. To execute this meta-analysis, a search was conducted across number of databases, including PubMed, Google Scholar, ResearchGate, Embase, and Scopus. Keywords such as “titanium miniplates”, “screws”, “maxillofacial surgery”, “complications”, and “removal” were utilized to identify pertinent studies. The search was constrained to studies published between 1989 and 2022. The analysis encompassed only studies reporting outcomes related to miniplates in maxillofacial surgery, including complication rates and removal frequencies. Eleven studies conformed to the inclusion criteria and were incorporated into the meta-analysis, encompassing a total of 2240 patients, ten of which were retrospectives and one prospective, with the largest study involving 434 patients. The overall complication rate was determined to be 13.3%. The most prevalent reasons for miniplate removal included patient preference, tooth extraction, and infections. The average time span for miniplate removal was 10.7 months, with the most prolonged reported duration being 24 years. These findings imply that immediate removal might not be imperative in the majority of instances. In conclusion, our meta-analysis underscores the necessity of removing miniplates in cases where hardware leads to a variety of complications and physical discomfort. Principal factors driving plate removal included patient requests, tooth extractions, and infections. Ordinarily, plate removal took place within the span of 6 to 12 months, with the mandible being the most frequent site for removal. These findings accentuate the significance of extended monitoring to assess the trajectory of miniplates in maxillofacial surgery and provide valuable insights for future clinical decisions. To validate these conclusions and gain deeper insights into the factors influencing plate removal in maxillofacial surgery, further research with larger participant cohorts and standardized outcome reporting is imperative. Full article

Background: Custom-made alloplastic temporomandibular joint replacement (ATMJR) is not validated in irradiated patients. However, in specific situations, after previous reconstructive surgical failures, the authors hypothesized the role of a customized ATMJR after radiotherapy. Methods: A 65-year-old male patient was referred to Instituto Português da Face—Lisbon, Portugal—after failed attempts of mandibular reconstruction secondary to oral carcinoma resection and partial hemi-mandibulectomy plus radiotherapy of 60 total Grays. Primary reconstruction was performed with fibula free flap. Due to failure, secondary reconstructions were performed with osteosynthesis plate without success. The patient was unable to have adequate mastication and deglutition due to a severe crossbite. The authors treated the patient with an extended customized alloplastic temporomandibular joint replacement (F0M2). Results: With 3 years of follow-up, the patient showed an improvement in masticatory function, mandibular motion, pain levels, and overall quality of life. No complications were observed related to ATMJR. Conclusions: The presented case described how ATMJR, although not a validated option after radiotherapy, can be considered to restore functionality in complex cases with bone and soft tissues problems. Full article

Background: Infection of orthopaedic implants after internal fixation of bone fractures remains a major complication with occasionally devastating consequences. Recent studies have reported that the use of absorbable materials, instead of metallic ones, may lead to a lower incidence of postoperative infection. In this experimental pre-clinical animal study, we compared the infection rate between absorbable implants consisting of copolymers composed from trimethylene carbonate, L-polylactic acid, and D, L-polylactic acid monomers, and titanium implants after the inoculation of a pathogenic microorganism. Material and Methods: We used an experimental implant-related infection model in rabbits. Sixty animals were randomly and equally divided into two groups. In all animals, the right femur was exposed via a lateral approach and a 2.5 mm two-hole titanium plate with screws (Group A), or a two-hole absorbable plate and screws (Group B), were applied in the femoral shaft. Afterwards, the implant surface was inoculated with Pseudomonas Aeruginosa at a concentration of 2 × 10⁸ CFU/mL. The primary outcome was the comparison of the incidence of developed infection between the two groups. The wound condition was monitored on a daily basis and radiographies were obtained at 12 weeks postoperatively. Infection-related laboratory markers (white blood cell count, erythrocyte sedimentation rate, and C-reactive protein values) were assessed at 3, 6, and 16 weeks postoperatively. Histologic analysis and cultures of tissue samples were also performed to evaluate the presence of infection. Results: Clinical and laboratory signs of infection were evident in 11 rabbits in Group A (36.7%), and 4 in Group B (13.3%). The difference between the groups was statistically significant (p = 0.04). Five animals in Group B (16.7%) had clinical and histologic signs of a foreign-body reaction with significantly elevated CRP and ESR values but no simultaneous presence of infection was identified (p = 0.04). Bone remodelling with thickening of the periosteum and surrounding sclerosis was demonstrated radiologically in animals developing infection or foreign-body reactions. Conclusions: Absorbable plates and screws show lower susceptibility to infection compared to titanium ones. However, their application is associated with foreign-body reaction and the potential need for a second surgical intervention. Full article