Rotational Deformity Research Articles

Simultaneous solution of implicitly defined curved, linear Timoshenko beams in two‐dimensional bulk domains

AbstractA novel formulation of curved Timoshenko beams which are defined by all level sets of a scalar function in a two‐dimensional bulk domain is presented, including a corresponding finite element method for the simultaneous solution of these beams. The required geometrical setup and differential operators are introduced and the model is defined in strong form. The weak form for the simultaneous solution involves the co‐area formula. A crucial aspect is how the difference vector, describing the rotational deformation in this model, is discretized wherefore two different approaches are shown in this paper. Higher‐order convergence studies in the residual errors confirm that the proposed method is valid and achieves expected convergence rates.

Evaluating the stability of architectural heritage from the perspective of InSAR: a practical study on Jianchuan Ancient Town

AbstractThe increase in human activities and natural degradation often leads to tilting, collapsing, and other forms of deterioration in architectural heritage, posing significant threats to its safety. Therefore, timely detection of abnormal deformation signals in buildings is essential for the protection of architectural heritage. Spaceborne synthetic aperture radar interferometry (InSAR) can detect slight displacements over large areas. However, relying solely on annual mean velocity maps derived from InSAR may not accurately assess the stability of ancient buildings. In this study, we developed a framework that evaluates the stability of individual buildings by integrating the InSAR displacements with building footprints. Vertical and rotational deformations, along with the temporal evolution of these deformations, are combined to generate the results for building stability assessment. We used 74 TerraSAR-X images captured from August 2017 to November 2019 to evaluate the stability of Jianchuan Ancient Town, a renowned National Historical and Cultural City in China. The displacement result suggests that the majority of Jianchuan Ancient Town remains stable, with over 93% of coherent points (CTs) displaying displacement velocities ranging from −5 to 5 mm/yr. Out of the 1,891 buildings in Jianchuan Ancient Town, 1404 are considered stable, 352 are of moderate stability, and 12 are deemed unstable. This study showed the potential of InSAR applications in assessing the stability of architectural heritages, emphasizing its crucial role in heritage preservation and management.

Machine learning based segmentation of delamination patterns from sparse ultrasound data of barely visible impact damage in composites

Composite laminates, known for their strength and flexibility, are widely used but can delaminate under certain barely visible impact. Ultrasound Transmission (UT) scans can detect such failures, but the noise in the scans makes automation of delamination morphology challenging. Machine learning could solve this, but it requires substantial training data. Furthermore, given the considerable time and cost of conducting impact tests on composite laminates, such data remains sparse. This study overcomes data sparsity by enlarging UT scan dataset using image augmentation techniques and synthetic data generation methods. A combination of rotation and elastic deformation of real UT images produced augmented data. Synthetic data was generated by mimicking the statistical variations in real data, including delamination length and rotation per ply, and adding gradients to match the original image noise. A U-Net based machine learning segmentation approach was utilized to capture local and global information through a series of convolutions to apply per-pixel classification. Systematic experimentation was conducted to study the influence of adding augmented and synthetic data on segmentation accuracy. The results show that the use of augmented data increases accuracy significantly. With the addition of synthetic data to the augmented data, there is a marginal improvement in accuracy. However, feature edge accuracy is significantly improved. The preliminary results presented here show the promising use of machine learning techniques for complex, non-destructive inspection methods.

Analytical investigation on the rotational behavior of dovetail mortise–tenon joints between beams and columns in traditional Chinese timber frames

We theoretically analyzed the rotational behavior of beam–column dovetail joints in traditional Chinese timber frames in this study. An analytical model of dovetail joints at both the column head and body was designed by clarifying the moment generation mechanism and effect of rotational embedment yielding in timber perpendicular to the grain on the rotational behavior of joints. An asynchronous manifestation of rotational embedment deformation across the column surface, tenon cheeks, and upper and lower surfaces of the tenon head was analyzed, and the corresponding characteristic yield points and consequent reduction in rotational stiffness were derived in the model. The Inayama embedment theory was used to clarify the effect of rotational embedment with varying end lengths on the movement of the joint rotation center and asymmetric moment generated in different rotation directions of the column head joint. The precision of the analytical model was validated through a comparative analysis by involving nine sets of experimental data, for estimating the initial stiffness, post-yield stiffness, and identified yield points. The implications of the parameters, including the initial gap between the tenon and mortise, geometric dimensions of the dovetail tenon, and friction coefficient, were also discussed. Controlling the ratio of the initial gap and tenon height within 0.01 to ensure a certain rotational resistance of dovetail beam–column joints within the collapse limits of traditional timber frames is recommended considering the significant effect of the initial gap on the initial sliding angle and moment reduction.

A review for design, mechanism, fabrication, and application of magnetically responsive microstructured functional surface

Abstract Magnetically responsive microstructured functional surface (MRMFS), capable of dynamically and reversibly switching the surface topography under magnetic actuation, provides a wireless, noninvasive, and instantaneous way to accurately control the microscale engineered surface. In the last decade, many studies have been conducted to design and optimize MRMFSs for diverse applications, and significant progress has been accomplished. This review comprehensively presents recent advancements and the potential prospects in MRMFSs. We first classify MRMFSs into one-dimensional linear array MRMFSs, two-dimensional planar array MRMFSs, and dynamic self-assembly MRMFSs based on their morphology. Subsequently, an overview of three deformation mechanisms, including magnetically actuated bending deformation, magnetically driven rotational deformation, and magnetically induced self-assembly deformation, are provided. Four main fabrication strategies employed to create MRMFSs are summarized, including replica molding, magnetization-induced self-assembly, laser cutting, and ferrofluid-infused method. Furthermore, the applications of MRMFS in droplet manipulation, solid transport, information encryption, light manipulation, triboelectric nanogenerators, and soft robotics are presented. Finally, the challenges that limit the practical applications of MRMFSs are discussed, and the future development of MRMFSs is proposed.

Initial construct stability of long cephalomedullary nails with superior locking for a complex trochanteric fracture model AO31A2.2– a biomechanical study

BackgroundComplex fractures of the trochanteric region, as well as fractures located in the directly subtrochanteric region, are controversially discussed around the world regarding the nail type to be used. A long nail is recommended by manufacturers but requires longer surgical and fluoroscopy times. A possible solution could be a nail with an appropriate length which can be locked in a minimally invasive manner by the main aiming device. We aimed to determine if such a nail model (DCN SL nail, SWEMAC, Linköping, Sweden) offers similar structural stability on biomechanical testing on artificial bone as a standard long nail when used to treat complex trochanteric fractures and compared it to long nails usually used in this setting.MethodsAn osteoporotic bone model was chosen. The Swemac Hansson DCN Nail System was used as osteosynthesis material. Two types of nails were chosen: a superior lock nail which can be implanted with a singular targeting device, and a long nail with distal locking using free-hand technique. AO31A2.2 fractures were simulated in a standardised manner. Axial height of the construct, varus collapse, and rotational deformity directly after nail insertion were simulated. A Universal Testing Machine was used. Measurements were made with a stereo-optic tracking system.FindingsThere was a detectable difference in the axial fracture movement resulting in narrowing of the fracture gap. There was no difference in varus collapse or rotational deformity between the nail variantsConclusionWe conclude that there are small differences which are clinically insignificant and that a superior locking nail can safely be used to manage complex trochanteric fractures.

Long-term functional outcomes of BIFOLD osteosynthesis in distal femoral fractures with metaphyseal comminution: A retrospective analysis

BackgroundThis retrospective study aimed to evaluate the long-term functional outcomes of BIFOLD osteosynthesis, employing retrograde nailing and distal femoral locked plating, in patients with distal femoral fractures and metaphyseal comminution. MethodsA retrospective analysis was conducted on patients treated for distal femur fractures with metaphyseal comminution between 2012 and 2022, with a minimum follow-up of 2 years. Inclusion criteria encompassed distal femur fractures with metaphyseal comminution, excluding specific conditions. BIFOLD osteosynthesis was employed in all 33 cases, utilizing retrograde SIGN (Surgical Implant Generation Network Nail) and distal femoral locking plates. Primary outcome measures included radiographic and functional outcomes assessed through the Sanders functional evaluation score, with secondary outcomes focusing on perioperative or postoperative complications. ResultsA total of 33 patients (21 male, 12 female) were included, with an average age of 51.4 years. BIFOLD osteosynthesis exhibited an average radiographic fracture healing time of 6.2 ± 2.5 months. The procedure's average operative time was 100 ± 15 min, and blood loss averaged 420 ± 50 ml. According to Sanders criteria, 28 patients (84.84 %) demonstrated well-to-excellent functional outcomes, while 3 patients (9.09 %) reported fair outcomes, and 2 patients (6.06 %) reported poor outcomes. No significant shortening or implant failure occurred, and all patients achieved over 90 degrees of knee range of motion within 8 weeks. One patient experienced superficial infection, and two patients exhibited insignificant coronal plane deformity. ConclusionBIFOLD osteosynthesis, combining intra and extra medullary fixation principles, offers a stable construct for distal femoral fractures with metaphyseal comminution. This approach facilitates faster ambulation, pain relief, early knee joint mobilization, and significant early union, resulting in improved functional outcomes. Additionally, BIFOLD osteosynthesis helps prevent collapse, translational and rotational deformities, as well as shortening.

Biomechanical investigation of positive reduction in the femoral neck fracture: a finite element analysis.

Gotfried positive reduction offers an alternative strategy for femoral neck fracture (FNF) when achieving anatomical reduction is challenging. However, the biomechanical consequences of positive reduction remain unclear. The purpose of this study was to investigate the biomechanical behavior of positive reduction across different Pauwels classification, providing a reference for quantifying positive reduction in clinical practice. Three-dimensional (3D) models of FNF were established and categorized according to the Pauwels classifications (Pauwels I, II, and III), each of them contained seven models with different reduction qualities, including an anatomical reduction model, two negative reduction models, and four positive reduction models, all of which were stabilized with dynamic hip screws (DHS) and cannulated screws (CS). We investigated the maximal von-Mises stress of internal fixation and proximal femoral, femoral fragment displacement, and maximal von-Mises strain at the proximal fragment fracture site when a 2100N load was applied to the femoral head. The maximum von-Mises stress on the internal fixators in each Pauwels group was lowest in the anatomical reduction model. In the Pauwels I group, positive reduction exceeding 3mm resulted in the maximum von-Mises stress on the internal fixators surpassing that of the negative reduction model. For the Pauwels II group, positive reduction beyond 2mm led to the maximum von-Mises stress on the internal fixators exceeding that of the negative reduction model. In the Pauwels III group, positive reduction beyond 1mm caused the maximum von-Mises stress on the internal fixators to be higher than that of the negative reduction model. The maximum von-Mises strain at the fracture site of proximal femur fragment increased with positive reduction. Varus displacement increased in positive reduction models as the Pauwels angle rose, potentially exacerbating rotation deformity in Pauwels III group. Excessive positive reduction may increase the risk of FNF failure after internal fixation. From a biomechanical stability perspective, positive reduction should be limited to 3mm or below in the Pauwels I group, restricted to not exceed 2mm in the Pauwels II group, and should not exceed 1mm in the Pauwels III group. Negative reduction should be avoided in all Pauwels groups.

Management of metacarpal shaft fractures: a survey of current UK practice.

Metacarpal shaft fractures (MSF) are common injuries that predominantly affect young, economically active people. However, there is limited evidence to guide their management. The aims of this study were to: evaluate the management of extra-articular MSF of the fingers; assess equipoise for surgical and nonsurgical treatments; and explore factors influencing clinician decision making to inform the design of a randomised controlled trial (RCT) comparing surgical and nonsurgical treatments. A cross-sectional, web-based survey was distributed to UK hand surgeons using membership directories of different professional networks. Practice setting, clinical experience, management strategies, willingness to participate in a RCT and factors affecting suitability for randomisation were recorded. There were 108 responses eligible for analysis. Distribution of clinical experience ranged from <5 to >20 years. A variety of treatments were used for transverse, long oblique/spiral and comminuted MSF. Rotational deformity (90%), step-off deformity (5%) and angulation (5%) were the most important indications for surgical fixation. Acceptable limits of fracture angulation and shortening varied among surgeons. Over 85% expressed interest in participating in a RCT and most showed equipoise and were willing to offer operative or nonoperative treatment as part of a research study. This survey demonstrates that UK hand surgeons have varying views on treatments, acceptable parameters of deformity and indications for surgical fixation of displaced MSF. There is equipoise for surgical and nonsurgical treatments, variability in factors influencing clinical decision making and support for RCTs to investigate best practice.

Nonunion of the distal one-fourth of the tibia treated by retrograde tibial intramedullary nail.

To evaluate the effectiveness of retrograde tibial intramedullary nail (RTN) in addressing nonunion in the distal one-fourth of the tibia. This retrospective study included consecutive patients who were treated with RTN for nonunion in the distal one-fourth of the tibia between December 2020 and August 2023. Data regarding age, sex, injury mechanism, fracture type, initial fixation method, nonunion duration and type, risk factors, surgical duration, hospital stay, time to bone union, ankle function at final follow-up, and any complications were extracted from hospital records and analysed. Five patients in total were included, with previous treatments comprising locking plates and/or external fixation. The mean duration of RTN surgery was 94.0 ± 13.7 min, and mean duration of hospital stay was 9.8 ± 1.9 days. Patients were monitored for 10-18 months post RTN, achieving complete bone healing within a mean of 4.8 months. At the latest follow-up, the mean American Orthopedic Foot and Ankle Society (AOFAS) score was 84.4 ± 6.8 (range, 77-95). No complications, such as infection, reoperation, implant issues, rotational deformity, or shortening were reported. RTN emerges as a dependable, minimally invasive, and safe treatment modality for managing nonunion in the distal one-fourth of the tibia.

Tidal Disruption of a Star on a Nearly Circular Orbit

We consider Roche lobe overflow (RLO) from a low-mass star on a nearly circular orbit, onto a supermassive black hole (SMBH). If mass transfer is unstable, its rate accelerates in a runaway process, resulting in highly super-Eddington mass accretion rates, accompanied by an optically thick outflow emanating from the SMBH vicinity. This produces a 1–4 week long, bright optical/ultraviolet flare, accompanied by a 1–10 year long X-ray precursor and post-cursor emitted from the accretion flow onto the SMBH. Such “Circular Tidal Disruption Events” (TDEs) represent a new class of nuclear transients, occurring at up to 1%–10% of the canonical parabolic tidal disruption event rate. Near-breakup rotation and strong tidal deformation of the star prior to disruption could lead to strong magnetic fields, making circular TDEs possible progenitors of jetted TDEs. Outflows prior to the final stellar disruption produce a circumnuclear environment (CNM) with ∼10−2 M⊙ at distances of ∼0.01–0.1 pc, likely leading to bright radio emission, and also similar to the CNM inferred for jetted TDEs. We discuss broader connections between circular TDEs and other recently identified classes of transients associated with galactic nuclei, such as repeating TDEs and quasi-periodic X-ray eruptions, as well as possible connections to luminous fast blue optical transients such as AT2018cow. We also discuss observational signatures of the analogous RLO of a white dwarf around an intermediate-mass BH, which may be a multimessenger source in the LISA era.

Association of Clinical Findings With Complications in the Cubitus Varus Deformity After Supracondylar Fracture.

Cubitus varus deformity is primarily a cosmetic complaint that causes some early and late complications. However, no studies have reported the cubitus varus deformity regarding the frequency of complications, relationship to the degree of deformity, and period from the occurrence of the initial injury. Overall, 83 patients with cubitus varus deformity were examined. The differences in the humerus-elbow-wrist angle (∆HEW-A), tilting angle (∆TA), and internal rotation angle (∆IRA) between the affected and normal sides were measured to determine varus and extension and internal rotation deformity. The period from the occurrence of the initial injury to the evaluation date was also investigated. Multivariate logistic regression analysis was conducted to identify the explanatory variables (period, ∆HEW-A, ∆TA, and ∆IRA) independently associated with complication events. Receiver-operating characteristic curve analysis was also conducted to predict the risk of events. ∆HEW-A was independently associated with the risk of cosmetic complaint (odds ratio [OR], 1.171; 95% confidence interval [95% CI], 1.056 to 1.336) and instability (OR, 1.111; 95% CI, 1.028 to 1.200). ∆TA was independently associated with the risk of limited elbow motion (OR, 1.176; 95% CI, 1.077 to 1.285) and sports disability (OR, 0.892; 95% CI, 0.836 to 0.952). The period from the occurrence of the initial injury was independently associated with risk of pain (OR, 1.063; 95% CI, 1.019 to 1.108), ulnar nerve neuropathy (OR, 1.065; 95% CI, 1.011 to 1.125), and osteoarthritis (OR, 1.188; 95% CI, 1.098 to 1.286). The receiver-operating characteristic curve analysis revealed the optimal cutoffs of 20° and 27° for ∆HEW-A to predict cosmetic complaint and instability; of 25° for ∆TA to predict limited elbow motion; and of 8.8, 8.0, and 16.0 years for the period to predict pain, ulnar nerve neuropathy, and osteoarthritis, respectively. The treatment of cubitus varus deformity should be determined because a residual deformity >20° of varus and 25° of extension could develop risk of complications over time.

3D Analysis of Metatarsal Torsion by Computed Tomography in Normal, Hallux Valgus, and Hallux Rigidus Feet.

One factor contributing to rotational deformity of the first metatarsal in hallux valgus is torsion of the metatarsal itself. Hallux rigidus also involves reduction of the longitudinal arch, but metatarsal torsion has not been discussed. We hypothesized that metatarsal torsion may be a morphologic change unique to hallux valgus. We compared 3-dimensional (3D) torsion of the first to fifth metatarsals between feet with hallux valgus, feet with hallux rigidus, and healthy control feet to investigate differences in the effects on pathologic conditions. Participants were women of East Asian descent. There were 16, 16, and 14 feet in the control, hallux valgus, and hallux rigidus groups, respectively. One randomly selected control foot was designated as the reference foot. For comparison, nonweightbearing computed tomography images of the metatarsals were reconstructed in 3D, and the proximal and distal areas were superimposed on the reference foot. Torsion angle was defined as the rotational angle of the distal part of the articular axis relative to the proximal area. In the hallux valgus group, correlations of torsion angle with hallux valgus angle and intermetatarsal angle were calculated. The hallux valgus group had greater average pronation torsion in the first metatarsal than the control group and hallux rigidus group (11 and 13 degrees greater, respectively, P < .01). No significant differences were observed for the second to fifth metatarsals (P > .05). There was no significant correlation with hallux valgus angle or first-second intermetatarsal angle in the hallux valgus group (P > .05). Hallux valgus feet had pronation deformities in the first metatarsals not observed in control or hallux rigidus feet, meaning that torsion toward pronation (eversion) in the first metatarsal was unique to hallux valgus. Improved surgical correction to diminish pronation may be necessary in patients with hallux valgus patients because of first metatarsal pronation in the first tarsometatarsal to normalize mechanical first-ray alignment.Level of Evidence: Level III, case-control stud.

Arthroscopically Assisted Reconstruction of Lateral Metatarsosesamoid Suspensory and Lateral Metatarsophalangeal Collateral Ligaments in the Management of Iatrogenic Hallux Varus Deformity

The medial and lateral metatarsosesamoid suspensory ligaments together with the sesamoid apparatus are the main contributors to the rotational stability of the first metatarsophalangeal joint (MTPJ). Rotational instability of first MTPJ is a major factor in the development of hallux valgus and varus deformities. As the great toe starts to rotate, the muscle pulls across the first MTPJ, causing it to become imbalanced and lead to progressive medial or lateral deviation of the great toe. The gold standard and most reliable option for hallux varus deformity is first MTPJ fusion. However, it results in stiffness and loss of joint function and is reserved for arthritic and stiff first MTPJ. Flexible iatrogenic hallux varus is corrected by optimally anatomic ligament reconstruction. The purpose of this Technical Note is to describe the details of arthroscopically assisted reconstruction of lateral metatarsosesamoid suspensory and lateral metatarsophalangeal collateral ligaments in management of iatrogenic hallux varus deformity. We reconstruct the lateral metatarsosesamoid suspensory ligament to restore the rotational stability of the first MTPJ in hallux varus deformity. This together with reconstruction of the lateral metatarsophalangeal collateral ligament anatomically corrects both the medial deviation and rotation deformity of the great toe.

Does the Surgeon's Handedness Affect the Complications Rate in the Inframammary Approach Breast Augmentation?

Humans show a preference for left or right handedness in most cases. For this reason, surgeons might find it more difficult to operate on the "nondominant breast", i.e. the breast opposite to the surgeon´s dominant hand (left breast for right-handed surgeons and right breast for left-handed surgeons). The nondominant breast might therefore potentially be prone to a higher complication rate. Retrospective data of all consecutive patients who underwent breast augmentations by the first author over the past 15years was reviewed. In all cases, the entire operation was carried out with the surgeon standing on the right side of the table. All the complications of the right and left breasts were analyzed individually. 1707 patients with a minimum follow-up of sixmonths were reviewed. Mean breast implant volume was 305.6 cc and mean follow-up was 16.12months. A total of 151 complications were found (8.8%), including rotational deformity, capsular contracture, hematoma, seroma, bottoming out, high riding implant, double bubble deformity, implant rupture and infection. Of these complications, 77 (4.51%) affected the left breast, 48 (2.87%) were found on the right breast and 25 (1.46%) were bilateral. This difference was statistically significant. Surgeons´ handedness seem to have an impact on the rate of complications after breast augmentation. As a result of some sort of unease when operating on the nondominant breast, this side might be prone to less precision during the dissection and, consequently, to more complications. Our study found that the rate of complications was higher in the nondominant breast. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Rotational deformation twins in a HfNbTaTiZr refractory high entropy alloy

Results of the analysis of deformation twins formed in a HfNbTaTiZr refractory high entropy alloy during compression deformation at 20 °C – 600 °C are reported. All studied twins were formed by rotation of the matrix crystal lattice around a 〈110〉 pole and have the common reciprocal twinning plane K2 = {001} and reciprocal twinning direction η2 = <11¯0>. At the same time, the twinning plane K1 and direction η1 depend on the degree of rotation of K2 and η2 around the common 〈110〉 pole. The following rotational twinning modes have been identified in HfNbTaTiZr: {11¯4}<22¯1¯> (38.94° rotation), {11¯5}<55¯2¯> (31.58°), {11¯6}<33¯1¯> (26.54°), {11¯7}<77¯2¯> (22.84°), and {11¯8}<44¯1¯> (20.04°). A rotational mechanism of twinning, with the rotation axis 〈011〉 or 〈001〉, is proposed as an alternative to the commonly accepted shear mechanism.

Distal Tibial Dome Osteotomy With Ilizarov Fixation in Correction of Ankle Deformity Resulting From Malunited Ankle Fusion

Background: Distal tibial osteotomy is used in the treatment of ankle deformities. Many methods of fixation of this osteotomy were described, including plates, pins, and ilizarov. Dome osteotomy is a cylindrical osteotomy with no bone loss, with the axis of bone is rotated around the center of the circle. We conducted a case series of treatment of ankle deformity due to malunited ankle fusion with distal tibial dome osteotomy. Methods: Eight patients with a history of poliomyelitis with ankle deformity due to a malunited ankle fusion underwent distal tibial dome osteotomy with ilizarov fixation for deformity correction. Postoperative follow up was done up to 12 months postoperatively. We intended to follow up the union of the osteotomy, the axis of the limb, the external clinical appearance, and patient satisfaction. Results: Deformity correction was achieved in all patients regarding the clinical alignment, with no apparent clinical residual deformity in coronal, sagittal plane, or rotational deformity, the limb was cosmetically straight with a plantigrade foot satisfactory to the patients with improving quality of gait. The osteotomy fully united in all patients in a period of 8 to 11 weeks with an average of 9.3 weeks, after which frame was removed. No patient had nonunion or delayed union of the osteotomy. Three patients had pin tract infection during the period of the fixator which was treated by local dressings and antibiotics. Conclusion: Distal tibial focal dome osteotomy fixed by ilizarov is an effective treatment option in malunited ankle fusion deformities.

Individualized C1-2 intra-articular three-dimensional printed porous titanium alloy cage for craniovertebral deformity

BackgroundCongenital craniovertebral deformity, including basilar invagination (BI) and atlantoaxial instability (AAI), are often associated with three-dimensional (3D) deformity, such as C1-2 rotational deformity, craniocervical kyphosis, C1 lateral inclination, among other abnormalities. Effective management of these conditions requires the restoration of the 3D alignment to achieve optimal reduction. Recently, 3D printing technology has emerged as a valuable tool in spine surgery, offering the significant advantage of allowing surgeons to customize the prosthesis design. This innovation provides an ideal solution for precise 3D reduction in the treatment of craniovertebral deformities.ObjectiveThis study aims to describe our approach to individualized computer-simulated reduction and the design of C1-2 intra-articular 3D printed porous titanium alloy cages for the quantitative correction of craniovertebral junction deformities.MethodsA retrospective analysis was conducted on patients with craniovertebral deformities treated at our institution using individualized 3D-printed porous titanium alloy cages. Preoperative CT data were used to construct models for 3D realignment simulations. Cage designs were tailored to the simulated joint morphology following computer-assisted realignment. Preoperative and postoperative parameters were statistically analyzed.ResultsFourteen patients were included in the study, with a total of 28 3D-printed porous titanium alloy cages implanted. There were no cases of C2 nerve root resection or vertebral artery injury. All patients experienced symptom relief and stable implant fixation achieved in all cases. No implant-related complications were reported.ConclusionThe use of individualized computer-simulated reduction and the design of C1-2 intra-articular 3D printed porous titanium alloy cage facilitates precise 3D realignment in patients with craniovertebral deformities, demonstrating effectiveness in symptom relief and stability.

Initial evaluation of the relationship between maximal axial vertebra rotation and the rotation deformity in adolescent idiopathic scoliosis.

This study evaluated the relationship between maximal axial vertebra rotation (maxAVR) and other clinical and radiological indexes, compared to apical vertebra rotation (AVR) in idiopathic adolescent scoliosis (AIS). Forty consecutive patients of AIS with Cobb angle of major curve > 40° were included. They were scanned by an EOS imaging system and had trunk rotational angle (TRA) measured by scoliometer. The correlation between variables was assessed using Pearson's correlation coefficient and loaded onto a meta-analysis model. There were (34 girls and 6 boys) with an average age of 13.8 ± 1.6years. AVR was maxAVR in only 47.5% (19/40) cases of the major curves and 42.3% (11/26) cases of the minor curves. The correlation between maxAVR and TRA was significantly higher than the correlation between AVR and TRA for the MT curves (p = 0.0001) and TL/L curves (p = 0.0001). On multivariate regression analysis, the magnitude of maxAVR showed a significant correlation with TRA (p = 0.0002), Cobb angle (p = 0.001), and coronal deformity angular ratio (C-DAR) (p = 0.027). The apical vertebra was not the most rotated in most cases. The correlation between maxAVR and TRA was significantly higher than the correlation between AVR and TRA. Moreover, the maxAVR was multivariately related to TRA, Cobb angle, and C-DAR. Level II, diagnostic.

Treatment of rotational tibial malunion after minimal invasive plate osteosynthesis (MIPO): Corrective osteotomy with original plate retention (PR-Osteotomy).

Residual axial and rotational deformities in tibial shaft fracture, after minimally invasive osteosynthesis (MIO) treatment, are widely described in literature. Nevertheless, there is still a lack of evidence about the malunion treatment strategies and results. The aim of our study is to present an innovative technique for tibial shaft malunion: a derotational proximal tibial osteotomy without removing the original plate (Plate-Retaining-Osteotomy: PR-Osteotomy). We present the results of two consecutive patients' treatment, affected by tibial shaft fracture malunion, as sequelae of MIO treatment. The two patients, male 60 years old and female 39 years old, underwent previous surgical treatment with an average of 9 months span time before surgical revision. The affected limb showed significant external torsional defect associated with gait impairment, pain and limping. The amount of rotational deformity and the bone healing condition is assessed through a methodical preoperative planning, including weight bearing lower limbs Xray and bilateral computed tomography (CT) scan of the lower limbs. The surgical technique involves a monoplanar tibial osteotomy, in a perpendicular fashion to the tibial axis, at a level that would allow at least 3 proximal screw-holes to become available for subsequent fixation. Proximal to the osteotomy line the screws are removed, while the distal ones, if stable after testing, are left in place. The amount of torsional correction, planned on CT, is reproduced intraoperatively with the assistance of graduated templates. A fibular osteotomy may be performed if required. After temporary stabilization, the correct functional reduction is checked with the aid of fluoroscopy and empirical rod measurement, using the contralateral limb alignment as a reference. Once the desired correction is achieved, absolute stability is applied to the osteotomy site. Postoperative rehabilitation protocol involves partial weight bearing for 6-8 weeks with progression to full weight bearing by 10-12 weeks. Both patients showed complete osteotomy healing at the 13th and 16th week respectively, with no complications and full recovery of normal gait and daily life activities. To our knowledge, this is the first description of such surgical technique. Less invasiveness, fast recovery time and cost reductions are the foremost proposed benefits. Further larger case series with longer follow up are needed to assess the advantages of the proposed treatment strategy.