Apprehension-Based Training: A Novel Treatment Concept for Anterior Shoulder Dislocation - A Case Report.

Background and Purpose: Conservative management of anterior shoulder dislocation (ASD) is associated with greater recurrence compared with surgical management. Current rehabilitation protocols may not adequately challenge shoulder stability to encourage adaptive coping strategies. Apprehension-based training (ABT) is a new treatment concept derived from the supine moving apprehension test (SMAT), a previously validated performance measure among patients with ASD. The purpose of this case report is to describe the application of ABT in a patient with recurrent ASD. Study Design: Case report. Case Description: The subject was a 23-year-old male with bilateral recurrent ASD. The subject underwent a 17-week exercise program involving gradual exposure to increased anterior instability loads based on the SMAT movement pattern. The Western Ontario Shoulder Instability Index (WOSI), Patient-Specific Functional Scale (PFPS), Tampa Scale of Kinesiophobia, SMAT, shoulder internal and external rotation muscle strength were measured via hand-held dynomometry before and after training. Outcomes: Following treatment, clinically meaningful gains in quality of life (WOSI) and shoulder function (PSFS) were noted. Kinesiophobia decreased, SMAT and shoulder internal rotator strength increased beyond their respective minimal detectable change. Four months after treatment, quality of life and shoulder function remained improved, and the subject reported a reduced rate of ASD. Discussion: Apprehension-based training involving gradual exposure to shoulder instability loads may hold potential for improving the management of patients with ASD. Further testing of this concept is warranted. Level of Evidence: 4, single case report.

Medial swivel dislocation with impacted navicular bone into the talar head: A case report.

Medial swivel dislocation is a rare subtype of midtarsal bone dislocation, mostly associated with fracture rather than isolated dislocation. It is caused by medially or laterally direct forces to the midfoot. In case of failed closed reduction of the deformity, the patient should undergo open reduction and stabilization of the injury as soon as possible. We are presenting a 17-year-old, male, who sustained a left ankle injury and presented with a deformity, closed reduction of the deformity failed multiple times, and the patient was taken for open reduction and stabilization of the deformity in the operating theater. Intra-operatively, the dislocation was locked with the lateral process of the navicular being impacted into the taller head. Six months following the injury the patient was back to his pre-injury status and did not have any recurrent dislocation of the midfoot.

Open reduction for hip dislocation in children with arthrogryposis multiplex congenital: Outcomes of a systematic review.

Introduction: The incidence of hip dislocation (HD) in arthrogryposis multiplex congenital ranges from 15 to 30 %. Besides a stable hip, the ambulation potential of an AMC child is also dependent on severity of associated knee and foot deformations. The primary objective of this review is to determine the proportion of ambulators in AMC children treated by open reduction for HD. Methods: We searched major electronic bibliographic databases for reports on the treatment of HD among AMC children. Based on the surgical approach for open reduction of HD in AMC children, we divided the included studies into groups 1 (Anterior approach open reduction) and 2 (Medial approach open reduction). Results: We pooled 59 children/94 hips in this review from 7 studies. We identified 45 children/71 hips and 14 children/23 hips with a mean age of 20 (4-64) and 4.5 (0.5-11) months in groups 1 and 2, respectively. There were 97 % (44) and 92 %(Obeidat et al., 2011) 13 ambulators in groups 1 and 2, respectively. 47 % and 36 % of hips in groups 1 and 2 required additional procedures besides open reduction for redislocation and maintenance of hip reduction. 31 %22 and 13 %(Fisher et al., 1970 Feb) 3 of the hips sustained avascular necrosis in group 1 and 2. Conclusion: Children with AMC associated HD can be expected to ambulate with and without assistance in 90 % of the cases however, the foot and knee problems also need concomitant management. In children less than 6 months of age the medial approach based open reduction may be more efficacious and less complicating than anterior approach based open reduction however, at a later age anterior approach based open reduction is more effective due to need for pelvic and femur sided additional procedures.

Comparison of Outcomes in Dual-Mobility Versus Fixed-Bearing Implants in Primary Total Hip Arthroplasty: A Systematic Review and Meta-Analysis.

Total hip arthroplasty (THA) is often regarded as one of the most successful surgical techniques developed in the twenty-first century. However, it is associated with complications such as prosthetic instability, dislocations, or infections. Dual-mobility (DM) implants have been developed with the goal of reducing the incidence of dislocations by increasing the femoral head-neck ratio, maximising hip stability, and improving the range of motion (ROM) before impingement and dislocation. This systematic review aims to comprehensively compare the safety and efficacy of DM versus fixed-bearing (FB) implants in primary THA patients. A comprehensive search strategy of PubMed, Embase, Scopus, and Web of Science Core Collection databases was executed to identify pertinent literature comparing DM and FB implants in THAs. Eligible studies underwent independent screening, and data were systematically extracted. The analysis employed pooled risk ratios (RR) for dichotomous outcomes and mean differences (MD) for continuous variables, each accompanied by their respective 95% confidence intervals (CI). Our systematic review and meta-analysis included nine studies encompassing 22,277 patients. The DM group had a significantly reduced incidence of dislocations compared to the FB group (RR 0.25, 95%CI [0.13, 0.47]; p-value <0.0001) and a significantly shorter length of stay (MD -9.92, 95%CI [-15.53, -4.32]; p-value = 0.0005). The FB group, however, had a significantly shorter operative time compared to the DM group (MD 10.41, 95%CI [7.64, 13.17]; p-value < 0.00001). We did not identify any significant statistical differences between the DM and FB groups regarding patient-reported outcome measures, the incidence of all-cause readmissions, the incidence of peri-prosthetic fractures, the incidence of infections, or the incidence of groyne pain.

Effects of different doses of dexmedetomidine combined with sufentanil in intravenous controlled analgesia after Salter osteotomy in children.

Background: This study aimed to investigate the effect of different doses of dexmedetomidine combined with sufentanil on postoperative analgesia in developmental hip dislocation in children after Salter osteotomy. Methods: The clinical data of 98 children with developmental hip dislocation, who underwent Salter osteotomy in our center between January 2020 and February 2023, were selected. The children were randomly divided into four groups based on the application of patient-controlled intravenous analgesia (sufentanil + granisetron ± dexmedetomidine). All children received 1 µg/kg/day of sufentanil and 3 mg of granisetron. Group A did not receive dexmedetomidine, and Groups B, C, and D received 0.5, 0.75, and 1.0 µg/kg/day of dexmedetomidine, respectively. The pain indicators and immune factor levels of children in each group were compared. Results: The heart rate (HR) and respiratory rate (RR) 2 h after operation in Groups C and D were significantly lower than those in Groups A and B (P < 0.05). The pain scores decreased over time after treatment in all groups. When compared at the same time point, children in Group D had the lowest pain scores, which were significantly lower than the other three groups (P < 0.05). The total consumption of sufentanil in Groups C and D was significantly lower than that in Group A (P < 0.05). On the first day after surgery, the children in Group D had lower levels of serum adrenocorticotropic hormone, interleukin-6, and corticosterone than those in Group A (P < 0.05). Conclusion: Administration of 1.0 µg/kg/day of dexmedetomidine combined with sufentanil in intravenous controlled analgesia after Salter osteotomy for developmental hip dislocation in children has a better analgesic effect, less consumption of sufentanil, and low incidence of opioid adverse reactions.

Combined Anterolateral and Posterior Approach in Total Hip Arthroplasty for Chronic Post-traumatic Hip Dislocation: A Case Report.

Hip dislocation is rare, and it typically results from high-energy trauma such as traffic accidents. Its management involves prompt reduction of the dislocated hip to minimize the risk of subsequent femoral head necrosis. Consequently, cases of chronic hip dislocation are extremely rare. This report presents a case of a 33-year-old male with chronic posterior hip dislocation due to a traffic accident 13 years ago. The left femoral head was completely dislocated posteriorly from the acetabulum, forming a false acetabulum with an arthritic change. The patient experienced difficulty walking and performing daily activities due to pain. We performed a total hip arthroplasty (THA) using a combined anterolateral and posterior approach. The outcome was favorable, with no complications during the two-year follow-up period. THA using a combined anterolateral and posterior approach is a valuable option for patients with chronic post-traumatic hip dislocation because it offers the advantages of optical visibility and the management of the adhered soft tissues.

Irreducible traumatic pure hip dislocation by the entrapment of the lateral rotator muscle group of the hip: A case report.

Introduction: Irreducibility is a rare complication of pure posterior hip dislocation requiring surgical intervention. Case presentation: We present a case of a 22-year-old female with posterior hip dislocation following a motor vehicle accident. Despite unsuccessful closed reduction attempts, open surgical reduction successfully released the incarcerated muscles and achieved reduction. Follow-up examinations showed excellent functional outcomes without complications. Clinical discussion: Irreducibility remains a rare complication of traumatic posterior hip dislocation. Three possible entities can cause soft tissue incarceration: labral buttonholing, intra-articular osteochondral bodies, and entrapment of the piriformis muscle. The posterior-lateral approach provides excellent exposure of the posterior hip structures, but it carries the risk of injury to the medial circumflex artery. After successfully reducing the dislocation, it is essential to perform a computed tomography (CT) scan to detect any osteochondral lesions, including femoral head impaction. Functional outcomes are better with early mobilization and prompt resumption of weight-bearing. However, femoral head osteonecrosis complicates 52.9 % of hip dislocations reduced beyond 6 h, whereas it occurs in only 4.8 % of dislocations reduced within this timeframe. Conclusion: This case underscores the importance of prompt recognition and appropriate surgical intervention for irreducible hip dislocations to prevent further complications and optimize patient outcomes.

Atlantoaxial subluxation and Down syndrome: A cross-sectional analysis.

Background: Atlantoaxial subluxation (AAS) is a diagnosis describing misalignment of the C1 vertebra relative to C2. Excessive translation of this joint, located adjacent to the medullary brain stem, can lead to devastating neurological consequences. A higher prevalence of AAS within the Down syndrome (DS) population has been well-established. This study aims to establish a prevalence rate of DS in patients hospitalized for AAS and compare outcomes between AAS patients with and without DS. Methods: This study utilized the National Inpatient Sample (NIS) provided by the Healthcare Cost and Utilization Project (HCUP). In accordance with HCUP 2023 Clinical Classifications Software Refined files, data were queried using the International Classification of Diseases 10th Edition codes for DS and AAS. Demographics, comorbidities, hospital course, and outcomes were examined and compared using binary and linear multivariate regression. IBM SPSS software was used for data analysis. Results: Of the 213,095 patients in the NIS database admitted between 2016 and 2020 with AAS as their primary diagnosis, 7.2% were DS patients. DS patients were significantly younger (26.56 ± 20.81 vs. 49.39 ± 27.63, P < 0.01), less likely to be female (33.30% vs. 52.10%), and had fewer comorbidities (diabetes mellitus, hypertension, and hyperlipidemia) than non-DS patients. There was no significant difference in likelihood to undergo surgical fusion between DS patients and non-DS patients with AAS. Conclusion: This large-scale study using NIS data determined that 7.2% of all patients admitted to hospitals for AAS are DS patients. The analysis of demographics, hospital course, and outcomes can influence the development of treatment protocols for AAS in the DS population.

A novel variant of type-II Monteggia equivalent in an adult: A case report with a 6-year follow-up.

Case: An 18-year-old right-handed male student presented after a road-traffic-accident; he had type-II Monteggia fracture dislocation associated with ipsilateral type-I capitellum fracture and comminuted lateral condyle avulsion fracture. He underwent open reduction and fixation of ulna with 3.5 DCP with autologous olecranon bone grafting and fixation of capitellum using Herbert screw along with lateral collateral ligament (LCL) repair using fiber wire. At 6-years follow-up good outcome was seen without functional restrictions despite 15 degrees of restriction in pronation. Conclusion: Monteggia type-II variant with type-I capitellum fracture and LCL avulsion is a unique combination that represents a novel variant of type-II Monteggia equivalent, which adds to the existing classification of Monteggia equivalents.

Dislocation response of ECC-RC composite supporting structures of tunnels passing through active fault.

To address the problems of the conventional composite supporting structures (CCSSs) such as insufficient anti-dislocation performance and deformation capacity, this study used Engineered Cementitious Composite (ECC) lining sections instead of the traditional lining sections and optimized support design parameters, resulting in the development of novel ECC-RC composite supporting structures (ECSSs) of tunnels passing through active fault. The dislocation response characteristics and their parameter sensitivity of the ECSS was revealed by way of 1/25-scale fault dislocation model tests and finite element analysis. The test results show that the mechanical response characteristics and the failure modes of the CCSS and the ECSS are similar under reverse fault dislocation. Compared with the CCSS, the anti-dislocation performance of the ECSS is significantly improved by introducing of the ECC lining and optimizing the design parameters. The vertical deformation of the ECSS and the range of influence under the same dislocation are significantly decreased, and the strain are reduced to different degrees. This phenomenon shows that by improving the material properties, shortening the spacing of aseismatic joints and optimising the thickness of the shock absorption layer, the stress conditions and applicability under deformation of the structure are improved. The ECSS benefits from the crack resistance and toughening effect of fibres, the degree and scope of cracking of the ECSS are significantly reduced compared with those of the CCSS, and internal and external through cracks and local spalling are absent. The results of finite element analysis show that the overall damage degree of the ECSS is decreased and the damage range is increased by decreasing the strength of the surrounding rock in the fault zone. The fault dislocation response pattern of the ECSS varies depending on the fault type. The damage degree caused by different fault types follows the order of normal fault, strike-slip fault, and reverse fault from large to small. However, the damage range caused by the strike-slip fault is significantly larger compared to normal fault and reverse fault. In the design of fault resistance, the surrounding rock conditions of the fault zone and the form of fault dislocation should be considered.

Surgical Treatment and Outcomes of Trans-Ulnar Basal Coronoid Fracture-Dislocations.

BACKGROUND: Trans-ulnar fracture-dislocations of the elbow are complex injuries that can be difficult to classify and treat. Trans-ulnar basal coronoid injuries, in which the coronoid is not attached to either the olecranon or the metaphysis, present substantial challenges to achieve anatomic reduction and stable internal fixation. The purpose of this study was to analyze the outcome of surgical treatment of trans-ulnar basal coronoid fracture-dislocations. MATERIALS & METHODS: Between 2002 and 2019, 32 consecutive trans-ulnar basal coronoid fracture-dislocations underwent open reduction and internal fixation (ORIF) at our institution. Four elbows were lost to follow-up within the first 6 months after surgery and were excluded. Among the 28 elbows remaining, there were 13 females and 15 males with a mean age of 56 (range 28-78) years at the time of injury. The mean clinical and radiographic follow-up times were 37 months and 29 months, respectively. Radiographs were reviewed to determine rates of union, Hastings and Graham heterotopic ossification (HO) grade, and Broberg and Morrey arthritis grade. RESULTS: Union occurred in 25 elbows. Union could not be determined for 1 elbow at most recent follow-up and the remaining 2 elbows developed nonunion of the coronoid. Complications occurred in 10 elbows (36%): deep infection (4), ulnar neuropathy (2), elbow contracture (2), and nonunion (2). There were reoperations in 11 elbows (39%): irrigation and débridement with hardware removal (4), hardware removal (2), ulnar nerve transposition (2), contracture release with HO removal (2), and revision ORIF with iliac crest autograft (1). At most recent follow-up, the mean flexion-extension arc was 106° (range 10-150°), and the mean pronation-supination arc was 137° (range 0-170°). The mean Quick Disabilities of Arm, Shoulder, and Hand score was 11 (range 0-39) points with a mean Single Assessment Numeric Evaluation-Elbow score of 81 (range 55-100) points. At final radiographic follow-up, 16 elbows (57%) had HO (8 class I and 8 class II), and 20 elbows (71%) had arthritis (8 grade 1, 6 grade 2, and 6 grade 3). DISCUSSION: Trans-ulnar basal coronoid fracture dislocations are severe injuries associated with high rates of reoperation, heterotopic ossification, and post-traumatic arthritis. However, the majority of elbows achieve union, a functional range of motion, and reasonable patient reported outcome measures. Over the study period, surgeons were more likely to utilize multiple deep approaches and separate fixation of the coronoid (either with lag screws or anteromedial plates) to ensure anatomic reduction.

Severe traumatic dislocation of the lower cervical spine with mild neurological symptoms: Case reports and literature review.

CONTEXT: Severe traumatic fractures and dislocations of the lower cervical spine are usually accompanied by irreversible spinal cord injuries. Such patients rarely have mild or no neurological symptoms. FINDINGS: We report three cases of severe lower cervical dislocation without spinal cord injury and discuss the mechanisms underlying this type of injury. All three patients had severe lower cervical dislocation, but their neurological symptoms were mild. In all cases, the fractures occurred at the bilateral junctions of the lamina and pedicle, resulting in severe cervical spondylolisthesis, whereas the posterior structure remained in place, thereby increasing the cross-sectional area of the spinal canal. After preoperative skull traction for a few days, the patients underwent anterior or combined anterior and posterior cervical surgeries. All surgeries were successfully completed and the patient's symptoms disappeared at the last follow-up. CONCLUSION: Severe traumatic dislocation of the lower cervical spine with an intact neurological status is rare in clinical practice. Pathological canal enlargement preserves neurological function, and the most commonly injured segment is C7. Preoperative traction for closed reduction remains controversial. We suggest that if no obvious anterior compression is observed, closed reduction should be pursued. Anterior or combined anterior and posterior cervical surgeries can provide rigid fixation with satisfactory results.

Ulnohumeral Cross-Pinning in the Management of Traumatic Elbow Instability.

PURPOSE: Traumatic elbow instability (subluxation and dislocation) represents a challenging clinical entity that can be complicated by persistent intraoperative instability after attempted stabilization or recurrent postoperative instability. Both static and dynamic supplemental stabilization procedures have been described for cases where fracture fixation and ligament repair fail to restore stability. There is a paucity of prior studies involving ulnohumeral cross-pinning (UCP), which is a type of static supplemental stabilization. Our purpose was to assess complications and outcomes after UCP. METHODS: We reviewed all surgical cases involving primary and revision UCP for traumatic elbow instability at a single center from 2017-2023. Baseline demographics were recorded. Outcomes including radiographs, range of motion, patient-reported outcome measures, and surgical complications were analyzed. RESULTS: Fourteen patients undergoing UCP were included with a mean follow-up of 27 months. Five cross-pinnings (36%) were performed during revision procedures. Mean visual analog scale (VAS) pain, Disabilities of the Arm, Shoulder, and Hand (QuickDASH), and the Single Assessment Numeric Evaluation (SANE) scores were 2.4, 34, and 69, respectively. The mean flexion-extension and pronation-supination arcs were 114° and 140°, with 85% achieving at least a 100° arc for flexion and forearm rotation. Five patients (36%) had complications, all of which required reoperation. Two complications involved postoperative instability: one radial head subluxation and one radial head dislocation. Both occurred in revision UCP cases indicated for recurrent postoperative instability. CONCLUSIONS: Ulnohumeral cross-pinning for persistent and recurrent elbow instability results in maintained ulnohumeral joint alignment, functional arcs of elbow range of motion, and acceptable patient-reported outcome measures, particularly in the setting of a primary procedure indicated for persistent intraoperative instability. Ulnohumeral cross-pinning is a reasonable supplemental stabilization procedure for complex elbow instability. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Combined Hip and Knee Strengthening Compared With Knee Strengthening for Individuals With Lateral Patellar Dislocation: A Single-blind, Superiority, Randomized Controlled Trial.

Objective: To investigate whether a combined hip and knee muscle strengthening program is superior to a knee strengthening program for people after lateral patellar dislocation (LPD). Design: Single-blind, superiority, randomized controlled trial with 48 weeks follow-up. Setting: Physiotherapy out-patient clinic. Participants: Forty individuals aged 16 or older, with a history of non-traumatic LPD were randomized to a knee-based strengthening (KBSG) or quadriceps and hip strengthening exercise (HQSG) program (N=40). Inclusion criteria included a positive apprehension sign, pain on palpation along the medial retinaculum, and J sign. Exclusion criteria included restricted range of motion (<90° knee flexion), and traumatic or postsurgical LPD. Interventions: Concealed randomization was performed using random permuted blocks of size 4. Individuals received their corresponding exercise program according to randomization and group allocation: knee-based strengthening (n=20) or combined hip and quadriceps strengthening (n=20) twice weekly for 8 weeks over 16 appointments. Main Outcome Measures: Primary outcome was the Lysholm Knee Score. Secondary outcomes included Numerical Pain Ratings Scale (NPRS) at rest and during effort, Norwich Patellar Instability Score (NPIS), Kujala Anterior Knee Pain Scale (AKPS), Lower Extremity Functional Scale (LEFS), 4 domains of the WHOQOL-Bref, and recurrence rate. Patient-reported outcome measures were assessed from the baseline to 48 weeks. Assessments were performed by a physiotherapist who was blinded to the group allocation. Data were analyzed by using a repeated-measures ANOVA model with Tukey's post hoc test after an intention-to-treat principle. Results: At the primary time-point of 8 weeks, there were no substantial between-group differences in the Lysholm Knee Score: mean difference=-6.8 (95% CI -14.3 to 3.7); NPIS: mean difference=23.5 (95% CI 5.6 to 41.3); AKPS: mean difference=-1.54 (95% CI -8.6 to 5.6), NPRS at rest and during effort (mean difference=0.32 (95% CI -0.37 to 1); and mean difference=0.68 (95% CI -0.9 to 1.86); LEFS mean difference=-1.08 (95% CI -5.9 to 2.4), WHOQOL-Bref domains (physical health: mean difference=-0.12, (95% CI -1.26 to 1.02); psychological: mean difference=-0.32 (95% CI -2.04 to 1.4); social relations: mean difference=-0.7 (95% CI -2.2 to 0.82); environment: mean difference=0.44 (95% CI -1 to 1.9), and recurrence rate (P=.69). Conclusion: This study indicates that combined hip and knee muscle strengthening is not superior to knee-based strengthening for LPD treatment. The limitations stemming from the underpowered nature of the trial must be acknowledged, concerning the potential oversight of moderate intervention effects.

Application of Weak-Beam Dark-Field STEM for Dislocation Loop Analysis †.

Nanoscale dislocation loops formed by irradiation can significantly contribute to both irradiation hardening and embrittlement of materials when subjected to extreme nuclear reactor environments. This study explores the application of weak-beam dark-field (WBDF) scanning transmission electron microscopy (STEM) methods for quantitative irradiation-induced defect analysis in crystalline materials, with a specific focus on dislocation loop imaging and analysis. A high-purity Fe-5 wt% Cr model alloy was irradiated with 8 MeV Fe2+ ions at 450°C to a fluence of 8.8 × 1019 m-2, inducing dislocation loops for analysis. While transmission electron microscopy (TEM) has traditionally been the primary tool for dislocation imaging, recent advancements in STEM technology have reignited interest in using STEM for defect imaging. This study introduces and compares three WBDF STEM methods, demonstrating their effectiveness in suppressing background contrasts, isolating defect information for dislocation loop type classification, providing finer dislocation line images for small loop analysis, and presenting inside-outside contrast for identifying loop nature. Experimental findings indicate that WBDF STEM methods surpass traditional TEM approaches, yielding clearer and more detailed images of dislocation loops. The study concludes by discussing the potential applications of WBDF STEM techniques in defect analysis, emphasizing their adaptability across various material systems beyond nuclear materials.

Single-Center Long-Term Results of Popliteal Artery Blunt Trauma Management Following Knee Dislocation - A Case Series Study.

OBJECTIVES: Injury to the popliteal artery after knee dislocation, if not promptly diagnosed and properly treated, can have devastating results. The purpose of this retrospective study was to describe the diagnostic and the treatment protocol we use, as well as provide long-term outcomes for a series of patients treated in our tertiary hospital, emphasizing on the importance of ankle-brachial index (ABI) measurement as an integral component of the diagnostic approach. METHODS: A retrospective analysis of all admissions to our hospital trauma center between November 1996 and July 2023, with a diagnosis of knee dislocation and the presence or absence of concomitant arterial injury resulting from blunt high energy trauma, was conducted. Before 2006, digital subtraction angiography (DSA) and/or computed tomography angiography (CTA) were part of the diagnostic approach (Group A). After 2006, the ankle-brachial index (ABI) was used as a first-line test to diagnose arterial damage (Group B). The Tegner and Lysholm scores were chosen to assess patients' postoperative impairment between groups, taking also in account the presence or absence of vascular injury. The Mann-Whitney U test and a univariate analysis of variance were used for the statistical analysis of scores. RESULTS: Overall, 55 patients were identified, and 21 of them (38.2%) had injuries to the popliteal artery, all of which were treated with a reversed great saphenous venous bypass. Out of the 21 patients, 4 (4.3%) developed compartment syndrome, which was treated with fasciotomies, and 1 leg (1.8%) was amputated above the knee. With no patients lost to follow-up, all but one (95%) of the vascular repairs are still patent, and the limbs show no signs of ischemia after a mean follow-up of 6 years. The Tegner and Lysholm score means were similar between groups A and B and independent of the presence of vascular injury and the diagnostic protocol used. Interestingly, an ABI below 0.9 proved to be predictive of arterial injury. CONCLUSION: A high level of awareness for the presence of popliteal artery injury should exist and an ABI measurement should be routinely performed in the management of all cases of knee dislocation. This way, less patients will undergo unnecessary CTA scanning, and hardly any popliteal artery injuries can go missing, as suggested by our study.

Dislocation of primary total hip arthroplasty: Analysis of risk factors and preventive options.

Total hip arthroplasty (THA) is one of the most successful elective operations in orthopedic surgery for improving pain and functional disability in patients with end-stage joint disease. However, dislocation continues to be a troublesome complication after THA, as it is a leading cause of revision and is associated with substantial social, health, and economic costs. It is a relatively rare, usually early occurrence that depends on both the patients' characteristics and the surgical aspects. The most recent and important finding is the special attention to be given preoperatively to spinopelvic mobility, which is closely related to the incidence of dislocation. Consequently, clinical and radiographic assessment of the lumbar spine is mandatory to identify an altered pelvic tilt that could suggest a different positioning of the cup. Lumbar spinal fusion is currently considered a risk factor for dislocation and revision regardless of whether it is performed prior to or after THA. Surgical options for its treatment and prevention include the use of prostheses with large diameter of femoral head size, dual mobility constructs, constrained liners, and modular neck stems.

Direct anterior compared to posterior approach for hip hemiarthroplasty following femoral neck fractures.

The differences in complication rates between the direct anterior and posterior approaches for hemiarthroplasty in elderly patients with femoral neck fractures are not yet fully understood. Dislocation, a severe complication associated with increased mortality and often requiring additional surgery, may occur less frequently with the direct anterior approach compared to the posterior approach. Careful consideration of patient demographics is essential when planning the surgical approach. Future research in this area should focus on robust randomized controlled trials involving elderly patients recovering from femoral neck fractures.

The Role of Dislocation Type in the Thermal Stability of Cellular Structures in Additively Manufactured Austenitic Stainless Steel.

The ultrafine cellular structure promotes the extraordinary mechanical performance of metals manufactured by laser powder-bed-fusion (L-PBF). An in-depth understanding of the mechanisms governing the thermal stability of such structures is crucial for designing reliable L-PBF components for high-temperature applications. Here, characterizations and 3D discrete dislocation dynamics simulations are performed to comprehensively understand the evolution of cellular structures in 316L stainless steel during annealing. The dominance of screw-type dislocation dipoles in the dislocation cells is reported. However, the majority of dislocations in sub-grain boundaries (SGBs) are geometrically necessary dislocations (GNDs) with varying types. The disparity in dislocation types can be attributed to the variation in local stacking fault energy (SFE) arising from chemical heterogeneity. The presence of screw-type dislocations facilitates the unpinning of dislocations from dislocation cells/SGBs, resulting in a high dislocation mobility. In contrast, the migration of SGBs with dominating edge-type GNDs requires collaborative motion of dislocations, leading to a sluggish migration rate and an enhanced thermal stability. This work emphasizes the significant role of dislocation type in the thermal stability of cellular structures. Furthermore, it sheds light on how to locally tune dislocation structures with desired dislocation types by adjusting local chemistry-dependent SFE and heat treatment.

C1 Facetectomy and Ventral Fixation of Occipitoatlantoaxial Complex for Concurrent Congenital Atlanto-Occipital Dislocation and Atlantoaxial Instability in a Toy Poodle.

An 8-month-old, 3.4 kg, castrated male Toy Poodle was referred for progressive tetraparesis and respiratory disorder without a history of trauma. Repeated computed tomography (CT) and magnetic resonance imaging (MRI) with different positions of the neck revealed concurrent atlanto-occipital dislocation (AOD) and atlantoaxial instability (AAI) with spinal cord compression. This case was unique due to its congenital nature and the absence of trauma. The surgical treatment involved precise removal of the C1 vertebra's ventral articular facet, which was compressing on the spinal cord, attributed to its fixed and malaligned position within the atlantooccipital joint. Following facetectomy, the stabilization of the occipital bone to the C2 vertebra was achieved by screws, wire, and polymethyl methacrylate. Two days after surgery, the dog recovered ambulation and showed gradual improvement in gait, despite mild residual ataxia. Postoperative CT and radiographs showed successful decompression of the spinal cord. The screw loosening was confirmed at 114 days, which was managed successfully by extracting the affected screws. Through the 21-month monitoring period, the dog showed a normal gait with a wide-based stance of the pelvic limbs when standing and experienced no pain. This case represents the first report of concurrent congenital AOD and AAI treated with a ventral surgical approach, contributing new insights to the understanding and management of such complex cranio-cervical junction disorders in veterinary neurosurgery.