Stabilization Procedure Research Articles

An anteromedial stabilization procedure has the most protective effect on the anterior cruciate ligament in tibial external rotation. A human knee model study

IntroductionAnterior cruciate ligament (ACL) reconstruction remains associated with the risk of re-rupture and persisting rotational instability. Additional extraarticular anterolateral stabilization procedures stabilize the tibial internal rotation and lead to lower ACL failure rate and improved knee stability. However, data for additional stabilization of tibial external rotation is lacking and the importance of an anteromedial stabilization procedure is less well evaluated. Aim of this study is to investigate the influence of an extraarticular anteromedial stabilization procedure for the stabilization of the tibial external rotation and protection of the ACL from these rotational forces.MethodsInternal and external rotations of the tibia were applied to a finite element (FE) model with anatomical ACL, posterior cruciate ligament (PCL), lateral collateral ligament (LCL), medial collateral ligament (MCL) and intact medial and lateral meniscus. Five additional anatomic structures (Anteromedial stabilization/anteromedial ligament, AML, augmented superficial medial collateral ligament, sMCL, posterior oblique ligament, POL, anterolateral ligament, ALL, and popliteal tendon, PLT) were added to the FE model separately and then combined. The force histories within all structures were measured and determined for each case.ResultsThe anteromedial stabilization or imaginary AML was the main secondary stabilizer of tibial external rotation (90% of overall ACL force reduction). The AML reduced the load on the ACL by 9% in tibial external rotation which could not be achieved by an augmented sMCL (-1%). The AML had no influence in tibial internal rotation (-1%). In the combined measurements with all additional structures (AML, ALL, PLT, POL) the load on the ACL was reduced by 10% in tibial external rotation.ConclusionThis study showed that an additional anteromedial stabilization procedure secures the tibial external rotation and has the most protective effect on the ACL during these external rotational forces.

Fibular hemimelia: reconstruction of difficult cases with tibial lengthening and ankle arthrodesis.

Management of fibular hemimelia includes either prosthetic care with or without a suitable amputation or tibial lengthening. Many studies have documented the success of both procedures. Most parents of these children refuse an amputation or have no access to good prosthetic care. The author presents a limb-salvage procedure with tibial lengthening and ankle stabilization. Twelve children of fibular hemimelia with 14 extremities had been subjected to limb lengthening after lateral leg release. To correct the valgus procurvatum, double oblique diaphyseal osteotomy (DODO) of the tibia was performed in 11 extremities. The age of the patients ranged from two to 15years with the median of fiveyears. All were male. The proposed procedure included three stages of loosening, lengthening, and stabilization with ankle arthrodesis at a later stage. All patients returned for follow-up for the first fouryears and had been walking on their sensate feet. With DODO followed by fixator/traction could straighten and lengthen the tibia simultaneously and correct the valgus procurvatum. Ankle stabilization provided stability and a plantigrade foot. A follow-up of six to30years with a median of tenyears has been reported. A new procedure of loosening, lengthening, and stabilization of the leg with ankle arthrodesis has been proposed. A follow-up of 30years with a median of tenyears of the said procedure has been reported. The procedure provides a long-lasting plantigrade and painless foot that has sensation and proprioception. An amputation at any level has not been recommended.

Homeostasis: Design and Implementation of a Self-Stabilizing Compiler

Mainstream compilers perform a multitude of analyses and optimizations on the given input program. Each analysis (such as points-to analysis) may generate a program-abstraction (such as points-to graph). Each optimization is typically composed of multiple alternating phases of inspection of such program-abstractions and transformations of the program. Upon transformation of a program, the program-abstractions generated by various analyses may become inconsistent with the modified program. Consequently, the correctness of the downstream inspection (and consequent transformation) phases cannot be ensured until the relevant program-abstractions are stabilized ; that is, the program-abstractions are either invalidated or made consistent with the modified program. In general, the existing compiler frameworks do not perform automated stabilization of the program-abstractions and instead leave it to the compiler pass writers to deal with the complex task of identifying the relevant program-abstractions to be stabilized, the points where the stabilization is to be performed, and the exact procedure of stabilization. In this article, we address these challenges by providing the design and implementation of a novel compiler-design framework called Homeostasis . Homeostasis automatically captures all the program changes performed by each transformation phase, and later, triggers the required stabilization using the captured information, if needed. We also provide a formal description of Homeostasis and a correctness proof thereof. To assess the feasibility of using Homeostasis in compilers of parallel programs, we have implemented our proposed idea in IMOP, a compiler framework for OpenMP C programs. Furthermore, to illustrate the benefits of using Homeostasis , we have implemented a set of standard data-flow passes, and a set of involved optimizations that are used to remove redundant barriers in OpenMP C programs. Implementations of none of these optimizations in IMOP required any additional lines of code for stabilization of the program-abstractions. We present an evaluation in the context of these optimizations and analyses, which demonstrates that Homeostasis is efficient and easy to use.

Investigating the role connective tissue fibroblasts play in the altered muscle anatomy associated with the limb abnormality, Radial Dysplasia.

Radial dysplasia (RD) is a congenital upper limb birth defect that presents with changes to the upper limb anatomy, including a shortened or absent radius, bowed ulna, thumb malformations, a radially deviated hand and a range of muscle and tendon malformations, including absent or abnormally shaped muscle bundles. Current treatments to address wrist instability caused by a shortened or absent radius frequently require an initial soft tissue distraction intervention followed by a wrist stabilisation procedure. Following these surgical interventions, however, recurrence of the wrist deviation remains a common, long-term problem following treatment. The impact of the abnormal soft connective tissue (muscle and tendon) anatomy on the clinical presentation of RD and the complications following surgery are not understood. To address this, we have examined the muscle, fascia and the fascial irregular connective tissue (ICT) fibroblasts found within soft connective tissues, from RD patients. We show that ICT fibroblasts isolated from RD patients are functionally abnormal when compared to the same cells isolated from control patients and secrete a relatively disordered extracellular matrix (ECM). Furthermore, we show that ICT fibroblast dysfunction is a unifying feature found in RD patients, even when the RD clinical presentation is caused by distinct genetic syndromes.

Arthroscopic Shoulder Stabilization in High School Football Players.

Destabilizing shoulder injuries are common in high school American football players; however, the rate of recurrent glenohumeral instability and return to play after arthroscopic labral stabilization surgery remains unknown. The purpose of this study was to determine the rate of recurrent instability on return to competitive high school football after arthroscopic shoulder labral stabilization and capsulorrhaphy procedures. It was hypothesized that the instability rate would be greater in players with more years of eligibility remaining (YER) to play at the high school level. Case series; Level of evidence, 4. Consecutive male high school football players with at least 1 YER who sustained at least 1 anterior traumatic inseason shoulder instability episode and underwent arthroscopic stabilization between 2012 and 2017 were identified. Patients and/or families were contacted by phone to discuss (1) recurrent instability episodes and (2) return to competitive sport and/or recreational athletic activity. Statistical analysis was conducted using chi-square tests to compare recurrent shoulder instability with return to play and YER. A total of 45 football players aged 14 to 17 years were included, with a mean follow-up of 4.1 years. Most patients (60%) chose not to return to competitive football, due mainly to fear of recurrent injury. Overall, the recurrent instability rate was 15.6% (7/45). The instability rate in players who returned to football was 16.7%, with 66.7% requiring revision surgery. The instability rate in patients who did not return to football was 14.8%, with no revision procedures required. In players who returned to football, the instability rate in YER group 4 was significantly higher than that in YER groups 1 to 3 (42% vs 10.5%, respectively, P = .03), with each year of play conferring an additional 10% risk of reinjury. There was a significant difference in the type of recurrent instability in players who returned to any sport versus those who did not (P = .029). High school football players who returned to competitive play after arthroscopic shoulder stabilization surgery experienced a higher rate of recurrent instability that was dependent on their YER. Over half of the players chose not to return to football, with fear of reinjury being the most common reason.

Glenoid augmentation for subcritical bone loss: a narrative review.

Anterior shoulder instability can be debilitating for young, active individuals, and increasing magnitudes of glenoid bone loss (GBL) predisposes patients to recurrent instability and increases the likelihood of failure of soft-tissue only repairs. It is widely accepted that GBL >25% should be treated with a glenoid bone grafting procedure. However, consensus is lacking on the optimal management in the setting of subcritical GBL, typically classified as >13.5%. This article reviews the pathoanatomy relevant to anterior shoulder instability and subcritical GBL, while highlighting existing evidence regarding open augmentation procedures in comparison to other treatment options for this subpopulation. A narrative review of the current literature was conducted focusing on subcritical GBL in anterior glenoid stabilization procedures, including review of forward citation and reference lists of selected articles. Computed tomography (CT) is the modality of choice for obtaining precise measurements of subcritical GBL, defined as <13.5%, using the best-fit circle method. There is debate surrounding the optimal surgical management of subcritical GBL. Arthroscopic Bankart repair (ABR) remains the predominate surgery performed for primary anterior shoulder instability, while glenoid augmentation and open Bankart repair continue to be used sparingly in the United States. Historically, the Latarjet procedure was considered for substantial glenoid defects, but the illumination of subcritical GBL has expanded its indications. Arthroscopic, soft tissue-only repairs with the addition of remplissage, has been shown to have similar 2-year outcomes to the Latarjet in patients with >15% GBL, which has been limited in the study of subcritical GBL. Additionally, utilization of distal tibial allograft and local autograft is becoming increasingly prevalent. However, again, with limited prospective studies in the subcritical GBL population. There is no consensus regarding the optimal treatment approach to recurrent shoulder instability in the setting of subcritical GBL. Conversely, there is a growing agreement that isolated ABR is likely inadequate and subcritical GBL should prompt consideration of a more robust operation. To this end, interest in glenoid bone augmentation continues to grow as a reliable technique for recreating the native architecture and restoring glenohumeral stability are developed.

Radiological and Clinical Outcome of Thoracolumbar Burst Fracture Following Short Segment and Long Segment Pedicle Screw Fixation

INTRODUCTION: The indications for operative treatment and type of stabilization procedures for the treatment of thoracolumbar fracture remains controversial. Long-segment pedicle screw fixation permits correction of kyphotic deformity while short-segment pedicle screw fixation preserves motion segments, reduces costs and time of surgery. Our aim is to study the correlation and comparison between clinical and radiological outcome of both fixations and identify factors that might contribute to the outcome. MATERIALS AND METHODS: 60 patients with thoracolumbar spine fracture from 2017 to 2022 were identified. Age, gender, mechanism of injury, classification of fracture, duration of hospital stays and one-year post-operative outcome of Visual Analogue (VAS) pain score, and Oswestry Disability Index (ODI) score were documented. Pre- and post-operative AP/Lateral radiographs measurements of local kyphotic angle, Cobb angle were measured. Signs of fixation failure were examined at follow-up. RESULTS: Subjects mean age is 42.4, male predominance (85%) and work-related. The highest incidence was at level of L1 (56.7 %) in the long-segment and 46.7 % in short-segment. Most common injury was burst fracture (AO classification A3 A4 group) due to fall from height. There is shorter hospital stay documented in the short-segment fixation. Radiological outcome measured in both groups were comparable with no signs of fixation failure. Short-segment fixation group also resulted in better clinical and functional outcome at one-year follow-up. CONCLUSION: There is no significant difference in radiologic outcome of Cobb and kyphotic angle in both fixation groups. Short-segment fixation has significantly better clinical and functional outcome post-operative and at 1-year follow up.

Effects of rice bran stabilization procedures and proteases on rice bran protein hydrolysates

Rice bran stabilization is typically performed after rice milling to improve storage performance. In the present study, we investigated the effect of extrusion (EX) and superheated steam (SS) on the physicochemical and functional characteristics of rice bran protein hydrolysates (RBPHs) obtained with acid, alkaline, and neutral proteases (AP, ALP, and NP). The deactivation parameters were optimized as EX (140 °C, water content: 25%) and SS (130 °C, 5 min). After stabilization, the enzymatic hydrolysis of proteins was inhibited. The untreated RBPHs obtained with ALP exhibited the highest degree of hydrolysis (15.93%), while RBPH-EX-NP presented the lowest (10.75%). EX reduced the solubility of RBPHs, while SS improved the solubility at pH 2–4. Both stabilizations increased the β-sheet and β-turn contents of RBPHs while reducing the α-helix and random coil contents. The antioxidant activity of RBPHs decreased, while their emulsifying activity and ferrous chelating ability increased. This study could contribute to insight into the effects of industrial stabilization on RBPHs.

Chemistry and Pharmacology of Delta-8-Tetrahydrocannabinol.

Cannabis sativa is one of the oldest plants utilized by humans for both economic and medical purposes. Although the use of cannabis started millennia ago in the Eastern hemisphere, its use has moved and flourished in the Western nations in more recent centuries. C. sativa is the source of psychoactive cannabinoids that are consumed as recreational drugs worldwide. The C21 aromatic hydrocarbons are restricted in their natural occurrence to cannabis (with a few exceptions). Delta-9-tetrahydrocannabinol (Δ9-THC) is the main psychoactive component in cannabis, with many pharmacological effects and various approved medical applications. However, a wide range of side effects are associated with the use of Δ9-THC, limiting its medical use. In 1966, another psychoactive cannabinoid, Delta-8-tetrahydrocannabinol (Δ8-THC) was isolated from marijuana grown in Maryland but in very low yield. Δ8-THC is gaining increased popularity due to its better stability and easier synthetic manufacturing procedures compared to Δ9-THC. The passing of the U.S. Farm Bill in 2018 led to an increase in the sale of Δ8-THC in the United States. The marketed products contain Δ8-THC from synthetic sources. In this review, methods of extraction, purification, and structure elucidation of Δ8-THC will be presented. The issue of whether Δ8-THC is a natural compound or an artifact will be discussed, and the different strategies for its chemical synthesis will be presented. Δ8-THC of synthetic origin is expected to contain some impurities due to residual amounts of starting materials and reagents, as well as side products of the reactions. The various methods of analysis and detection of impurities present in the marketed products will be discussed. The pharmacological effects of Δ8-THC, including its interaction with CB1 and CB2 cannabinoid receptors in comparison with Δ9-THC, will be reviewed.

Time performance of scoop stretcher versus vacuum mattress for prehospital spinal stabilization: open-label simulation-based randomized controlled trial

Recent research has yielded conflicting results on the use of spinal stabilization in prehospital care, with some guidelines expressing concerns about its potential lack of benefit or harm. Transportation on a backboard can cause pain, discomfort, and pressure ulcers, whereas the log-roll technique can cause unnecessary movement and aggravate existing injuries. The scoop stretcher and vacuum mattress provide comparable or better immobilization and comfort than the backboard. Prehospital time is critical, and patients with life-threatening conditions should undergo rapid stabilization procedures. Despite this, some studies have overlooked the scoop stretcher as a spinal stabilization device. The primary goal was to compare the time required to achieve spinal stabilization using a scoop stretcher versus a vacuum mattress. This was a monocentric, parallel, randomized (sealed envelope), superiority, open-label, controlled simulation experiment. All student paramedics, registered paramedics, and EMTs who work in the participating EMS were eligible to participate in the study apart of the study team. The experimental group had to use a scoop stretcher, whereas the control group used a vacuum mattress. Fifteen participants were included. The scoop stretcher group required less time to complete the stabilization procedure (median [Q1; Q3]: 127 seconds [111;145] versus 212 [156;237], p=0.005). Using a scoop stretcher for spinal stabilization is more time-efficient than a vacuum mattress, making it a viable option for unstable trauma patients in the prehospital setting. More research is needed to determine its efficacy in actual clinical practice.

Evaluation of Differences in Patellar Height After Patellar Stabilization Procedures Not Intended to Address Patella Alta: A Multicenter Study.

Recent studies have reported conflicting results as to whether isolated medial patellofemoral ligament reconstruction (MPFLr) leads to decreased patellar height. To investigate if patellar stabilization surgery not intended to address patella alta influences patellar height. Cohort study; Level of evidence, 3. A multicenter retrospective chart review was conducted, and patients who underwent MPFLr, medializing tibial tuberosity osteotomy (TTO), and/or trochleoplasty between 2016 and 2020 were included. The Caton-Deschamps index (CDI) was calculated from radiographs obtained preoperatively, 2 weeks postoperatively, and 3 months postoperatively. The preoperative CDI value was compared with the 2-week postoperative and 3-month postoperative values according to stabilization procedure (isolated MPFLr, isolated TTO, MPFLr + TTO, MPFLr + trochleoplasty, and MPFLr + trochleoplasty + TTO) using the paired t test. Analyses of the 1-bundle versus 2-bundle MPFLr technique and the presence of lateral retinacular release or lateral retinacular lengthening were conducted on the isolated MPFLr and combined MPFLr + TTO cohorts. A total of 356 knees were included. Statistically significant pre- to postoperative decreases in CDI were seen in all stabilization procedures analyzed (P≤ .017 for all). Within the isolated MPFLr cohort, this significant decrease was seen at 2 weeks postoperatively with the 2-bundle technique (ΔCDI = -0.09; P < .001) but not with the 1-bundle technique (ΔCDI = -0.01; P = .621). The different surgical techniques analyzed in the current study affected patellar height, even when a distalizing TTO was not performed. The decrease was dependent on surgical technique, with a 2-bundle MPFLr leading to a statistically significant decrease and a 1-bundle MPFLr effecting no change.

CUIDADOS E HUMANIZAÇÃO: PERSPECTIVAS DA EQUIPE DE ENFERMAGEM NA SALA DE ESTABILIZAÇÃO COMO AÇÕES PRIMORDIAIS

Nursing is one of the professions dedicated to caring for others. In this sense, it is recognized that interpersonal relationships become of great importance. Hence, the focus of this research is to understand the significance of caring in the hospital setting, particularly in the stabilization room – a space where the patient still feels insecure and requires trust and reassurance regarding the procedures to be performed and the care the profession entails.To achieve this, the following objectives were established: to characterize the essential care and humanization for the success of the nurse’s role in relation to stabilization procedures, considering the situations experienced as palliative measures to alleviate distress and suffering. The research and literature review in the field highlight the connections between healthcare work and attitudes that go beyond theories, bringing professionals closer to patients and their real needs.The investigation into this topic is justified by the concerns affecting patients who feel insecure and sometimes frightened by the circumstances they are facing. Additionally, it is influenced by the promptness of nursing professionals who may not always perform their duties with excellence due to the patient’s apprehension about what lies ahead or a lack of preparation for such dramatic moments. Hence, there is a need for a more tender and caring approach, fostering a synergy between the healthcare professional and the patient, aiming to help them overcome anxieties and embarrassing situations presented by the circumstances.

High Rates of Return to Play and Low Recurrence Rate After Arthroscopic Latarjet Procedure for Anterior Shoulder Instability in Rugby Players

PurposeTo analyze the rate of return to play, changes in athletic level, recurrence rate and to report subjective outcomes in a series of rugby players with anterior shoulder instability that underwent an arthroscopic Latarjet procedure. MethodA multicenter retrospective study done in 2 centers on rugby players who were operated on between January 2011 and December 2020 was performed. Rugby players who underwent arthroscopic Latarjet procedure for anterior shoulder stabilization with a minimum follow-up period of two years were included. Rugby players were grouped according to their competitive level in their country (recreative, regional, national, and international level). Data collected included return to sport after surgery, time to return to rugby, athletic level before and after surgery, patient satisfaction, and subjective scores. Recurrence and apprehension rates were also evaluated. ResultsA total of 73 subjects were included. Mean age at time of surgery was 23 ± 5 years. Mean duration of follow-up was 5 years ±2.6. Eighty-four percent of rugby players returned to rugby within a mean period of 6.6 months. Initial athletic level was a significant factor (p=0.012) for not returning to sport, with 67% of patients not returning to rugby who initially played at a recreational level, and 33% at a regional league level. All national and international players returned to play. Of the 12 non returning rugby players, only 30% did not return because of their shoulder. Mean SSV was 90% ± 9. Recurrence rate was 7%. ConclusionOur study confirmed the efficacy of Arthroscopic Latarjet procedure in managing recurrent anterior instability in rugby players, leading to patient satisfaction. Return to play was achieved in almost all cases with low recurrence rate. Despite high global return to the same level of sports, the higher the level of competition is, the harder it is to resume sport at the same level for rugby players. Level of EvidenceLevel IV, therapeutic case series.

Synchronization of uncertain chaotic systems with minimal parametric information

The chaotic synchronization is mainly hampered by uncertain system dynamics in terms of underlying parameters. To obtain accurate parameter estimates for the proper synchronization of uncertain chaotic systems (UCSs) through adaptive control, it is necessary to satisfy the persistence of excitation (PE) condition. Furthermore, the challenges imposed by the explosion of complexity in sequential stabilization procedures, slow performances, and lack of information in UCSs hinder the synchronization process through existing control techniques. Therefore, the contribution of this research is two-fold: First, a systematic stabilization approach with minimal calculations is proposed to achieve proper synchronization between chaotic drive and response systems. The key concept of the proposed theory is to obtain an invariant manifold by immersing the error dynamics (resulting from the mismatch between the drive and response systems) into lower-order target dynamics. From there, the control law for synchronizing these chaotic systems can be derived by defining passive outputs and associated storage functions. The proposed framework, which combines the concepts of immersion and passivity, is referred to as the Passivity and Immersion (P&I) approach. Second, unlike adaptive control, the synchronization of UCSs is made possible by selecting the appropriate target dynamics without any parameter estimation (or with minimal parametric information in certain cases). The simplicity and superiority of the proposed approach over existing techniques are preserved and demonstrated by application to a number of well-known chaotic systems.

Does an early post traumatic knee brace reduce the incidence of knee rotational instability?

Several anterolateral stabilization procedures have been developed recently to address rotational instability of the knee. Currently, these procedures tend to be systematically used by some practitioners. However, antero-lateral structures of the knee (including the anterolateral ligament, ALL) have a self-healing potential which can reduce the need to perform an antero-lateral procedure. In this study, it was hypothesized that early post-traumatic immobilization of the knee with a knee brace would allow partial healing of antero-lateral structures and also allow control of the pivot shift, thus avoiding antero-lateral extra-articular stabilization. The objective of this study was to compare the severity of pivot shift between two groups of patients who all experienced anterior cruciate ligament (ACL) tear and respectively underwent post-traumatic immobilization of the knee versus no immobilization. This was a comparative, multicentric (three centers' study) retrospective, consecutive study including 168 patients who underwent ACL reconstruction between May and September 2022. The application or not of post-traumatic immobilization and its duration, the severity of pivot shift observed in the operating room under general anesthesia, the presence of anterolateral lesions as revealed by MRI and the patients' pre-injury sport activity were recorded. A grade 3 pivot shift was found in 44 patients (27%). It was more frequently observed in the group without a brace compared to the group with a knee brace (18 patients out of 36: 50% versus 26 patients out of 132: 19.7%; p = 0.0012). Wearing a brace, whether hinged (OR = 0.221, [0.070-0.652]; p = 0.006) or not (OR = 0.232, [0.076-0.667]; p = 0.0064), was protective from the risk of developing a significant pivot shift. This study demonstrated that the presence of pivot-shift was lower in the patients that had an early post-injury knee brace before their ACL reconstruction. Based on this result, systematic brace placement could be advocated for in patients after knee trauma. III, prognostic retrospective case-control study.

Clinical Observation of Posterior Approach for Surgical Treatment of Thoracolumbar Pseudarthrosis in Ankylosing Spinal Disorders

To evaluate the surgical effectiveness of posterior procedure with long segment stabilization for treating thoracolumbar pseudarthrosis associated with ankylosing spinal disorders (ASD) without anterior fusion or osteotomy. Twelve patients with thoracolumbar pseudarthrosis in ASD were enrolled. All patients underwent posterior long-segment stabilization procedures. In some patients, the percutaneous technique or the aid of a robot or O-arm navigation was utilized for pedicle screw implantation. The clinical results were evaluated by means of the Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI). Radiological outcomes were evaluated for bone fusion, anterior column defect, local kyphotic correction (LK) and position of the pedicle screws. All patients experienced effective bone fusion at the sites of pseudarthrosis. The mean operative time was 161.7±57.1 min, and the average amount of blood loss was 305.8 ± 293.2 ml. For six patients who underwent surgery with the assistance of a robot or O-arm navigation, there was no statistically significant difference observed in terms of operative time and mean blood loss compared to those who used the freehand technique (P>0.05). The VAS score, ODI value, and mean LK angle showed significant improvements at the final follow-up (P<0.05). The accuracy of pedicle screw placement was 96%. Posterior surgery with long-segment fixation, without anterior fusion or osteotomy, can achieve satisfactory outcomes in ASD patients with thoracolumbar pseudarthrosis. The application of percutaneous techniques, as well as the assistance of robots or navigation technique may be a good choice for the treatment of pseudarthrosis in ASD patients.

An enhanced corotational Virtual Element Method for large displacements in plane elasticity

An enhanced virtual element formulation for large displacement analyses is presented. Relying on the corotational approach, the nonlinear geometric effects are introduced by assuming nodal large displacements but small strains in the element. The element deformable behavior is analyzed with reference to the local system, corotating with the element during its motion. Then, the large displacement-induced nonlinearity is accounted for through the transformation matrices relating the local and global quantities. At the local level, the Virtual Element Method is adopted, proposing an enhanced procedure for strain interpolation within the element. The reliability of the proposed approach is explored through several benchmark tests by comparing the results with those evaluated by standard virtual elements, finite element formulations, and analytical solutions. The results prove that: (i) the corotational formulation can be efficiently used within the virtual element framework to account for geometric nonlinearity in the presence of large displacements and small strains; (ii) the adoption of enhanced polynomial approximation for the strain field in the virtual element avoids, in many cases, the need for ad-hoc stabilization procedures also in the nonlinear geometric framework.

High Tibial Osteotomy in Knee Reconstruction and Joint Preservation.

High tibial osteotomy is a dynamic operation, used as an effective procedure in both joint preservation and knee stability. Applications and indications are expanding, with good results in the treatment of malalignment associated with arthrosis, knee instability, meniscus deficiency or transplants, and/or cartilage restoration. Appropriate patient selection and preoperative planning are critical to achieving good outcomes after surgery. Coronal and sagittal plane corrections made through the proximal tibia can effectively alter joint mechanics creating a more favorable environment for cartilage, meniscus, and ligamentous structures about the knee. Advancing techniques and technologies have allowed for more precise planning and execution of osteotomies.

Establishing the Minimal Clinically Important Difference, Substantial Clinical Benefit, and Patient Acceptable Symptomatic State After Arthroscopic Posterior Labral Repair for Posterior Glenohumeral Instability

Background: Posterior glenohumeral instability is an increasingly recognized cause of shoulder pain and dysfunction among young, active populations. Outcomes after posterior stabilization procedures are commonly assessed using patient-reported outcome measures including the Single Assessment Numeric Evaluation (SANE), the Rowe instability score, the American Shoulder and Elbow Surgeons (ASES) score, and the visual analog scale (VAS) for pain. The clinical significance thresholds for these measures after arthroscopic posterior labral repair (aPLR), however, remain undefined. Purpose: We aimed to define the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) for the SANE, Rowe score, and ASES score as well as the VAS pain after aPLR. Additionally, we sought to determine preoperative factors predictive of reaching, as well as failing to reach, clinical significance. Study Design: Case-control study; Level of evidence, 3. Methods: This study was a retrospective analysis of patient-reported outcome scores collected from patients who underwent aPLR between January 2011 and December 2018. To determine the clinically significant threshold that corresponded to achieving a meaningful outcome, the MCID, SCB, and PASS were calculated for the SANE, Rowe score, ASES score, and VAS pain utilizing either an anchor- or distribution-based method. Additionally, univariate and multivariate logistic regression analyses were performed to determine the factors associated with achieving, or not achieving, the MCID, SCB, and PASS. Results: A total of 73 patients with a mean follow-up of 82.55 ± 24.20 months were available for final analysis. MCID, SCB, and PASS values for the VAS pain were 1.10, 6, and 3, respectively; for the ASES score were 7.8, 34, and 80, respectively; for the SANE were 10.15, 33, and 85, respectively; and for the Rowe score were 11.3, 60, and 90, respectively. To meet the MCID, male sex (odds ratio [OR], 1.1639; P = .0293) was found to be a positive predictor for the VAS pain, and a lower preoperative SANE score (OR, 0.9939; P = .0003) was found to be a negative predictor for the SANE. Dominant arm involvement was associated with lower odds of achieving the PASS for the ASES score (OR, 0.7834; P = .0259) and VAS pain (OR, 0.7887; P = .0436). Patients who reported a history of shoulder trauma were more likely to reach the PASS for the SANE (OR, 1.3501; P = .0089), Rowe score (OR, 1.3938; P = .0052), and VAS pain (OR, 1.3507; P = .0104) as well as the SCB for the ASES score (OR, 1.2642; P = .0469) and SANE (OR, 1.2554; P = .0444). A higher preoperative VAS pain score was associated with higher odds of achieving the SCB for both the VAS pain (OR, 1.1653; P = .0110) and Rowe score (OR, 1.1282; P = .0175). Lastly, concomitant biceps tenodesis was associated with greater odds of achieving the SCB for the ASES score (OR, 1.3490; P = .0130) and reaching the PASS for the SANE (OR, 1.3825; P = .0038) and Rowe score (OR, 1.4040; P = .0035). Conclusion: To our knowledge, this study is the first to define the MCID, SCB, and PASS for the ASES score, Rowe score, SANE, and VAS pain in patients undergoing aPLR. Furthermore, we found that patients who reported a history of shoulder trauma and those who underwent concomitant biceps tenodesis demonstrated a greater likelihood of achieving clinical significance. Dominant arm involvement was associated with lower odds of achieving clinical significance.

Shoulder Stabilization Technique Using the Medial Glenohumeral Ligament in Patients With the Buford Complex

The Buford complex is an anatomic variation defined as the association of a cordlike middle glenohumeral ligament (MGHL) and an absent anterosuperior labrum. It can be challenging to properly identify on preoperative imaging and remains mostly an arthroscopic finding. It may, however, lead to problematic situations when encountered during an arthroscopic soft-tissue stabilization procedure, as the treatment of choice in such cases is a bone block. Moreover, reattaching the MGHL to the anterior border of the glenoid rim has traditionally not been recommended because it theoretically leads to severe restriction in external rotation. This technical note describes arthroscopic stabilization for anterior traumatic glenohumeral instability associated with the Buford complex. The cordlike MGHL is used to reconstruct a neo-labrum, associated with an anteroinferior glenohumeral ligament plication. Glenohumeral stabilization using the cordlike MGHL of the Buford complex may be an efficient alternative to a bone block procedure.