Rotational Instability Research Articles

A review of Marcel Lemaire's original work on lateral extra-articular tenodesis

This classic discusses Marcel Lemaire's original publications in the context of modern surgical practice, including a description of his original lateral extra-articular tenodesis. Previously published in French, these translations shed light on his revelations regarding the anterior cruciate ligament's role in knee stability and his detailed insights into the ressaut rotatoire or the pivot shift phenomenon. We track the evolution of Lemaire's procedure since the publication of his original technique in 1967 which used a nylon cord superficial to the lateral collateral ligament followed by cast immobilisation for one month. We report his patient outcomes as he refines his methods through experiential learning.Lemaire's fundamental concepts in relation to anterior cruciate ligament deficiency remain relevant in contemporary clinical practice. Furthermore, the “modified Lemaire technique” has emerged as one of the preferred methods for lateral extra-articular tenodesis. We hope that disseminating his thoughts to a wider audience will help enlighten the ongoing debate regarding the management of rotatory instability. Level of EvidenceV – Expert Opinion.

Clinical and Functional Results of Lateral Ulnar Collateral Ligament Repair for Posterolateral Rotatory Instability of the Elbow.

Background Posterolateral rotatory instability of the elbow arises from damage to the lateral ulnar collateral ligament (LUCL). While various methods exist for reconstructing or repairing the LUCL's attachment to the humerus, the most effective approach remains debatable. This study aims to assess the outcomes of directly repairing the LUCL when the injury occurs at the humeral attachment. Methodology This retrospective study, conducted at the Royal Berkshire Foundation Trust NHS hospital in Reading, UK, assessed outcomes through a review of 15 patients who underwent direct repair of the lateral ulnar collateral ligament between 2017 and 2022, evaluating a range of motion, the Mayo Elbow Performance Score, and the Nestor grading system. Results This study included nine males and six females, with an average age of 38.8 years. Most LUCL injuries arose from elbow dislocation (46.7%). The average follow-up period for patients was 26 months. At the final assessment, the mean Mayo Elbow Performance Score reached 99. According to the Nestor grading system, 12 patients achieved excellent results, and three had good outcomes. On average, there was an 11.3° loss of final extension and 5° of final flexion, yet achieving a comparable pronation-supination arch to the contralateral side. Conclusion Direct repair of the LUCL for elbow posterolateral rotary instability yielded excellent outcomes, obviating ligament reconstruction. Recognized as minimally invasive, it accelerates recovery, minimizes trauma, and offers a cost-effective procedure for managing instability.

A Lateral Extra-articular Procedure Reduces the Failure Rate of Revision Anterior Cruciate Ligament Reconstruction Surgery Without Increasing Complications: A Systematic Review and Meta-analysis

Background: Lateral extra-articular procedures are becoming increasingly popular in association with anterior cruciate ligament (ACL) reconstruction, especially in patients with persistent rotatory instability and in a high-risk population. However, few studies have investigated the outcomes of the lateral extra-articular procedure as an associated procedure in an ACL revision (R-ACLR) setting and its benefit with respect to isolated intra-articular reconstruction. Hypothesis: Lateral extra-articular procedures reduce the failure rate of revision ACL reconstruction (R-ACLR). Purpose: To compare subjective outcomes, knee stability, and failure and complication rates between patients who underwent ACL revision with and without an associated lateral extra-articular procedure. Study Design: Systematic review and meta-analysis; Level of evidence, 3. Methods: A systematic search of the PubMed, Cochrane, and OVID databases was performed on September 2022 in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Eligible studies were trials directly comparing patients who had isolated ACL revision with patients who had ACL revision associated with lateral extra-articular procedures at a minimum follow-up of 2 years. A meta-analysis was performed, and bias and the quality of the evidence were rated according to the Newcastle-Ottawa Scale. The meta-analysis was conducted according to the PRISMA guidelines. Results: Eight studies were included: a total of 334 patients were treated with isolated revision (isolated (R-ACLR)) and 342 treated with combined revision and a lateral extra-articular procedure (combined (R-ACLR)). For the failure rate, the meta-analysis showed a significantly decreased relative risk reduction of 54% (P = .004) in patients with combined (R-ACLR) with respect to isolated R-ACL, whereas no difference in complication rate was observed. The combined (R-ACLR) group demonstrated a decreased risk ratio of 50% (P = .002) for having a positive pivot-shift test result and a relative risk reduction of 68% (P = .003) for having a grade 2-3 pivot shift when compared with the isolated (R-ACLR) group. Finally, no significant differences were observed among the lateral extra-articular procedures. Conclusion: The addition of a lateral extra-articular procedure to revision ACL significantly reduced the failure rate and postoperative pivot shift without increasing the complication rate. Anterolateral ligament reconstruction and a lateral extra-articular procedure with iliotibial band were effective in improving the outcomes of revision ACL reconstruction. Further high-level studies could help to clarify which subgroup of patients could particularly benefit from an anterolateral procedure in the context of ACL revision.

Imaging of posterolateral rotational instability of the knee joint

Posterolateral instability of the knee joint typically occurs with injuries to the posterolateral corner of the joint or with additional combined injuries involving the anterior and posterior cruciate ligaments. In addition to numerous, smaller anatomical structures, the most important are the lateral collateral ligament (LCL), the popliteus muscle with its tendon, and the popliteofibular ligament (PFL), which can usually be assessed using magnetic resonance imaging (MRI). On the contrary, small structures like the arcuate ligament and fabellofibular ligament cannot always be identified. However, they are also of lesser importance in the development of posterolateral rotational instability. Overlooked injuries to the posterolateral joint corner promote instability with the complication of inadequate ligament reconstruction and early onset posttraumatic osteoarthritis. Knowledge of MRI morphology of the anatomical structures involved, taking into account their biomechanical significance, is crucial to recognize and use the corresponding imaging findings.

A High-Grade Lachman’s Exam Predicts a Ramp Tear of the Medial Meniscus in Patients with Anterior Cruciate Ligament Tear: A Prospective Clinical and Radiological Evaluation

Background: Medial meniscus ramp tears are present in 22.9–40.8% of anterior cruciate ligament tears. The diagnosis of ramp tears is difficult on MRI, with sensitivity reported around 48%, which has recently emphasized the importance of proper arthroscopic probing for ramp tears. Methods: A prospective evaluation was performed on patients undergoing a single bundle ACL reconstruction to assess patient demographics, posterior tibial slope, posterior cruciate ligament angle, Lachman’s exam, and rotational instability to determine secondary findings associated with medial meniscal ramp tears. Results: A total of 96 patients underwent ACL reconstruction, of these, 63 patients had an isolated ACL tear, and 33 patients had an ACL tear with a concomitant medial meniscus ramp tear. A high-grade Lachman’s exam and male sex were associated with medial meniscus ramp tears. There were no differences in posterior tibial slope, posterior cruciate ligament angle, or rotational instability between groups. Conclusions: This study found that a high-grade Lachman’s exam and male sex were significantly associated with patients with an ACL tear with a concomitant medial meniscus ramp tear. These findings suggest that an ACL tear with concomitant medial meniscus ramp tear may be better diagnosed based upon the clinical evaluation rather than other secondary radiological findings.

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.

Bilateral External Torque CT Reliably Detects Syndesmotic Lesions in an Experimental Cadaveric Study.

If tibiofibular syndesmotic injury is undetected, chronic instability may lead to persistent pain and osteoarthritis. So far, no reliable diagnostic method has been available. The primary objectives of this study were to determine whether defined lesions of the syndesmosis can be correlated with specific tibiofibular joint displacements caused by external rotational torque and to compare the performance of bilateral external torque computed tomography (BET-CT) and arthroscopy. Secondary objectives included an evaluation of the reliability of CT measurements and the suitability of the healthy contralateral ankle as a reference. Seven pairs of healthy, cadaveric lower legs were tested and assigned to 2 groups: (1) supination-external rotation (SER) and (2) pronation-external rotation (PER). In the intact state and after each surgical step, an ankle arthroscopy and 3 CT scans were performed. During the scans, the specimens were placed in an external torque device with 2.5, 5.0, and 7.5 Nm of torque applied. The arthroscopic and CT parameters showed significant correlations in all pairwise comparisons. The receiver operating characteristic (ROC) curve analyses yielded the best prediction of syndesmotic instability with the anterior tibiofibular distance on CT, with a sensitivity of 84.1% and a specificity of 95.2% (area under the curve [AUC], 94.8%; 95% confidence interval [CI], 0.916 to 0.979; p < 0.0001) and with the middle tibiofibular distance on arthroscopy, with a sensitivity of 76.2% and specificity of 92.3% (AUC, 91.2%; 95% CI, 0.837 to 0.987; p < 0.0001). Higher torque amounts increased the rate of true-positive results. BET-CT reliably detects experimental syndesmotic rotational instability, compared with the healthy side, with greater sensitivity and similar specificity compared with the arthroscopic lateral hook test. Translation of these experimental findings to clinical practice remains to be established. Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Lateral Extra-Articular Tenodesis with Indirect Femoral Fixation Using an Anterior Cruciate Ligament Reconstruction Suspensory Device.

The lateral extra-articular tenodesis (LET) procedure associated with anterior cruciate ligament (ACL) reconstruction can be considered in selected patients to diminish the risk of persistent rotatory instability and achieve a protective effect on the graft. Several techniques have been described in the literature to treat rotatory instability. Usually, a strip of the iliotibial band (ITB) is harvested from its middle while leaving the distal insertion, then passed underneath the lateral collateral ligament and fixed on the lateral aspect of the distal femur with various fixation methods such as staples, screws, anchors or extracortical suspensory devices. Despite their effectiveness, these fixation methods may be associated with complications such as lateral pain, over-constraint and tunnel convergence. This study presents a detailed surgical description of a new technique to perform an LET during ACL reconstruction with any type of graft fixing the ITB strip with the sutures of the ACL femoral button, comparing its pros and cons in relation to similar techniques found in the literature. This technique represents a reproducible, easy to learn and inexpensive solution to perform a lateral extra-articular tenodesis associated with an ACL reconstruction using the high-resistance sutures of the femoral button.

Graft Reorientation and Lateral Extra-articular Tenodesis in Revision Surgery for Persistent Rotational Instability of a Verticalized Anterior Cruciate Ligament Graft

Persistent rotational instability after anterior cruciate ligament reconstruction is a relatively common postoperative complication, typically associated with graft verticalization due to improper femoral tunnel placement, especially with classic transtibial femoral tunnel techniques. This article describes a technique designed to reorient a verticalized anterior cruciate ligament graft at its femoral insertion to a more anatomic position in the coronal and sagittal planes, aiming to restore knee stability without the need for a complete revision operation. Additionally, a lateral extra-articular tenodesis with fascia lata is added to reinforce rotational stability.

Double Vector: A Combined Biomechanical and Anatomical Posterolateral Corner Reconstruction Technique

Posterolateral corner (PLC) injuries are complex knee injuries that are becoming increasingly frequent. Often undiagnosed and underestimated, a systematic diagnostic workup is necessary to assess the severity of PLC injury in order to then be able to select the proper surgery approach. Anatomical and nonanatomical PLC-reconstruction techniques have been described. In this Technical Note, we describe our technique of biomechanical reconstruction of PLC in case of severe posterolateral rotational instability.

Anconeus-sparing minimally invasive approach for lateral ulnar collateral ligament reconstruction using a triceps tendon autograft is an effective and safe treatment for chronic posterolateral instability of the elbow

Surgical treatment helps to restore stability of the elbow in patients with posterolateral rotatory instability (PLRI). The anconeus muscle is one of the most important active stabilizers against PLRI. A minimally invasive anconeus-sparing approach for lateral ulnar collateral ligament (LUCL) reconstruction using a triceps tendon autograft has been previously described. The purpose of this study was to evaluate the outcome of this intervention and identify risk factors that influenced the clinical and patient-reported outcomes. Sixty-one patients with chronic PLRI and no previous elbow surgery who underwent surgical reconstruction of the LUCL using a triceps tendon autograft in a minimally invasive anconeus-sparing approach during 2012 and 2018 were evaluated. Outcome measures included a clinical examination and the Oxford Elbow Score (OES) and the Mayo Elbow Performance Score (MEPS) questionnaires. Subjective patient outcomes were evaluated with the visual analog scale (VAS) for pain and the Subjective Elbow Value (SEV). Integrity of the common extensor tendons and centering of the radial head were assessed preoperatively on standardized magnetic resonance images (MRIs). Fifty-two patients were available at final follow-up. The mean age of patients was 51±12 years with a mean follow-up of 53±14 months (range 20-76). Clinical examination after surgery (n=41) showed no clinical signs of instability in 98% of the patients (P<.001) and a nonsignificant improvement in range of motion. OES, MEPS, and VAS scores averaged 40±10 of 48 points, 92±12 of 100 points, and 1±2 points, respectively, all corresponding with good or excellent outcomes. The SEV was 88%, indicating very high satisfaction with the surgery. Only 1 patient had revision surgery due to pain, and there were no reported postoperative complications in this cohort. A radial head subluxation in the MRI correlated significantly with worse postoperative outcomes. The anconeus-sparing minimally invasive technique for posterolateral stabilization of the elbow using a triceps tendon autograft is an effective and safe treatment for chronic posterolateral instability of the elbow with substantial improvements in elbow function and pain relief with a very low rate of persistent clinical instability.

Surgical Treatment of the Bony Mallet Injuries with Augmented Extension Block Technique: Clinical Outcomes of a New Modification

Surgical Treatment of The Bony Mallet Deformity with Augmented Extension Block Technique: Clinical Outcomes of a New Modification Introduction: Mallet finger deformity is a common pathology and the ‘Extension Block Technique’, is one of the most popular surgical techniques for the treatment of this condition. However, several complications may occur with this method such as fixation failure, compression failure of the dorsal part and loss of reduction. In the current study, it is aimed to report the result of our modification which is augmented extension block technique. Materials &amp; Method: The medical records of patients, who were operated with the diagnosis of bony mallet finger between 2015 and 2021, were evaluated retrospectively. Demographic data, mechanism of trauma, duration of operation, time from injury to surgery, follow-up period, implant removal time, and postoperative complications were collected from hospital records. Patients aged between 18 - 65 years who had been operated with augmented extension block technique with a minimum follow-up period of 6 months were included in the study. A total of 10 patients who met these criteria constituted the study group. Radiological evaluation of the cases was performed with anteroposterior and lateral radiographs. Range of motion and presence of pain were questioned and these data were evaluated according to Crawford criteria. Results: The mean age of the all patients was 40.2 ± 10.9 (range, 24-56) years. The mean follow-up period was 39.6 ± 26.7 (range, 13-76) months. Complete union was achieved in all patients on the final follow-up radiographs. According to Crawford evaluation criteria, the results were ‘excellent’ in six of the patients and ‘good’ in four of them. There were no patients with loss of flexion however, 5° extension loss was observed in four of the subjects. Discussion: This study demonstrates that the augmented extension block technique is a suitable option for the surgical treatment of bony mallet cases with lower complication rate and successful functional results. This modification can be considered as an alternative option for traditional extension block technique which avoids some related complications as postoperative reduction loss, rotational instability and extension loss. Keywords: Mallet finger, Bony mallet, Extension Block

Interpretable Severity Scoring of Pelvic Trauma Through Automated Fracture Detection and Bayesian Inference.

Pelvic ring disruptions result from blunt injury mechanisms and are potentially lethal mainly due to associated injuries and massive pelvic hemorrhage. The severity of pelvic fractures in trauma victims is frequently assessed by grading the fracture according to the Tile AO/OTA classification in whole-body Computed Tomography (CT) scans. Due to the high volume of whole-body CT scans generated in trauma centers, the overall information content of a single whole-body CT scan and low manual CT reading speed, an automatic approach to Tile classification would provide substantial value, e. g., to prioritize the reading sequence of the trauma radiologists or enable them to focus on other major injuries in multi-trauma patients. In such a high-stakes scenario, an automated method for Tile grading should ideally be transparent such that the symbolic information provided by the method follows the same logic a radiologist or orthopedic surgeon would use to determine the fracture grade. This paper introduces an automated yet interpretable pelvic trauma decision support system to assist radiologists in fracture detection and Tile grading. To achieve interpretability despite processing high-dimensional whole-body CT images, we design a neurosymbolic algorithm that operates similarly to human interpretation of CT scans. The algorithm first detects relevant pelvic fractures on CTs with high specificity using Faster-RCNN. To generate robust fracture detections and associated detection (un)certainties, we perform test-time augmentation of the CT scans to apply fracture detection several times in a self-ensembling approach. The fracture detections are interpreted using a structural causal model based on clinical best practices to infer an initial Tile grade. We apply a Bayesian causal model to recover likely co-occurring fractures that may have been rejected initially due to the highly specific operating point of the detector, resulting in an updated list of detected fractures and corresponding final Tile grade. Our method is transparent in that it provides fracture location and types, as well as information on important counterfactuals that would invalidate the system's recommendation. Our approach achieves an AUC of 0.89/0.74 for translational and rotational instability,which is comparable to radiologist performance. Despite being designed for human-machine teaming, our approach does not compromise on performance compared to previous black-box methods.

Research on the evolution of aggregate skeleton characteristics of asphalt mixture under uniaxial compression loading

The aggregate skeleton is the intrinsic core of asphalt mixtures for load transfer, which is quite different under various gradations. For evaluating the loading characteristics of the aggregate skeleton, this research combined the 3D blue-ray scanning technology and discrete element method (DEM) to establish the numerical models of different graded asphalt mixtures considering the real aggregate morphology. A linear parallel bond model was used to simulate the adhesion effect of asphalt, and the uniaxial compression numerical simulation was verified by indoor tests. In addition, the contact force, contact number, anisotropy, and rotation angle were used to evaluate the aggregate skeleton evolution under uniaxial compression loading. Furthermore, the contribution of each grade aggregate in the gradation to the skeleton structure was analyzed. Results show that the average contact force is higher in large-size aggregates above 9.5 mm, which exhibit greater load transfer efficiency. Moreover, 4.75–9.5 mm size aggregates combine the functions of bearing and filling, and its role is significantly affected by the gradation. It is also found that the internal skeleton structure can be optimized and adjusted under stress. The contact numbers of different graded mixtures follow a close decrease, and the strong contacts are mostly provided by coarse aggregates above 4.75 mm. The anisotropy development of aggregate skeleton contact force is induced by the stress, and the deviator fabric of asphalt mixtures show a good linear positive correlation with the uniaxial compressive strength (UCS). Besides, fine aggregates exhibit greater cumulative rotation angle and instability effect, it is feasible to detect asphalt mixture deformation by the rotation angle of particles.

Outcome of combined anatomic reconstruction of the anterior cruciate ligament with anterolateral ligament reconstruction versus with iliotibial band tenodesis

Abstract Background Isolated anterior cruciate ligament (ACL) tears without anterolateral structures injuries are treated successfully by isolated reconstruction of ACL. However, most ACL injuries are associated with the injuries of anterolateral stabilizers of the knee; mainly the iliotibial tract (ITB) and the anterolateral ligament (ALL). If ACL is only reconstructed in such a case, the incidence of postoperative rotational instability reaches 18%. New directions guided towards combined ACL reconstruction with extraarticular anatomical and nonanatomical reconstructions to improve knee rotation and translation and prevent pivot shift phenomena. Patients and methods We retrospectively reviewed all patients operated on for combined injuries of ACL and anterolateral stabilizers from February 2019 to February 2021. Preoperatively and postoperatively, all patients were examined clinically by knee stability tests: anterior drawer, Lachman, and pivot shift tests, applying the International Knee Documentation Committee score and return time to the sport. Results Forty patients were included with a mean age of 28 ± 8.33 years (range, 18–44 years). Patients were divided into two groups, group A 20 patients (18 males and two females) were treated by combined ACL with ALL reconstruction, and group B 20 patients (18 males and two females) were treated by combined ACL with ITB tenodesis. Sports injuries were the cause in 15 patients in group A and 14 in group B, while five injuries were due to nonsport activity in group A and six in group B. The mean follow-up period was 33.5 ± 2.1 months. Median postoperative subjective International Knee Documentation Committee scores in groups A and B were 95.4 and 94.25, respectively, without any statistically significant difference. Group A shows better postoperative improvement in pivot shift and one-leg hop test than group B with a significant difference (P&lt;0.05). Conclusion No significant difference between ALL reconstruction or ITB tenodesis with ACL reconstruction according to subjective knee functions but there was a significant difference according to objective functions, also lateral knee pain was reported in group B and not observed in group A.

Transtibial Lateral Meniscal Root Repair Technique to Appose Remnant Root With Torn Body: The Double Compression Knot

Anterior cruciate ligament reconstructions are often performed with associated procedures, most commonly for associated meniscal tears. The lateral meniscal root tear is a commonly associated injury, which increases rotational instability and results in altered tibiofemoral biomechanics. Lateral meniscectomy results in poorer functional and long-term outcomes, making repair vital. The position of the lateral root tear makes its repair technique complicated. Because of the proximity to vessels posteriorly, the all-inside technique is considered potentially unsafe, and current transtibial repair techniques fail to appose the body with the root remnant. In the lineage of Laprade, who proclaimed the use of a transtibial suture for radial tears elsewhere in the knee in order to reduce the shear force, we describe a transtibial technique that optimizes meniscal apposition, theoretically improving the repair biomechanics and is technically easier to perform in comparison to suture hook techniques with one tunnel and one suture.

Influence of the magnetic field and the mean flow configuration on spatial structure and growth rate of normal modes

The first part of the work presents the results of numerical experiments with the magnetohydrodynamic model of “shallow water” to assess the degree of influence of the magnetic field on the development of instabilities conditioned by a combination of inhomogeneities in the mean flow and the mean magnetic field. Normal mode calculations have confirmed the earlier obtained result on the different influence of weak and strong magnetic fields on the instability of differential rotation. Calculations have shown that a weak magnetic field stabilizes the development of instabilities, whereas a strong magnetic field, on the contrary, enhances the instability. Azimuthal inhomogeneities of differential rotation in all cases contribute to the development of instabilities. In the second part of the work, we examine the spatial structure of normal modes and make an attempt to interpret the torsional oscillations observed in the atmospheres of Earth and the Sun. Calculations have shown that regular axisymmetric disturbances can be caused by the formation of a cyclonic vortex above the pole, which is characteristic of Earth's atmosphere and, possibly, of the Sun's atmosphere. The least damped normal mode of a stable polar cyclone has a structure of torsional oscillations. Flow anomalies and the development of an anticyclonic eddy in winter at midlatitudes destroy torsional oscillations and lead to a rapid amplification of normal modes, which are more complex in structure.

Влияние магнитного поля и конфигурации среднего течения на пространственную структуру и скорость роста нормальных мод

The first part of the work presents the results of numerical experiments with the magnetohydrodynamic model of “shallow water” to assess the degree of influence of the magnetic field on the development of instabilities conditioned by a combination of inhomogeneities in the mean flow and the mean magnetic field. Numerical simulation of normal modes has confirmed the earlier obtained result on the different influence of weak and strong magnetic fields on the instability of differential rotation. Calculations have shown that a weak magnetic field stabilizes the development of instabilities, whereas a strong magnetic field, on the contrary, enhances the instability. Azimuthal inhomogeneities of differential rotation in all cases contribute to the development of instabilities. In the second part of the work, we examine the spatial structure of normal modes and make an attempt to interpret the torsional oscillations observed in the atmospheres of Earth and the Sun. Calculations have shown that regular axisymmetric disturbances (torsional oscillations) can be caused by the formation of a cyclonic vortex above the pole, which is characteristic of Earth’s atmosphere and, possibly, of the Sun’s atmosphere. The least damped normal mode of a stable polar cyclone has a structure of torsional oscillations. Flow anomalies and the development of an anticyclonic eddy in winter at midlatitudes destroy torsional oscillations and lead to a rapid amplification of normal modes, which are more complex in structure.

Surgical Treatment of Posterolateral Rotational Instability of the Elbow: a Systematic Review

Posterolateral rotational instability (PLRI) of the elbow joint can occur acutely as a result of dislocation of the bones of the forearm, and also be chronic, for example, after inadequate healing of a previous rupture of the lateral ligamentous complex, in particular the lateral ulnar collateral ligament (LUCL). It is necessary to take into account that, as a result of repeated microtraumas, persistent pain syndrome and recurrence of dislocation develop, which can lead to disability. We conducted a systematic review of the literature according to the protocol outlined in the PRISMA guidelines. From 1,903 publications, 11 studies were selected that met our criteria and assessed the results of treatment of 181 patients. The main reason for the development of PLRI was simple traumatic dislocation of the forearm bones (37.5%). Of the studies that assessed the elbow joint using the MEPS, 86.5% of patients had excellent or good results, with a mean MEBS score of 91 points. Before surgery, pain syndrome was present in 131 patients (87.3%) out of 150, and in the postoperative period it was observed in 55 (36.6%) out of 150 (p=0.01). The incidence of recurrent instability after surgery was observed in 6.6% of patients. A review of the literature on the problem of the elbow joint shows that this problem has not been fully studied, treatment strategies differ and should be performed based on the surgeon’s experience and available data, however, it has been proven that the key to the stability of the elbow joint is the LUCL, which requires its restoration through its refixation or plastic surgery.

Is antero-lateral complex of knee joint of critical importance in restoring rotational instability in patients with anterior cruciate ligament tear?

Antero-lateral ligament complex (ALC) is a vital structure for maintaining rotational stability of the knee. Evaluation of ALC radiologically (MRI) is still unpopular in setting of anterior cruciate ligament injury. A dire necessity exists for the orthopedic surgeons in outdoor patient department settings to rule out involvement of ALC. So, that it can be addressed during operating for Anterior Cruciate Ligament injury. The authors have formulated an algorithm on a personal level and have implemented this screening program and initiated screening of young to middle aged patients reporting with rotational knee instability for ALC involvement before recommending final operative plan. This screening program which uses specifically devised physical tests have significantly reduced the number of underdiagnosed Antero Lateral Ligament tear.