Posterior Bundle Research Articles

White Matter Correlates of Early-Onset Bipolar Illness and Predictors of One-Year Recurrence of Depression in Adults with Bipolar Disorder.

Diffusion Magnetic Resonance Imaging (dMRI) studies have reported abnormalities in emotion regulation circuits in BD; however, no study has examined the contribution of previous illness on these mechanisms. Using global probabilistic tractography, we aimed to identify neural correlates of previous BD illness and the extent to which these can help predict one-year recurrence of depressive episodes. dMRI data were collected in 70 adults with early-onset BD who were clinically followed for up to 18 years and 39 healthy controls. Higher number of depressive episodes during childhood/adolescence and higher percentage of time with syndromic depression during longitudinal follow-up was associated with lower fractional anisotropy (FA) in focal regions of the forceps minor (left, F = 4.4, p = 0.003; right, F = 3.1, p = 0.021) and anterior cingulum bundle (left, F = 4.7, p = 0.002; right, F = 7.0, p < 0.001). Lower FA in these regions was also associated with higher depressive and anxiety symptoms at scan. Remarkably, those having higher FA in the right cluster of the forceps minor (AOR = 0.43, p = 0.017) and in a cluster of the posterior cingulum bundle (right, AOR = 0.50, p = 0.032) were protected against the recurrence of depressive episodes. Previous depressive symptomatology may cause neurodegenerative effects in the forceps minor that are associated with worsening of BD symptomatology in subsequent years. Abnormalities in the posterior cingulum may also play a role.

Anatomic Study of the Medial Collateral Ligament in Thai Population: A Cadaveric Study of 56 Elbows.

This study aims to elucidate basic anatomic and geometric features of MCL, providing more accurate and detailed information, as guidance for surgeons, to improve patient's outcome of the treatment. The anterior bundle (AB), posterior bundle (PB) and transverse bundle (TB) ligament of 56 fresh frozen Thai cadaveric elbows, were measured and recorded, comprise key ligament's geometric features, footprints and dimensions, and its relation to bony landmarks. Sagittal and coronal planes were used in respect of the anatomical position. The mean distance between the center of AB origin and the apex of medial epicondyle is as follows: 2.97 ± 2.21mm anteriorly, 4.73 ± 1.60mm inferiorly in the sagittal plane, and 4.23 ± 1.13mm deep from the epicondyle in the coronal plane. Its dimension is 6.23 ± 1.02mm in width and 45.97 ± 6.75mm in length. The ligament's insertion triangular shape has its base located 28.44 ± 3.51mm anterior from the posterior olecranon border, and 22.52 ± 2.49mm superior from the inferior ulnar border. The tip located 50.79 ± 4.86mm anterior from the posterior olecranon border and 17.64 ± 2.80mm superior from the inferior ulnar border. Apprehension of the precise geometries and distances of the ligament's footprint relative to key anatomical point is crucial. This stereographically comprehended data are useful for surgeon as reference points to obtain stability, motion, kinetic, and kinematic properties of the elbow. Level V evidence. The online version contains supplementary material available at 10.1007/s43465-022-00648-x.

P144 PEMBROLIZUMAB–INDUCED MYOCARDITIS

Abstract Introduction Patients treated with Immunocheckpoint Inhibitors (ICI) can develop adverse cardiovascular events, most frequently myocarditis, but also arrhythmias, conduction abnormalities, pericarditis, Takotsubo syndrome, ACS, heart failure, cardiac arrest. Myocarditis occurs early, within the first 3–4 administrations of therapy, and is fraught with a high mortality rate. Case Presentation 80–year–old patient with renal pelvic carcinoma who underwent nephroureterectomy and subsequent adrenalectomy. Twenty days after the first cycle of Pembrolizumab, the patient is admitted to cardiology for syncope and ECG finding of Left Posterior Fascicular Block (LPFB) and right bundle branch block (RBBB) with significant increase in troponin without any alterations in regional kinetics and normal ventricular function (EF). The patient also complains of widespread muscle pain and severe hyponatremia on blood tests. On ECG monitoring, alternation of RBBB with associated LPFB and Left Posterior Fascicular Block, left bundle branch block, first and second degree atrio–ventricular block (AV block) and on day II appearance of complete paroxysmal AV block controlled with temporary pacemaker implantation. On the 4th day, we documented changes in the segmental motion of the left ventricle (LV) and progressive gradual worsening of the EF. During the hospitalization the patient manifested episodes of general malaise with profuse sweating and marked hypotension with possible SIADH picture. In suspicion of acute myocarditis, peripheral myositis and possible Pembrolizumab SIADH, the patient was treated with high dose methylprednisolone (1000 mg / day) with little benefit. On the 6th day the patient was found in critical condition, severely suffering, hypotensive and oliguric, resigned herself. Conclusions Our case highlights how even a single dose of Pembrolizumab can trigger an acute inflammatory pattern affecting the myocardium with prevalent involvement of the conduction tissue even before the appearance of alterations in the kinetics and ventricular dysfunction. During ICI therapy cycles it is therefore important to monitor the ECG and troponin levels in order to be able to diagnose myocardial involvement early. In fact, although this complication is rare, it is burdened by a high mortality rate. The only treatment currently available involves the suspension of immunotherapy and the administration of high–dose methylprednisolone.

Sinus node exit, crista terminalis conduction, interatrial connection, and wavefront collision: Key features of human atrial activation in sinus rhythm.

An understanding of normal atrial activation during sinus rhythm can inform catheter ablation strategies to avoid deleterious impacts of ablation lesions on atrial conduction and mechanics. The purpose of this study was to describe how the sinus node impulse originates, propagates, and collides in right and left atria with normal voltage. Fifty consecutive patients undergoing catheter ablation of atrial fibrillation with endocardial atrial voltage >0.5 mV during high-density 3-dimensional mapping were studied. Sinus node exits varied among patients along a lateral oblique arc extending from the anterior aspect of the superior vena cava (SVC) to the mid-posterior wall of the right atrium (RA). Conduction slowing or block at one of the smooth components that faces the crista terminalis was observed in 54% of cases, including complete block at the SVC musculature and systemic venous sinus in 6% of cases. Depending on these 2 key features of RA activation, interatrial conduction was mediated by the Bachmann bundle (64%) and posterior bundles (54%), with an overlap of the resulting left atrial breakthrough location. Wavefront collision was consistently observed at 3 sites: the septal aspect of the cavotricuspid isthmus, and the lower aspects of the dome and of the mitral isthmus. During sinus rhythm, atrial activation occurs via distinct sequences mediated by a complex interaction of anatomic factors.

Avoidance of injury to the posterior neurovascular bundle during total ankle arthroplasty – A simple technical tip

Iatrogenic nerve injury to the tibial nerve is a serious but avoidable complication of total ankle replacements and may be under-reported as it may go unrecognised or thought to be due to tarsal tunnel syndrome. The tibial nerve is particularly vulnerable during the saw cuts at the posteromedial corner without appropriate protection. Prior to drilling the tibial and talar pins of the adjustment block for the Infinity ankle replacement we perform a 2 cm incision behind the medial malleolus. The tibialis posterior tendon sheath is identified and incised. A periosteal elevator is used to develop a plane between the back of the tibia and the tibialis posterior tendon and then exchanged for a mini Hohmann retractor protecting the neurovascular bundle. This allows us to drill the pins and saw cuts safely. The Hohmann retractor can be felt at the tip of the saw blade providing reassurance that the blade is not too deep. Our technique has not previously been reported in the literature. It acts as a simple reproducible way of avoiding injury to structures at the back of the ankle joint.

Biomechanical Evaluation of a Low-Invasive Elbow Medial Collateral Ligament Reconstruction Technique With Fascia and Tendon Patches.

Background: Injury to the medial collateral ligament (MCL) of the elbow has become increasingly common in sports, and the elbow is prone to contracture and ossification in trauma. Effective reconstruction of the MCL with reduction of irritation to the elbow has rarely been reported. This study introduces a minimally invasive elbow MCL reconstruction technique and evaluates the valgus stability. Methods: Eight fresh-frozen elbow specimens underwent reconstruction of the anterior bundle of the MCL (AMCL) first with the flexor carpi ulnaris fascia patches, followed by reconstruction of the posterior bundle of the MCL (PMCL) with the triceps tendon patches. The valgus angles of each specimen were examined in three stages as follows: intact MCL, reconstruction of the AMCL alone, and reconstruction of the MCL (including AMCL and PMCL). Finally, specimens were loaded to failure, and failure modes were recorded. Results: AMCL reconstruction alone had similar valgus stability at all testing angles (p = 0.080, 30° flexion; p = 0.064, 60° flexion; p = 0.151, 90° flexion; p = 0.283, 120° flexion) compared with the intact MCL, as did MCL reconstruction (p = 0.951, 30° flexion; p = 0.739, 60° flexion; p = 0.841, 90° flexion; p = 0.538, 120° flexion). More importantly, a significant difference existed between the MCL reconstruction and the AMCL reconstruction alone at 30° flexion (p = 0.043) and 60° flexion (p = 0.013) but not at the 90° flexion (p = 0.369) and 120° flexion (p = 0.879). The mean maximum failure torque of MCL reconstruction was 24.02 Nm at 90° elbow flexion. Conclusion: Both AMCL reconstruction alone and MCL reconstruction provided valgus stability comparable with the native MCL, and importantly, MCL reconstruction provided more valgus stability than AMCL reconstruction alone at 30° flexion and 60° flexion of the elbow. Therefore, the new MCL reconstruction technique might be a useful guide for the treatment of elbow MCL injuries or deficiencies.

Dimensions of Formal Thought Disorder and Their Relation to Gray- and White Matter Brain Structure in Affective and Psychotic Disorders.

Factorial dimensions and neurobiological underpinnings of formal thought disorders (FTD) have been extensively investigated in schizophrenia spectrum disorders (SSD). However, FTD are also highly prevalent in other disorders. Still, there is a lack of knowledge about transdiagnostic, structural brain correlates of FTD. In N = 1071 patients suffering from DSM-IV major depressive disorder, bipolar disorder, or SSD, we calculated a psychopathological factor model of FTD based on the SAPS and SANS scales. We tested the association of FTD dimensions with 3 T MRI measured gray matter volume (GMV) and white matter fractional anisotropy (FA) using regression and interaction models in SPM12. We performed post hoc confirmatory analyses in diagnostically equally distributed, age- and sex-matched sub-samples to test whether results were driven by diagnostic categories. Cross-validation (explorative and confirmatory) factor analyses revealed three psychopathological FTD factors: disorganization, emptiness, and incoherence. Disorganization was negatively correlated with a GMV cluster comprising parts of the middle occipital and angular gyri and positively with FA in the right posterior cingulum bundle and inferior longitudinal fascicle. Emptiness was negatively associated with left hippocampus and thalamus GMV. Incoherence was negatively associated with FA in bilateral anterior thalamic radiation, and positively with the hippocampal part of the right cingulum bundle. None of the gray or white matter associations interacted with diagnosis. Our results provide a refined mapping of cross-disorder FTD phenotype dimensions. For the first time, we demonstrated that their neuroanatomical signatures are associated with language-related gray and white matter structures independent of diagnosis.

A macroscopic anatomical study of the appropriate palpation zone of the gluteus medius muscle.

[Purpose] Few previous studies have delimitated the palpation zone of the gluteus medius muscle with a focus on its fiber bundles. The purpose of this study was to clarify the morphological characteristics of the gluteus medius muscle using an anatomical approach, and to define its proper palpation zone. [Participants and Methods] In this study, we evaluated thirteen halves of the pelvic region in seven formalin-fixed cadavers. We identified the borders between the iliotibial band and gluteus medius muscle, and between the gluteus medius and gluteus maximus muscles, on the iliac crest. Furthermore, we quantified the border points of the gluteus medius’ fiber bundles and observed its anatomical and morphological characteristics. [Results] We identified two fiber bundles in the gluteus medius muscle, an anterior and a posterior fiber bundle, and detected that a portion of the posterior fibers was located subcutaneously. [Conclusion] We propose that the region where the posterior fibers of the gluteus medius muscle are located subcutaneously is an appropriate zone for the palpation of this muscle.

The radiological findings in complex elbow fracture-dislocation injuries.

Elbow fracture-dislocation is a complex injury which can lead to significant bony and soft tissue damage. Surgical intervention is guided towards restoring joint stability, allowing early mobilization and preventing long-term joint stiffness. The most common types are posterolateral, posteromedial, Monteggia type (and variants), and anterior trans-olecranon fracture-dislocations. Posterolateral fracture-dislocation is characterized by a radial head fracture (± anterolateral coronoid fracture) and typically capsuloligamentous disruption (lateral collateral ligaments injury is the most common). A posterolateral fracture-dislocation with radial head and coronoid anterolateral facet fractures is termed a terrible triad injury. In posteromedial fracture-dislocation, there is a fracture of the anteromedial facet of the coronoid, typically with proximal avulsion of the lateral collateral ligaments (± injury to the posterior bundle of the ulnar collateral ligament). Monteggia fracture-dislocation injuries demonstrate proximal ulnar fracture (with possible involvement of the olecranon and the coronoid) and radial head dislocation. These can be divided into apex anterior or apex posterior variants. The latter are commonly associated with radial head fractures and lateral ligamentous injury, and have a worse prognosis. In trans-olecranon fracture-dislocation, there is significant disruption of the greater sigmoid notch and the olecranon, with various involvement of the coronoid and the proximal ulna. The article describes the radiological findings and outlines the management principles in complex elbow fracture-dislocation injuries.

Topographic and Histologic Analysis of the Collateral Ligament Complex around the Elbow

Purpose: The purpose of this study was to evaluate topographic anatomy of the footprints of key ligaments of the elbow and assess their relationships with bony parameters using micro-computed tomography (micro-CT). Additionally, the ratios of type I/III collagen at the medial collateral ligament (MCL) and lateral collateral ligament (LCL) of elbow were investigated.Methods: Eleven cadaveric elbows attached by both the MCL and LCL were scanned using micro-CT and reconstructed three-dimensionally. Additionally, the ligaments were examined under polarized light microscopy to determine the histological characteristics of collagen patterns. Results: Areas of footprints of the MCL and LCL attaching onto the humerus were 133.2±25.8 mm² and 128.3±23.2 mm², respectively. Footprint sizes of anterior and posterior bundles of the MCL in the proximal ulna and lateral ulnar collateral ligament (LUCL) attaching to the proximal ulna averaged to 109.9 mm², 89.2 mm², and 89.7 mm², respectively. There were a positive correlation between footprint size of the MCL and LUCL at the humeral side and a negative correlation between the footprint size of the MCL at humeral side and maximal diameter of the radial head. The collagen I/III ratio of the humeral attachment of the MCL was higher than distal attachment of the MCL. Conclusion: This study provides a better understanding of the pathologies of the MCL and LCL complex of the elbow and their relationships with osseous anatomy and may assist the clinician with an anatomic reconstruction of the ligaments.

Failure load of the femoral insertion site of the anterior cruciate ligament in a porcine model: comparison of different portions and knee flexion angles

BackgroundThis study compared the failure load of the femoral insertion site of the anterior cruciate ligament between different portions and knee flexion angles.MethodsIn total, 87 fresh-frozen, porcine knees were used in this study. Three knees were used for histological evaluation; the remaining 84 knees were randomly divided into 4 groups: anterior anteromedial bundle, posterior anteromedial bundle, anterior posterolateral bundle, and posterior posterolateral bundle groups (n=21 per group). The anterior cruciate ligament femoral insertion site was divided into these four areas and excised, leaving a 3-mm square attachment in the center of each bundle. Tibia-anterior cruciate ligament-femur complexes were placed in a material testing machine at 30°, 120°, and 150° of knee flexion (n=7), and the failure load for each portion was measured under anterior tibial loading (0.33 mm/s).ResultsHistological study showed that the anterior cruciate ligament femoral insertion site consisted of direct and indirect insertions. Comparison of the failure load between the knee flexion angles revealed that all the failure loads decreased with knee flexion; significant decreases were observed in the failure load between 30 and 150° knee flexion in the posterior anteromedial bundle and posterior posterolateral bundle groups. Comparison of the failure load according to different portions revealed a significant difference between the anteromedial and posterolateral bundle groups at 150° of knee flexion, but no significant difference among the groups at 30° of flexion.ConclusionsAlthough the failure load of the posterior portion decreased significantly in the knee flexion position, it (mainly consisting of indirect insertion) plays a significant role against anterior tibial load in the knee extension position; this appears to be related to the characteristics of the insertion site. Reflecting the complex structure and function of the ACL, this study showed that the failure load of the femoral insertion site varies with differences in positions and knee flexion angles.

Исследование сосудов голени при атипичной анатомии берцовых сосудов с помощью ультразвукового дуплексного ангиосканирования

Background. Knowledge of vascular anatomy is the basis for precise diagnosis and, accordingly, of treatment. At the same time, variant anatomy complicates this task, as it requires a non-standard algorithm. Among all areas of the lower extremities, the shin presents the greatest difficulty because of small diameter of vessels and a large muscular mass. Therefore, the aim of this work was to determine the incidence of the variant of the development of the shin vessels with predomination of fibular vessels and to develop an algorithm for ultrasound examination in atypical anatomy. Materials and Methods. A morphological study of the venous system in 85 lower extremities was carried out, as well as analysis of the results of ultrasound examination of the vessels of the lower extremities in 2000 patients (aged from 18 to 90) who underwent routine examination in an outpatient setting. Ultrasound examination was performed on Samsung Sonoace X8, Siemens Acuson Сypress, Saoyte My Lab Alfa devices. A linear sensor with 7 to 12 MHz frequency, a convex sensor with 2 to 5 MHz frequency were used. Results. According to the data of anatomical preparation, the incidence of the structural variant of the tibial vessels with predomination of the fibular vascular bundle was 2.35% of cases. In all cases, the posterior tibial vessels were hypoplastic and were traced to the middle third of the leg. According to ultrasound data, an atypical variant of the structure of the tibial vessels was noted in 2.9% of cases. In 1.7% of cases, the posterior tibial vascular bundle was completely absent (in 0.35% of cases bilaterally), and in 1.2% of cases, the posterior tibial vascular bundle was hypoplastic and was traced to the middle third of the leg (in 0.3% cases bilaterally). Conclusion. The variant of development of tibial vessels with predomination of the fibular vascular bundle is quite rare. Ultrasound examination helps precisely and reliably identify this variant of the structure of blood vessels.

Evaluation of a connectivity-based imaging metric that reflects functional decline in Multiple Sclerosis.

Cognitive impairment is a common symptom in individuals with Multiple Sclerosis (MS), but meaningful, reliable biomarkers relating to cognitive decline have been elusive, making evaluation of the impact of therapeutics on cognitive function difficult. Here, we combine pathway-based MRI measures of structural and functional connectivity to construct a metric of functional decline in MS. The Structural and Functional Connectivity Index (SFCI) is proposed as a simple, z-scored metric of structural and functional connectivity, where changes in the metric have a simple statistical interpretation and may be suitable for use in clinical trials. Using data collected at six time points from a 2-year longitudinal study of 20 participants with MS and 9 age- and sex-matched healthy controls, we probe two common symptomatic domains, motor and cognitive function, by measuring structural and functional connectivity in the transcallosal motor pathway and posterior cingulum bundle. The SFCI is significantly lower in participants with MS compared to controls (p = 0.009) and shows a significant decrease over time in MS (p = 0.012). The change in SFCI over two years performed favorably compared to measures of brain parenchymal fraction and lesion volume, relating to follow-up measures of processing speed (r = 0.60, p = 0.005), verbal fluency (r = 0.57, p = 0.009), and score on the Multiple Sclerosis Functional Composite (r = 0.67, p = 0.003). These initial results show that the SFCI is a suitable metric for longitudinal evaluation of functional decline in MS.

Age-related differences in negative cognitive empathy but similarities in positive affective empathy

Empathy, among other social-cognitive processes, changes across adulthood. More specifically, cognitive components of empathy (understanding another’s perspective) appear to decline with age, while findings for affective empathy (sharing another’s emotional state) are rather mixed. Structural and functional correlates underlying cognitive and affective empathy in aging and the extent to which valence affects empathic response in brain and behavior are not well understood yet. To fill these research gaps, younger and older adults completed a modified version of the Multifaceted Empathy Test, which measures both cognitive and affective empathy as well as empathic responding to both positive and negative stimuli (i.e., positive vs. negative empathy). Adopting a multimodal imaging approach and applying multivariate analysis, the study found that for cognitive empathy to negative emotions, regions of the salience network including the anterior insula and anterior cingulate were more involved in older than younger adults. For affective empathy to positive emotions, in contrast, younger and older adults recruited a similar brain network including main nodes of the default mode network. Additionally, increased structural microstructure (fractional anisotropy values) of the posterior cingulum bundle (right henisphere) was related to activation of default mode regions during affective empathy for positive emotions in both age groups. These findings provide novel insights into the functional networks subserving cognitive and affective empathy in younger and older adults and highlight the importance of considering valence in empathic response in aging research. Further this study, for the first time, underscores the role of the posterior cingulum bundle in higher-order social-cognitive processes such as empathy, specifically for positive emotions, in aging.

Effect of Bone Resection on Posterior Talofibular Ligament Integrity for Posterior Ankle Impingement Syndrome: A Cadaveric Study

PurposeThe purpose of this study was to evaluate the attachment areas of the posterior talofibular ligament (PTFL) on the posterolateral tubercle of the talus and the remaining PTFL attachment areas after consequential bony excision.MethodsThirty fresh cadaveric ankles were dissected to study the proximal and distal attachment of the PTFL and separated the PTFL into anterior and posterior bundles. The description of the PTFL footprint and the anatomic landmarks from the surrounding structures were analyzed during consequential posterolateral bony excision.ResultsThe average PTFL dimension was 26.11 mm (length), 7.65 mm (width), and 1.82 mm (thickness). The footprint area of the PTFL on the talar site consists of the posterior bundle (76.82%) and the anterior bundle (23.18%). If posterolateral tubercle excision was stayed up to a line of a bottom of the flexor hallucis longus (FHL) groove, at least 89% of the PTFL can be preserved.ConclusionThe posterior bundle of the PTFL is the main bundle on the talar footprint area. To maintain the majority of the attachment of the PTFL, the resection of the posterolateral process could be performed to the bottom of the FHL tendon groove. If resection reaches to the posterior articular cartilage, less than 50% of the PTFL will be preserved. Understanding the footprint of the PTFL plays a key role in posterior ankle impingement surgery.Clinical RelevanceThis study provides guidance for resection of the posterolateral tubercle of the talus and a portion of the PTFL attachment for posterior ankle impingement syndrome. Too much resection of the tubercle may cause instability symptoms.

Relationship between morphology of transverse bundle of ulnar collateral ligament and adjacent tissues.

The purpose of this study was to clarify the incidence of the transverse bundle (TB) of the ulnar collateral ligament (UCL), the relationships between TB morphology and morphology of the anterior bundle (AB) or posterior bundle (PB) of the UCL, and the relationship between the TB and the posterior common tendon (PCT). This study examined 38 elbows from 23 cadavers. TB, AB, and PB were classified morphologically. The TB was classified as: type I, TB does not continue the entire length of the AB; or type II, TB continues the entire length of the AB. The AB and PB were classified as: type I, could be separated as single bundles; or type II, could not be separated. We also observed specimens by focusing on the continuity between the TB and PCT. Fisher's exact test was used to examine the relationship between TB type and AB or PB type. A TB was identified in all 38 elbows (100%), and continued to the AB in all specimens. No significant relationship was evident between TB type and AB or PB type. Continuity of TB fibers and the PCT was seen in 26 elbows (72%). This study suggested that the morphology of the transverse bundle may be unrelated to the morphology of the anterior bundle or posterior bundle.

Anatomic grounds for the transposition of the thoracodorsal nerve in case of neurotization of brachial plexus nerve damage

The goal is to identify topographic, anatomic, and constitutional features of thoracodorsal and musculocutaneous nerves of brachial plexus. Materials and methods . Anthropometry of 45 corpses was carried out to determine growth; length of the trunk and upper extremities; circumference of neck, thoracic cage, shoulder and forearm; lateral dimensions of shoulders, thoracic cage and pelvis; anteroposterior size of thoracic cage; neck circumference. Morphometry of all brachial plexus components (length, thickness of nerves and angles of their origin) was performed after its anatomic preparation. Results . The cephalic type of brachial plexus with participation of C4 spinal nerve was found in 7% of cases. The caudal type with inclusion of Th2 spinal nerve was found in 4% of cases. In 4% of cases, there was no musculocutaneous nerve, at the same time shoulder biceps innervates median nerve. In 93% of cases, the thoracodorsal nerve originates from posterior secondary bundle along lower posterior surface, in 7% it is an axillary nerve branch. Neck circumference is directly correlated with thoracodorsal nerve length: the larger the neck circumference is, the greater is the nerve length. In females, linear regression equations were derived, which allow estimating thoracodorsal nerve length knowing the thoracic cage width. Conclusion. The length of the thoracodorsal nerve determines the possibility of its transplantation into the musculocutaneous position. The size of neck circumference and, in females, the width of the thoracic cage, for reliability, should be used as external size biomarkers for donor and recipient nerves.

In Vivo Elongation Patterns of the Collateral Ligaments in Healthy Knees During Functional Activities.

Improved knowledge of in vivo function of the collateral ligaments is essential for enhancing rehabilitation and guiding surgical reconstruction as well as soft-tissue balancing in total knee arthroplasty. The aim of this study was to quantify in vivo elongation patterns of the collateral ligaments throughout complete cycles of functional activities. Knee kinematics were measured using radiographic images captured with a mobile fluoroscope while healthy subjects performed level walking, downhill walking, and stair descent. The registered in vivo tibiofemoral kinematics were then used to drive subject-specific multibody knee models to track collateral ligament elongation. The elongation patterns of the medial collateral ligament varied distinctly among its bundles, ranging from lengthening of the anterior fibers to shortening of the posterior bundle with increases in the knee flexion angle. The elongation patterns of the lateral collateral ligament varied considerably among subjects. It showed an average 4% shortening with increasing flexion until 60% to 70% of the gait cycle, and then recovered during the terminal-swing phase until reaching its reference length (defined at heel strike). The observed nonuniform elongation of the medial collateral ligament bundles suggests that single-bundle reconstruction techniques may not fully restore healthy ligament function. Moreover, the observed ligament elongation patterns indicate greater varus than valgus laxity in the loaded knee. Through providing key knowledge about the in vivo elongation patterns of the collateral ligaments throughout complete cycles of functional activities, this study offers in vivo evidence for benchmarking ligament reconstruction and soft-tissue balancing in total knee arthroplasty.

Effect of the medial collateral ligament and the lateral ulnar collateral ligament injury on elbow stability: a finite element analysis

Ligaments are the most important stabilizer of elbow. However, the stress of ligaments is hard to measure because of the complex biomechanical environment in the elbow. Our objective was to develop a human elbow finite element model and to validate it by a comparison with previous experimental data. Then several different ligaments injury conditions and elbow flexion were simulated to analyse the elbow instability and to stress the biomechanical consequences. The computational investigation of different effects of ligament constraints of elbow was studied by means of finite element analysis. The stress of the anterior bundle was almost greater than other ligaments in all conditions, which played the most important role during the elbow flexion. The posterior bundle was the secondary stabilizer during flexion after the anterior bundle. The lateral ulnar collateral ligament (LUCL) injury could result in an increase of the ulnar cartilage stress. The anterior bundle and the LUCL were recommended to be repaired in elbow joint dislocations and fractures. This study could help understand the dynamic effects of ligaments on the joint over the entire extension by investigating the tissue stress.

Anatomical study of the proximal tibiofibular ligaments using ultrasound

ObjectivesNo description of the proximal tibiofibular (PTF) ligaments by means of high ultrasound has yet been reported in the literature. The purpose of this study was to assess whether ultrasound may allow the assessment of these ligaments.MethodsThis study was initially undertaken in three cadaveric knees, followed by an ultrasound study performed by two musculoskeletal radiologists working in consensus of 52 patients without history of trauma or surgery of the knee, and without lateral knee pain. The visibility, echogenicity, length and thickness of the PTF ligaments were assessed.ResultsRegarding the anterior PTF ligament, the superior bundle and the upper and lower middle bundles were clearly seen in 42.3%, 100% and 75% of the knees, respectively. Regarding the posterior PTF ligament, the superior and middle bundles were clearly seen in 88.4% and 51.9% of the knees, respectively. The echo-anatomy of these ligaments and the probe positioning allowing their best depiction were described in this study.ConclusionMost of the PTF ligaments can be visualized by means of ultrasound. This possible assessment may have clinical applications, particularly in patients with lateral knee pain.