The precision of technical aspects in the minimally invasive Broström-Gould procedure: a cadaveric anatomical study.

BACKGROUND: A comprehensive understanding of the anatomy of the anterolateral ankle joint and its interrelationships is essential for advancing the development of minimally invasive Broström-Gould procedure, thereby enhancing surgical efficacy and minimizing postoperative complications. METHODS: Ten fresh human ankle specimens were dissected to observe the shape and trajectory of the lateral bundle of the inferior extensor retinaculum (IER) and its relationship with the deep fascia. To observe the relationship between the ankle capsule and the anterior talofibular ligament (ATFL). The center of the insertion point of ATFL at the lateral malleolus was used as the reference point. The vertical distance from the reference point to the fibula tip, the horizontal distance from the reference point to the lateral branch of the superficial peroneal nerve, the shortest distance from the reference point to IER, the narrowest width of the IER, the angle between the line connecting the shortest distance from the reference point to the IER and the longitudinal axis of the fibula were measured. The tension and elasticity of ATFL was understood. To describe the minimally invasive Broström-Gould procedure according to the anatomical characteristics of the anterolateral ankle joint. RESULTS: Among the 10 cases, 8 cases (80%) had double bundles of ATFL, 2 cases (20%) had single bundle of ATFL, and no outer superior oblique bundle was observed in IER. The vertical distance from the reference point to the fibula tip was 1.2 ± 0.3 (range 1.1-1.3) mm. The shortest distance from the reference point to the level of the superficial peroneal branch was 28.2 ± 4.3 (range 24.5-32.4) mm. The shortest distance from the reference point to IER was 12.5 ± 0.6 (range 12.1-12.9) mm, and the width of IER at this point was 7.2 ± 0.3 (range 7.0-7.6) mm. The angle between the line connecting the shortest distance from the reference point to the IER and the longitudinal axis of the fibula was about 60° ± 2.8° (range 58.1°-62.1°) mm. The space between the anterolateral deep fascia of the ankle joint and the ankle capsule is very small, and only a few fat granules are separated between them. The ATFL is largely fused to the ankle capsule. The ATFL exhibited high tension and poor elasticity after traction with the probe hook. CONCLUSIONS: The results showed that in the minimally invasive Broström-Gould technique for lateral ankle stabilization, the Broström procedure actually sutured the insertion of the ATFL together with the ankle capsule to the anterior edge of the lateral malleolus. In the Gould procedure, the deep fascia was mostly reinforced with the ankle capsule. The minimum suture span was obtained when the Gould suture needle direction was at an Angle of 60° to the longitudinal axis of the fibula.

Anatomical evaluations of the adipose tissue surrounding the flexor hallucis longus tendon.

This study aimed to evaluate the presence of adipose tissue surrounding the flexor hallucis longus (FHL) tendon through gross dissection and magnetic resonance imaging (MRI). Grossly, we observed the FHL tendon and surrounding tissues in nine cadavers. Using MRI, we quantitatively evaluated each tissue from the horizontal plane in 40 healthy ankles. Macroscopic autopsy revealed the presence of adipose tissue behind the ankle joint between the FHL and fibula, and horizontal cross-sections showed an oval-shaped adipose tissue surrounding the tendon. The cross-sectional area on MRI was 14.4 mm2 (11.7-16.7) for the FHL tendon and 120.5 mm2 (100.3-149.4) for the adipose tissue. Additionally, the volume of the adipose tissue was 963.3 mm3 (896.2-1115.6). There is an adipose tissue around FHL tendon and maybe this close anatomical relationship might influence the function of the tendon and be involved in its pathologies.

A Cadaveric Study: Does Ankle Positioning Affect the Quality of Anatomic Syndesmosis Reduction?

OBJECTIVE: The objective of this study was to compare the quality of syndesmotic reduction with the ankle in maximal dorsiflexion versus neutral plantarflexion (normal resting position). METHODS: Baseline computed tomography (CT) imaging of 10 cadaveric ankle specimens from 5 donors was obtained with the ankles placed in normal resting position. Two fellowship-trained orthopaedic surgeons disrupted the syndesmosis of each ankle specimen. All ankles were then placed in neutral plantarflexion and were subsequently reduced with thumb pressure under direct visualization through an anterolateral approach and stabilized with one 0.062-inch K-wire placed from lateral to medial in a quadricortical fashion across the syndesmosis. Postreduction CT scans were then obtained with the ankle in normal resting position. This process was repeated with the ankles placed in maximal dorsiflexion during reduction and stabilization. Postreduction CT scans were then obtained with the ankles placed in normal resting position. All postreduction CT scans were compared with baseline CT imaging using mixed-effects linear regression with significance set at P < 0.05. RESULTS: Syndesmotic reduction and stabilization in maximal dorsiflexion led to increased external rotation of the fibula compared with baseline scans [13.0 ± 5.4 degrees (mean ± SD) vs. 7.5 ± 2.4 degrees, P = 0.002]. There was a tendency toward lateral translation of the fibula with the ankle reduced in maximal dorsiflexion (3.3 ± 1.0 vs. 2.7 ± 0.7 mm, P = 0.096). No other statistically significant differences between measurements of reduction with the ankle placed in neutral plantarflexion or maximal dorsiflexion compared with baseline were present (P > 0.05). CONCLUSIONS: Reducing the syndesmosis with the ankle in maximal dorsiflexion may lead to malreduction with external rotation of the fibula. There was no statistically significant difference in reduction quality with the ankle placed in neutral plantarflexion compared with baseline. Future studies should assess the clinical implications of ankle positioning during syndesmotic fixation.

The morphometry of distal tibia and posterior malleolus and its clinical implications in total ankle prosthesis.

PURPOSE: The aim of this study is to reveal the morphometry of the distal tibia and posterior malleolus and to generate morphometric reference data for the tibial component of total ankle prosthesis. METHODS: This study was performed on 121 human dry tibiae (47 right, 74 left). The morphometric measurements of distal tibial structures, tibial length and the distance between the medial and posterior malleolus were measured in this study. Measurements on 44 tibiae were repeated three times and averaged for minimizing intra-observer error. RESULTS: The tibial length was found 34.19 ± 2.31 cm. Mean values of width of fibular notch at tibial plafond and 10 mm proximal to the tibial plafond were 25.71 ± 2.44 mm and 17.81 ± 2.46 mm, respectively. Mean depth of fibular notch at tibial plafond and 10 mm proximal to the tibial plafond were 3.60 ± 1.04 mm and 3.37 ± 1.24 mm, respectively. Mean height of fibular notch was found 48.21 ± 10.51 mm. Mean width and height of medial malleolus were 25.08 ± 2.13 mm and 14.73 ± 1.85 mm, respectively. Mean width and length of tibial plafond were 27.71 ± 2.74 mm and 26.96 ± 2.62 mm, respectively. Mean values of width and height of posterior malleolus were measured 21.41 ± 3.26 mm and 6.74 ± 1.56 mm, respectively. Mean distance between medial and posterior malleolus was found 37.17 ± 3.53 mm. Mean width and depth of malleolar groove were 10.26 ± 1.84 mm and 1.73 ± 0.75 mm, respectively. The mean intra-class correlation values were found between the 0.959 and 0.999. CONCLUSIONS: Knowing the distal tibial morphometry is crucial for designing convenient ankle replacement implants for Turkish population. To our knowledge, this study is the first in the literature that identifies posterior malleolar morphometry on dry tibiae. We believe that this study will make a significant contribution to the literature about distal tibial morphometry and especially the posterior malleolus and the data of our study can be used for designing total ankle prosthesis in Turkish population.

An Applied Anatomical Study on the Inferior Extensor Retinaculum of Ankle / Un Estudio de Anatomía Aplicada del Retináculo Extensor Inferior del Tobillo

SUMMARY: Through anatomical observations, the anatomical characteristics of the inferior extensor retinaculum of ankle (IER) of the ankle joint were elucidated, and its potential applications in treating lateral ankle instability or other conditions were discussed. A total of 12 adult foot specimens were dissected to expose the inferior extensor retinaculum of ankle, and a standard model was established. The pre-experimental scheme guided the recording of general findings, adjacent structures, lateral attachment in the tarsal sinus region, and influence on movement of inferior tendons. 1, attachment mean width: lateral band of IER 6.6±1.38 mm, oblique superomedial band of IER (32.3±3.97 mm), oblique inferomedial band of IER (30.0±5.30 mm) ; 2, mean length: lateral band of IER (78.1±4.20 mm) , oblique superomedial band of IER (14.2±0.80 mm), oblique inferomedial band of IER (71.8±2.61 mm); 3, maximum mean thickness: lateral band of IER (1.52±0.03 mm), oblique superomedial band of IER (0.89±0.05 mm), oblique inferomedial band of IER (0.73±0.16 mm); 4, the closest distance between IER and the tip of lateral malleolus: 23.9±0.83 mm; 5, mean width of the fiber tunnel:lateral fiber tunnel (11.9±1.16 mm), intermedium fiber tunnel (6.8±1.24 mm), medial fiber tunnel (8.6±0.79 mm); 6, mean distance from tunnel midpoint to lateral malleolar tip: lateral fiber tunnel (38.0±3.74 mm), intermedium fiber tunnel (69.8±4.15 mm), medial fiber tunnel (181.1±6.00 mm); 7, the distance between medial dorsal cutaneous nerve and the tip of lateral malleolus on the level of the IER (79.2±8.3 mm) the distance between intermediate cutaneous nerve of dorsum and the tip of lateral malleolus on the level of the IER (57.9±1.02 mm). The inferior extensor retinaculum of ankle is a crucial restraint unit of the anterior ankle tendon, and a comprehensive understanding of its anatomical characteristics holds significant implications for treating chronic ankle instability and exploring potential clinical applications.

A través de observaciones anatómicas, se dilucidaron las características anatómicas del retináculo extensor inferior (IER) de la articulación del tobillo y se discutieron sus posibles aplicaciones en el tratamiento de la inestabilidad lateral de esta articulación u otras afecciones. Se disecaron 12 muestras de pies de individuos adultos para exponer el retináculo extensor inferior del tobillo y se estableció un modelo estándar. El esquema preexperimental guió el registro de los hallazgos generales, las estructuras adyacentes, la inserción lateral en la región del seno tarsal y la influencia en el movimiento de los tendones inferiores. Se determino: 1. Ancho medio de inserción: banda lateral de IER (6,6 ± 1,38 mm), banda superomedial oblicua de IER (32,3 ± 3,97 mm), banda inferomedial oblicua de IER (30,0 ± 5,30 mm); 2. Longitud media: banda lateral de IER (78,1 ± 4,20 mm), banda superomedial oblicua de IER (14,2 ± 0,80 mm), banda inferomedial oblicua de IER (71,8 ± 2,61 mm); 3. Espesor medio máximo: banda lateral de IER (1,52 ± 0,03 mm), banda superomedial oblicua de IER (0,89 ± 0,05 mm), banda inferomedial oblicua de IER (0,73 ± 0,16 mm); 4. Distancia más próxima entre IER y el ápice del maléolo lateral: (23,9 ± 0,83 mm); 5.Ancho medio del túnel de fibra: túnel de fibra lateral (11,9 ± 1,16 mm), túnel de fibra intermedio (6,8 ± 1,24 mm), túnel de fibra medial (8,6 ± 0,79 mm); 6. Distancia media desde el punto medio del túnel hasta la punta del maléolor lateral: túnel de fibra lateral (38,0 ± 3,74 mm), túnel de fibra intermedio (69,8 ± 4,15 mm), túnel de fibra medial (181,1 ± 6,00 mm); 7. Distancia entre el nervio cutáneo dorsal medial y el a´pice del maléolo lateral en el nivel del IER (79,2 ± 8,3 mm); la distancia entre el nervio cutáneo intermedio dorsal y el ápice del maléolo lateral en el nivel del IER (57,9 ±1,02 mm). El retináculo extensor inferior del tobillo es una unidad de restricción crucial del tendón anterior del tobillo, y una comprensión integral de sus características anatómicas tiene implicaciones significativas para el tratamiento de la inestabilidad crónica del tobillo y la exploración de posibles aplicaciones clínicas.

Comparison of Neurovascular Structures at Risk During Ankle Arthroscopy: A Cadaveric Study.

BACKGROUND: Arthroscopy has become increasingly common for diagnosis and treatment of ankle joint pathology. The four most common portals used for ankle arthroscopy are the anteromedial, anterolateral, posteromedial, and posterolateral. Anatomy of neurovascular structures along the ankle can significantly vary. METHODS: The distance of neurovascular structures was compared with anatomical landmarks of ankle arthroscopic portals to verify safe zones for scope insertion. Twenty-six fresh frozen cadavers were used, with dissection of standard anatomical landmarks and neurovascular structures. Portals were made and verified with a 2.7-mm arthroscope. RESULTS: Significant differences were found in mean distances between anatomical landmarks except for the peroneus tertius tendon to the intermediate dorsal cutaneous nerve (P = .181; all others, P < .0001). In quantifying a scope space, the anteromedial and anterolateral portals had the largest margin of error at 0.82 cm and 1.04 cm, respectively. The saphenous nerve and vein were an average of 1.39 cm and 1.23 cm, respectively, from the anteromedial portal. The peroneus tertius tendon was an average of 0.23 cm from the intermediate dorsal cutaneous nerve. The tibialis anterior tendon was an average of 1.10 cm lateral to the medial gutter; the peroneus tertius tendon, 1.31 cm medial to the lateral gutter; and the Achilles tendon, 0.94 and 0.73 cm from the medial and lateral gutters, respectively. CONCLUSIONS: Among common ankle arthroscopic approaches, the anterolateral portal features the highest anatomic variability. These data support the standard protocol of beginning with the anteromedial portal to facilitate visualization of lateral-sided anatomy before anterolateral portal placement.

Recommendation of minimal distal tibial length for long axis coordinate system definitions.

Accurate anatomical coordinate systems for the foot and ankle are critical for interpreting their complex biomechanics. The tibial superior-inferior axis is crucial for analyzing joint kinematics, influencing bone motion analysis during gait using CT imaging and biplane fluoroscopy. However, the lack of consensus on how to define the tibial axis has led to variability in research, hindering generalizability. Even as advanced imaging techniques evolve, including biplane fluoroscopy and weightbearing CT, there exist limitations to imaging the entire foot together with the full length of the tibia. These limitations highlight the need to refine axis definitions. This study investigated various superior-inferior axes using multiple distal tibia lengths to determine the minimal field of view for representing the full tibia long-axis. Twenty human cadaver tibias were imaged and segmented to generate 3D bone models. Axes were calculated based on coordinate definitions that required user manual input, and a gold standard mean superior-inferior axis was calculated based on the population's principal component analysis axis. Four manually calculated superior-inferior tibial axes groups were established based on landmarks and geometric fittings. Statistical analysis revealed that geometrically fitting a cylinder 1.5 times the mediolateral tibial width, starting 5 cm above the tibial plafond, yielded the smallest angular deviation from the gold standard. From these findings, we recommend a minimum field of view that includes 1.5 times the mediolateral tibial width, starting 5 cm above the tibial plafond for tibial long-axis definitions. Implementing these findings will help improve foot and ankle research generalizability and impact clinical decisions.

Anatomic Variations of the Calcaneofibular Ligament.

BACKGROUND: The lateral ankle joint comprises the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL). The purpose of this study was to propose a classification of CFL morphology. METHODS: The material comprised 120 paired lower limbs from human cadavers (30 male, 30 female), mean age 62.3 years. The morphology was carefully assessed, and morphometric measurements were performed. RESULTS: A 4-part method for anatomic classification can be suggested based on our study. Type 1 (48.3%), the most common type, was characterized by a bandlike morphology. Type 2 (9.2%) was characterized by a Y-shaped band, and type 3 (21.7%) by a V-shaped band. Type 4 (20.8%) was characterized by the presence of 2 or 3 bands. Type 2 and 4 were divided into further subtypes based on origin footprint. CONCLUSION: The aim of our study was to describe variations of calcaneofibular ligament. Our proposed 4-part classification may be of value in clinical practice in future recognition of CFL injuries and in its repair or reconstruction. CLINICAL RELEVANCE: The anatomy of the CFL plays an important role in stability of the ankle. Greater recognition of anatomical variation may help improve reconstructive options for patients with chronic lateral ankle instability.

The calcaneofibular ligament groove at the inferior fibula, an ultrasonographic anatomical landmark.

PURPOSE: Calcaneofibular ligament (CFL) injuries are harder to diagnose than anterior talofibular ligament (ATFL) ones. This study aimed to clarify the fibular attachment of the CFL and verify the bony landmark for evaluating the CFL on ultrasonography. METHODS: Fifty-nine ankles were used in this anatomical study. To confirm the control function of the CFL, we performed passive movement manually using cadaveric ankles and observed the ankle positions where the CFLs were tense. Histological observation of CFL attachment of the fibula was performed using Masson's trichrome stain. The ATFL and CFL were removed, and the bone morphology of the CFL attachment and inferior fibular end was imaged using a stereomicroscope and a 3D scanner. Using ultrasonography, we evaluated the bone morphology of the fibular attachment of the CFL in short-axis images of 27 healthy adult ankles. RESULTS: The CFL was tensed according to ankle motions: supination, maximum dorsi flexion, maximum plantar flexion, and mild plantar flexion-external rotation. Below the CFL attachment of the fibula was a slight groove between the inferior tip and the obscure tubercle of the fibula. This groove was observed in 81.5% of cases using short-axis ultrasonography. CONCLUSION: The CFL was tensed in various ankle positions to control the movements of the talocrural and subtalar joints. There was a slight groove at the inferior end of the fibula where the CFL coursed downward. We called it the CFL groove and proposed that it could serve as a landmark for the short-axis image of ultrasonography.

A hybrid statistical morphometry free-form deformation approach to 3D personalized foot-ankle models.

Foot and ankle joint models are widely used in the biomechanics community for musculoskeletal and finite element analysis. However, personalizing a foot and ankle joint model is highly time-consuming in terms of medical image collection and data processing. This study aims to develop and evaluate a framework for constructing a comprehensive 3D foot model that integrates statistical shape modeling (SSM) with free-form deformation (FFD) of internal bones. The SSM component is derived from external foot surface scans (skin measurements) of 50 participants, utilizing principal component analysis (PCA) to capture the variance in foot shapes. The derived surface shapes from SSM then guide the FFD process to accurately reconstruct the internal bone structures. The workflow accuracy was established by comparing three model-generated foot models against corresponding skin and bone geometries manually segmented and not part of the original training set. We used the top ten principal components representing 85 % of the population variation to create the model. For prediction validation, the average Dice similarity coefficient, Hausdorff distance error, and root mean square error were 0.92 ± 0.01, 2.2 ± 0.19 mm, and 2.95 ± 0.23 mm for soft tissues, and 0.84 ± 0.03, 1.83 ± 0.1 mm, and 2.36 ± 0.12 mm for bones, respectively. This study presents an efficient approach for 3D personalized foot model reconstruction via SSM generation of the foot surface that informs bone reconstruction based on FFD. The proposed workflow is part of the open-source Musculoskeletal Atlas Project linked to OpenSim and makes it feasible to accurately generate foot models informed by population anatomy, and suitable for rigid body analysis and finite element simulation.

Who Are the Anatomic Outliers Undergoing Total Knee Arthroplasty? A Computed Tomography-Based Analysis of the Hip-Knee-Ankle Axis Across 1,352 Preoperative Computed Tomographies Using a Deep Learning and Computer Vision-Based Pipeline.

BACKGROUND: Dissatisfaction after total knee arthroplasty (TKA) ranges from 15 to 30%. While patient selection may be partially responsible, morphological and reconstructive challenges may be determinants. Preoperative computed tomography (CT) scans for TKA planning allow us to evaluate the hip-knee-ankle axis and establish a baseline phenotypic distribution across anatomic parameters. The purpose of this cross-sectional analysis was to establish the distributions of 27 parameters in a pre-TKA cohort and perform threshold analysis to identify anatomic outliers. METHODS: There were 1,352 pre-TKA CTs that were processed. A 2-step deep learning pipeline of classification and segmentation models identified landmark images and then generated contour representations. We used an open-source computer vision library to compute measurements for 27 anatomic metrics along the hip-knee axis. Normative distribution plots were established, and thresholds for the 15th percentile at both extremes were calculated. Metrics falling outside the central 70th percentile were considered outlier indices. A threshold analysis of outlier indices against the proportion of the cohort was performed. RESULTS: Significant variation exists in pre-TKA anatomy across 27 normally distributed metrics. Threshold analysis revealed a sigmoid function with a critical point at 9 outlier indices, representing 31.2% of subjects as anatomic outliers. Metrics with the greatest variation related to deformity (tibiofemoral angle, medial proximal tibial angle, lateral distal femoral angle), bony size (tibial width, anteroposterior femoral size, femoral head size, medial femoral condyle size), intraoperative landmarks (posterior tibial slope, transepicondylar and posterior condylar axes), and neglected rotational considerations (acetabular and femoral version, femoral torsion). CONCLUSIONS: In the largest non-industry database of pre-TKA CTs using a fully automated 3-stage deep learning and computer vision-based pipeline, marked anatomic variation exists. In the pursuit of understanding the dissatisfaction rate after TKA, acknowledging that 31% of patients represent anatomic outliers may help us better achieve anatomically personalized TKA, with or without adjunctive technology.

3D isotropic MRI of ankle: review of literature with comparison to 2D MRI.

The ankle joint has complex anatomy with different tissue structures and is commonly involved in traumatic injuries. Magnetic resonance imaging (MRI) is the primary imaging modality used to assess the soft tissue structures around the ankle joint including the ligaments, tendons, and articular cartilage. Two-dimensional (2D) fast spin echo/turbo spin echo (FSE/TSE) sequences are routinely used for ankle joint imaging. While the 2D sequences provide a good signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) with high spatial resolution, there are some limitations to their use owing to the thick slices, interslice gaps leading to partial volume effects, limited fluid contrast, and the need to acquire separate images in different orthogonal planes. The 3D MR imaging can overcome these limitations and recent advances have led to technical improvements that enable its widespread clinical use in acceptable time periods. The volume imaging renders the advantage of reconstructing into thin continuous slices with isotropic voxels enabling multiplanar reconstructions that helps in visualizing complex anatomy of the structure of interest throughout their course with improved sharpness, definition of anatomic variants, and fluid conspicuity of lesions and injuries. Recent advances have also reduced the acquisition time of the 3D datasets making it more efficient than 2D sequences. This article reviews the recent technical developments in the domain 3D MRI, compares imaging with 3D versus 2D sequences, and demonstrates the use-case scenarios with interesting cases, and benefits of 3D MRI in evaluating various ankle joint components and their lesions.

The use of deep learning enables high diagnostic accuracy in detecting syndesmotic instability on weight-bearing CT scanning.

PURPOSE: Delayed diagnosis of syndesmosis instability can lead to significant morbidity and accelerated arthritic change in the ankle joint. Weight-bearing computed tomography (WBCT) has shown promising potential for early and reliable detection of isolated syndesmotic instability using 3D volumetric measurements. While these measurements have been reported to be highly accurate, they are also experience-dependent, time-consuming, and need a particular 3D measurement software tool that leads the clinicians to still show more interest in the conventional diagnostic methods for syndesmotic instability. The purpose of this study was to increase accuracy, accelerate analysis time, and reduce interobserver bias by automating 3D volume assessment of syndesmosis anatomy using WBCT scans. METHODS: A retrospective study was conducted using previously collected WBCT scans of patients with unilateral syndesmotic instability. One-hundred and forty-four bilateral ankle WBCT scans were evaluated (48 unstable, 96 control). We developed three deep learning models for analyzing WBCT scans to recognize syndesmosis instability. These three models included two state-of-the-art models (Model 1-3D Convolutional Neural Network [CNN], and Model 2-CNN with long short-term memory [LSTM]), and a new model (Model 3-differential CNN LSTM) that we introduced in this study. RESULTS: Model 1 failed to analyze the WBCT scans (F1 score = 0). Model 2 only misclassified two cases (F1 score = 0.80). Model 3 outperformed Model 2 and achieved a nearly perfect performance, misclassifying only one case (F1 score = 0.91) in the control group as unstable while being faster than Model 2. CONCLUSIONS: In this study, a deep learning model for 3D WBCT syndesmosis assessment was developed that achieved very high accuracy and accelerated analytics. This deep learning model shows promise for use by clinicians to improve diagnostic accuracy, reduce measurement bias, and save both time and expenditure for the healthcare system. LEVEL OF EVIDENCE: II.

The increased anterior talofibular ligament-posterior talofibular ligament angle on MRI may help evaluate chronic ankle instability.

PURPOSE: This study intended to compare the difference between the anterior talofibular ligament (ATFL) and posterior talofibular ligament (PTFL) angle with chronic ankle instability (CAI) patients and healthy volunteers, and to confirm whether using the ATFL-PTFL angle could be a reliable assessment method for CAI, so as to improve the accuracy and specificity of clinical diagnosis. METHODS: This retrospective study included 240 participants: 120 CAI patients and 120 healthy volunteers between 2015 and 2021. The ATFL-PTFL angle of the ankle region was gaged in the cross-sectional supine position on MRI between two groups. After participants undergoing a comprehensive MRI scanning, ATFL-PTFL angles were regarded as the main indicator of patients with the injured ATFLs and healthy volunteers to compare, and were measured by an experienced musculoskeletal radiologist. Moreover, other qualitative and quantitative indicators referring to anatomical and morphological characteristics of the AFTL were included in this study with MRI, such as the length, width, thickness, shape, continuity, and signal intensity of the ATFL, which can be used as secondary indicators. RESULTS: In the CAI group, the ATFL-PTFL angle was 90.8° ± 5.7°, which was significantly different from the non-CAI group where the ATFL-PTFL angle for 80.0° ± 3.7° (p < 0.001). As for the ATFL-MRI characteristics, the length (p = 0.003), width (p < 0.001), and thickness (p < 0.001) in the CAI group were also significantly different from the non-CAI group. Over 90% of the cases, patients of the CAI group had injured ATFL with an irregular shape, non-continuous, and high or mixed signal intensity. CONCLUSION: Compared with healthy people, the ATFL-PTFL angle of most CAI patients is larger, which can be used as a secondary index to diagnose CAI. However, the MRI characteristic changes of ATFL may not relate to the increased ATFL-PTFL angle.

Anatomical variations of the calcaneofibular ligament in human foetuses.

Ligaments anatomy often show a huge anatomy variations between species and individuals. For example calcaneofibular ligaments (CFL) characterize the great variability of morphological shape or presence of additional bands. The aim of this study was to propose first anatomical classification of CFL concerning on human fetuses. We investigated thirty spontaneously-aborted human fetuses aged 18-38 weeks of gestation at death. Sixty lower limbs (30 left and 30 right) fixed in 10% formalin solution were examined. The morphological variability of CFL was assessed. Four types of CFL morphology were observed. Type I was characterized by a band shape. This was the most common type, occurring in 53% of all cases. Based on our study we are proposing a classification based on four morphological types of CFL. Types 2 and 4 are further divided into subtypes. Present classification may be useful to better understand the anatomical development of ankle joint.

Advantages of ultrasound identification of the distal insertion of the calcaneofibular ligament during ligament reconstructions.

INTRODUCTION: In lateral ankle instability, anatomical ligament reconstructions are generally performed using arthroscopy. The ligament graft is passed through the talar, fibular and calcaneal tunnels, reconstructing the anterior talofibular and calcaneofibular (CFL) bundles. However, the calcaneal insertion of the CFL needs to be performed in an extra-articular fashion, and cannot be carried out under arthroscopy, thus requiring specific anatomical landmarks. For obtaining these landmarks, methods based on radiography or surface anatomy have already been described but can only offer an approximate identification of the actual CFL anatomical insertion point. In contrast, an ultrasound technique allows direct visualization of the insertion point and of the sural nerve that may be injured during surgery. Our study aimed to assess the reliability and accuracy of ultrasound visualization when performing calcaneal insertion of the CFL with specific monitoring of the sural nerve. MATERIALS AND METHODS: Our anatomical study was carried out on 15 ankles available from a body donation program. Ultrasound identification of the sural nerve was obtained first with injection of dye. A needle was positioned at the level of the calcaneal insertion of the CFL. After dissection, in all the ankles, the dye was in contact with the sural nerve and the needle was located in the calcaneal insertion area of the CFL. The mean distance between the sural nerve and the needle was 4.8 mm (range 3-7 mm). DISCUSSION AND CONCLUSION: A pre- or intra-operative ultrasound technique is a simple and reliable means for obtaining anatomical landmarks when drilling the calcaneal tunnel for ligament reconstruction of the lateral plane of the ankle. This tunnel should preferably be drilled obliquely from the heel towards the subtalar joint (1 h-3 h direction on an ultrasound cross section), which preserves a maximum distance from the sural nerve for safety purposes, while allowing an accurate anatomical positioning of the osseous tunnel.

Variation in the anterior talofibular ligament and the impact of sex, height, weight, and age.

The anterior talofibular ligament (ATFL) is one of the lateral ankle ligaments stabilizing the ankle joint, primarily involved with restricting foot supination. There has been limited research on precise ATFL anatomy and variations, and several studies have conflicting results. The objective of this study was to determine if a correlation exists between ATFL variation and sex, height, weight, and age. In this study, 15 male ankles and 24 female ankles were dissected free of overlying structures to reveal the ATFL, which was classified based on the number of fascicles. Nine of the ligaments had one fascicle, 13 had two incompletely separated fascicles, 12 had two completely separated fascicles, and three had three fascicles. Two ankles had no ATFL. Ligament length and width were measured using the program ImageJ; average length was 19.2 mm and average width was 9.59 mm. Male ligaments were longer and wider than female ligaments. A multivariate regression model was used to assess the influence of sex, height, weight, age, ligament length, and ligament width in predicting ligament variant type; these factors were determined to have no influence. This study found a large amount of ATFL variability, but no correlation between height, weight, age, ligament length, ligament width and ATFL variation. Male ligaments were longer and wider than female ligaments.

Anatomy of the Ankle and Subtalar Joint Ligaments: What We Do Not Know About It?

Understanding of the ankle and subtalar joint ligaments is essential to recognize and manage foot and ankle disorders. The stability of both joints relies on the integrity of its ligaments. The ankle joint is stabilized by the lateral and medial ligamentous complexes while the subtalar joint is stabilized by its extrinsic and intrinsic ligaments. Most injuries to these ligaments are linked with ankle sprains. Inversion or eversion mechanics affect the ligamentous complexes. A profound knowledge of the ligament's anatomy allows orthopedic surgeons to further understand anatomic or nonanatomic reconstructions.

Ankle Joint Microinstability: You Might Have Never Seen It but It Has Definitely Seen You.

Ankle microinstability results from the superior fascicle of anterior talofibular ligament (ATFL) injury and is a potential cause of chronic pain and disability after an ankle sprain. Ankle microinstability is usually asymptomatic. When symptoms appear, patients describe a subjective ankle instability feeling, recurrent symptomatic ankle sprains, anterolateral pain, or a combination of them. A subtle anterior drawer test can usually be observed, with no talar tilt. Ankle microinstability should be initially treated conservatively. If this fails, and because superior fascicle of ATFL is an intra-articular ligament, an arthroscopic procedure is recommended to address.

Complejo ligamentoso lateral de la articulación talocrural (tobillo): biometría y patrones de división / Lateral ankle ligamentous complex: biometrics and division patterns

El complejo ligamentoso lateral de la articulación talocrural o «tobillo» (CLT) contempla básicamente tres estructuras denominadas como ligamento talofibular anterior (LTFA), ligamento calcaneofibular (LCF) y ligamento talofibular posterior (LTFP). En los últimos artículos publicados en relación con la morfología del CLT, se clasifica al LTFA en tres tipos, basada en el número de bandas o fascículos. Esta variabilidad morfológica plantea nuevos desafíos de estudios anatómicos en la biomecánica y estabilidad de la región talocrural. El objetivo de este estudio fue profundizar la anatomía de este complejo, en base a disecciones por capa que nos permitan visualizar las relaciones existentes entre estos ligamentos y estructuras aledañas. Se utilizaron 10 piezas congeladas pertenecientes al Departamento de Anatomía y Medicina Legal de la Facultad de Medicina de la Universidad de Chile, cuyos ligamentos fueron localizados y medidos en ancho y longitud. Para el LTFA se observó un patrón único en 5 muestras, bifurcado en 4, mientras que en un caso se visualizó un patrón trifurcado. El conocimiento del complejo ligamentoso lateral de tobillo, así como de su dirección, biometría y bandas o fascículos son un importante aporte para la imagenología, rehabilitación, clínica y cirugías que aborden esta región.

SUMMARY: The lateral ankle complex (LAC) basically includes three structures called anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL). In recent works published in relation to the morphology of LAC, ATFL is classified into three types, based on the number of bands or fascicles. This morphological modification poses new challenges for anatomical studies in biomechanics and ankle stability. The objective of this is to deepen in greater detail the anatomy of this complex, based on dissections by layer that allow us to study the existing relationships between these ligaments and surrounding structures. 10 frozen pieces belonging to the Department of Anatomy and Legal Medicine of the Faculty of Medicine of the University of Chile were used; whose ligaments were located and measured in width and length. For ATFL, a single pattern was found in 5 samples, bifurcated in 4, while a trifurcated pattern was seen in one case. Knowledge of the lateral ligamentous complex of the ankle, as well as its direction, biometry and bands or fascicles, are an important contribution to imaging, rehabilitation, clinics and surgeries that address this region.