Anatomical review of the lateral collateral ligaments of the ankle: a cadaveric study

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.

Investigation into the effect of deltoid ligament injury on rotational ankle instability using a three-dimensional ankle finite element model

Background

Injury to the lateral collateral ligament of the ankle may cause ankle instability and, when combined with deltoid ligament (DL) injury, may lead to a more complex situation known as rotational ankle instability (RAI). It is unclear how DL rupture interferes with the mechanical function of an ankle joint with RAI.

Purpose

To study the influence of DL injury on the biomechanical function of the ankle joint.

Methods

A comprehensive finite element model of an ankle joint, incorporating detailed ligaments, was developed from MRI scans of an adult female. A range of ligament injury scenarios were simulated in the ankle joint model, which was then subjected to a static standing load of 300 N and a 1.5 Nm internal and external rotation torque. The analysis focused on comparing the distribution and peak values of von Mises stress in the articular cartilages of both the tibia and talus and measuring the talus rotation angle and contact area of the talocrural joint.

Results

The dimensions and location of insertion points of ligaments in the finite element ankle model were adopted from previous anatomical research and dissection studies. The anterior drawer distance in the finite element model was within 6.5% of the anatomical range, and the talus tilt angle was within 3% of anatomical results. During static standing, a combined rupture of the anterior talofibular ligament (ATFL) and anterior tibiotalar ligament (ATTL) generates new stress concentrations on the talus cartilage, which markedly increases the joint contact area and stress on the cartilage. During static standing with external rotation, the anterior talofibular ligament and anterior tibiotalar ligament ruptured the ankle's rotational angle by 21.8% compared to an intact joint. In contrast, static standing with internal rotation led to a similar increase in stress and a nearly 2.5 times increase in the talus rotational angle.

Conclusion

Injury to the DL altered the stress distribution in the tibiotalar joint and increased the talus rotation angle when subjected to a rotational torque, which may increase the risk of RAI. When treating RAI, it is essential to address not only multi-band DL injuries but also single-band deep DL injuries, especially those affecting the ATTL.

Clinical Relevance and Function of Anterior Talofibular Ligament Superior and Inferior Fascicles: A Robotic Study

BACKGROUND

Ankle lateral ligament sprains are common injuries in sports, and some may result in persistent ankle pain and a feeling of instability without clinical evidence of instability. The anterior talofibular ligament (ATFL) has 2 distinct fascicles, and recent publications have suggested that injury isolated to the superior fascicle might be the cause of these chronic symptoms. This study aimed to identify the biomechanical properties conferred by the fascicles in stabilizing the ankle in order to understand potential clinical problems that may follow when the fascicles are injured.

PURPOSE/HYPOTHESIS

The aim of this study was to determine the contribution of superior and inferior fascicles of the ATFL in restraining anteroposterior tibiotalar resistance, internal external tibial rotation resistance, and inversion eversion talar rotation resistance. It was hypothesized that an isolated injury of the ATFL superior fascicle would have a measurable effect on ankle stability and that the superior and inferior fascicles would restrain different motions of the ankle.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A robotic system with 6 degrees of freedom was used to test ankle instability in 10 cadavers. Serial sectioning following the most common injury pattern (from superior to inferior fascicles) was performed on the ATFL while the robot ensured reproducible movement through a physiological range of dorsiflexion and plantarflexion.

RESULTS

Sectioning of only the ATFL superior fascicle had a significant and measurable effect on ankle stability, resulting in increased internal rotation and anterior translation of the talus, especially in plantarflexion. Sectioning of the entire ATFL resulted in significantly decreased resistance in anterior translation, internal rotation, and inversion of the talus.

CONCLUSION

Rupture of only the superior fascicle of the ATFL may lead to minor instability or microinstability of the ankle joint, without objective clinical findings of gross clinical laxity.

CLINICAL RELEVANCE

Some patients develop chronic symptoms after an ankle sprain without overt signs of instability. This may be explained by an isolated injury to the ATFL superior fascicle, and diagnosis may require careful clinical evaluation and magnetic resonance imaging examination looking at the individual fascicles. It is possible that such patients may benefit from lateral ligament repair despite having no gross clinical instability.

Computer-Aided Ankle Ligament Injury Diagnosis from Magnetic Resonance Images Using Machine Learning Techniques

Ankle injuries caused by the Anterior Talofibular Ligament (ATFL) are the most common type of injury. Thus, finding new ways to analyze these injuries through novel technologies is critical for assisting medical diagnosis and, as a result, reducing the subjectivity of this process. As a result, the purpose of this study is to compare the ability of specialists to diagnose lateral tibial tuberosity advancement (LTTA) injury using computer vision analysis on magnetic resonance imaging (MRI). The experiments were carried out on a database obtained from the Vue PACS-Carestream software, which contained 132 images of ATFL and normal (healthy) ankles. Because there were only a few images, image augmentation techniques was used to increase the number of images in the database. Following that, various feature extraction algorithms (GLCM, LBP, and HU invariant moments) and classifiers such as Multi-Layer Perceptron (MLP), Support Vector Machine (SVM), k-Nearest Neighbors (kNN), and Random Forest (RF) were used. Based on the results from this analysis, for cases that lack clear morphologies, the method delivers a hit rate of 85.03% with an increase of 22% over the human expert-based analysis.

The anterior talofibular ligament: A thin-slice three-dimensional magnetic resonance imaging study

PURPOSE

The aim of this study was to provide an accurate and improved understanding of anterior talofibular ligament (ATFL) anatomy, and to determine the exact positioning and diameter of the bony tunnel during ATFL repair and/or reconstruction surgery.

METHOD

A total of 58 healthy asymptomatic volunteers were examined, wherein 38 underwent bilateral ankle 3D MRI, and 20 underwent unilateral ankle 3D MRI (10 left and 10 right ankles). Data from a total of 96 MRI datasets were collected. The MRI data from these cases were exported into Mimics to enable reconstruction of 3D ATFL models. The resulting image quality was evaluated using a 5-point subjective scoring system. In addition, the length, width, thickness, and positioning of each ATFL and the area of the ATFL footprints were identified within the 3D model using Mimics and SolidWorks.

RESULTS

The image quality score was 4.48 ± 0.50. The ATFL formed one (65.6%), two (31.3%), or three (3.1%) bundles forms. The footprint area was 31.25 ± 6.29 mm² on the fibular side, and 17.48 ± 4.49 mm² on the talar side.

CONCLUSION

Thin-slice 3D MRI aids in the reconstruction of the 3D ATFL model, and it provides reference for the accurate anatomy of the area and location of the ATFL. This technology will facilitate diagnosis of ATFL injuries and choice of surgical methods.

LEVEL OF EVIDENCE

level IV.

Major change in morphology of the talofibular ligaments during fetal development and growth

BACKGROUND AND PURPOSE

Ankle sprain is often attributed to damage of the anterior and posterior talofibular ligaments (ATFL, PTFL). We compared the morphology of these ligaments in fetuses of different gestational ages (GAs) with the horizontal configuration in adults.

MATERIALS AND METHODS

Histological sections of unilateral ankles were examined in 22 fetuses, 10 at GA of 9-12 weeks and 12 at GA of 26-39 weeks.

RESULTS

At a GA of 9 to 10 weeks, the ATFL and PTFL consisted of horizontally running straight fibers. The initial ATFL appeared as a thickening of the capsule of the talocrural joint, although the initial PTFL was distant from this joint. Until a GA of 12 weeks, the talus and fibula were separated by an expanding joint cavity. Thus, the initial horizontal ligaments were "pulled" in a distal direction. The distal parts of the ligaments consisted of thin collagenous fibers that had an irregular array, whereas the short proximal parts had thick fibers and a horizontal array. In near-term fetuses, the ligaments contained no horizontal fibers. The ATFL had a wavy course around the thick synovial fold, and was exposed to the joint cavity along the entire course; the distal part was thinner than the proximal part. The PTFL was bulky and consisted of fibers with an irregular array. Therefore, the morphology in a near-term fetus was quite different from that in adults.

CONCLUSION

The horizontal and straight composite ankle fibers in adults apparently result from postnatal reconstruction, depending on mechanical demand.

The L-shaped tunnel technique showed favourable outcomes similar to those of the Y-graft technique in anatomic lateral ankle ligament reconstruction

PURPOSE

To compare the mid- to long-term clinical and radiological outcomes of the confluent L-shaped tunnel technique with the Y-graft technique for anatomic lateral ankle ligament reconstruction.

METHODS

This retrospective study involved 41 patients who underwent lateral ankle ligament reconstruction between 2013 and 2018. Based on the tunnel direction and tendon fixation method at the fibula side, patients were divided into two groups, with 17 patients in the L-shaped tunnel group and 24 patients in the Y-graft group. The American Orthopaedic Foot and Ankle Society (AOFAS) score, visual analogue scale (VAS) pain score, Tegner score, and Karlsson score were evaluated and compared preoperatively and at follow-up. Anterior talar translation and talar tilt at stress radiographs, postoperative sprain recurrence, range of motion (ROM) restriction, sensory disturbance, etc., were also collected and compared.

RESULTS

The mean follow-up times were 72 and 42 months for the L-shaped group and Y-graft group, respectively. The median VAS pain score, Tegner score, AOFAS score, Karlsson score significantly improved from a preoperative level in both groups (all with p < 0.01). No significant difference was found between the two groups regarding the changes from preoperatively to postoperatively except for the VAS pain score reduction (1.58 ± 1.58 in the L-shaped group vs. 2.53 ± 1.29 in the Y-graft group, p = 0.035). The incidence of flexion-extension ROM restriction (≥ 5°) was significantly higher in the Y-graft group (41.2%) than in the L-shaped group (12.5%) (p = 0.035).

CONCLUSIONS

Both the confluent L-shaped tunnel technique and the Y-graft technique significantly improved symptoms, ankle function, and radiographic outcomes in patients with chronic lateral ankle instability (CLAI) at mid- to long-term follow-up. The confluent L-shaped tunnel technique resulted in lower rates of flexion-extension ROM restriction, while the Y-graft technique showed better VAS pain reduction. This result could provide further evidence for the surgical treatment of CLAI.

LEVEL OF EVIDENCE

III.

Anatomic Measurement and Variability Analysis of the Anterior Talofibular Ligament and Calcaneofibular Ligament of the Ankle

Background:

The anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) contribute greatly to the overall stability of the ankle joint; however, ATFL and combined ATFL-CFL sprains are common. Anatomic reconstruction of the lateral collateral ligament with grafts has been proposed for patients with poor tissue quality or inadequate local tissue. Anatomic reconstruction of the lateral ankle ligaments requires a good understanding of their anatomic location.

Purpose:

To describe the anatomy of the ATFL and CFL ligaments quantitatively and qualitatively and explore the relationship of some morphological parameters.

Study Design:

Descriptive laboratory study.

Methods:

A total of 66 adult ankle specimens were analyzed for ATFL band type, origin, length, width, thickness, and angle between the ATFL and CFL, and 73 adult ankle specimens were used for measuring the origin of the CFL. The coefficient of variation was used to describe and compare the respective variability of angle, length, width, and thickness. The origin of the ATFL was labeled as point A, and the leading edge of the CFL intersection with the articular surface of the calcaneus was considered point B.

Results:

The ATFL had a variable number of bands. A high degree of variability (coefficient of variation >0.2) was seen for most morphological measurements of the ATFL. In addition, the length of distance AB also varied. The CFL originated at the tip of the fibula in only 9% of specimens. It was found more commonly at the anterior border of the lateral malleolus (4.94 ± 1.70 mm from the tip). The angle between the ATFL and CFL was consistent at 100° to 105º.

Conclusion:

A fair amount of variability of ATFL length, width, and thickness were found in our study, with less variability in the ATFL-CFL angle. Most CFLs attached anterior to the tip of the fibula.

Clinical Relevance:

Providing relevant anatomic data of ATFL and CFL is important in ensuring proper surgical treatment of ankle joint injuries.

Morphometric relationships between dimensions the anterior talofibular ligament and calcaneofibular ligament in routine magnetic resonance imaging

Purpose

This study aimed to test the hypothesis that routine MRI ankle can be used to evaluate dimensions and correlations between dimensions of single and double fascicular variants of the ATFL and the CFL.

Methods

We reviewed ankle MRIs for 251 patients. Differences between the length, thickness, width, and length of the bony attachments were evaluated twice. P < .05 was considered as significant.

Results

For the ATFL, we observed a negative correlation between thickness and width, with a positive correlation between thickness and length (p < 0.001). The average values for the ATFL were thickness, 2.2 ± 0.05 mm; length, 21.5 ± 0.5 mm; and width, 7.6 ± 0.6 mm. The average values for the CFL were thickness, 2.1 ± 0.04 mm; length, 27.5 ± 0.5 mm; and width, 5.6 ± 0.3 mm. A negative correlation was found between length and width for the CFL (p < 0.001).

Conclusions

Routine MRI showed that most dimensions of the ATFL and CFL correlate with each other, which should be considered when planning new reconstruction techniques and developing a virtual biomechanical model of the human foot.

Level of evidence

III

Number of fiber bundles in the fetal anterior talofibular ligament

PURPOSE

For the anterior talofibular ligament (ATFL), a three-fiber bundle has recently been suggested to be weaker than a single or double fiber bundle in terms of ankle plantarflexion and inversion braking function. However, the studies leading to those results all used elderly specimens. Whether the difference in fiber bundles is a congenital or an acquired morphology is important when considering methods to prevent ATFL damage. The purpose of this study was to classify the number of fiber bundles in the ATFL of fetuses.

METHODS

This study was conducted using 30 legs from 15 Japanese fetuses (mean weight, 1764.6 ± 616.9 g; mean crown-rump length, 283.5 ± 38.7 mm; 8 males, 7 females. The ATFL was then classified by the number of fiber bundles: Type I, one fiber bundle; Type II, two fiber bundles; and Type III, three fiber bundles.

RESULTS

Ligament type was Type I in 5 legs (16.7%), Type II in 21 legs (70%), and Type III in 4 legs (13.3%).

CONCLUSION

The present results suggest that the three fiber bundles of the structure of the ATFL may be an innate structure.

Hamstring autograft and anatomical footprint evaluation for anterior talofibular ligament reconstruction: Cadaveric study

PURPOSE

The aim of the study was to evaluate whether or not there was any incompatibility between two-strand hamstring tendons taken from the same knee and the ATFL and it was the determination of suitable footprint points in the fibula and talus for anatomical ATFL reconstruction.

METHODS

16 fresh frozen cadaver specimens were dissected to gracilis and semitendinosus tendons and the anterior talofibular ligament. The origins, insertions, distances from osseous landmarks of fibular talus of ATFL were determined. The diameters of gracilis, semitendinosus and ATFL were calculated. There was a moderate correlation between body height and the distance between the distal of inferior lateral malleolus and the fibular adhesion site of ATFL (r: 36.5 p: 0.036). There was a weak correlation between body height and the distance between the apex of the lateral talar process and the talus adhesion site of ATFL in a single bundle (r: 28.4 p: 0.002). There was no correlation between the distance from proximal and distal adhesion side of ATFL and body height in the double bundle (p: 0.241).

RESULTS

There was no significant relationship between ATFL diameter and gracilis, semitendinosus and both hamstring in women. A significant relationship at 80.5% was determined between the ATFL and the gracilis diameter in man. A significant relationship at 92.6% was determined between the ATFL and the semitendinosus diameter in man.

CONCLUSION

It was determined that there is not compatibility between the gracilis tendons, the semitendinosus tendon and ATFL in women. It should be supported by biomechanical and clinical studies whether this incompatibility has a clinical effect or not.

The double fascicular variations of the anterior talofibular ligament and the calcaneofibular ligament correlate with interconnections between lateral ankle structures revealed on magnetic resonance imaging

The anterior talofibular ligament and the calcaneofibular ligament are the most commonly injured ankle ligaments. This study aimed to investigate if the double fascicular anterior talofibular ligament and the calcaneofibular ligament are associated with the presence of interconnections between those two ligaments and connections with non-ligamentous structures. A retrospective re-evaluation of 198 magnetic resonance imaging examinations of the ankle joint was conducted. The correlation between the double fascicular anterior talofibular ligament and calcaneofibular ligament and connections with the superior peroneal retinaculum, the peroneal tendon sheath, the tibiofibular ligaments, and the inferior extensor retinaculum was studied. The relationships between the anterior talofibular ligament's and the calcaneofibular ligament's diameters with the presence of connections were investigated. Most of the connections were visible in a group of double fascicular ligaments. Most often, one was between the anterior talofibular ligament and calcaneofibular ligament (74.7%). Statistically significant differences between groups of single and double fascicular ligaments were visible in groups of connections between the anterior talofibular ligament and the peroneal tendon sheath (p < 0.001) as well as the calcaneofibular ligament and the posterior tibiofibular ligament (p < 0.05), superior peroneal retinaculum (p < 0.001), and peroneal tendon sheath (p < 0.001). Differences between the thickness of the anterior talofibular ligament and the calcaneofibular ligament (p < 0.001), the diameter of the fibular insertion of the anterior talofibular ligament (p < 0.001), the diameter of calcaneal attachment of the calcaneofibular ligament (p < 0.05), and tibiocalcaneal angle (p < 0.01) were statistically significant. The presence of the double fascicular anterior talofibular ligament and the calcaneofibular ligament fascicles correlate with connections to adjacent structures.

Morphological characteristics of the lateral ankle ligament complex

PURPOSE

The relevance of each ligament comprising the lateral ankle ligament complex, including the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL), has not been sufficiently elucidated; therefore, we aimed to clarify the morphological characteristics and relevance of these ligaments.

METHODS

Total 152 legs from 152 Japanese cadavers were investigated. The lengths and widths of the ATFL, CFL, and PTFL were measured using a caliper. The ATFL was classified according to the number of fiber bundles (Types I, II, and III corresponded to one, two, and three fiber bundles, respectively), and the lengths and widths of the three ligaments were compared between the Type groups. In addition, the ratio of each ligament's length and width to the tibial length was calculated, and the correlation of the ratio of ligament length and width between the ATFL, CFL, and PTFL was examined about 34 legs.

RESULTS

The ATFL, CFL, and PTFL were found to connect at the anterior/inferior tip of the lateral malleolus each other. The Type II group of the ATFL was most common (54.6%) in our investigated specimens. However, there were no significant inter-group differences in the lengths and widths of the CFL and PTFL.

CONCLUSIONS

This study demonstrates that the lateral ankle ligaments may stabilize the ankle joint through interconnections.

The lateral ankle ligaments are interconnected: the medial connecting fibres between the anterior talofibular, calcaneofibular and posterior talofibular ligaments

PURPOSE

A deep knowledge of lateral ankle ligaments is necessary to understand its function, pathophysiology and treatment options. The ankle lateral collateral ligament is formed by the anterior talofibular ligament (ATFL), the calcaneofibular (CFL) and the posterior talofibular ligament (PTFL). Although previous studies have reported connections between these ligaments on its lateral side, no studies have specifically assessed connections on the medial side. The aim of this study was to assess the morphology and consistency of the medial connections between the components of the lateral collateral ligament complex of the ankle.

METHODS

Forty fresh-frozen ankle specimens were dissected to look for connections between the three lateral ankle ligaments. After visualization of the lateral ligaments was achieved, the fibula was amputated and ligament insertions were released at the talar and calcaneal insertion points. Observation of the connections and video analysis of the dynamic relationships of ligament connections were performed.

RESULTS

Connections were found in all cases between the ATFL and PTFL, the ATFL and CFL, and the CFL and PTFL. Connections between ATFL and PTFL were not homogeneous. Although connections between the ATFLif and PTFL were noted in all cases (40), only 17 ankles (42.5%) had connections between the ATFLsf and PTFL. The amount of fibres of connection was also variable.

CONCLUSION

Connections between the three components of the lateral collateral ligament of the ankle may be observed from the medial aspect of the ankle, and this may have important implications for arthroscopic lateral ligament repair.

Increased ATFL-PTFL angle could be an indirect MRI sign in diagnosis of chronic ATFL injury

PURPOSE

Magnetic resonance imaging (MRI) has relatively low accuracy in diagnosing chronic anterior talofibular ligament (ATFL) injury. This study's purpose was to evaluate the angle between the ATFL and posterior talofibular ligament (PTFL) as a new indirect MRI sign of chronic ATFL injury in patients with mechanical ankle instability (MAI).

METHODS

This study included 200 participants: 105 patients with MAI and 95 patients seen at our institution for reasons unrelated to ankle instability. MR images of all 200 participants were reviewed. The ATFL-PTFL angle in the axial plane was measured and compared between groups. Receiver operating characteristic curves (ROC) were used to analyze ATFL-PTFL angles in participants with and without ATFL injury. The sensitivity and specificity of this method for diagnosing ATFL injury were calculated.

RESULTS

The mean ATFL-PTFL angle was significantly larger among MAI patients than among control patients (81.5° ± 9.8° vs 75.2° ± 8.9°, respectively; P < 0.01). The area under the ROC was 0.789 (P < 0.01). The optimal cut-off point for diagnosing ATFL injury on the basis of the ATFL-PTFL angle was 79.0° (sensitivity 0.89, specificity 0.67).

CONCLUSION

The ATFL-PTFL angle was significantly larger among MAI patients than among those without MAI. Increased ATFL-PTFL angle offers a new indirect MRI sign for diagnosing chronic ATFL injury. The ATFL-PTFL angle can be used not only to improve the accuracy of diagnosis of chronic ATFL injury, but also to evaluate the restoration of normal ankle joint geometry after lateral ligament reconstruction.

LEVEL OF EVIDENCE

III.

Independent Attachment of Lateral Ankle Ligaments: Anterior Talofibular and Calcaneofibular Ligaments - A Cadaveric Study

Anatomic knowledge of lateral ligaments around the lateral malleolus is important for repair or reconstruction of ankle instability. The detailed structure of the connective fibers between the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) is unknown. To clarify the anatomic structure of ATFL and CFL and the connective fiber between the 2 ligaments, the lateral ligament was dissected in 60 ankles of formalin-fixed cadavers, and the distance was measured between bony landmarks and fibular attachment of ATFL and CFL using a digital caliper. All ankles had connective fibers between ATFL and CFL. The structure of connective fibers consisted of a thin fiber above the surface layer of ATFL and CFL; it comprised thin fibrils of the surface layer covering the lower part of ATFL and the front part of CFL. Both ATFL and CFL were independent fibers, and both attachments of the fibula were isolated. Single bands of ATFL were noted in 14 of 60 (23.3%) ankles, double bands that divided the superior and inferior bands were observed in 42 of 60 (70.0%) ankles, and multiple bands were observed in 4 of 60 (6.7%) ankles. A cord-like and a flat and fanning type of CFL was noted in 22 (36.7%) and 38 (63.3%) of the 60 ankles, respectively. Distances between ATFL/CFL and articular and inferior tips of the fibula were 4.3 ± 1.1 mm/7.6 ± 1.6 mm and 14.3 ± 1.9 mm/7.4 ± 1.7 mm, respectively (mean ± standard deviation). The results of this study suggest that knowledge of more anatomic structures of ATFL, CFL, and connective fiber will be beneficial for surgeons in the repair or reconstruction of the lateral ligament of the ankle.

Relationships between differences in the number of fiber bundles of the anterior talofibular ligament and differences in the angle of the calcaneofibular ligament and their effects on ankle-braking function

PURPOSE

The aim was to clarify the relationships between differences in the number of fiber bundles of the anterior talofibular ligament (ATFL) and differences in the angle of the calcaneofibular ligament (CFL) with respect to the long axis of the fibula and their effects on ankle braking function.

METHODS

The study sample included 110 Japanese cadavers. ATFLs were categorized as: Type I with one fiber bundle; Type II with two fiber bundles with incomplete separation and complete separation; and Type III with three fiber bundles. The CFLs were categorized according to the angles of the CFLs with respect to the long axis of the fibula and the number of fiber bundles. Six categories were established: CFL10° (angle of the CFL with respect to the long axis of the fibula from 10° to 19°); CFL20° (range 20°-29°); CFL30° (range 30°-39°); CFL40° (range 40°-49°); CFL50° (range 50°-59°); and CFL2 (CFLs with two crossing fiber bundles).

RESULTS

ATFL was Type I in 34 legs (31%), Type II in 66 legs (60%), and Type III in 10 legs (9%). Five CFL categories were identified: CFL10° in 4 feet (3.7%); CFL20° in 23 feet (20.9%); CFL30° in 34 feet (30.9%); CFL40° in 33 feet (30%); CFL50° in 15 feet (13.6%); and CFL2 in one foot (0.9%). Type III contained mainly CFL40° and CFL50° (7 of 10 feet).

CONCLUSIONS

ATFL and CFL appear to cooperate in the ankle joint braking function.

Morphological evaluation of the calcaneofibular ligament in different ankle positions using a three-dimensional MRI sequence

PURPOSE

Evaluating images of the lateral ligament of the ankle is not easy, and evaluation of the calcaneofibular ligament (CFL) in particular is difficult. We prospectively conducted morphological measurements of the CFL in different ankle positions and obtain basic data for use in functional assessment of the CFL, diagnosis of CFL injury, and determination of treatment effects.

METHODS

The subjects were ten healthy volunteers (ten ankles) with a mean age of 27.8 years and no history of ankle disease. Imaging was done using a 3-T magnetic resonance imaging (MRI) machine and fast imaging employing steady-state acquisition cycled phases (FIESTA-C), a three-dimensional (3D) sequence, with the ankle in a neutral position, maximum dorsiflexion, and maximum plantar flexion. 3D images of the CFL, peroneal muscle tendons, fibula, and calcaneus were prepared at a workstation, and morphological measurements of the CFL were made.

RESULTS

In all positions, the CFL showed a gently curving course with the peroneal muscle tendons as a fulcrum. The tortuosity angle was significantly smaller in plantar flexion (30.0° ± 7.4°) than in the neutral position (41.7° ± 8.3°).

CONCLUSIONS

3D MRI sequences showed that, in all positions, the CFL curved due to the influence of the peroneal muscle tendons. With maximum plantar flexion, the CFL tortuosity angle was small, which was thought to have been due to the tension in the CFL.

Anatomical variation in the form of inter- and intra-individual laterality of the calcaneofibular ligament

The lateral ligament complex of the ankle is involved in a large proportion of ankle sprains. The calcaneofibular ligament (CFL) is often involved in severe injuries. The purpose of this study was to evaluate the anatomical variation and laterality of the CFL to improve our understanding of the mechanisms of CFL-related injuries. This study utilized 110 paired ankles from 55 formalin-fixed Japanese cadavers (33 male and 22 female). The length and width of the CFL and the angle created by the CFL and long axis of the fibula (CF angle) were measured after exposing the CFL by careful dissection from the surrounding tissues. The results revealed that each parameter exhibited a wide range of values and showed unique patterns of frequency distribution, among which only the length was normally distributed. Among the parameters, only the CF angle showed no significant correlation with the other parameters. Analysis of laterality revealed that the mean left CF angle was significantly greater than the value on the opposite side (p < 0.05) and that the values of the bilateral CF angle showed no significant correlation at the individual level. The present results revealed not only detailed information regarding the CFL morphology, but also inter- and intra-individual laterality regarding the CFL traveling angle. It is likely that the differences in the quality and quantity of mechanical stress against each leg may have caused this morphologic laterality of the CFL.

Morphological features of the anterior talofibular ligament by the number of fiber bundles

The aims of this study have been to clarify differences in morphological features based on the number of fiber bundles in the anterior talofibular ligament (ATFL), and to investigate the relationship between the ATFL and the calcaneofibular ligament (CFL). This study used 81 legs from 43 cadavers. The ATFL was classified according to differences in the number of fiber bundles as: Type I, with one fiber bundle; Type II-a, with two fiber bundles that were incompletely separated; Type II-b, with two fiber bundles that were completely separated; and Type III, with three fiber bundles. The morphological features measured were fiber bundle length, fiber bundle width, and fiber bundle angle. For the relationship between the ATFL and CFL, the positional relationship and attachment sites of the two ligaments were examined. Type I was present in 33%, Type II-a in 17%, Type II-b in 40%, and Type III in 10%. The morphological features of superior fiber bundles and inferior fiber bundles were significantly different within each type. Among types, there were significant differences in the morphological features of Type II-a and Type III inferior fiber bundles. In the relationship between the ATFL and CFL, there was a connection between the ATFL and CFL in all specimens. Various types were present in the positional relationship and attachment sites of the two ligaments. The results of this study suggest that, among different ligament types with two or three fiber bundles, the control function of the ankle may differ within each type and among types.

Anatomy of anterior talofibular ligament and calcaneofibular ligament for minimally invasive surgery: a systematic review

PURPOSE

To gain a better understanding of the precise anatomy of the lateral ligaments of the ankle through a systematic review of published cadaveric studies in order to improve anatomical minimally invasive surgery (MIS) for treatment of chronic ankle instability (CAI).

METHODS

A systematic review of the literature was performed using the PubMed, EMBASE, Cochrane databases and Web of Science on June 2015 with the two search concepts: "lateral ligament of the ankle" and "anatomy". Anatomical studies that reported gross anatomy of the anterior talar fibular ligament (ATFL) and calcaneal fibular ligament (CFL) in English were included to assess the morphology and origins and insertions of the ligaments. All records found in the literature search were screened by title and abstract. Potentially relevant articles were selected for full-text review. Each of the identified articles was reviewed and included in qualitative synthesis. The following data were abstracted from the included articles: authors, date of publication, sample size, mean age, the length and the width of the each ligament, number of bundle of the ATFL and the location and the footprint of the origins and insertions for the ATFL and CFL.

RESULTS

Sixteen studies were identified indicating the length of the ATFL and CFL was 12-24.8 and 18.5-35.8 mm, respectively, while the width was 5-11.1 and 4.6-7.6 mm, respectively. Fibular origins of the ATFL and CFL were located on the anterior border of distal fibula at a distance of 10-13.8 and 5.3-8.5 mm proximal to the tip of the fibula, respectively. The talar insertion of the ATFL was located 14.2-18.1 mm to the subtalar joint or 11.3-14.8 mm to the anterolateral corner of the talar body. The calcaneal insertion of the CFL was located 12.1-13 mm to the subtalar joint or 13.2-27.1 mm to the peroneal tubercle on the lateral wall of calcaneus.

CONCLUSION

Systematic review of the literature of the research for the ATFL and CFL has identified the morphology of the ligaments and their location of origins and insertions. This is the best available data about the ATFL and CFL which will facilitate more precise anatomical MIS for treatment of CAI.

LEVEL OF EVIDENCE

Systematic review, Level IV.

Novel stress radiography technique for avulsion fracture of the lateral malleolus in children: a report of three cases

This study reports a novel stress radiography technique to evaluate an avulsion fracture at the lateral malleolus in children. Radiographs in the stress anteroposterior view or the Haraguchi calcaneofibular ligament or anterior tarofibular ligament (ATFL) projection could not detect any fracture; only manual inversion stress radiography in the Haraguchi ATFL projection could identify the avulsion fracture.

The anterior talofibular ligament: A detailed morphological study

The anterior talofibular ligament (ATFL) is commonly injured and may result in ankle instability. Good results from ATFL reconstruction have been reported; however complications and movement restrictions have also been observed. ATFL differences have been reported; however details of its precise bony attachment are lacking. This study provides a detailed morphology of the ATFL with respect to surgical and clinical applications. ATFL morphology, number of bands and the exact insertion points were studied in 50 formaldehyde embalmed feet. ATFL length was measured in different joint positions to assess its functional role: ATFL length varied from 18.81 mm in dorsiflexion to 21.06 mm in plantarflexion: mid-length width and thickness were 4.97 mm and 1.01 mm respectively. The bony attachment lengths were also measured: mean proximal and distal bony attachment lengths were 4.68 mm and 3.1mm respectively, while 13.04 mm had no bony attachment. One (22.9%), two (56.3%) and three (20.8%) band morphologies were observed originating 10.37 mm anterosuperior to the lateral malleolar tip and inserting 3.92 mm anterior to the anterior lateral malleolar line (ALML). Detailed morphology of the ATFL may help in restoring injured ATFL function by appropriate ligament reconstruction, as well as aid the understanding of the mechanism of ligament injury.

Radiographic identification of the primary lateral ankle structures

BACKGROUND

Lateral ankle ligament injuries rank among the most frequently observed athletic injuries, requiring repair or reconstruction when indicated. However, there is a lack of quantitative data detailing the ligament attachment sites on standard radiographic views.

PURPOSE

To quantitatively describe the anatomic attachment sites of the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL) on standard radiographic views with respect to reproducible osseous landmarks to assist with intraoperative and postoperative assessment of lateral ankle ligament repairs and reconstructions.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Twelve nonpaired, fresh-frozen cadaveric foot and ankle specimens were dissected to identify the origins and insertions of the 3 primary lateral ankle ligaments. Ligament footprint centers were marked with 2-mm stainless steel spheres shallowly embedded at the level of the cortical bone prior to obtaining standard lateral and mortise radiographs. Measurements were performed twice by 2 blinded raters independently to calculate mean distances and assess reliability via intraclass correlation coefficients (ICCs).

RESULTS

Radiographic measurements demonstrated excellent reproducibility between raters (all interobserver ICCs>0.97) and across trials (all intraobserver ICCs>0.99). On the lateral view, the ATFL fibular attachment (mean±SD) was 8.4±1.8 mm proximal and anterior to the inferior tip of the lateral malleolus and attached on the talus 13.8±2.0 mm proximal and anterior to the apex of the lateral talar process. The CFL originated 5.0±1.4 mm superior and anterior to the inferior tip of the lateral malleolus and inserted on the calcaneus 18.5±4.6 mm posterior and superior to the posterior point of the peroneal tubercle. On the mortise view, the ATFL origin was 4.9±1.4 mm proximal to the inferior tip of the lateral malleolus and inserted on the talus 9.0±2.1 mm medial and superior of the apex of the lateral talar process and 18.9±3.1 mm inferior and slightly lateral to the superior lateral corner of the talar dome. The fibular CFL origin was 2.9±1.6 mm proximal and slightly medial to the inferior tip of the lateral malleolus and inserted on the calcaneus 18.0±5.1 mm distal to the apex of the lateral talar process.

CONCLUSION

Radiographic parameters quantitatively describing the anatomic origins and insertions of the lateral ankle ligaments were defined with excellent reproducibility and agreement between reviewers.

CLINICAL RELEVANCE

Quantitative radiographic anatomy data will assist in preoperative planning, improve intraoperative localization, and provide objective measures for postoperative assessment of anatomic repairs and reconstructions.

Differences in lateral ankle ligaments between affected and unaffected legs in children with spastic hemiplegic cerebral palsy

OBJECTIVES

To investigate the architectural alterations of the lateral ankle ligaments in spastic hemiplegic cerebral palsy.

METHODS

Eight children (5 male and 3 female; mean age ± SD, 5.2 ± 2.7 years) with spastic hemiplegic cerebral palsy were recruited. A modified Ashworth scale and passive ankle dorsiflexion angle were evaluated. Sonograms of the anterior talofibular ligament and calcaneofibular ligament were obtained to measure ligament thickness, and the anterior talofibular/calcaneofibular ligament thickness ratio was calculated. Two sonographic measurements were taken to check for intra-rater reliability.

RESULTS

The interclass correlation coefficients of the repeated anterior talofibular ligament and calcaneofibular ligament thickness measurements in the unaffected/affected legs were 0.960/0.945 and 0.922/0.933, respectively. The anterior talofibular ligament thickness in the affected legs was significantly greater than that in the unaffected legs (2.50 ± 0.35 versus 1.40 ± 0.28 mm; P = .011), but the calcaneofibular ligament thickness in the affected legs was significantly less than that in the unaffected legs (0.80 ± 0.18 versus 1.28 ± 0.31 mm; P = .021). The anterior talofibular/calcaneofibular ligament thickness ratio in the affected legs was significantly greater than that in unaffected legs (2.10 ± 0.81 versus 1.03 ± 0.13; P = .012). The ratio was positively correlated with the modified Ashworth scale and age but negatively correlated with the passive ankle dorsiflexion angle in the affected legs.

CONCLUSIONS

This study revealed an increased anterior talofibular ligament thickness and a decreased calcaneofibular ligament thickness in the affected legs compared with the unaffected legs. These architectural features of the lateral ankle ligaments may contribute to the equinovarus deformity of the ankle together with spastic leg muscles in children with spastic hemiplegic cerebral palsy.

The anterior talofibular and calcaneofibular ligaments: an anatomic study

Inversion injuries of the ankle are the most common sport injuries. Extreme inversion of the ankle affects frequently lateral ankle ligaments, especially the anterior talofibular and calcaneofibular ligaments. The aim of this study is to investigate the ligaments in detail to contribute to accurate evaluation of radiological investigations and more precise surgical interventions by clarifying the anatomic structure of the ligaments by considering their functional importance. In the study, length between the attachment points and width at the midpoint of the anterior talofibular and calcaneofibular ligaments, length and width of the bands of anterior talofibular ligament, and connecting ligaments extending from the talus to calcaneus exchanging from the both ligaments were measured on the 46 ankles. In addition, angles between these ligaments and between longitudinal axis of the fibula and both ligaments were measured. Relationship between determined variables on the right and left sides was statistically analyzed. In diagnosis and treatment methods, the clinical importance of the anatomy of the lateral collateral ligaments of the ankle, especially the anterior talofibular and calcaneofibular ligaments, was frequently reported in the literature. Angular measurements benefit in determination of the ligament injury. Therefore, knowledge about normal anatomic angles between each other and angles between longitudinal axis of the fibula and both ligaments was certainly important for the correct diagnosis. Nowadays, surgical reconstructions of the ligaments are frequently used. During the surgical invention, length and width of the ligaments are necessary to determine quantity of ligament loss. Nonetheless, knowledge of ligament attachments contributes to more accurate reconstructions.