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

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.

Description of the lateral fibulotalocalcaneal ligament in fetal specimens and its potential clinical implications

PURPOSE

The increase in ankle sprains in children is a reflection of the greater inclusion of this population in sports. This places the calcaneofibular (CFL) and the anterior talofibular (ATFL) ligaments in focus for study. In adults, the presence of arcuate fibers extending between these two ligaments suggests the existence of a new anatomical and functional complex called the lateral fibulotalocalcaneal ligament of the ankle (LFTCL), which can be associated with the persistence of instability of the talocrural joint in ankle sprains. This study aimed to verify the presence of arciform fibers between the CFL and ATFL in human fetuses and to study the topography of the lateral ankle region.

METHODS

Forty matched fetal ankles aged between 28 and 38 weeks, fixed in 4% formalin, were macroscopically, chemically and mesoscopically dissected and analyzed in stereoscope.

RESULTS

The ATFL was characterized as a capsular ligament consisting of two fascicles (proximal and distal). The CFL was characterized as an extracapsular ligament. The LFTCL complex was verified in all specimens, characterized by the arcuate fibers between the ATFL and the CFL.

CONCLUSION

Such results suggest that this functional unit is congenital and that it should be taken into consideration in the treatment of persistent ankle instabilities in the pediatric population.

The ATFL inferior fascicle, the CFL and the PTFL have a continuous footprint at the medial side of the fibula

PURPOSE

Knowledge of the complex anatomy of the lateral ankle ligaments is essential to understand its function, pathophysiology and treatment options. This study aimed to assess the lateral ligaments and their relationships through a 3D view achieved by digitally marking their footprints.

METHODS

Eleven fresh-frozen ankle specimens were dissected. The calcaneus, talus and fibula were separated, maintaining the lateral ligament footprints. Subsequently, each bone was assessed by a light scanner machine. Finally, all the scans were converted to 3D polygonal models. The footprint areas of the talus, calcaneus and fibula were selected, analysed and the surface area was quantified in cm2.

RESULTS

After scanning the bones, the anterior talofibular ligament inferior fascicle (ATFLif), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL) footprints were continuous at the medial side of the fibula, corresponding to a continuous footprint with a mean area of 4.8 cm2 (± 0.7). The anterior talofibular ligament (ATFL) footprint on the talus consisted of 2 parts in 9 of the 11 feet, whilst there was a continuous insertion in the other 2 feet. The CFL insertion on the calcaneus was one single footprint in all cases.

CONCLUSION

The tridimensional analysis of the lateral ligaments of the ankle demonstrates that the ATFLif, CFL and PTFL have a continuous footprint at the medial side of the fibula in all analysed specimens. These data can assist the surgeon in interpreting the ligament injuries, improving the imaging assessment and guiding the surgeon to repair and reconstruct the ligaments in an anatomical position.

Indications and possible limitations using medio-plantar plate systems in tarsometatarsal 1 fusions - A cadaveric study

BACKGROUND

The tarsometatarsal 1 arthrodesis is an adequate treatment for moderate to severe hallux valgus deformity and instability of the first ray. Plantar plating arthrodesis has been shown to provide better mechanical stability and fewer postoperative complications than screw fixation or medial plating. The medio-plantar plate is a new plate design for Lapidus arthrodesis. It could combine the biomechanical advantages of the plantar plate and the anatomical overview of a medial plate. However, the implanted material can cause irritation of the tibialis anterior, which in some cases may require removal of the material. The purpose of this study was to examine the possibility of tendon irritation following medio-plantar first tarsometatarsal joint arthrodesis using cadaveric specimens.

METHODS

The study involved the simulated surgical procedure of medio-plantar plate arthrodesis on 30 lower extremities. After the plates were fixed, a thorough examination of the feet was conducted to assess any tendon irritation and to determine a recommendation for placement of the medio-plantar plate based on the Olewnik classification.

RESULTS

Irritation of the tibialis anterior tendon components with the medio-plantar plate depends mainly on the anatomic norm variant, classified according to Olewnik et al. A medio-plantar plate is particularly recommended in TA tendon Olewnik type 3 and type 5. The positioning of a medio-plantar plate in Olewnik type 1 and type 2 tendons depends on the anatomic fit of the medio-plantar plate and the bony configuration of the TMT 1 joint. A large portion of the TA tendon must be detached, so a different plate design may be preferred in these patients.

CONCLUSIONS

TMT 1 arthrodesis with medio-plantar plating of the first tarsometatarsal joint should be performed considering the anatomic TA tendon variations.

LEVEL OF EVIDENCE

Level V, Expert Opinion includes Case Reports and Technique Tips.

Anatomical study of the bone morphology of the anterior talofibular ligament attachment

Anterior talofibular ligament (ATFL) injuries are the most common cause of ankle sprains. To ensure anatomically accurate surgery and ultrasound imaging of the ATFL, anatomical knowledge of the bony landmarks around the ATFL attachment to the distal fibula is required. The purpose of the present study was to anatomically investigate the ATFL attachment to the fibula with respect to bone morphology and attachment structures. First, we analyzed 36 feet using microcomputed tomography. After excluding 9 feet for deformities, the remaining 27 feet were used for chemically debrided bone analysis and macroscopic and histological observations. Ten feet of living specimens were observed using ultrasonography. We found that a bony ridge was present at the boundary between the attachments of the ATFL and calcaneofibular ligament (CFL) to the fibula. These two attachments could be distinguished based on a difference in fiber orientation. Histologically, the ATFL was attached to the anterodistal part of the fibula via fibrocartilage anterior to the bony ridge indicating the border with the CFL attachment. Using ultrasonography in living specimens, the bony ridge and hyperechoic fibrillar pattern of the ATFL could be visualized. We established that the bony ridge corresponded to the posterior margin of the ATFL attachment itself. The ridge was obvious, and the superior fibers of the ATFL have directly attached anteriorly to it. This bony ridge could become a valuable and easy-to-use landmark for ultrasound imaging of the ATFL attachment if combined with the identification of the fibrillar pattern of the ATFL.

The lowest point of fibula (LPF) could be used as a reliable bony landmark for arthroscopic anchor placement of lateral ankle ligaments ----compared with open Broström procedure

BACKGROUND

Arthroscopic technique procedures was wide accepted for the treatment of chronic ankle instability (CAI). But little acknowledge was involved to the bony landmarks and anatomic features of different bundles of lateral ligaments under arthroscopic view.

METHODS

Sixty patients with acute or chronic lateral ankle ligaments injury (LAI) were collected prospectively, and divided randomly into two groups. In arthroscopic group, the bone tunnels were made on the LPF arthroscopically. And in open group, the bone tunnels were made on the Fibular obscure tubercle (FOT) in open procedure. The inferior bundle of ATFL and Arcuate fibre was also identified reference to the LPF and labeled by a PDS II suture penetration. Following that, The distances of the bone tunnels to the different bony markers were measured and compare between two groups. The penetrating locations of PDS II on the inferior bundle of ATFL and Arcuate fibre were also confirmed intraoperatively. And the safe angle of anchor implantation on the axial view was measured on postoperative CT scan.

RESULTS

The distances of bone tunnel to the fibular tip, the fibular insertion of anterior-inferior tibiofibular ligament (AITFL), and the FOT in arthroscopic and open locating groups were 4.9 ± 2.2 and 6.3 ± 2.2 mm, 13.5 ± 2.7 and 12.4 ± 1.1 mm, 5.8 ± 2.2 and 5.6 ± 1.0 mm, respectively. The distances of bone tunnels to the FOT and fibular tip on 3d-CT view was 4.4 ± 1.5 and 4.6 ± 0.9 mm, 14.4 ± 3.2 and 13.2 ± 1.8 mm in arthroscopic and open group, and there were no significant differences between two groups. The safe angle of arthroscopic anchor placement on the axial plan was ranged from 24.9 ± 6.3o to 58.1 ± 8.0o. The PDS II sutures penetrating on the inferior bundles of ATFL and the arciform fibres were also comfirmed successfully by open visualizaion.The average distance of penetration point to the horizontal line cross the fibular tip was 2.3 ± 2.7 mm (ranged from - 3.1 to 6.0 mm), and to the vertical line cross the FOT was 2.7 ± 2.7 mm (ranged from - 2.5 to 7.5 mm).

CONCLUSION

Take the lowest point of fibula under arthroscopy (LPF) as a bony reference, we could identify the iATFL under arthroscopic visualization. By this way, we could place the suture anchors properly to the fibular footprint and suture the iATFL fibres successfully.

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.

Particularities on Anatomy and Normal Postsurgical Appearances of the Ankle and Foot

The anatomy of the ankle and foot is complex, allowing for a wide range of functionality. The movements of the joints represent a complex dynamic interaction. A solid understanding of the characteristics and actions of the anatomic elements helps explain the mechanisms and patterns of injury. This article reviews the anatomy, with special focus on concepts that are the object of recent study and the features that favor the development of symptoms. Good understanding of the surgical procedures helps in providing information to guarantee a favorable outcome. We review the commonly expected postsurgical appearances and the most common postsurgical complications.

Double-bundle reconstruction of the anterior talofibular ligament by partial peroneal brevis tendon

BACKGROUND

Anatomic anterior talofibular ligament (ATFL) reconstruction with autologous single-bundle tendon has been widely used in the treatment of ATFL injury. However, there are few clinical reports of using the peroneus brevis tendon (PBT) for double-bundle ATFL reconstruction. The aim of this study was to investigate the clinical effect of double-bundle ATFL reconstruction with PBT.

METHODS

This was a retrospective review of all patients diagnosed with ATFL injury presenting from August 2019 to December 2021. Fifty-three patients were selected after screening based on the inclusion and exclusion criteria. The following data were compared before and after surgery: Visual Analogue Scale (VAS) score, American Orthopedic Foot and Ankle Society (AOFAS) score, Karlsson Ankle Functional Score (KAFS), the pain interference (PI) and physical function (PF) scores of the Patient-Reported Outcomes Measurement Information System (PROMIS), the diameter and width of PBT in ultrasound and muscle strength.

RESULTS

All functional scores (VAS, PI/PF, AO-FAS, KAFS) and muscle strength were significantly improved at the last follow-up (P < 0.05). The diameter and width of the PBT on ultrasound postoperation were smaller than those preoperatively.

CONCLUSION

Double-bundle ATFL reconstruction with the partial PBT technique is a feasible, anatomic reconstruction technique for chronic lateral instability of the ankle, which meets the anatomical characteristics of the double bundle of the ligament, and the absence of partial PBT does not affect the peroneal muscle strength.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Difference in the fibular attachment structure between the superior and inferior fascicles of the anterior talofibular ligament using ultrasonography and histological examinations

PURPOSE

The anterior talofibular ligament (ATFL) is divided into superior (SB) and inferior bands (IB). Although the differences in length and width are known, the structure of the fibular attachment had not been elucidated. The present study aimed to clarify the differences in the fibular attachment structure between ATFL's SB and IB using cross-sectional images along the ligament.

METHODS

An anatomical study using 15 formalin-fixed ankles was performed. The lateral ankle ligament complex was collected after a longitudinal image of SB/IB was visualized by ultrasonography. The specimens were decalcified and sectioned longitudinally at the center of SB/IB using a microtome. Histological evaluation of the enthesis structure at the fibular attachment of SB/IB was performed using hematoxylin-eosin and Masson's trichrome stains.

RESULTS

A fibrillar pattern could not be observed in the longitudinal image at the IB level by ultrasonography. The lengths of ATFL's SB and IB were 20.6 ± 1.6 and 15.3 ± 1.3 mm, respectively, with thicknesses of 1.8 ± 0.4 and 1.0 ± 0.4 mm, respectively. The ATFL's IB was significantly shorter and thinner than the ATFL's SB. The fibular attachment of ATFL's SB had distinct enthesis structure, whereas in the attachment structure of the ATFL's IB, there were several variations including a type with a narrower enthesis structure than the ATFL's SB and a type that merged with or wrapped around the calcaneofibular ligament.

CONCLUSION

The fibular attachment structure between ATFL's SB and IB differs. Our results could be useful information when performing ultrasonography and MRI diagnosis.

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.

MRI appearance of the lateral fibulotalocalcaneal ligament complex injury in the patients with chronic lateral ankle instability

BACKGROUND

The anterior talofibular ligament (ATFL) comprises the superior and inferior fascicles. The inferior fascicle is connected to the calcaneofibular ligament, and forms "lateral fibulotalocalcaneal ligament (LFTCL) complex". This study aimed to evaluate the feasibility of diagnosing LFTCL complex injuries in patients with chronic lateral ankle instability (CLAI).

METHODS

Forty-eight ankles (35 with CLAI and 13 without CLAI) underwent arthroscopic surgery, and preoperative magnetic resonance imaging (MRI) was conducted with 0.8 mm- thick axial and oblique slices. The diagnostic accuracy of injuries to the superior fascicle and LFTCL complex was evaluated by two observers.

RESULTS

The sensitivity and specificity of the LFTCL complex injury were 94.7% and 92.3% for observer 1 and 84.2% and 84.6% for observer 2, respectively.

CONCLUSIONS

MRI with 0.8 mm slices could detect LFTCL complex injury in patients with CLAI. Diagnosing the LFTCL complex injury on MRI will improve outcomes of an arthroscopic isolated ATFL repair.

Morphologic evaluation of injured and contralateral uninjured ankles in patients with unilateral chronic ankle instability

OBJECTIVE

To compare the morphological anatomy and abnormalities of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) in unilateral chronic ankle instability (CAI).

METHODS

22 patients (men: women, 13:9; mean age, 28.95 ± 8.127 years) with unilateral CAI and 18 healthy volunteers (men: women, 9:9, mean age, 28.33 ± 3.678 years) were recruited. MRI scans were divided into Group 1 (22 injured ankles), Group 2 (22 contralateral uninjured ankles), and Group 3 (36 healthy volunteer ankles). The morphologic variables, MRI signal intensity (SI) values were evaluated.

RESULTS

The ATFL proximal, intermediate, and distal sites and the CFL proximal and distal sites in Group 3 were narrower than those in Group 1 (P ＜0.05). Both ATFL and CFL in Group 1 were thicker than those in Group 3 (P ＜0.01). The proximal and intermediate sites of the ATFL and the proximal site of the CFL in Group 3 were narrower than those in Group 2 (P ＜0.01). The intermediate site of the ATFL and the proximal and distal sites of the CFL in Group 2 were thicker than those in Group 3 (P ＜0.01). The mean SI values of the ATFL in Group 1 were higher than those in Groups 2 and 3 (P ＜0.01). The ATFL and CFL SI values were higher in Group 2 than those in Group 3 (P ＜0.05).

CONCLUSION

Both the injured and contralateral uninjured ankles had wider ATFL and CFL, more thickness, and higher SI values compared with those of healthy volunteer ankles.

ADVANCES IN KNOWLEDGE

High-resolution three-dimensional MRI provides a potential tool assisting clinical decision on the treatment and rehabilitation therapy of patients with unilateral CAI.

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.

Relationship between inferior fascicle of anterior talofibular ligament and articular capsule in lateral ankle ligament complex

PURPOSE

The lateral ankle ligament complex (LALC) is composed of anterior talofibular (ATFL), calcaneofibular (CFL), and posterior talofibular (PTFL) ligaments, all of which have a connection/continuous fiber. However, the structural link between the LALC and the articular capsule remains unknown. The goal of our study was to determine the connection between ATFL's inferior fascicle and the articular capsule.

METHODS

In this study, we utilized 84 formalin-fixed ankles to elucidate the structure of LALC. Between ATFL and CFL, the bundle number of ATFL and arciform fiber was investigated. The specimens were decalcified and sectioned coronally using a freezing microtome, in the case of double bundles of ATFL, to study the connection between the inferior fascicle of ATFL and the articular capsule.

RESULTS

ATFL had a single (25%), double (74%), and triple (1%) bundle number, respectively. The arciform fiber connecting the ATFL and the CFL was found in the superficial layer of all ankles (100%). There were two types of relationships between the inferior fascicle of ATFL and the articular capsule: 36 ankles (58%) were extracapsular, and 26 of 62 ankles (42%) were integrated with the inferior-lateral articular capsule. There are two kinds of relationships between the inferior fascicle of the ATFL and the articular capsule: extracapsular and integrated-capsular.

CONCLUSIONS

The inferior fascicle of ATFL has a variant and integrated-capsular type is reinforced inferior-lateral articular capsule and enters the joint to form continuous fibers with PTFL, making LALC. These anatomical findings are helpful in ultrasonography diagnosis and arthroscopic ankle surgery.

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.

Continuous and Connective Fibers of the Lateral Ankle Ligament Complex

The lateral ankle ligament complex (LALC) is an intricate structure; therefore precise anatomic knowledge is required by the surgeon. However, the structural relationship of the LALC remains unclear. Here, the features of the posterior talofibular ligament (PTFL) and the relationship to the LALC at the distal fibula were clarified in a cadaver study. The lengths of most of the anterior and posterior parts, and the widths of the anterior-posterior and superior-inferior parts, were measured with a digital caliper. In addition, the relationship between the anterior talofibular ligament (ATFL) and PTFL inside of the capsule is described. The small fiber bundles of the PTFL were manually divided, and the footprint of each bundle at the fibula and talus was clarified. The relationship between the ATFL and CFL, outside of the capsule, was examined on axial slices at the inferior fibula. The lengths of the most anterior and most posterior parts of the PTFL were 9.8 ± 1.7 and 29.4 ± 1.9 mm, respectively. The widths of the anterior-posterior and superior-inferior parts were 10.0 ± 0.9 and 5.8 ± 1.1 mm, respectively. Approximately 83% of the fibers between the ATFL and PTFL were continuous. The anterior-inferior fibers of the PTFL were continuous with the inferior fibers of the ATFL inside of the capsule. The ATFL and CFL converged with connective tissue from outside of the capsule at the distal fibula. The results of this study should prove useful to further clarify the relationships of the LALC both inside and outside of the capsule at the distal fibula.

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 Location of the Fibular Tunnel for Anatomically Accurate Reconstruction of the Lateral Ankle Ligament: A Cadaveric Study

We aimed to describe the location of fibular footprint of each anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL), as well as their common origin in relation to bony landmarks of the fibula in order to determine the location of the fibular tunnel. In 105 ankle specimens, the center of the footprints of the ATFL and CFL (cATFL and cCFL, respectively) and the intersection point of their origin (intATFL-CFL) were investigated, and the distances from selected bony landmarks (the articular tip (AT) and the inferior tip (IT) of the fibula) were measured. Forty-two (40%) specimens had single-bundle ATFL, and 63 (60%) had double-bundle patterns. The distance between intATFL-CFL and IT was 12.0 ± 2.5 mm, and a significant difference was observed between the two groups (p = 0.001). Moreover, the ratio of the intATFL-CFL location based on the anterior fibular border for all cadavers was 0.386. The present study suggests a reference ratio that can help surgeons locate the fibular tunnel for a more anatomically accurate reconstruction of the lateral ankle ligament. Also, it may be necessary to make a difference in the location of the fibular tunnel according to the number of ATFL bundles during surgery.

Anatomical variations and interconnections of the superior peroneal retinaculum to adjacent lateral ankle structures: a preliminary imaging anatomy study

Aim

This imaging anatomy study aimed at detecting anatomical variations and potential interconnections of the superior peroneal retinaculum to other lateral stabilizing structures.

Materials and methods

We retrospectively reviewed the imaging archives of 63 patients (38 females, 25 males, mean age 32.7, range 18–58 years) with available ankle US, MR and CT images to detect whether US and MR can detect the presence of interconnections between the superior peroneal retinaculum and the anterior talofibular ligament, inferior extensor retinaculum and peroneal tendon sheath. We evaluated the presence of common anatomical variations including low peroneus brevis muscle belly, peroneal tubercle, os peroneum, and retromalleolar fibular groove shape in relation to the presence of superior peroneal retinaculum connections.

Results

The connections of the superior peroneal retinaculum can be revealed on magnetic resonance imaging (MRI) and ultrasound (US). The connection to the anterior talofibular ligament was located (a) inferior to the lateral malleolus, (b) at the level of the lateral malleolus and (c) on both levels, respectively (a) 49.2% on MRI and 39.7% on US, p <0.05, (b) 44.4% and 58.7%, p <0.05, 36.5% and (c) 27%, p <0.05. Superior peroneal retinaculum–inferior extensor retinaculum (MRI 47.6%, US 28.6% p <0.001) and superior peroneal retinaculum–peroneal tendon sheath (MRI 22.2%, US 25.4% p >0.05) connections were also found both on MR and US.

Conclusion

Ankle US and MR revealed interconnections between the superior peroneal retinaculum and the anterior talofibular ligament, inferior extensor retinaculum, and superior peroneal retinaculum. Our results are a starting point for further studies on the connections of the superior peroneal retinaculum and the applicability of ultrasound and MRI in assessing their occurrence. Knowledge of the anatomical connections of the superior peroneal retinaculum may help radiologists with the assessment of lateral ankle injuries, and surgeons with treatment planning.

Chronic Lateral Ankle Instability: Topical Review

Chronic ankle instability can result from untreated or badly managed acute lateral ankle ligament injuries. Conservative management is the modality of choice for acute lateral ankle ligament injuries, and operative treatment is reserved for special cases. Failure after strict rehabilitation may be an indication for surgery. Several operative options are available, including anatomic repair, anatomic reconstruction, and tenodesis procedures. Anatomic repair can be performed when the quality of the damaged ligaments permits. Anatomic reconstruction with an autograft or allograft should be considered when the torn ligaments are not adequate. Ankle arthroscopy is a useful adjunct to ligamentous procedures, performed at the time of repair to identify and treat intra-articular conditions that may be associated with chronic ankle instability. Tenodesis techniques are not recommended because of their suboptimal long-term results related to the modification of ankle and hindfoot biomechanics.Level of Evidence: Level V, expert opinion.

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 fibulotalocalcaneal ligament complex: an ankle stabilizing isometric structure

PURPOSE

Ankle lateral collateral ligament complex has been the focus of multiple studies. However, there are no specific descriptions of how these ligaments are connected to each other as part of the same complex. The aim of this study was to describe in detail the components of the lateral collateral ligament complex-ATFL and CFL-and determine its anatomical relationships.

METHODS

An anatomical study was performed in 32 fresh-frozen below-the-knee ankle specimens. A plane-per-plane anatomical dissection was performed. Overdissecting the area just distal to the inferior ATFL fascicle was avoided to not alter the original morphology of the ligaments and the connecting fibers between them. The characteristics of the ATFL and CFL, as well as any connecting fibers between them were recorded. Measures were obtained in plantar and dorsal flexion, and by two different observers.

RESULTS

The ATFL was observed as a two-fascicle ligament in all the specimens. The superior ATFL fascicle was observed intra-articular in the ankle, in contrast to the inferior fascicle. The mean distance measured between superior ATFL fascicle insertions increases in plantar flexion (median 19.2 mm in plantar flexion, and 12.6 mm in dorsal flexion, p < 0.001), while the same measures observed in the inferior ATFL fascicle does not vary (median 10.6 mm in plantar flexion, and 10.6 mm in dorsal flexion, n.s.). The inferior ATFL fascicle was observed with a common fibular origin with the CFL. The CFL distance between insertions does not vary with ankle movement (median 20.1 mm in plantar flexion, and 19.9 mm in dorsal flexion, n.s.). The inferior ATFL fascicle and the CFL were connected by arciform fibers, that were observed as an intrinsic reinforcement of the subtalar joint capsule.

CONCLUSION

The superior fascicle of the ATFL is a distinct anatomical structure, whereas the inferior ATFL fascicle and the CFL share some features being both isometric ligaments, having a common fibular insertion, and being connected by arciform fibers, and forming a functional and anatomical entity, that has been named the lateral fibulotalocalcaneal ligament (LFTCL) complex. The clinical relevance of this study is that the superior fascicle of the ATFL is anatomical and functionally a distinct structure from the inferior ATFL fascicle. The superior ATFL fascicle is an intra-articular ligament, that will most probably not be able to heal after a rupture, and a microinstability of the ankle is developed. However, when the LFTCL complex is injured, classical ankle instability resulted. In addition, because of the presence of LFTCL complex, excellent results are observed when an isolated repair of the ATFL is performed even when an injury of both the ATFL and CFL exists.

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.

Anatomical Arthroscopic Anterior Talofibular Ligament Repair and Reconstruction Using a Free Tendon

Arthroscopic techniques for anterior talofibular ligament (ATFL) repair and reconstruction have been developed in recent years. We simultaneously performed anatomical arthroscopic ATFL repair and reconstruction using a free tendon graft. The ATFL remnant is carefully dissected only at the footprint of the superior limb of the ATFL, and a bone tunnel is created on each side of the fibula and talus. A soft suture anchor with 2 sets of threads is inserted into the fibular tunnel. One set of threads is used to grab the ATFL remnant via a lasso-loop technique, whereas the other set of threads is used to introduce the ATFL graft. The graft is first fixed with a screw in the talar tunnel. Subsequently, the ATFL remnant and the graft are tightened simultaneously by pulling the 2 sets of suture anchor threads at the fibular tunnel and are fixed with a screw. This technique provides the possible advantages of remnant preservation and promotion of load sharing by the repaired ATFL remnant and the reconstructed ATFL graft.

Morphological features of the cervical ligament

PURPOSE

The purpose of this study was to clarify the morphological characteristics of the cervical ligament (CL).

METHODS

This study examined 80 legs from 40 Japanese cadavers. The CL was classified by the number of fiber bundles. The morphological features measured were fiber bundle length, width, thickness, and angle with the sagittal plane.

RESULTS

The CL was classified as follows: Type I, the CL is a single fiber; Type II, the CL consists of a superficial fiber and an inferior fiber; and Type III, the CL consists of a superficial fiber, intermediate fiber, and inferior fiber. Type I was seen in 15 feet, Type II in 57 feet, and Type III in 8 feet. In comparisons of morphological features within each type, significant differences were seen in fiber bundle length, width, and angle between superior fiber bundles and inferior fiber bundles of Type II and Type III. In comparison among types, the total fiber bundle width was significantly wider in Type II and Type III than in Type I, and the angle was significantly smaller in Type III than in Type I.

CONCLUSION

The results of this study suggested that each type may have different sub-talar joint control functions.

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.

Anatomical Arthroscopic Anterior Talofibular Ligament and Calcaneofibular Ligament Reconstruction Using an Autogenic Hamstring Tendon: Safe Creation of Anatomical Fibular Tunnel

Ankle sprains are the most common lower extremity injuries associated with sports activity. Although ligament repair techniques are popular, reconstruction methods using free tendons are considered when the ligament remnant is insufficiently strong, when high-demand athletes sustain repeat ankle sprains, or in revision cases after repair. Recently, some arthroscopic reconstruction techniques have been reported. The distal fibular end is thin; therefore, surgeons must be careful while drilling the fibular tunnel. This report indicates the safe creation method of an anatomical fibular tunnel during anatomical arthroscopic reconstruction of the anterior talofibular ligament and calcaneofibular ligament. This also provides a stronger reconstruction using a 2-strand tendon graft for the anterior talofibular ligament substitute, which is thought to have less risk for postoperative graft failure.

The effect of differences in the number of fiber bundles of the anterior tibial ligament on ankle braking function: a simulation study

PURPOSE

The aim was to clarify the effect of differences in the number of fiber bundles of the anterior tibial ligament (ATFL) on ankle braking function.

METHODS

The study sample included 81Japanese cadavers. ATFLs were categorized as: Type I with one fiber bundle; Type II with two fiber bundles that were completely separated; and Type III with three fiber bundles. Three-dimensional reconstructions of a single specimen from each category were then created. These were used to simulate and calculate ATFL strain during dorsiflexion (20°) and plantarflexion (30°) on the talocrural joint axis and inversion (20°) on the subtalar joint axis.

RESULTS

Almost all types of superior fiber lines were stretched with dorsiflexion and plantarflexion. Regardless of Type, the inferior fiber line was shortened with plantarflexion and stretched with dorsiflexion. The inferior fiber bundle of Type III was shortened only at plantarflexion 30° and inversion 20°, but in all others it was stretched.

CONCLUSIONS

The results suggest that Type III was weaker than Type I and Type II in terms of ankle plantarflexion and inversion braking function.