Dimensions and attachments of the ankle ligaments: evaluation for ligament reconstruction

Do lateral ankle ligaments contribute to syndesmotic stability: a finite element analysis study

Whether the lateral ankle ligaments contribute to syndesmotic stability is still controversial and has been the subject of frequent research recently. In our study, we tried to elucidate this situation using the finite element analysis method. Intact model and thirteen different injury models were created to simulate injuries of the lateral ankle ligaments (ATFL, CFL, PTFL), injuries of the syndesmotic ligaments (AITFL, IOL, PITFL) and their combined injuries. The models were compared in terms of LFT, PFT and EFR. It was observed that 0.537 mm LFT, 0.626 mm PFT and 1.25° EFR occurred in the intact model (M#1), 0.539 mm LFT, 0.761 mm PFT and 2.31° EFR occurred in the isolated ATFL injury (M#2), 0.547 mm LFT, 0.791 mm PFT and 2.50° EFR occurred in the isolated AITFL injury (M#8). The LFT, PFT and EFR amounts were higher in the both M#2 and M#8 compared to the M#1. LFT, PFT and EFR amounts in M#2 and M#8 were found to be extremely close. In terms of LFT and PFT, when we compare models with (LFT: 0.650 mm, PFT: 1.104) and without (LFT: 0.457 mm, PFT: 1.150) IOL injury, it is seen that the amount of LFT increases and the amount of PFT decreases with IOL injury. We also observed that injuries to the CFL, PTFL and PITFL did not cause significant changes in fibular translations and PFT and EFR values show an almost linear correlation. Our results suggest that ATFL injury plays a crucial role in syndesmotic stability.

Anterior talofibular ligament footprint dimension measured using three-dimensional magnetic resonance imaging

OBJECTIVE

Knowledge of footprint anatomy is essential for ankle anterior talofibular ligament repair and reconstruction. We aimed to determine the intra- and inter-rater measurement reliability of the anterior talofibular ligament footprint dimension using three-dimensional MRI.

METHODS

MRI images of 20 ankles with intact ligaments, including 11 with a single bundle and nine with double-bundle ligaments, were analyzed. Imaging was performed using a 3.0-Tesla MRI. Isotropic three-dimensional proton density-weighted images with a voxel size of 0.6 mm were obtained. The fibular and talar footprints were manually segmented using image processing software to create three-dimensional ligament footprints. The lengths, widths, and areas of each sample were measured. A certified orthopedic surgeon and a senior orthopedic fellow performed the measurements twice at 6-week intervals. The intra- and inter-rater differences in the measurements were calculated.

RESULTS

The length, width, and area of the single-bundle fibular footprint were 8.7 mm, 5.4 mm, and 37.4 mm2, respectively. Those of the talar footprint were 8.4 mm, 4.3 mm, and 30.1 mm2, respectively. The inferior bundle of the double-bundle ligament was significantly smaller than the single and superior bundles (p < 0.001). No differences were observed between intra-rater measurements by either rater, with maximum differences of 0.7 mm, 0.5, and 1.7 mm2, in length, width, and area, respectively. The maximum inter-rater measurement differences were 1.9 mm, 0.5, and 2.4 mm2, respectively.

CONCLUSION

Measurements of the anterior talofibular ligament dimensions using three-dimensional MRI were sufficiently reliable. This measurement method provides in vivo quantitative data on ligament footprint anatomy.

Intra- and interrater measurement reliability of lateral ankle ligament attachment locations using three-dimensional magnetic resonance imaging

BACKGROUND

We aimed to evaluate the intra- and interrater measurement reliability of the lateral ankle ligament attachment locations using three-dimensional magnetic resonance imaging.

METHODS

We analysed 54 participants with a mean age of 43 years who underwent three-dimensional ankle magnetic resonance imaging and had normal lateral ligaments. Bony landmarks of the distal fibula, talus, and calcaneus were identified in the reconstructed images. The centers of the anterior talofibular ligament and calcaneofibular ligament attachments were also identified. The distances between the landmarks and attachments were measured. Two raters performed the measurements twice, and intra- and interrater intraclass correlation coefficients were calculated.

RESULTS

The intrarater intraclass correlation coefficient values were between 0.71 and 0.96 for the anterior talofibular ligament attachment measurements and between 0.77 and 0.95 for the calcaneofibular ligament attachments. The interrater intraclass correlation coefficient was higher than 0.7, except for the distance between the anterior talofibular ligament superior bundle and fibular obscure tubercle. The fibular attachment of a single-bundle anterior talofibular ligament was located 13.3 mm from the inferior tip and 43% along the anterior edge of the distal fibula. The superior and inferior bundles of the double-bundle ligament were located at 43% and 23%, respectively. The calcaneofibular ligament fibular attachment was 5.5 mm from the inferior tip, at 16% along the anterior edge of the distal fibula.

CONCLUSION

The measurements of anterior talofibular ligament and calcaneofibular ligament attachment locations identified on three-dimensional magnetic resonance imaging were sufficiently reliable. This measurement method provides in vivo anatomical data on the lateral ankle ligament anatomy.

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.

The deltoid ligament is constantly formed by four fascicles reaching the navicular, spring ligament complex, calcaneus and talus

PURPOSE

The medial collateral ligament of the ankle, or deltoid ligament, can be injured in up to 40% of patients who sustain an ankle inversion sprain. Reporting injuries of the deltoid ligament is not easy due to confusion in the current anatomical descriptions, with up to 16 fascicles described, with variable frequencies. The purpose of this study was to clarify the anatomy of the deltoid ligament.

METHODS

Thirty-two fresh-frozen ankle specimens were used for this study. Careful dissection was undergone until full visualization of the deltoid ligament was achieved and measurements taken.

RESULTS

The deltoid ligament was found to have four constant fascicles in two layers. The superficial layer consists of the tibionavicular, tibiospring and tibiocalcaneal fascicles, while the deep layer consists of the tibiotalar fascicle. Measurements of these fascicles are given in detail. The tibiotalar fascicle and the anterior part of the tibionavicular fascicle were found to be intra-articular structures.

CONCLUSION

The deltoid ligament has a constant number of fascicles divided into a superficial and a deep layer. This clarification of the anatomy and terminology of the deltoid ligament and its fascicles will help clinical view, diagnosis and (interdoctor)communication and treatment. The ligamentous fibres of the deep layer, as well as the anterior fibres of the superficial layer (tibionavicular fascicle) are intra-articular, which could negatively impact its healing capacity, explaining chronicity of these types of injuries.

LEVEL OF EVIDENCE

Not applicable (cadaveric study).

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.

The Specific Anatomical Morphology of Lateral Ankle Ligament: Qualitative and Quantitative Cadaveric based Study

OBJECTIVE

The accurate understanding in morphological features of the lateral ankle ligaments is necessary for the diagnosis and management of ankle instability and other ankle problems. The purpose of this study was to evaluate the anatomical morphology and the attachment areas of lateral ligament complex of ankle joint based on the cadaveric study.

METHODS

Fifty-four fresh frozen cadaveric ankles were dissected to evaluate the lateral ankle ligaments. Each ligament was separated into two or three small bundles. In the investigated footprint areas, acrylic colors were used as a marker point to locate specific areas of ligament bundle attached to the bone. The Image J software was used to measure and analyze the sizes of the specific footprint areas to achieve descriptive statistical analysis.

RESULTS

The double bands of anterior talofibular ligament (ATFL) were found as a major type in the present study with 57.41% (31 of 54 ankles) while the single band of ATFL was observed in 42.59% (23 of 54 ankles). The attachment sizes of the ATFL, posterior talofibular ligament (PTFL) and calcaneofibular ligament (CFL) were evaluated into two areas; proximal and distal attachments. The average of proximal or fibular part of ATFL, PTFL and CFL were 85.06, 134.27, 93.91 mm2 respectively. The average of distal part of ATFL, PTFL and CFL were 100.07, 277.61, 249.39 mm2 respectively.

CONCLUSION

Considering the lateral ankle ligament repaired or reconstruction especially using arthroscopy, the precise understanding in specific detail of the lateral ankle ligament may help both diagnose and select the appropriate treatment for solving the ankle problems. These observations may help the surgeon to perform the surgical procedure for determining the appropriate techniques and avoid complication to patients.

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.

Biomechanical Analysis of Tibiofibular Syndesmosis Injury Fixation Methods: A Finite Element Analysis

The optimal treatment strategy after syndesmotic injuries is still controversial. In our study, we aimed to evaluate ideal fixation method in syndesmotic injury by using finite element analysis method. A 3D SolidWorks model file was created by taking computed tomography (CT) images of the area from the right foot base to the knee joint level of a healthy adult male. The intact model, injury model, and 8 different fixation models were created that 3.5 mm screw and suture-button were used in. The models were compared in terms of lateral fibular translation, posterior fibular translation and external rotation of fibula compared to tibia and stress values occurred on screws and suture-buttons. In the hybrid-1 model, lateral fibular translation and external fibular rotation values were obtained as close to the intact model. Von Mises stresses occurred in the screw (435.7 MPa) and suture-button (424.7 MPa) that used in hybrid-1 model was more than single screw at 4 cm model (316.8 MPa) and single suture-button at 2 cm model (160.7 MPa). In the Hybrid-1 model, the screw compensates for posterior fibular translation and external fibular rotation, while the suture-button compensates for lateral fibular translation. Also, the effect of the distal suture-button preventing diastasis in case of proximal screw failure, it was concluded that the hybrid-1 model can be used as a good treatment alternative in the surgical treatment of distal tibiofibular syndesmotic injuries.

Distal tibiofibular syndesmosis: A meta-analysis of cadaveric studies

Though injuries to the distal tibiofibular (DTF) syndesmosis are commonly encountered in orthopedic and trauma settings, its anatomical structures have been poorly researched. The commonly overlooked DTF ligament injuries are known to cause chronic ankle pain, instability and post-traumatic osteoarthritis. Quantitative and morphological evidence synthesis has not been yet conducted. A meta-analysis was conducted to collect data from morphological studies to document more accurate details on the prevalence, size, and insertion sites of its components. The Checklist for Anatomical Reviews and Meta-Analyses (CARMA) was followed. Ten studies met the inclusion criteria with a total of 265 investigated ankles. The analysis demonstrated that the anterior and posterior tibiofibular ligaments along with the interosseous ligament were present in 100% of joints. The inferior transverse tibiofibular and the distal fascicle of the anterior tibiofibular ligament were the least prevalent with frequencies of 96% and 86.5%, respectively. The inferior transverse ligament was recorded as the longest ligament. The widest ligament was found to be the interosseous tibiofibular ligament at its fibular attachment. The thickest of the ligamentous components was the posterior tibiofibular ligament. While more cadaveric research is warranted, these results would help directing future biomechanical investigations and planning new research to further aid in diagnostic and therapeutic approaches to the injuries of the distal tibiofibular syndesmosis.

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.

Anatomic reconstruction of the lateral ligaments using allograft tendon and suspensory fixation for chronic lateral ankle instability with poor remnant quality: results and complications

PURPOSE

Treatment of chronic lateral ankle instability (CLAI) with poor remnant quality is challenging. The aim of the present study was to evaluate clinical results and complications of anatomic reconstruction of the lateral ligaments using allograft tendon and suspensory fixation in the treatment of such patients.

METHODS

One hundred and eight patients with CLAI, who were treated surgically using anatomic reconstruction with allograft tendon and suspensory fixation between April 2016 and January 2018 at our hospital, were retrospectively analysed. None of the patients had sufficient ligament remnants for the modified Broström procedure during the intraoperative evaluation. Eighteen patients were excluded. Seventeen patients were lost to follow-up and 73 patients completed the study. The mean duration of instability symptoms was 39.1 months (range, 6-480 months). The mean follow-up time was 57.5 months (range, 48-69 months). Clinical results were evaluated using the Karlsson scoring scale, American Orthopaedic Foot and Ankle Society-Ankle and Hindfoot (AOFAS-AH) score, visual analogue scale (VAS), patients' subjective satisfaction, and incidence of complications. Mechanical stability was evaluated using the varus talar tilt angle (TTA) and anterior talar displacement (ATD).

RESULTS

The AOFAS-AH scores significantly improved from 67.7 ± 8.5 points to 89.8 ± 9.5 (p < 0.001). The Karlsson scoring scales evolved from 58.8 ± 16.5 to 88.4 ± 11.2 (p < 0.001). VAS scores significantly decreased from 2.9 ± 1.3 to 1.1 ± 1.0 (p < 0.001). On stress radiographs, TTA decreased from 15.1 ± 2.5 degrees to 5.8 ± 2.1 degrees (p < 0.001), whereas ATD reduced from 13.4 ± 2.9 mm to 5.7 ± 1.5 mm (p < 0.001). Patients' subjective satisfaction indicated 46 excellent, 20 good, 5 fair, and 2 bad results. Postoperatively, 15 cases (20.5%) did not achieve complete relief of discomfort or swelling, 9 cases (12.3%) experienced joint stiffness or decreased range of motion, and 6 cases (8.2%) had soft tissue irritation. Residual instability and reoperation are rare. Allograft rejection or wound infection was not observed.

CONCLUSION

For the CLAI patients with poor remnant quality, anatomic reconstruction of the lateral ligaments using allograft tendon and suspensory fixation is an effective procedure, while the top three complications in incidence were residual discomfort, joint stiffness, and soft tissue irritation.

LEVELS OF EVIDENCE

Level IV, retrospective case series.

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.

Articular Cartilage of the Syndesmosis: Avoiding Iatrogenic Cartilage Injury During Syndesmotic Fixation

BACKGROUND

The optimal surgical management of syndesmosis injuries consists of internal fixation between the distal fibula and tibia. Much of the available data on this joint details the anatomy of the syndesmotic ligaments. Little is published evaluating the distribution of articular cartilage of the syndesmosis, which is of importance to minimize the risk of iatrogenic damage during surgical treatment. The purpose of this study is to describe the articular cartilage of the syndesmosis.

METHODS

Twenty cadaveric ankles were dissected to identify the cartilage of the syndesmosis. Digital images of the articular cartilage were taken and measured using calibrated digital imaging software.

RESULTS

On the tibial side, distinct articular cartilage extending above the plafond was identified in 19/20 (95%) specimens. The tibial cartilage extended a mean of 6 ± 3 (range, 2-13) mm above the plafond. On the fibular side, 6/20 (30%) specimens demonstrated cartilage proximal to the talar facet, which extended a mean of 24 ± 4 (range, 20-31) mm above the tip of the fibula. The superior extent of the syndesmotic recess was a mean of 10 ± 3 (range, 5-17) mm in height. In all specimens, the syndesmosis cartilage did not extend more than 13 mm proximal to the tibial plafond and the syndesmotic recess did not extend more than 17 mm proximal to the tibial plafond.

CONCLUSION

Syndesmosis fixation placed more than 13 mm proximal to the tibial plafond would have safely avoided the articular cartilage in all specimens and the synovial-lined syndesmotic recess in most.

CLINICAL RELEVANCE

This study details the articular anatomy of the distal tibiofibular joint and provides measurements that can guide implant placement during syndesmotic fixation to minimize the risk of iatrogenic cartilage damage.

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

Outcomes of ossicle resection and anatomic reconstruction of lateral ligaments for chronic ankle instability with large malleolar accessory ossicles

BACKGROUND

Malleolar accessory ossicles can be found in patients with chronic lateral ankle instability (CLAI). Ossicle resection combined with the modified Broström procedure is the most commonly used surgical method. However, an unrepairable gap after ossicle resection often occurs in patients with large ossicles.

PURPOSE

This study analysed the clinical outcomes of ossicle resection and anatomic ligament reconstruction (ALR) for CLAI with large malleolar accessory ossicles.

METHODS

This study was a retrospective case series. Since 2014, we have adopted ALR for patients with difficulties using the modified Broström procedure after ossicle resection. Sixteen patients with chronic ankle instability and malleolar accessory ossicles were treated with this method between December 2014 and February 2018. The average age of the patients at the time of surgery was 28.9 (range, 16-65) years. They were followed up for an average time of 26.9 (range, 12-47) months. The clinical outcomes were evaluated using the Visual Analogue Scale, Karlsson-Peterson ankle scoring system, subjective satisfaction of patients, and radiographic parameters.

RESULTS

All unrepairable cases occurred in patients with ossicles larger than or equal to 10 mm. The VAS score improved from 3.5 ± 1.6 preoperatively to 1.4 ± 1.0 at the final follow-up (p < 0.05), and the Karlsson-Peterson score improved significantly from 52.7 ± 15.1 to 86.4 ± 8.2 (p < 0.05). There was also an obvious change in the varus talar tilt angle (15.4 ± 2.0° vs 6.2 ± 1.6°, p < 0.05) and anterior talar displacement (14.3 ± 2.1 mm vs 6.3 ± 1.4 mm, p < 0.05). Fourteen patients (87.5%) were satisfied (excellent or good) with their clinical outcomes.

CONCLUSION

If modified Broström procedure is difficult to accomplish effectively after ossicle resection for chronic ankle instability with large malleolar accessory ossicles, ALR is a viable option with satisfactory clinical results.

PT4: New arthroscopic technique for isolated reconstruction of the anterior talofibular ligament using a quadrupled plantaris tendon

The strategy for surgical treatment of chronic ankle instability is becoming increasingly refined. In instances of isolated symptomatic non-repairable anterior talofibular ligament (ATFL) injury, there is a surgical indication for isolated ATFL reconstruction. However, we feel that the typical gracilis tendon graft is not always appropriate. Interest in using the plantaris tendon as a graft has picked up since a biomechanics study found the tensile strength of a quadrupled plantaris tendon is comparable to that of the ATFL. Here, we describe an original arthroscopic technique for isolated ATFL reconstruction using a quadrupled plantaris tendon (PT4) graft.

Anatomical Study on the Reconstruction of the Anterior Talofibular Ligament

The purpose of this study aimed to (1) identify the relationship between the fibula and the talus of the anterior talofibular ligament (ATFL); (2) collect detailed anatomical data and provide anatomical basis for ATFL anatomical reconstruction. We selected 27 ankle specimens of adult cadavers (9 left feet and 18 right feet in 11 males and 16 females; mean age 41.6 years) with the exception of ankle deformities, fractures, underdevelopment and degenerative diseases. In these 27 specimens,15 cases of ATFL were divided into two bundles and 12 cases of ATFL were single bundles. The average ATFL length was 20.31 ± 3.12mm. The center of the ATFL in 11 specimens was located in the calcaneofibular ligament (CFL) foot print area. The long axis of the fibula side stop point was 8.83±1.82 mm, and the short axis was 3.12±0.49 mm. The distance from the center of the ATFL fibula attachment area to the tip of the fibula was 14.22±2.87 mm, and the distance from the center of the CFL is 5.57±1.80mm. The distance from the center of the ATFL talar attachment area to the tibiotalar articular surface was (9.74±2.12) mm, and the distance from the anterior external cartilage surface of the talus was (4.87±1.82) mm. The angle between ATFL and the long axis of the fibula is 78°±12°. Our results suggest that in ATFL reconstruction, the anatomical attachment points around the ATFL or the angle between ATFL and the long axis of the fibula both can be used for bone canal positioning.

Predicting Syndesmotic Injury in OTA/AO 44-B2.1 (Danis-Weber B) Fractures

OBJECTIVE

To establish if preoperative radiographs could predict the rate of syndesmotic injury.

SETTING

Level 1 trauma center.

DESIGN

Retrospective cohort study.

PATIENTS/PARTICIPANTS

There were 548 OTA/AO 44-B2.1 fractures that were reviewed, and 287 patients were included in the study.

MAIN OUTCOME MEASUREMENTS

Ankle radiographs were used to determine the zone of distal extent of the proximal fracture fragment. Syndesmotic injury was defined as positive intraoperative stress examination that required syndesmotic fixation.

RESULTS

There were 191 zone 1 (ending below the plafond) injuries, 57 zone 2 (ending between the physeal scar and the plafond) injuries, and 39 zone 3 (ending above the physeal scar) injuries. Of these, 17% (33 patients) of zone 1, 42% (24) of zone 2, and 74% (29) of zone 3 fractures had syndesmotic injuries. The relative risk of syndesmotic injury of zone 1 compared with zone 2 was 2.4 (P < 0.001), zone 1 to zone 3 was 4.3 (P < 0.001), and zone 2 to zone 3 was 1.8 (P = 0.002). The interobserver and intraobserver reliability was excellent (κ = 0.86, 0.94).

CONCLUSION

OTA/AO 44-B2.1 fractures have a varying rate of syndesmotic injury. Weber B fractures that end between the level of the plafond and the physeal scar (zone 2) are 2.4 times more likely to have a syndesmotic injury compared with those that end below the plafond (zone 1). This is magnified in those injuries ending above the scar (zone 3). This simple classification of OTA/AO 44-B2.1 fractures is predictive of syndesmotic injury and may aid in preoperative counseling and planning.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

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.

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

Purpose

The purpose of this study was to evaluate the attachment areas of the posterior talofibular ligament (PTFL) on the posterolateral tubercle of the talus and the remaining PTFL attachment areas after consequential bony excision.

Methods

Thirty fresh cadaveric ankles were dissected to study the proximal and distal attachment of the PTFL and separated the PTFL into anterior and posterior bundles. The description of the PTFL footprint and the anatomic landmarks from the surrounding structures were analyzed during consequential posterolateral bony excision.

Results

The average PTFL dimension was 26.11 mm (length), 7.65 mm (width), and 1.82 mm (thickness). The footprint area of the PTFL on the talar site consists of the posterior bundle (76.82%) and the anterior bundle (23.18%). If posterolateral tubercle excision was stayed up to a line of a bottom of the flexor hallucis longus (FHL) groove, at least 89% of the PTFL can be preserved.

Conclusion

The posterior bundle of the PTFL is the main bundle on the talar footprint area. To maintain the majority of the attachment of the PTFL, the resection of the posterolateral process could be performed to the bottom of the FHL tendon groove. If resection reaches to the posterior articular cartilage, less than 50% of the PTFL will be preserved. Understanding the footprint of the PTFL plays a key role in posterior ankle impingement surgery.

Clinical Relevance

This study provides guidance for resection of the posterolateral tubercle of the talus and a portion of the PTFL attachment for posterior ankle impingement syndrome. Too much resection of the tubercle may cause instability symptoms.

A calcaneal tunnel for CFL reconstruction should be directed to the posterior inferior medial edge of the calcaneal tuberosity

PURPOSE

Anatomical reconstruction of the calcaneofibular ligament (CFL) is a common technique to treat chronic lateral ankle instability. A bone tunnel is used to fix the graft in the calcaneus. The purpose of this study is to provide some recommendations about tunnel entrance and tunnel direction based on anatomical landmarks.

METHODS

The study consisted of two parts. The first part assessed the lateral tunnel entrance for location and safety. The second part addressed the tunnel direction and safety upon exiting the calcaneum on the medial side. In the first part, 29 specimens were used to locate the anatomical insertion of the CFL based on the intersection of two lines related to the fibular axis and specific landmarks on the lateral malleolus. In the second part, 22 specimens were dissected to determine the position of the neurovascular structures at risk during tunnel drilling. Therefore, a method based on four imaginary squares using external anatomical landmarks was developed.

RESULTS

For the tunnel entrance on the lateral side, the mean distance to the centre of the CFL footprint was 2.8 ± 3.0 mm (0-10.4 mm). The mean distance between both observers was 4.2 ± 3.2 mm (0-10.3 mm). The mean distance to the sural nerve was 1.4 ± 2 mm (0-5.8 mm). The mean distance to the peroneal tendons was 7.3 ± 3.1 mm (1.2-12.4 mm). For the tunnel exit on the medial side, the two anterior squares always contained the neurovascular bundle. A safe zone without important neurovascular structures was found and corresponded to the two posterior squares.

CONCLUSION

Lateral landmarks enabled to locate the CFL footprint. Precautions should be taken to protect the nearby sural nerve. A safe zone on the medial side could be determined to guide safe tunnel direction. A calcaneal tunnel should be directed to the posterior inferior medial edge of the calcaneal tuberosity.

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.

Anatomy of Ankle Syndesmotic Ligaments: A Systematic Review of Cadaveric Studies

Diagnosis and management of isolated syndesmotic injuries are controversial and highly debated. Hence, the aim of this study is to explore and gain the current understanding pertaining to detailed anatomy of syndesmotic ligaments through a systematic review of published cadaveric studies. A systematic review was conducted online for literature published in English using PubMed and Google Scholar, as per PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, up to April 30, 2019. Predefined eligibility criteria were applied, and the data thus compiled was analyzed. Study quality was assessed based on Quality Appraisal for Cadaveric Studies (QUACS) scale. A total of 12 studies reporting 365 ankles were included in this review. Considerable inconsistency in the naming and description of syndesmotic ligaments was observed, with only 2 studies reporting the vasculature of the ligaments. Hence further investigation of the anatomy of the syndesmotic ligaments is recommended so as to better inform clinical practice, as awareness of anatomy is critical for assessment, healing, and successful surgical management.Levels of Evidence: Level III: Systematic review of anatomical dissections.

The tibialis posterior tendon footprint: an anatomical dissection study

BACKGROUND

The tibialis posterior tendon (TPT) is the main dynamic stabilizer of the medial longitudinal arch of the foot. Especially in adult acquired flatfoot deformity (AAFD) the TPT plays a detrimental role. The pathology and function of the tendon have been extensively investigated, but knowledge of its insertional anatomy is paramount for surgical procedures. This study aimed to analyze the complex distal footprint anatomy of the TPT.

METHODS

Forty-one human anatomical specimens were dissected and the distal TPT was followed to its bony footprints. After tendon removal the footprints were marked with ink. Standardized photographs were taken and consecutively analyzed by digital imaging measurements. Footprint length, width, area of insertion, location, and shape was studied regarding the main insertion at the navicular bone.

RESULTS

All specimens had the main TPT insertion at the navicular bone (41/41, 100%). Sixty-three percent of navicular TPT insertions were located at the plantar aspect. The mean navicular footprint measured 12.1 mm × 6.9 mm in length and width, respectively. The tendon further spread into several slips which anchored the tibialis posterior deep in the plantar arch. TPT insertions were highly variable with an involvement of up to eight distinct bony footprints in the mid- and hindfoot. The second most common additional footprint was the lateral cuneiform (93% of dissected feet), followed by the medial cuneiform (80%), the metatarsal bases [1-5] (80%), the cuboid (46%), the intermediate cuneiform (19%), and the calcaneus (12%).

CONCLUSIONS

The present study adds to current knowledge on the footprint anatomy of the TPT. Based on the findings of this study we advocate a plantar location of flexor digitorum longus tendon transfer in flexible AAFD in order to restore the anatomical lever and insertion of the TPT.

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.

Characteristic features of the insertions of the distal tibiofibular ligaments on three-dimensional computed tomography- cadaveric study

Purpose

The purpose of this study was to clarify the insertion sites of the anterior inferior tibiofibular ligament (AITFL) and posterior inferior tibiofibular ligament (PITFL) and related osseous landmarks on three-dimensional computed tomography images.

Methods

Twenty-nine non-paired, formalin-fixed human cadaveric ankles were evaluated. The tibial and fibular insertion sites of the AITFL and PITFL were identified. The morphology and location of the insertion sites and their positional relationships with osseous structures were analyzed on three-dimensional computed tomography images.

Results

The AITFL had a trapezoidal shape, with fibers that ran obliquely lateral from a wider insertion at the lateral distal tibia to the medial distal fibula. The PITFL had a similar shape to the AITFL; however, it ran more horizontally, with fibers running in the same direction. In the tibia, the anterior capsular ridge and the Chaput’s and Volkmann’s tubercles were useful osseous landmarks for the insertion sites. In the fibula, the centers of the insertion sites of the AITFL and PITFL were located on the edges of the distal anterior and posterior fibula, which were useful osseous landmarks. The mean distances between the center points of the tibial and fibular insertion sites of the AITFL and PITFL were 10.1 ± 2.4 mm and 11.7 ± 2.6 mm, respectively.

Conclusions

The relationships between the characteristic features of the distal tibia and fibula and the insertions of the AITFL and PITFL were consistent. The present findings improve the understanding of the anatomy of the insertions of the distal tibiofibular syndesmotic joint.

The calcaneofibular ligament has distinct anatomic morphological variants: an anatomical cadaveric study

PURPOSE

The purpose of this study was to investigate if the calcaneofibular ligament (CFL) presents morphologic variants and measure the morphometrics of the ligament and its footprints METHODS: An anatomical study of 47 fresh-frozen below-the-knee ankle specimens was performed. Lateral ankle structures were dissected to expose the CFL. Overdissection was avoided to not modify the native morphology. The morphology (number and orientation of CFL bundles) and measurements of CFL insertions were recorded with ankle secured in neutral position.

RESULTS

Four distinct morphological-oriented shapes of the CFL were observed. These included single bundle, Y-shape double bundle, V-shape double bundle, and associated with the lateral talocalcaneal ligament. The most frequent CFL morphology observed was the single bundle and the Y-shape double bundle, present in 21 (44.7%) and 13 (27.7%) ankles. The V-shape double bundle and the CFL double bundle associated with the lateral talocalcaneal ligaments were less common, appearing only in eight (17.0%) and five (10.6%) ankles. The CFL length was higher in single bundle and Y-shaped double bundle CFL variants, about 30 mm each. Footprint morphometrics were heterogenous amongst the different CFL variants.

CONCLUSION

The CFL presents four distinct morphological-oriented shapes. The double bundle, V-shaped and Y-shaped CFL variants are uncommon and poorly reported in the literature. Their relation to the lateral talocalcaneal ligament and the inferior fascicle of the anterior talofibular ligament requires further research. The CFL morphology provides detailed knowledge of CFL anatomy that can improve diagnostic procedures. Furthermore, this information can fine-tune graft selection and sizing and allow a more precise anatomic placement during surgical reconstruction.

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.

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.

A new minimally invasive method for anatomic reconstruction of the lateral ankle ligaments with a Tightrope system

BACKGROUND

Several minimally invasive anatomic reconstruction techniques of the lateral ligaments have been introduced for the treatment of chronic lateral ankle instability. However, these strategies may not always follow accurate ligament anatomic attachments, especially in the construction of the fibular bone tunnels.

OBJECTIVES

This study reported a new percutaneous technique for reconstruction of the ligaments of lateral ankle anatomically with a Tightrope system.

METHODS

From April 2016 to August 2016, 25 ankles of 24 patients with chronic ankle instability underwent our new percutaneous anatomic reconstruction of the lateral ligaments with a Tightrope system. The operation was performed through several small incisions. The fibular tunnel was made obliquely from the anteromedial side of lateral malleolus tip towards retro-malleolar cortex. The graft was fixed in the tunnel with the help of a Tightrope system. The calcaneal tunnel and talar tunnel were made as our previous method. The mean final follow-up was 12.2 months (range 10-14). Visual Analogue Scale for pain, American Orthopaedic Foot and Ankle Society score, and patients' subjective satisfaction were used to measure clinical outcomes. Preoperative and postoperative stress tests were performed and radiographic parameters were measured.

RESULTS

The Visual Analogue Scale decreased from 3.0 ± 1.4 to 1.3 ± 0.8 at the last follow-up (p < 0.01). The American Orthopaedic Foot and Ankle Society score was improved from 70.2 ± 5.4 preoperatively to 92.4 ± 5.3 at the final follow-up (p < 0.01). Radiologically, the mean anterior talar displacement was 13.1 ± 2.7 mm preoperatively versus 5.6 ± 1.3 mm at last follow-up (p < 0.01),and the mean varus talar tilt angle was 15.0° ± 2.4° preoperatively versus 5.6° ± 1.9° at the last follow-up (p < 0.01). Patients were satisfied ('excellent' or 'good') in 23 ankles (92%). Two patients reported residual instability but less apprehension than the preoperative condition.

CONCLUSIONS

Percutaneous anatomic reconstruction of the lateral ligaments of the ankle with a Tightrope system is an anatomic and effective procedure for the treatment of chronic lateral ankle instability.

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.

Anatomical Footprint of the Tibialis Anterior Tendon: Surgical Implications for Foot and Ankle Reconstructions

This study aimed to analyze precisely the dimensions, shapes, and variations of the insertional footprints of the tibialis anterior tendon (TAT) at the medial cuneiform (MC) and first metatarsal (MT1) base. Forty-one formalin-fixed human cadaveric specimens were dissected. After preparation of the TAT footprint, standardized photographs were made and the following parameters were evaluated: the footprint length, width, area of insertion, dorsoplantar location, shape, and additional tendon slips. Twenty feet (48.8%) showed an equal insertion at the MC and MT1, another 20 feet (48.8%) had a wide insertion at the MC and a narrow insertion at the MT1, and 1 foot (2.4%) demonstrated a narrow insertion at the MC and a wide insertion at the MT1. Additional tendon slips inserting at the metatarsal shaft were found in two feet (4.8%). Regarding the dorsoplantar orientation, the footprints were located medial in 29 feet (70.7%) and medioplantar in 12 feet (29.3%). The most common shape at the MT1 base was the crescent type (75.6%) and the oval type at the MC (58.5%). The present study provided more detailed data on the dimensions and morphologic types of the tibialis anterior tendon footprint. The established anatomical data may allow for a safer surgical preparation and a more anatomical reconstruction.

Bony landmarks available for minimally invasive lateral ankle stabilization surgery: a cadaveric anatomical study

PURPOSE

The purpose of this study was to determine the clinical utility of three bony tubercles: fibular obscure tubercle, talar obscure tubercle and tuberculum ligamenti calcaneofibularis, to serve as anatomical landmarks for defining the precise location of the origins and insertions of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL).

METHODS

Twelve lower extremity cadaveric specimens were procured. The detectability of the tubercles was tested using palpation and fluoroscopy with subsequent confirmation after dissection. If the tubercles were present, then distances from the identified tubercles to the footprint centres and the intersection of the ATFL and CFL were measured to allow precise localization of the ATFL and CFL origin and intersection sites. Further, if the tubercles were not detectable, then an attempt to provide an alternative means of localizing ATFL and CFL origin and insertion sites was made by measuring distances between alternative landmarks and other important structures. All the measurements were performed by two researchers, and the results were averaged.

RESULTS

The fibular obscure tubercle existed and was detectable in all specimens. It was located 1.3 mm proximal to the articular tip of the fibula, 2.7 mm to the intersection of the ATFL and CFL, 3.7 mm distal to the ATFL and 4.9 mm proximal to the CFL origins. The talar obscure tubercle existed 58 % of specimens and was detectable in 57 %. The talar obscure tubercle was located 1.4 mm to the ATFL. The ATFL insertion point was located 60 % of the distance from the inferolateral corner to the anterolateral corner of the of talar body along the anterior border of the talar lateral articular facet. The tuberculum ligamenti calcaneofibularis existed in 33 % of specimens and was detectable in 8 %. The CFL inserted 17 mm on a perpendicular projected line distal from the subtalar joint.

CONCLUSIONS

The fibular obscure tubercle was clinically relevant and reliable bony landmark of the ATFL and CFL origin location. However, the talar obscure tubercle was less reliable and the tuberculum ligamenti calcaneofibularis was rarely available and as such alternative landmarks for the ATFL and CFL insertion location should be utilized. The present study describes the utility of clinically relevant bony landmarks that may assist in identifying the origins and insertions of the ATFL and CFL to facilitate minimally invasive ankle stabilization surgery.

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.

Morphological variations of the deltoid ligament of the medial ankle

Morphological variations of the deltoid ligament were investigated in this study, with the aim of classifying the different types on the basis of their components. Sixty ankles from 39 cadavers were dissected. The origin and insertion sites of the deltoid ligament were identified, and its length, width, and thickness were measured. The deltoid ligament was divided into two layers, superficial and deep, which respectively comprised four components (tibionavicular, tibiospring, tibiocalcaneal, and superficial posterior tibiotalar ligaments) and two components (anterior tibiotalar and deep posterior tibiotalar ligaments). The tibiospring and tibiocalcaneal ligaments were found in 100% of the specimens, while the prevalence rates of other components lay within the range 63.3-96.7%. The tibionavicular and deep posterior tibiotalar ligaments were the thinnest and thickest, respectively, while the other ligaments had similar thicknesses. The deltoid ligament was classified into types I-IV according to the combinations of these components: all components were present in type I (48.3%), the tibionavicular ligament was absent in type II (36.7%), only the superficial posterior tibiotalar ligament was absent in type III (6.7%), and only the anterior tibiotalar ligament was absent in type IV (8.3%). In conclusion, these results improve knowledge of the morphological and morphometric characteristics of the deltoid ligament and thus provide helpful information for surgical procedures in this region. Clin. Anat. 29:1059-1065, 2016. © 2016 Wiley Periodicals, Inc.

Cadaveric Analysis of the Distal Tibiofibular Syndesmosis

BACKGROUND

Unstable ankle fractures with syndesmotic injuries commonly occur and can result in significant morbidity. Although the need for an anatomic reduction is clear, there is still debate surrounding the optimal operative treatment. Recent literature shows an increasing interest in anatomic ligament repair or reconstruction in the acute and chronic syndesmosis injury. Despite this trend, there is insufficient literature detailing anatomy of the distal tibiofibular syndesmosis. In the literature that does exist, there is controversy regarding the ligamentous anatomy of the syndesmosis. None of the current literature describes an anatomic constant that may be used as an intraoperative reference for anatomic ligament reconstructions.

METHODS

Ten sets of tibia and fibula free of all soft tissue were used to analyze osseous structures. Another 10 nonpaired, fresh-frozen specimens were used to study the distal tibiofibular syndesmosis. These were measured using a 3-dimensional tracking system. Measurement of each ligament width at origin and insertion, length, and distance from the tibial articular cartilage was performed.

RESULTS

The superior and inferior insertions of the anterior inferior tibiofibular ligament measured 22.7 mm and 3.4 mm proximal to the distal articular cartilage of the tibia, respectively. The superior insertion of the posterior inferior tibiofibular ligament measured 15.2 mm proximal to the articular cartilage. The superior and inferior insertions of the interosseous ligament measured 31.8 mm and 9.2 mm proximal to the distal articular cartilage, respectively. The inferior transverse ligament was a prominent identifiable structure in 70% of specimens.

CONCLUSIONS

The superior margin of the distal articular cartilage could serve as a consistent anatomic landmark for reconstruction. The inferior transverse ligament is an identifiable structure in 70% of the specimens studied.

CLINICAL RELEVANCE

This article clarifies the anatomy and provides measurements from an anatomic constant that can guide reconstruction and intraoperative evaluation of the syndesmosis.

Biomechanical stability of tape augmentation for anterior talofibular ligament (ATFL) repair compared to the native ATFL

PURPOSE

Current methods of anterior talofibular ligament (ATFL) reconstruction fail to restore the stability of the native ATFL. Therefore, augmented anatomic ATFL reconstruction gained popularity in patients with attenuated tissue and additional stress on the lateral ankle ligament complex. The aim of the present study was to evaluate the biomechanical stability of the InternalBrace (Arthrex Inc., Naples, FL, USA), a tape augmentation designed to augment the traditional Broström procedure.

METHODS

Twelve (12) fresh-frozen human anatomic lower leg specimens were randomized into two groups: a native ATFL (ATFL) and a tape augmentation group (IB). Dual-energy X-ray absorptiometry (DEXA) scans were carried out to determine bone mineral density (BMD) of the specimens. The ligaments were stressed by internally rotating the tibia against the inverted fixated hindfoot. Torque at failure (Nm) and angle at failure (°) were recorded.

RESULTS

The ATFL group failed at an angle of 33 ± 10°. In the IB group, construct failure occurred at an angle of 46 ± 16°. Failure torque reached 8.3 ± 4.5 Nm in the ATFL group, whereas the IB group achieved 11.2 ± 7.1 Nm. There was no correlation between angle at ATFL or IB construct failure or torque at failure, respectively, and BMD for both groups.

CONCLUSION

This study reveals that tape augmentation for ATFL reconstruction shows similar biomechanical stability compared to an intact native ATFL in terms of torque at failure and angle at failure. BMD did not influence the construct stability. Tape augmentation proved an enhanced initial stability in ATFL reconstruction which may allow for an accelerated rehabilitation process.

LEVEL OF EVIDENCE

II.

Assessment of the feasibility of arthroscopic visualization of the lateral ligament of the ankle: a cadaveric study

PURPOSE

An anatomical study was performed to assess the feasibility of arthroscopic visualization of the lateral ligaments of the ankle.

METHODS

The fibular, talar and calcanear insertions of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) were identified by standard arthroscopy portals. After dissection of the ATFL and CFL, bone tunnels were created at the estimated centres of their footprints. Dissection was then performed to identify the footprints and their position in relation to bony landmarks. The distance from the real centre of the footprint to the corresponding tunnel entrance was measured.

RESULTS

Fourteen fresh frozen ankles were included. The ATFL and CFL were identified in all cases. The centre of the fibular ATFL footprint was found to be 16.1 ± 3.5 mm from the tip of the fibula, and the talar footprint was 18.4 ± 2.8 mm from the apex of the lateral talar process. The centre of the fibular CFL footprint was 4.2 ± 0.8 mm from the tip of the fibula, and the calcaneal footprint was 18.4 ± 2.5 mm from the fibular process of the calcaneum. The fibular tunnel was 2.9 ± 3 mm proximally from the centre of the ATFL fibular footprint, the talar tunnel was 4.4 ± 3.2 mm proximally from the centre of the talar footprint, and the calcaneal tunnel was 3.3 ± 2.8 mm too anterior from the CFL calcaneal footprint. No iatrogenic lesions were noted.

CONCLUSION

Arthroscopic identification of the ATFL, CFL and their corresponding footprints can be considered safe and reliable. Tunnels entrances, in preparation for arthroscopic ligament reconstruction, are precisely positioned. Arthroscopic anatomical ligament reconstruction is a feasible option.