Application of stretchable strain sensors and an inertial measurement unit for simulative tension analysis of the calcaneofibular ligament in formalin-fixed cadavers.

BACKGROUND: The calcaneofibular ligament, a component of the lateral ligament complex of the ankle joint, plays an essential role in ankle-joint stability. To understand the mechanism of sprain-induced calcaneofibular ligament injury, the effect of ankle positions on calcaneofibular ligament tension needs to be ascertained. METHODS: We propose a convenient method that combines stretchable strain sensors and an inertial measurement unit for simulative tension analysis of the calcaneofibular ligament in formalin-fixed cadavers. The stretchable strain sensor was pre-stretched approximately 1.3 times and, then set along the direction of the calcaneofibular ligament; a capacitance value from the sensor was used as a parameter to reflect the tension generated. Accurate three-axial inertial measurement unit-based monitoring of joint angles was undertaken for ten cadaveric ankles in measurements at 10° intervals from 30° plantarflexion to 20° dorsiflexion, followed by the investigation of additional effects with 10° inversion and eversion. FINDINGS: Two-way repeated-measures ANOVA revealed a significant interactive effect for plantar/dorsiflexion × inversion/eversion and main effects for plantar/dorsiflexion and inversion/eversion. Post hoc pairwise analysis confirmed that 20° dorsiflexion or 10° inversion induces tension, whereas 10° eversion causes relaxation. Moreover, a promotional interactive effect by 20° dorsiflexion and 10° inversion and an offsetting effect by 10° eversion to 20° dorsiflexion were revealed. The measured values showed high levels of reliability and reproducibility (intraclass correlation coefficient [1,1] = 0.89). INTERPRETATION: These results appropriately demonstrate the tensile action of calcaneofibular ligament. The novel approach investigated herein potentially opens new avenues for precise ligament-function evaluation.

Clinical significance of posterior talofibular ligament injury in chronic lateral ankle instability.

PURPOSE: Although arthroscopic repair of the anterior talofibular ligament (ATFL) is widely performed, the effect of posterior talofibular ligament (PTFL) injury on clinical outcomes remains unclear. This study aimed to evaluate the magnetic resonance imaging (MRI) findings of the PTFL in chronic lateral ankle instability (CLAI) and determine whether the presence or absence of PTFL injury affected the postoperative outcomes of arthroscopic ATFL repair. MATERIALS AND METHODS: Forty ankles of 35 patients who underwent arthroscopic repair for CLAI were included in this study as the experimental group, together with 25 ankles of 24 patients without CLAI as the control group. The PTFL thickness (PTFLT) and PTFL cross-sectional area (PTFLCSA) were measured using MRI and compared between the control and CLAI groups. The clinical outcomes of arthroscopic repair were compared between ankles with and without PTFL injuries. RESULTS: The mean PTFLT and PTFLCSA values were significantly higher in the CLAI group than in the control group. The PTFLT and PTFLCSA in the PTFL injury group were significantly larger than those in the non-injury group in the CLAI group. Postoperatively, there were no significant differences in clinical scores and talar tilt angles on stress radiographs between ankles with and without PTFL injury; however, instability recurrence was frequently observed in ankles with PTFL injury (32.1%) compared to the ankles without PTFL injury (16.7%). Poor-quality ATFL remnant, ATFL inferior fascicle, and calcaneofibular ligament injuries were frequently observed in ankles with PTFL injuries. CONCLUSIONS: Our findings indicate that PTFL injury is highly associated with CLAI but it does not affect postoperative clinical scores. However, postoperative instability recurrence was more often observed in ankles with PTFL injuries, given that they frequently have poor-quality ATFL remnants and CFL injuries. EVIDENCE LEVEL: Level III.

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.

Directly measured strain patterns of the anterior talofibular and calcaneofibular ligaments after isolated ATFL repair in a combined ATFL and CFL injury: A cadaver study.

BACKGROUND: Even though 20% of chronic lateral ankle instability results from a combined anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) injury, only the ATFL is sutured using arthroscopic ligament repair techniques. Although some biomechanical and clinical studies have proved that isolated ATFL repair yields excellent results, previous biomechanical studies were performed using systems that only allow indirect estimations. The purpose of this study was to clarify strain patterns by directly measuring repaired ATFL and CFL strain patterns on cadaveric models that underwent isolated ATFL repair of a combined ATFL and CFL injury. METHODS: The miniaturization ligament performance probe (MLPP) system was used for directly measuring the strain patterns to insert the strain gauges into the mid-substance of normal and repaired ATFL and CFL fibers in five cadaveric specimens to allow measurement of strain patterns in the axial and three-dimensional motion of the ankle. RESULTS: The normal and repaired ATFL showed similar strain patterns in axial and three-dimensional motions. During the axial range of motion of the ankle, the repaired CFL showed a strain pattern almost similar to that of normal CFL, but the strain increased as the plantar flexion or dorsiflexion angle increased to the maximum value of 100 at 30° plantarflexion or strain values of 17-55/100 at 15°dorsiflexion. During three-dimensional motion, the repaired CFL was under the maximum value of 100 during dorsiflexion-inversion and exhibited less strain (7-38/100) during plantar flexion-eversion. CONCLUSION: The repaired CFL did not show a strain pattern that was completely consistent with a normal strain pattern; however, it did have some degree of tension similar to a normal strain pattern, even though it was not directly repaired.

A previously unknown variant of the calcaneofibular ligament.

The lateral ankle joint is composed of three ligaments: the anterior talofibular ligament (ATFL), posterior talofibular ligament (PTFL) and calcaneofibular ligament (CFL). The ATFL and CFL demonstrate morphological variation, especially regarding their shape and number of bands. During standard anatomical dissection, an unusual type of triple CFL was observed: the CFL was composed of two bands originating on the lateral malleolus, and the presence of a lateral talocalcaneal ligament (LTC) originating on the talus bone. The insertion point of each band was located on the calcaneal bone. An understanding of these anatomical patterns provides a clearer view of ankle joint biomechanics, and improved the planning and performance of surgical treatment.

Modified Gracilis Autograft Preparation for Arthroscopic Anterior Talofibular and Calcaneofibular Ligament Anatomic Reconstruction: Technical Tip.

Visual AbstractThis is a visual representation of the abstract.

Comparative analysis of arthroscopic technique for anterior talofibular and calcaneofibular ligament reconstruction versus open modified brostrom-gould procedure in chronic lateral ankle instability management.

BACKGROUND: Chronic Lateral Ankle Instability (CLAI) is a common condition treated using either Anterior Talofibular and Calcaneofibular Ligament (ATFL and CFL) reconstruction or Modified Brostrom Procedure (MBP). However, the comparative efficacy of these approaches is not well-studied. METHODS: In this study, clinical data were retrospectively collected from 101 patients diagnosed with CLAI who underwent either ATFL and CFL reconstruction (n = 51) or the MBP (n = 50). Patients were comparable in terms of age, sex, Body Mass Index (BMI), post-injury duration, preoperative American Orthopedic Foot and Ankle Society (AOFAS) score, Karlsson score, Visual Analog Score (VAS), Anterior Talar Translation, and Talar Tilt Angle. RESULTS: The post-operative measures showed no significant differences in AOFAS Score, Karlsson Score, and VAS between both treatment groups. However, patients who underwent ATFL and CFL reconstruction showed significantly lower follow-up Anterior Talar Translation (mean = 4.1667 ± 1.3991 mm) and Talar Tilt Angle (mean = 5.0549 ± 1.6173°) compared to those who underwent MBP. Further, patients treated with ATFL and CFL reconstruction experienced a significantly longer postoperative recovery time (median = 6 weeks) compared to MBP (median = 3 weeks). CONCLUSIONS: Although both therapeutic techniques were generally effective in treating CLAI, the ATFL and CFL reconstruction approach delivered superior control of Anterior Talar Translation and Talar Tilt Angle. However, its longer recovery time merits further study to optimize the balance between therapeutic efficacy and recovery speed.

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 Relationship Between Calcaneofibular Ligament Injury and Ankle Osteoarthritis Progression: A Comprehensive Analysis of Stress Distribution and Osteophyte Formation in the Subtalar Joint.

BACKGROUND: Ankle osteoarthritis (OA) mainly arises from trauma, particularly lateral ligament injuries. Among lateral ligament injuries, ankles with calcaneofibular ligament (CFL) injuries exhibit increased instability and can be a risk factor ankle OA progression. However, the relationship between CFL injury and OA progression remains unclear. Therefore, this study aims to assess the relationship between CFL injuries and ankle OA by investigating stress changes and osteophyte formation in subtalar joint. METHODS: We retrospectively reviewed the magnetic resonance imaging (MRI) and plain radiographic evaluations of 100 ankles of 91 patients presenting with chronic ankle instability (CAI), ankle OA, or other ankle conditions. The association between CFL injuries on the oblique view of MRI and the severity of ankle OA (based on Takakura-Tanaka classification) was statistically evaluated. Additionally, 71 ankles were further subjected to CT evaluation to determine the association between the CFL injuries and the Hounsfield unit (HU) ratios of the subtalar joint and medial gutter, and the correlation between the subtalar HU ratios and osteophyte severity were statistically evaluated. RESULTS: CFL injury was observed in 35.9% (14/39) of patients with stage 0, 42.9% (9/21) with stage 1, 50.0% (10/20) with stage 2, 100% (9/9) with stage 3a, and 90.9% (10/11) with stage 3b. CFL-injured ankles exhibited higher HU ratios in the medial gutter and lower ratios in the medial posterior subtalar joint compared to uninjured ankles. A negative correlation was observed between medial osteophyte severity and the medial subtalar joint HU ratio. CONCLUSION: Our findings suggest that CFL injuries are common in severe ankle OA impairing the compensatory function of the subtalar joint through abnormal stress distribution and osteophyte formation.

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.

Prevalence and Injury Patterns of CFL Injury in Chronic Lateral Ankle Instability: An Observational Cross-Sectional Study Using Ultrasound.

The purpose of this paper is to assess the prevalence and injury patterns of the calcaneofibular ligament (CFL) in chronic lateral ankle instability (CAI) patients using ultrasound imaging. This retrospective study included 938 ankle ultrasound images from January 2016 to May 2018. The patients' demographic data and the injury pattern classified by the injury location and the remnant quality were recorded and correlated using t tests, Fisher's exact tests, and post hoc tests accordingly. Of the 938 CAI patients, CFL injury was found in 408/938 (44%). Among the 408 anterior talofibular ligament (ATFL) and CFL complex injury patients, 71/408 (17%) presented with a completely absorbed ATFL, whereas 13/71 (18%) presented with an absorbed CFL. The total CFL absorption proportion in all patients was relatively low (30/938 = 3%). Post hoc tests indicated a negative association between thickened ATFLs and complex injuries. In addition, a positive association existed between absorbed ATFLs and complex injuries as well as absorbed ATFLs and absorbed CFLs. Thus, the results indicated that total tearing and absorption injury patterns of the CFL in CAI are not common. Even when the ATFL is absorbed, only approximately one-fifth (13/71 = 18%) of CFLs require reconstruction, suggesting that it is unnecessary to routinely repair or reconstruct CFLs in all lateral ligament surgeries.

Comparison of Clinical Outcomes With Arthroscopic ATFL Repair With the CFL Repair and Open ATFL and CFL Repair in Chronic Lateral Ankle Instability.

It is important to eliminate instability related to chronic lateral ankle instability (CLAI) to prevent osteoarthritis progression. We performed arthroscopic anterior talofibular ligament (ATFL) repair and performed calcaneofibular ligament (CFL) repair if instability remained. This study aimed to assess the clinical outcomes of our arthroscopic procedure compared to that of open surgery. Forty ankles underwent arthroscopic surgery and 23 ankles underwent open surgery to repair the lateral ankle ligaments for CLAI. In the arthroscopic surgery, varus stress was applied under fluoroscopy after ATFL repair, and CFL repair was performed if instability remained. Open surgery was performed using the Broström procedure with ATFL and CFL repair. To assess clinical outcomes, American Orthopaedic Foot & Ankle Society (AOFAS) and Karlsson-Peterson (KP) scores were collected preoperatively and at the final follow-up. The talar tilt angle (TTA) was measured preoperatively and 1 year postoperatively. The arthroscopic group showed significantly higher AOFAS and KP scores at the final follow-up compared to the open surgery group. There was no significant difference in TTA at 1 year between the groups. In open surgery, 2 patients required revision surgery. There were no major complications, but scar-related pain in 2 cases of open surgery was reported. Arthroscopic ATFL repair with the CFL repair gave satisfactory clinical outcomes compared to open surgery in CLAI because of low invasive to soft tissue including the joint capsule. It is important to minimize soft tissue dissection in repairing the lateral ankle ligament in patients with CLAI.

Radiographic Anatomy of the Lateral Ankle Ligament Complex: A Cadaveric Study.

BACKGROUND: When lateral ankle sprains progress into chronic lateral ankle instability (CLAI), restoring precise anatomic relationships of the lateral ankle ligament complex (LALC) surgically is complex. This study quantifies the radiographic relationships between the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and prominent osseous landmarks visible under fluoroscopy to assist in perioperative practices for minimally invasive surgery for CLAI. METHODS: Ten fresh frozen ankle specimens were dissected to expose the LALC and prepared by threading a radiopaque filament through the ligamentous footprints of the ATFL and CFL. Fluoroscopic images were digitally analyzed to define dimensional characteristics of the ATFL and CFL. Directional measurements of the ligamentous footprints relative to the lateral process of the talus and the apex of the posterior facet of the calcaneus were calculated. RESULTS: Dimensional measurements of the ATFL were a mean length of 9.3 mm, fibular footprint of 9.4 mm, and talar footprint of 9.1 mm. Dimensional measurements of the CFL were a mean length of 19.4 mm, fibular footprint of 8.2 mm, and calcaneal footprint of 7.3 mm. From the radiographic apparent tip of the lateral process of the talus, the fibular attachment of the ATFL was found 13.3 mm superior and 4.4 mm posterior, whereas the talar attachment was found 11.5 mm superior and 4.8 mm anterior. From the radiographic apparent posterior apex of the posterior facet of the calcaneus, the fibular attachment of the CFL was found 0.2 mm inferior and 6.8 mm anterior, whereas the calcaneal attachment was found 14.3 mm inferior and 5.9 mm posterior. CONCLUSION: The ATFL and CFL were radiographically analyzed using radiopaque filaments to outline the ligamentous footprints in their native locations. These ligaments were also localized with reference to 2 prominent osseous landmarks. These findings may assist in perioperative practices for keyhole incision placement and arthroscopic guidance. Perfect lateral ankle joint imaging with talar domes superimposed is required to be able to do this. CLINICAL RELEVANCE: Radiographic evaluation of the ATFL and CFL with reference to prominent osseous landmarks identified under fluoroscopy may assist in perioperative practices for minimally invasive surgery to address CLAI for keyhole incision placement and arthroscopic guidance.

Magnetic Resonance Imaging Characteristics of a Lateral Ligament Injury in Acute Ankle Sprains Among Athletes.

Background: It is important to identify the location and pattern of lateral ligament injuries that are related to the development and prognosis of chronic ankle instability in athletes with ankle sprains. Purpose: To describe the location and pattern of lateral ligament injuries on magnetic resonance imaging (MRI) in elite-level or amateur athletes with acute ankle sprains and to further assess the risk of associated concomitant injuries. Study Design: Cross-sectional study; Level of evidence, 3. Methods: The anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) of 110 athletes with an ankle lateral ligament injury (mean age, 24.7 years) were evaluated. MRI scans were evaluated for the location and pattern of ATFL and CFL tears such as sleeve avulsions as well as concomitant deltoid ligament injuries, bone contusions, and osteochondral lesions of the talus (OLTs). Results: On MRI, 52 (47.3%) athletes had an isolated ATFL tear, 56 (50.9%) athletes had both ATFL and CFL tears, and 2 (1.8%) athletes had an isolated CFL tear. ATFL injuries occurred at the fibula, midsubstance, and talus in approximately equal numbers, whereas the majority of CFL injuries occurred at the calcaneal insertion. Concomitant deltoid ligament injuries were identified in 18 (16.4%) athletes. In addition, concomitant bone contusions and OLTs were identified in 38 (34.5%) and 6 (5.5%) athletes, respectively. Using linear-by-linear analysis, CFL injuries correlated with concomitant deltoid ligament and bone injuries (P = .023 and P = .001, respectively) and a sleeve injury pattern (P = .005). Conclusion: After an acute ankle ligament rupture, almost all athletes involved in this study had injured their ATFL, and approximately 50% had a concomitant injury to the CFL. The rate of sleeve-type CFL injuries at the calcaneal insertion was high, and concomitant deltoid ligament injuries and OLTs were associated with this pattern of injury.

Quantitative evaluation of calcaneofibular ligament injury on the oblique coronal view of magnetic resonance imaging in chronic lateral ankle instability.

BACKGROUND: In the treatment of chronic lateral ankle instability (CLAI), the repair of the calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL) is still being discussed, possibly due to the difficulty in assessing CFL injuries. In particular, it is challenging to evaluate the extent of CFL deficiency quantitively. We hypothesized that CFL tension change would alter morphology of the CFL on magnetic resonance imaging (MRI) and that measuring this morphological change allows assessing CFL injury quantitatively. Thus, this study aimed to analyze the feasibility of quantitatively assessing CFL injuries using MRI. METHODS: Sixty-four ankles with CLAI were included and divided into two groups: with (ATFL and CFL group, 31 ankles) or without CFL repair (ATFL group, 33 ankles) in addition to arthroscopic ATFL repair. The angle between the CFL and calcaneal axis (CFLCA) and the bending angles of the CFL was defined as the flexed CFL angle (FCA) were measured on the oblique CFL view of preoperative MRI. The diagnostic abilities of these angles for CFL injury and correlations between these angles and stress radiographs were analyzed. RESULTS: The sensitivity and specificity of CFLCA were 86.7 % and 88.7 %, and those of FCA were 63.3 % and 77.4 %, respectively. The combination of CFLCA and FCA improved the sensitivity to 93.3 %. The cutoff points of CFLCA and FCA were 3.8° and 121.2°, respectively. There were significant moderate and weak correlations between the talar tilting angle and CFLCA or FCA (rs = -0.533, and rs = -0.402, respectively). The CFLCA and FCA were significantly smaller in the ATFL and CFL group than those in the other groups. CONCLUSIONS: Measurement of CFLCA and FCA in oblique CFL view on MRI could be useful for the quantitative evaluation of CFL injury in patients with CLAI． LEVEL OF EVIDENCE: Level IV. case-control 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.

Pure Ankle Dislocation: A Case Report and a Narrative Literature Review.

Pure dislocation of the ankle is an extremely rare injury accounting for only 0.065% of all ankle injuries and 0.46% of all ankle dislocations. The mechanism of the injury generally consists of high-energy trauma which is associated with a combination of plantar flexion and inversion or eversion of the foot. We present a case of a 22-year-old male patient who sustained a closed pure ankle dislocation after a fall from a small height. He was treated conservatively with closed reduction and circumferential cast immobilization for six weeks, followed by a functional rehabilitation program. The patient presented to the emergency department with an acutely painful and deformed right ankle after falling from a height of 1 m (stairs). Radiographs showed a posteromedial ankle dislocation without fracture. Urgent closed reduction of the dislocation was performed and a posterior below-knee back slab was applied to immobilize the ankle. Dorsalis pedis and posterior tibial arteries were intact. Check X-rays confirmed proper reduction of the ankle joint. Post reduction computed tomography (CT) scan did not show any associated fractures. Magnetic resonance imaging (MRI) revealed a multiligamentous ankle injury and a small osteochondral lesion of the anteromedial talar dome. The back slab was changed to a below-knee circular cast two weeks later, as soon as the soft tissue swelling subsided. The cast was removed at the six-week follow-up and physiotherapy was initiated in order to gain functional rehabilitation and improve the range of motion. At the final follow-up (12 months), the ankle range of motion (ROM) was the same as the pre-injury status and the patient was able to return to his work. Pure ankle dislocation is a rare injury. A satisfactory outcome can be expected, provided that the appropriate conservative treatment followed by a strict rehabilitation protocol is applied.

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.

Subtalar instability.

Subtalar instability is a confusing yet important condition in patients with lateral ankle instability. The author will explore subtalar kinematics, and how they are closely related to the joint stability of the subtalar joint, both with respect to its intrinsic ligaments and its extrinsic ligaments. As subtalar instability is difficult to diagnose, this article will provide readers with a better understanding of its clinical presentation. Discussions will also include useful radiographic modalities and the most recent evidence regarding their accuracy. The last section discusses surgical options and what the readers need to know in order to make a decision.

Evaluation of chronic ankle instability and subtalar instability using the angle between the anterior talofibular ligament and calcaneofibular ligament.

PURPOSE: A series of studies have reported a change in the length or thickness of the anterior talofibular (ATFL) and calcaneofibular (CFL) ligaments in patients with chronic ankle instability. However, no study has examined the changes in the angle between the ATFL and CFL in patients diagnosed with chronic ankle instability. Therefore, this study analyzed the change in the angle between the ATFL and CFL in patients diagnosed with chronic ankle instability to confirm its relevance. METHODS: This retrospective study included 60 patients who had undergone surgery for chronic ankle instability. Stress radiographs comprising the anterior drawer test, varus stress test, Broden's view stress test, and magnetic resonance imaging (MRI) were performed in all patients. The angle between the ATFL and CFL was measured by indicating the vector at the attachment site, as seen on the sagittal plane. Three groups were classified according to the angle between the two ligaments measured by MRI: group I when the angle was > 90°, Group II when the angle was 71-90°, and Group III when the angle was ≤ 70°. The accompanying injuries to the subtalar joint ligament were analyzed via MRI. RESULTS: A comparison of the angles between the ATFL and CFL measured on MRI in Group I, Group II, and Group III with the angles measured in the operating room revealed a significant correlation. Broden's view stress test revealed a statistically significant difference among the three groups (p < 0.05). The accompanying subtalar joint ligament injuries differed significantly among the three groups (p < 0.05). CONCLUSION: The ATFL-CFL angle in patients with ankle instability is smaller than the average angle in ordinary people. Therefore, the ATFL-CFL angle might be a reliable and representative measurement tool to assess chronic ankle instability, and subtalar joint instability should be considered if the ATFL-CFL angle is 70° or less. LEVEL OF EVIDENCE: Level III.