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

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

Imaging diagnosis for anterior talofibular ligament injury: a systemic review with meta-analysis

A definite diagnosis of ankle ligament injury is crucial, and many imaging examinations can be used. This review systematically analyzed the effectiveness of various examination methods in the diagnosis of anterior talofibular ligament (ATFL) injuries. Three English databases (PubMed, Embase, and Cochrane Library) and three Chinese databases (CNKI, VIP Database, and Wanfang Database) were searched and relevant studies were summarized. A total of 25 randomized controlled trials met the selection criteria, including six, 16, and three studies recruiting patients with acute, chronic, and both acute and chronic ATFL injuries, respectively. A total of 1409 participants were included. The pooled sensitivity rates of acute ATFL injuries were 82.1% (77.1%-86.5%) by magnetic resonance imaging (MRI) and 88.6% (82.0%-93.5%) by ultrasonography (US). The pooled sensitivity rates of chronic ATFL injuries were 86.3% (82.5%-89.5%) by MRI, 98.7% (95.3%-99.8%) by US, 74.4% (63.6%-83.4%) by stress radiography, and 100% (87.7%-100.0%) for MR arthrography. The pooled specificity rates of acute ATFL injuries were 37.8% (29.1%-47.2%) by MRI and 90.3% (80.1%-96.4%) by US. The pooled specificity rates of chronic ATFL injuries were 86.8% (81.3%-91.2%) by MRI, 94.0% (85.4%-98.3%) for US, 89.4% (76.9%- 96.5%) by stress radiography and 100% (54.1%-100.0%) by MR arthrography. In conclusion, US may be a valuable imaging technique with high sensitivity for diagnosing chronic lateral ankle ligament injuries.

Isolated, periosteal stripping injuries of the Flexor Retinaculum: Case series of 3 patients with clinico-radiological review

Isolated periosteal avulsion injuries of the flexor retinaculum on the medial side of the ankle are rare and may mimic osseous injuries or deltoid ligament tears. We describe a case series of 3 individuals with isolated, stripping injuries of the tibial attachment of the flexor retinaculum without underlying fracture or deltoid ligament disruption. A new classification system of flexor retinaculum periosteal stripping injuries of the ankle is proposed with clinico-radiological features.

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.

Needle arthroscopy in anatomical reconstruction of the lateral ankle: a report of three cases with a parallel comparison to the standard arthroscopy procedure

Purpose

This study evaluates the use of the needle arthroscopy in anatomical reconstruction of the lateral ankle. We hypothesized that the needle arthroscopy would allow anatomical reconstruction to be performed under arthroscopy.

Methods

Three patients underwent treatment of chronic ankle instability. The comparative procedure was performed in the following four steps: 1) anteromedial articular exploration (medial/lateral gutter/anterior chamber/syndesmosis); 2)creation of the talar tunnel via the anteromedial arthroscopic approach; 3) anterolateral fibular tunneling; and 4) positioning of the graft by the anteromedial arthroscopic approach.

For each of these steps, the planned procedure using the needle arthroscope was compared to the standard arthroscope. For each step, the planned procedure using the needle arthroscopy was compared to the standard arthroscope and the act was classified based on level of difficulty: facilitated, similar, complicated and impossible.

Results

The exploration of the medial and lateral gutter, the creation of the tunnel of the talus and graft positioning were not accomplished using the needle arthroscope. While the syndesmosis visualization was facilitated by the needle arthroscope in comparison to the standard arthroscope.

Conclusion

The anatomical reconstruction of the lateral ankle, using the needle arthroscopy-only approach, was impossible in all three cases, regarding: ankle joint exploration, creation of the tunnel of the talus and graft positioning. The needle arthroscope should not be considered as a "mini arthroscope" but as a new tool with which it is necessary to rethink procedures to take advantage of the benefits of this instrument.

Magnetic resonance imaging of ankle ligaments: A pictorial essay

Ankle trauma is commonly encountered and is most often a sprain injury affecting the ligaments. Accurate diagnosis and appropriate treatment rest on knowledge of complex ligamentous anatomy of ankle and the entire spectrum of pathologies. Magnetic resonance imaging (MRI) is the imaging modality of choice for diagnosing ligament pathologies because of its multiplanar capability and high soft tissue contrast. With MRI, it is possible to triage and attribute the cause of post traumatic ankle pain to bone, ligament, or tendon pathologies, which otherwise overlap clinically. In this pictorial essay, emphasis is given to the intricate and unique anatomy and orientation of ankle ligaments. Pathologies of ankle ligaments have been elaborated.

Anatomy of the Deltoid-Spring Ligament Complex

A thorough knowledge of the anatomy of the deltoid and spring ligament complex is important for treatment of deformities that impact the foot and ankle. Both ligaments are interconnected, and the study of their anatomic characteristics is better performed together than in isolation. The deltoid ligament is a group of ligaments that derives its origin from the medial malleolus, and the spring ligament complex consist of a group of ligaments that connects the navicular and the sustentaculum tali of the calcaneus. They both play an important role in stabilization of the medial ankle and medial column of the foot.

Sonographic visibility of the main posterior ankle ligaments and para-ligamentous structures in 15 healthy subjects

The present article describes the ultrasound (US) appearance of ligaments and paraligamentous structures which are not included in standard US imaging of the ankle: the posterior inferior tibiofibular ligament (PITFL), the transverse tibiofibular ligament (TTFL), the posterior talofibular ligament (PTFL), the posterior intermalleolar ligament (PIL), the synovial recess (SR) of the posterior joint and the os trigonum (OT). Two skilled operators examined 15 ankles in 15 healthy volunteers. Correlation between thickness of the main ligaments and body mass index (BMI) was also analyzed. Compound and tissue harmonic imaging (THI) were carried out using 12-, 6-15- and 9-MHz linear probes. Exploration of the posterior ankle ligament complex is accurately described including correct ankle position, echogenicity, shape, direction and thickness. Both operators identified and measured the main ligaments (PITFL, TTFL and PTFL) in all volunteers (Intraclass Correlation Coefficient ranged from 0.8 to 1); both operators also detected SR and OT in 2/15 ankles and posterior intermalleolar ligament (PIL) in 5/15 ankles. Pearson's test showed a significant correlation (< 0.05) between TTFL thickness and BMI. Also, a dynamic study was carried out showing tension of the PTFL during dorsiflexion in 7/15 subjects. Our results highlight the potential role of accurate US imaging in detecting posterior ankle ligament involvement in acute and chronic traumas. To our knowledge, there are no previous articles in the literature dealing with this topic providing an accurate description of the US procedure, and in particular, no study has been carried out to identify OT.

The lateral fibulotalocalcaneal ligament complex: an ankle stabilizing isometric structure

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The 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.

The CFL fails before the ATFL immediately after combined ligament repair in a biomechanical cadaveric model

PURPOSE

To assess the impact on ankle stability after repairing the ATFL alone compared to repairing both the ATFL and CFL in a biomechanical cadaver model.

METHODS

Ten matched pairs of intact, fresh frozen human cadaver ankles (normal) were mounted to a test machine in 20.0° plantar flexion and 15.0° of internal rotation. Each ankle was loaded to body weight and then tested from 0.0° to 20.0° of inversion. The data recorded were torque at 20.0° and stiffness, peak pressure and contact area in the ankle joint using a Tekscan sensor, rotation of the talus and calcaneus, and translation of the calcaneus using a three-dimensional motion capture system. Ankles then underwent sectioning of the ATFL and CFL (injured), retested, then randomly assigned to ATFL-only Broström repair or combined ATFL and CFL repair. Testing was repeated after repair then loaded in inversion to failure (LTF).

RESULTS

The stiffness of the ankle was not significantly increased compared to the injured condition by repairing the ATFL only (n.s.) or the ATFL/CFL (n.s.). The calcaneus had significantly more rotation than the injured condition in the ATFL-only repair (p = 0.037) but not in the ATFL/CFL repair (n.s.). The ATFL failed at 40.3% higher torque than the CFL, at 17.4 ± 7.0 N m and 12.4 ± 4.1 N m, respectively, and 62.0% more rotation, at 43.9 ± 5.6° and 27.1 ± 6.8°, respectively.

CONCLUSIONS

There was a greater increase in stiffness following combined ATFL/CFL repair compared to ATFL-only repair, although this did not reach statistical significance. The CFL fails before the ATFL, potentially indicating its vulnerability immediately following repair.

LEVEL OF EVIDENCE

III, case-control therapeutic study.

Imaging diagnosis for chronic lateral ankle ligament injury: a systemic review with meta-analysis

Background

Various imaging techniques have been utilized for the diagnosis of chronic lateral ankle ligament injury. This systemic review will explore the effectiveness of different imaging techniques in diagnosing chronic lateral ankle ligament injury.

Methods

Relative studies were retrieved after searching 3 databases (MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trails). Eligible studies were summarized. Data were extracted to calculate pooled sensitivity and specificity of magnetic resonance imaging (MRI), ultrasonography (US), stress radiography, and arthrography.

Results

Fifteen studies met our inclusion and exclusion criteria. A total of 695 participants were included. The pooled sensitivities in diagnosing chronic ATFL injury were 0.83 [0.78, 0.87] for MRI, 0.99 [0.96, 1.00] for US, and 0.81 [0.68, 0.90] for stress radiography. The pooled specificities in diagnosing chronic ATFL injury were 0.79 [0.69, 0.87] for MRI, 0.91 [0.82, 0.97] for US, and 0.92 [0.79, 0.98] for stress radiography. The pooled sensitivities in diagnosing chronic CFL injury were 0.56 [0.46, 0.66] for MRI, 0.94 [0.85, 0.98] for US, and 0.90 [0.73, 0.98] for arthrography. The pooled specificities in diagnosing chronic CFL injury were 0.88 [0.82, 0.93] for MRI, 0.91 [0.80, 0.97] for US, and 0.90 [0.77, 0.97] for arthrography.

Conclusion

This systematic review with meta-analysis investigated the accuracy of imaging for the diagnosis of chronic lateral ankle ligament injury. Ultrasound manifested high diagnostic accuracy in diagnosing chronic lateral ankle ligament injury. Clinicians should be aware of the limitations of MRI in detecting chronic CFL injuries.

Clinical and radiological predictors for persistent complaints five years after a lateral ankle sprain: A long-term follow-up study in primary care

OBJECTIVES

To examine the five-year prognosis and potential prognostic factors of patients with an acute lateral ankle sprain in primary care setting.

DESIGN

Observational study.

METHODS

206 patients who participated in a cross-sectional study and visited their general practitioner with an acute lateral ankle sprain 6-12 months prior to inclusion were approached for a 5-year follow-up measurement consisting of an online questionnaire. At baseline patients completed standardized questionnaires, underwent a standardized physical examination and radiological examination (radiography and Magnetic Resonance Imaging) and scored their perceived recovery. Logistic regression analysis was used to examine potential predictive factors at baseline for the presence of persistent complaints after 5 years.

RESULTS

132 (64.1%) patients completed the 5-year follow-up. 18.2% reported persistent complaints and 30.3% had a re-sprain during follow-up. Baseline persistent complaints 6-12 months after an acute lateral ankle sprain (OR 6.38; CI 95% 1.54-26.44), dominant leg injury (OR 4.89; CI 95% 1.16-20.62) and a recurrent ankle sprain (OR 9.81; CI 95% 2.17-44.47) were significant predictors for persistent complaints 5 years after an acute ankle sprain. Physical examination and radiological findings did not add to the predictive value of the prognostic model.

CONCLUSIONS

Almost 20% of patients with an acute lateral ankle sprain experience persistent complaints after 5 years follow-up. Predictive factors for persistent complaints can be identified.

Determination of the in situ mechanical behavior of ankle ligaments

The mechanical behavior of ankle ligaments at the structural level can be characterized by force-displacement curves in the physiologic phase up to the initiation of failure. However, these properties are difficult to characterize in vitro due to the experimental difficulties in replicating the complex geometry and non-uniformity of the loading state in situ. This study used a finite element parametric modeling approach to determine the in situ mechanical behavior of ankle ligaments at neutral foot position for a mid-sized adult foot from experimental derived bony kinematics. Nine major ankle ligaments were represented as a group of fibers, with the force-elongation behavior of each fiber element characterized by a zero-force region and a region of constant stiffness. The zero-force region, representing the initial tension or slackness of the whole ligament and the progressive fiber uncrimping, was identified against a series of quasi-static experiments of single foot motion using simultaneous optimization. A range of 0.33-3.84mm of the zero-force region was obtained, accounting for a relative length of 6.7±3.9%. The posterior ligaments generally exhibit high-stiffness in the loading region. Following this, the ankle model implemented with in situ ligament behavior was evaluated in response to multiple loading conditions and proved capable of predicting the bony kinematics accurately in comparison to the cadaveric response. Overall, the parametric ligament modeling demonstrated the feasibility of linking the gross structural behavior and the underlying bone and ligament mechanics that generate them. Determination of the in situ mechanical properties of ankle ligaments provides a better understanding of the nonlinear nature of the ankle joint. Applications of this knowledge include functional ankle joint mechanics and injury biomechanics.

A historical perspective on ankle ligaments reconstructive surgery

Ankle sprains are by far the most common injuries treated by sport medicine physicians. Treatment is mainly conservative, but in some cases surgical intervention is required. The aim of the present manuscript is to give an insight into the origins and developments of ankle ligaments reconstructive surgery, underlining the fundamental steps that marked the transition from a mere conservative approach to surgical treatment options. In this historical note, the most illustrious figures who contributed to this particular field of orthopaedic practice are also acknowledged. Level of evidence V.

Isolated syndesmotic injuries in acute ankle sprains: diagnostic significance of clinical examination and MRI

PURPOSE

Acute ankle sprains are frequently accompanied by syndesmotic injuries. These injuries are often overlooked in clinical examinations. The aim of this study was (1) to evaluate the incidence of syndesmotic injuries in acute ankle sprains using MRI, (2) to determine the accuracy of common clinical diagnostic tests, (3) to analyse their inter-rater reliability, and (4) to evaluate the role of clinical symptoms in the diagnosis of syndesmotic injuries.

METHODS

A total of 100 patients with acute ankle sprain injury without associated fractures in plane radiographs were enrolled. The clinical assessment was performed by two independent examiners. Local findings, ankle ligament palpation, squeeze test, external rotation test, Drawer test, Cotton test, and the crossed-leg test (two examiners) were compared with MRI results (read by two blinded radiologists) as a reference standard.

RESULTS

Ninety-six participants (57% male) met the inclusion criteria. MRI detected a ruptured anterior inferior tibiofibular ligament (AITFL) in 14 patients (15%); 9 partial tears and 5 complete tears were evident. Evidence of pain at rest was found to predict syndesmotic injuries most accurately (p = 0.039). The palpation test over the proximal fibula produced the highest inter-rater correlation (κ = 0.65), but the lowest sensitivity for syndesmotic injuries of 8%. All other clinical tests demonstrated moderate to fair inter-rater reliabilities (κ = 0.37-0.52). Low sensitivity values were found with all clinical tests (13.9-55.6%).

CONCLUSION

In this study, clinical examination was insufficient to detect syndesmotic injuries in acute ankle sprains. MRI scanning revealed a syndesmotic lesion in 15% of patients. MRI scanning should be recommended in patients with ongoing pain at rest following ankle sprains.

LEVEL OF EVIDENCE

I.

Anatomy of the inferior extensor retinaculum and its role in lateral ankle ligament reconstruction: a pictorial essay

The inferior extensor retinaculum (IER) is an aponeurotic structure, which is in continuation with the anterior part of the sural fascia. The IER has often been used to augment the reconstruction of the lateral ankle ligaments, for instance in the Broström-Gould procedure, with good outcomes reported. However, its anatomy has not been described in detail and only a few studies are available on this structure. The presence of a non-constant oblique supero-lateral band appears to be important. This structure defines whether the augmentation of the lateral ankle ligaments reconstruction is performed using true IER or only the anterior part of the sural fascia. It is concluded that the use of this structure will have an impact on the resulting ankle stability.

A historical perspective on ankle ligaments reconstructive surgery

Ankle sprains are by far the most common injuries treated by sport medicine physicians. Treatment is mainly conservative, but in some cases surgical intervention is required. The aim of the present manuscript is to give an insight into the origins and developments of ankle ligaments reconstructive surgery, underlining the fundamental steps that marked the transition from a mere conservative approach to surgical treatment options. In this historical note, the most illustrious figures who contributed to this particular field of orthopaedic practice are also acknowledged. Level of evidence V.