Subtalar Ligaments Research Articles

Talocalcaneal Ligament Reconstruction Kinematic Simulation for Progressive Collapsing Foot Deformity.

In progressive collapsing foot deformity (PCFD), an internal and plantar rotation of the talus relative to the calcaneus may result in painful peritalar subluxation. Medial soft tissue procedures (eg, spring ligament repair) aim to correct the talar position via the navicular bone if bony correction alone is not sufficient. The effect of the medial soft tissue reconstruction on the talar reposition remains unclear. We hypothesized that a subtalar talocalcaneal ligament reconstruction might be favorable in PCFD to correct talar internal malposition directly. This pilot study aims to evaluate the anatomical feasibility and kinematic behavior of a subtalar ligament reconstruction in PCFD. Three-dimensional surface model from 10 healthy ankles were produced. A total of 1089 different potential ligament courses were evaluated in a standardized manner. A motion of inversion/eversion and talar internal/external in relation to the calcaneus were simulated and the ligament strain, expressed as a positive length variation, for each ligament was analyzed. The optimal combination for the ligament reconstruction with increased length in internal rotation of the talus, isometric kinematic behavior in inversion/eversion, and extraarticular insertion on talus and calcaneus was selected. A laterodistal orientation of the talar insertion point in respect to the subtalar joint axis and laterodistal deviation of the calcaneal insertion point presents the highest ligament lengthening in internal talar rotation (+0.56 mm [3.8% of total length]) and presented a near-isometric performance in inversion/eversion (+0.01 to -0.01 mm [0.1% of total length]). This kinematic model shows that a ligament reconstruction in the subtalar space presents a pattern of length variation that may stabilize the internal talar rotation without impeding the physiological subtalar motion. This study investigates the optimal location, feasibility, and kinematic behavior of a ligament reconstruction that could help stabilize peritalar subluxation in progressive collapsing foot deformity.

Reconstruction of the interosseous talocalcaneal ligament using allograft for subtalar joint stabilization is effective

PurposeThe aim of this study was to assess the biomechanical effects of subtalar ligament injury and reconstruction on stability of the subtalar joint in all three spatial planes.MethodsFifteen fresh frozen cadaveric legs were used, with transfixed tibiotalar joints to isolate motion to the subtalar joint. An arthrometer fixed to the lateral aspect of the calcaneus measured angular displacement in all three spatial planes on the inversion and eversion stress tests. Stress manoeuvres were tested with the intact joint, and then repeated after sequentially sectioning the inferior extensor retinaculum (IER), cervical ligament (CL), interosseous talocalcaneal ligament (ITCL), arthroscopic graft reconstruction of the ITCL, and sectioning of the calcaneo-fibular ligament (CFL).ResultsSectioning the ITCL significantly increased angular displacement upon inversion and eversion in the coronal and sagittal planes. Reconstruction of the ITCL significantly improved angular stability against eversion in the axial and sagittal planes, and against inversion in the axial and coronal planes, at the zero time point after reconstruction. After sectioning the CFL, resistance to eversion decreased significantly in all three planes.ConclusionProgressive injury of ligamentous stabilisers, particularly the ITCL, led to increasing angular displacement of the subtalar joint measured with the inversion and eversion stress tests, used in clinical practice. Reconstruction of the ITCL using tendon graft significantly stabilised the subtalar joint in the axial and sagittal planes against eversion and in the axial and coronal planes against inversion, immediately after surgery.

Role of the intrinsic subtalar ligaments in subtalar instability and consequences for clinical practice.

Subtalar instability (STI) is a disabling complication after an acute lateral ankle sprain and remains a challenging problem. The pathophysiology is difficult to understand. Especially the relative contribution of the intrinsic subtalar ligaments in the stability of the subtalar joint is still controversial. Diagnosis is difficult because of the overlapping clinical signs with talocrural instability and the absence of a reliable diagnostic reference test. This often results in misdiagnosis and inappropriate treatment. Recent research offers new insights in the pathophysiology of subtalar instability and the importance of the intrinsic subtalar ligaments. Recent publications clarify the local anatomical and biomechanical characteristics of the subtalar ligaments. The cervical ligament and interosseous talocalcaneal ligament seem to play an important function in the normal kinematics and stability of the subtalar joint. In addition to the calcaneofibular ligament (CFL), these ligaments seem to have an important role in the pathomechanics of subtalar instability (STI). These new insights have an impact on the approach to STI in clinical practice. Diagnosis of STI can be performed be performed by a step-by-step approach to raise the suspicion to STI. This approach consists of clinical signs, abnormalities of the subtalar ligaments on MRI and intraoperative evaluation. Surgical treatment should address all the aspects of the instability and focus on a restoration of the normal anatomical and biomechanical properties. Besides a low threshold to reconstruct the CFL, a reconstruction of the subtalar ligaments should be considered in complex cases of instability. The purpose of this review is to provide a comprehensive update of the current literature focused on the contribution of the different ligaments in the stability of the subtalar joint. This review aims to introduce the more recent findings in the earlier hypotheses on normal kinesiology, pathophysiology and relation with talocrural instability. The consequences of this improved understanding of pathophysiology on patient identification, treatment and future research are described.

Effect of Ligament Mapping from Different Magnetic Resonance Image Quality on Joint Stability in a Personalized Dynamic Model of the Human Ankle Complex

Background. Mechanical models of the human ankle complex are used to study the stabilizing role of ligaments. Identification of ligament function may be improved via image-based personalized approach. The aim of this study is to compare the effect of the ligament origin and insertion site definitions obtained with different magnetic resonance imaging (MRI) modalities on the mechanical behaviour of a dynamic model of the ankle complex. Methods. MRI scans, both via 1.5 T and 3.0 T, were performed on a lower-limb specimen, free from anatomical defects, to obtain morphological information on ligament-to-bone attachment sites. This specimen was used previously to develop the dynamic model. A third ligament attachment site mapping scheme was based on anatomical dissection of the scanned specimen. Following morphological comparison of the ligament attachment sites, their effect on the mechanical behaviour of the ankle complex, expressed by three-dimensional load–displacement properties, was assessed through the model. Results. Large differences were observed in the subtalar ligament attachment sites between those obtained through the two MRI scanning modalities. The 3.0 T MRI mapping was more consistent with dissection than the 1.5 T MRI. Load–displacement curves showed similar mechanical behaviours between the three mappings in the frontal plane, but those obtained from the 3.0 T MRI mapping were closer to those obtained from dissection. Conclusions. The state-of-the-art 3.0 T MRI image analysis resulted in more realistic mapping of ligament fibre origin and insertion site definitions; corresponding load–displacement predictions from a subject-specific model of the ankle complex showed a mechanical behaviour more similar to that using direct ligament attachment observations.

Comparative Analysis of Subtalar Ligaments Between Patients With Talocalcaneal Coalition and Control Subjects Using 3-Dimensional Magnetic Resonance Imaging.

The purpose of this study was to find the differences in the subtalar ligaments between patients with talocalcaneal (TC) coalition and control subjects using 3-dimensional isotropic magnetic resonance imaging. Magnetic resonance imaging of 27 ankles with TC coalition and 27 age- and sex-matched controls were retrospectively reviewed. Absence of cervical ligament, anterior capsular ligament (ACL), interosseous TC ligament (ITCL), and partial or complete absence of 3 roots of the inferior extensor retinaculum was analyzed. Thickness and width of ACL and ITCL were measured when possible. Absence of ACL and ITCL was significantly more frequent in TC coalition patients than in controls (59.2% vs 7.4%, P < 0.0001; 44.4% vs 7.4%, P = 0.004). Absence of cervical ligament and 3 roots of the inferior extensor retinaculum did not differ between the 2 groups. Thickness and width of ACL were significantly smaller in TC coalition patients than in control subjects (0.81 ± 0.23 vs 1.27 ± 0.41 mm, P < 0.0001; 5.26 ± 1.17 vs 7.07 ± 1.46 mm, P = 0.001). Thickness and width of ITCL did not differ between the 2 groups. In the TC coalition group, the absence of ACL and ITCL did not differ according to coalition type, patient demographics, and magnetic resonance imaging units. Anterior capsular ligament and ITCL are frequently absent in TC coalition patients. Even when present, the ACL is attenuated in TC coalition patients compared with controls.

The different subtalar ligaments show significant differences in their mechanical properties

BackgroundToday, the relative contribution of each ligamentous structure in the stability of the subtalar joint is still unclear. The purpose of this study is to assess the material properties of the different ligamentous structures of the subtalar joint. MethodsEighteen paired fresh-frozen cadaveric feet were used to obtain bone–ligament–bone complexes of the calcaneofibular ligament (CFL), the cervical ligament (CL) and the anterior capsular ligament-interosseous talocalcaneal ligament complex (ACaL-ITCL). The samples were subjected to uniaxial testing to calculate their respective stiffness and failure load. ResultsThe stiffness of ACaL-ITCL complex (mean: 150 ± 51 N/mm, 95% confidence interval (CI): 125.0–176.6 N/mm) was significantly higher than both CFL (mean: 55.8 ± 23.0 N/mm, CI: 43.8–67.7 N/mm) and CL (mean: 63.9 ± 38.0 N/mm, CI: 44.4–83.3 N/mm). The failure load of both the ACaL-ITCL complex (mean:382.5 ± 158 N, CI: 304.1–460.8 N) and the CFL (mean:320.4 ± 122.0 N, CI: 257.5–383.2 N) were significantly higher than that of the CL (mean:163.5 ± 58.0 N, CI: 131.3–195.7 N). The injury pattern demonstrated a partial rupture in all CFL and ACaL-ITCL specimens and in 60% of the CL specimens. ConclusionThe CFL, CL and ACaL-ITCL show significant differences in their intrinsic mechanical properties. Both the CFL and CL are more compliant ligaments and seem to be involved in the development of subtalar instability. Based on the material properties, a gracilis tendon graft seems more appropriate than a synthetic ligament to reconstruct a CL or CFL. A partial rupture was the most commonly seen injury pattern in all ligaments. A fibular avulsion of the CFL was only rarely seen. The injury patterns need further investigation as they are important to optimize diagnosis and treatment.

The ACL of the Ankle Joint: A Cadaveric Evaluation of the Subtalar Intrinsic Ligaments and Optimal Surgical Approach

Category:Ankle; Basic Sciences/Biologics; SportsIntroduction/Purpose:The biomechanics of ankle sprains involves a multiplanar-supination motion and not the strict inversion as is often described. During supination, calcaneal inversion occurs at the anatomic subtalar joint. The intrinsic subtalar ligaments include a series of broad thick ligaments situated in the tarsal canal that separate the anterior and posterior compartments. The subtalar intrinsic ligaments are damaged in an estimated 25% to 80% of all lateral ankle sprains. We hypothesize that the intrinsic subtalar ligaments have a multiplanar role in ankle joint stabilization similar to that of the anterior cruciate ligament at the knee. The purpose of this study is to evaluate the efficacy of four surgical approaches to the subtalar ligaments through cadaveric dissection.Methods:Four fresh-frozen cadaveric ankle specimens were utilized. Ability to access the extrinsic lateral ankle ligament (anterior talofibular), the extrinsic subtalar ligaments (calcaneofibular, lateral talocalcaneal) and the intrinsic subtalar ligaments (interosseous talocalcaneal, cervical) was evaluated. The first cadaveric specimen was dissected as a baseline to identify the extrinsic and intrinsic subtalar ligaments. The three remaining cadaveric specimens were utilized to evaluate the efficacy of three standard surgical approaches (a curvilinear incision made over the distal anterior border of lateral malleolus, a posterolateral longitudinal incision, and an extensile sinus tarsi approach) to access both the extrinsic ankle and subtalar ligaments as well as the intrinsic subtalar ligaments. Ability to access all ligaments as well as identification of neurovascular structures at risk during the dissection was recorded for each approach.Results:The curvilinear incision made over the distal anterior border of the lateral malleolus provided access to the anterior talofibular, calcaneofibular ligaments. Branches of the superficial peroneal nerve were noted to be at direct risk. The posterior longitudinal incision provided access to the calcaneofibular, lateral talocalcaneal ligaments. Branches of the sural nerve were noted to be at direct risk with this approach. An extensile posterolateral incision improved access to the anterior talofibular ligament. An extensile sinus tarsi approach provided the most direct access to the interosseous talocalcaneal and cervical ligaments. Visualization of the calcaneofibular and lateral talocalcaneal was also provided with this incision. The saphenous and superficial nerve branches and the sinus tarsi artery were noted to be at risk.Conclusion:We hypothesize that the intrinsic subtalar ligaments have a multiplanar role in ankle joint stabilization similar to that of the anterior cruciate ligament at the knee. Accurate identification and optimal surgical approach to these structures has not been well described in the orthopaedic foot and ankle literature. This cadaveric study provides evidence that an extensile sinus tarsi approach can provide access to the extrinsic ankle and subtalar ligaments as well as the intrinsic ligaments of the subtalar joint.

The intrinsic subtalar ligaments have a consistent presence, location and morphology

BackgroundChronic subtalar instability is a disabling complication after acute ankle sprains. Currently, the literature describing the anatomy of the intrinsic subtalar ligaments is limited and equivocal which causes difficulties in diagnosis and treatment of subtalar instability. The purpose of this study is to assess the anatomical characteristics of the subtalar ligaments and to clarify some points of confusion. MethodsIn 16 cadaveric feet, the dimensions and locations of the subtalar ankle ligaments were assessed and measured. CT-scans before dissection and after indication of the footprints with radio-opaque paint allowed to generate 3D models and assess the footprint characteristics. ResultsThe cervical ligament (CL) had similar dimensions as the lateral ligaments: anterior length 13.9 ± 1.5 mm, posterior length 18.5 ± 2.9 mm, talar width 13.6 ± 2.2 mm, calcaneal width 15.8 ± 3.7 mm. The anterior capsular ligament (ACaL) and interosseous talocalcaneal ligament (ITCL) were found to be smaller structures with consistent dimensions and locations. ConclusionThis study identified consistent characteristics of the intrinsic subtalar ligaments and clarifies the local anatomical situation. The dimensions and footprints of the intrinsic ligaments of the subtalar joint suggest a more important role of the CL and ACaL in the stability of the subtalar joint. The results of this study are relevant to improve diagnostic tools and offer some guidelines when reconstructing the injured ligaments.

Estimating the stabilizing function of ankle and subtalar ligaments via a morphology-specific three-dimensional dynamic model

Knowledge of the stabilizing role of the ankle and subtalar ligaments is important for improving clinical techniques such as ligament repair and reconstruction. However, this knowledge is incomplete. The goal of this study was to expand this knowledge by investigating the stabilizing function of the ligaments using multiple morphologically subject-specific computational models.Nine models were created from the lower extremities of nine donors. Each model consisted of the articulating bones, articular cartilage, and ligaments. Simulations were conducted in ADAMS™ – a dynamic simulation program. During simulation, tibia and fibula were fixed while cyclic moments in all three anatomical planes were applied to the calcaneus one-at-a-time. The resulting displacements between the bones and the forces in each ligament were computed. Simulations were conducted with all ligaments intact and after simulated ligament serial sectioning. Each model was validated by comparing the simulation results to experimental data obtained from the specimen used to construct the model. From the results the stabilizing role of each ligament was established and the effect of ligament sectioning on Range of Motion and Overall Laxity was identified.On the lateral side, ATFL provided stabilization in supination, CFL restrained inversion, external rotation and dorsiflexion and PTFL limited dorsiflexion and external rotation. On the medial side, PTTL restrained dorsiflexion and internal rotation, ATTL limited plantarflexion and external rotation, and TCL limited dorsiflexion, eversion and external rotation. At the subtalar joint, ITCL limited plantarflexion and its posterior-lateral bundle restrained subtalar inversion. CL restrained plantarflexion/dorsiflexion, and internal and external rotation.The large inter-model variability observed in the results indicate the importance of using multiple subject-specific models rather than relying on one “representative” model.

The Interosseous Talocalcaneal Ligament Injury Findings in Lateral Ankle Instability with Sinus Tarsi Pain

Category:Ankle, Arthroscopy, SportsIntroduction/Purpose:Lateral ankle instability (LAI) with concomitant sinus tarsi pain is a quite common finding. However, there has been few studies evaluating the subtalar arthroscopic findings for LAI with sinus tarsi pain. The purpose of the study is to evaluate the ST arthroscopic findings of chronic ankle instability with sinus tarsi syndrome. We hypothesized that chronic ankle instability with sinus tarsi pain is highly associated with interosseous talocalcaneal ligament (ITCL) tear which may be the cause for subtalar instability (STI).Methods:The study is based on 104 LAI with sinus tarsi pain ankles who had performed lateral ankle ligament stabilization. i.e. Modified Brostrum procedure (MBP), lateral ankle reconstruction (LAR) or subtalar ligament reconstruction (STR) with subtalar arthroscopic (STA) examinations from 2007 to 2018. The STA has been mainly focused on the ITCL injury and debridement of the ITCL tears and synovitis were performed when present. VAS pain score, AOFAS, Karlsson-Peterson functional score were evaluated.Results:According to the ST arthrosopic findings, ITCL tears were present in 94% (98/104) of the ankles. Lateral ankle instability (LAI), subtalar instability (STI), and LAI and STI combined were 32%, 30% and 38% respectively. MBP, LAR and STR were performed in 23%, 22% and 56% respectively. VAS pain score was improved from 5.3 to 1.9 (p<0.05). AOFAS score was improved from 67 to 89 (p<0.05), while K-P score improved from 50 to 83 (p<0.05). Sinus tarsi pain was relieved in 65% of the patients.Conclusion:We found the high incidence of the ITCL tears (98%) in LAI with sinus tarsi pain, and also diagnosed the STI in 68% of the ankles. We believe that in case of LAI with sinus tarsi pain, ST arthroscopic evaluation for ITCL tears is necessary and the possibility

Suture Anchor Construct for an Exogenous Ligament Repair for Subtalar Joint Instability-A Novel Technique

Subtalar joint ligament sprains are often missed in the setting of chronic inversion ankle injuries. This can lead to pain and instability of the subtalar joint. In many cases, without proper identification, the patient may eventually undergo an unnecessary subtalar joint fusion rather than a ligament reconstruction. Achilles, peroneus brevis, and gracilis tendon grafts have been described to repair subtalar ligament instability in the literature.

Differences Between Subtalar Instability and Lateral Ankle Instability Focusing on Subtalar Ligaments Based on Three Dimensional Isotropic Magnetic Resonance Imaging.

The purpose of this study was to assess the differences between subtalar instability (STI) and lateral ankle instability (LAI) focusing on subtalar ligaments using 3-dimensional (3D) isotropic magnetic resonance imaging (MRI). Preoperative MRIs of 10 patients with STI who failed nonoperative treatment and consequently underwent arthroscopic subtalar reconstruction were compared with preoperative MRIs of 23 patients with LAI who underwent ligament repair or reconstruction. Dimensions of anterior capsular ligament (ACL), interosseous talocalcaneal ligament (ITCL), calcaneofibular ligament (CFL), and anterior talofibular ligament (ATFL) were measured. Tears of ACL, ITCL, CFL, ATFL, cervical ligament, and inferior extensor retinaculum were analyzed. Patients with subtalar instability had significantly lower ACL thickness and width than patients with LAI (thickness: 1.48 vs 2.12 mm, P = 0.045; width: 7.30 vs 8.64 mm, P = 0.029). An ACL thickness of 1.8 mm or less had sensitivity and specificity both at 75.0%, and an ACL width of 8 mm or less had sensitivity of 75.0% and specificity of 85.0% for discriminating STI from LAI. Absence or complete tear of ACL was more frequent in patients with STI than in patients with LAI (60.0% vs 13.0%, P = 0.010). The ATFL thickness was significantly greater in patients with LAI (P = 0.001). Complete tear of ATFL was more common in patients with LAI (P = 0.008). Complete tear of CFL was common in both the STI and LAI groups without significant difference (20.0% vs 21.7%). There was no significant difference in thickness and width of ITCL and in CFL thickness. Complete tear of ITCL, cervical ligament, and inferior extensor retinaculum were rare without significant difference. In patients with STI, the ACL is thin and narrow and more commonly absent or torn compared with patients with LAI. Complete tear of ATFL was more common in patients with LAI. Complete tear of CFL was commonly encountered in both the STI and LAI groups.

Subtalar instability: imaging features of subtalar ligaments on 3D isotropic ankle MRI

BackgroundMRI analysis of subtalar ligaments in the tarsal sinus has not been well performed. We retrospectively investigated the appearance of subtalar ligaments using 3D isotropic MRI and compared imaging findings of subtalar ligaments between patients with subtalar instability (STI) and controls.MethodsPreoperative MRIs of 23 STI patients treated with arthroscopic subtalar reconstruction were compared to MRIs of 23 age- and sex-matched control subjects without STI. Thickness and width of anterior capsular ligament (ACL) and interosseous talocalcaneal ligament (ITCL) as well as thickness of calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL) were measured. Abnormalities in ACL, ITCL, CFL, ATFL, cervical ligament, and inferior extensor retinaculum were analyzed.ResultsSTI patients had significantly smaller ACL thickness and ACL width than controls (ACL thickness: 1.73 mm vs. 2.22 mm, p = 0.007; ACL width: 7.21 mm vs. 8.80 mm, p = 0.004). ACL thickness of ≤2.1 mm had a sensitivity of 66.7% and a specificity of 66.7% for diagnosis of STI. ACL width of ≤7.9 mm had a sensitivity of 80.0% and a specificity of 76.2% for the diagnosis of STI. However, thickness and width of ITCL, thickness of CFL, or thickness of ATFL was not significantly different between the two groups. Absence or complete tear of ACL was significantly more frequent in STI patients than that in controls (34.8% vs. 8.7%, p = 0.035). Complete tear of CFL and ATFL was more common in STI patients than that in controls, although the difference between the two groups was not statistically significant. Abnormalities of ITCL, cervical ligament, or inferior extensor retinaculum were not significantly different between the two groups.ConclusionsMRI features of thin or narrow ACLs may suggest STI. Absence or complete tear of ACL was significantly more common in STI patients than that in controls.

Anatomical Study of the Cervical and Interosseous Talocalcaneal Ligaments of the Foot with Surgical Relevance.

There is conflicting evidence regarding the morphology and orientation of the cervical ligament (CL) and interosseous talocalcaneal ligament (ITCL). The morphology of the CL and its relationship to the ITCL were studied to obtain an understanding of these structures. Twenty-six feet (13 left, 13 right) were obtained from formalin-fixed cadavers (14 females, four males) with the mean standard deviation (SD) age at death 80.9 (12.9) years. All measurements were made with a digital caliper. The length and width of the foot, the width and height of the talus, were measured. The talus was cut coronally to expose the ITCL and qualitative observations were noted. The mean (SD) heights and widths of the CL at the anterior, posterior, superior, and inferior points were 8.27 (2.52), 13.95 (5.96), 9.15 (2.45), and 11.90 (4.30) mm, respectively. The mean (SD) thicknesses of the CL at the superoanterior, superoposterior, inferoanterior, inferoposterior, and central points were 0.62 (0.24), 1.05 (0.30), 0.70 (0.26), 1.20 (0.34), and 0.97 (0.31) mm, respectively. The fibers of the CL are oriented at a slight superoanterior to inferoposterior angle, whereas the fibers of the ITCL are oriented in a slight superomedial to inferolateral angle. The fibers of the CL and ITCL overlap inside the tarsal sinus with the CL positioned anteriorly, which helps to distinguish the two ligaments. In this study, we identified the morphometrics of the CL and described the CL and ITCL qualitatively. These results are relevant to introducing innovative techniques for reconstructive surgery of the subtalar ligaments in order to repair, for example, subtalar instability.

Ligament Structures in the Tarsal Sinus and Canal

The concrete anatomy and functional characteristics of the subtalar ligaments have been a matter of debate that some believe has hampered the progress of clinical ligament reconstruction. In 32 fresh-frozen cadaver feet, the course of the inferior extensor retinaculum (IER) and other subtalar ligaments was carefully measured and photographed both from the portal of the tarsal sinus and from a posterior view. The IER inserted inside the tarsal sinus and canal by means of 3 roots: a lateral, an intermediate, and a medial one. These roots, along with the tarsal canal, divided the subtalar space into 3 parts. In front of the IER and inside the tarsal sinus, the thick cervical ligament (CL) lay at a 45-degree angle to the calcaneus. Behind the IER and inside the posterior capsule, in most cases (25 of 32 specimens), the posterior capsular ligament (PCaL) lay directly in front of the posterior talocalcaneal facet. Inside the tarsal canal, the fan-shaped medial root of the IER spread from outside upper lateral to lower medial, and the interosseous talocalcaneal ligament (ITCL) ran from upper medial to lower lateral; fibers of these 2 ligaments blended tightly together to form a V-shaped ligament complex. Just anterior to this complex in some cases (20 of 32 specimens), a short narrow upright ligament, the tarsal canal ligament (TCL), was located behind the middle talocalcaneal joint. The results of this study show that the CL is the primary ligament in the tarsal sinus and that the ITCL is a thin single band rather than a strong bilaminar ligament located inside the tarsal canal. Instead, the medial root of the IER is the primary ligamentous structure in the tarsal canal. The anatomical description provided here may provide a more accurate theoretical foundation for clinical subtalar stability restoration.

Talonavicular synostosis with lateral ankle instability—A case report and review of the literature

Talonavicular coalition is a rare autosomal recessive congenital anomaly that is usually asymptomatic and detected incidentally on radiographs. It is associated with symphalangism, clinodactyly, a great toe that is shorter than the second toe, clubfoot, calcaneonavicular coalition, talocalcaneal coalition and a ball-and-socket ankle joint. The authors present a review of the literature and case report of a patient with complete osseous talonavicular coalition, talocalcaneal coalition and lateral ankle instability which was successfully treated with subtalar fusion and lateral ligament reconstruction.

Posterior Subtalar Dislocation

A subtalar dislocation of the foot is an uncommon injury, and cases of posterior subtalar dislocation are even rarer. This injury is characterized by a simultaneous dislocation of talocalcaneal and talonavicular joints while tibiotalar and calcaneocuboid articulations remain intact. Subtalar dislocation is commonly accompanied by fractures of the malleoli, talus, or fifth metatarsal and by a rotational component of the subtalar joint. Subtalar dislocation can occur in any direction and produces significant deformity. This article presents a case of pure posterior subtalar dislocation in an 80-year-old man who presented with pain and deformity in his left ankle following a motorcycle accident. Radiographs demonstrated dislocation of both the talonavicular and talocalcaneal joints. The calcaneus was displaced posteriorly without medial or lateral displacement. No rotational component of the calcaneus was noted, suggesting the trauma was in pure hyperplantar flexion. We hypothesize that pure hyperplantar flexion could lead to a progressive subtalar ligament weakening that may result in a complete ligament rupture if the plantar flexion force is prolonged. This could be observed in the presence of good bone quality and if the force is applied distally at the navicular bone.

Subtalar Release in Clubfeet: A Retrospective Study of 10-Year Outcomes

Optimal management of congenital talipes equinovarus continues to be controversial. There is a dramatically renewed emphasis on non-operative management partly because there has been a high recurrence rate among operated feet. Our hypothesis is that early, extensive subtalar ligament release as the cornerstone of aggressive hindfoot realignment prevents recurrence and retains mobility. Twenty-two congenital clubfeet (14 patients) corrected by one surgeon were evaluated using two validated patient-based outcome instruments, dynamic pedobarographic analysis, hindfoot mobility, and weightbearing radiographs. Pedobarographic analysis consisted of quantifying peak plantar forces and pressures during the gait cycle in 22 corrected feet and 24 control feet using the FSCAN in-shoe device. The mean age at surgery was 8 months and mean followup was 10 years. No patients experienced recurrence of deformity. Reported foot function and satisfaction were very high for all patients and were comparable to reported normal population values. AP and lateral talocalcaneal angles for each foot were within normal limits for age. Hindfoot range of motion, including dorsiflexion, was preserved in all feet. Peak regional forces throughout the gait cycle and plantar pressures at foot flat were mildly, but statistically significantly, higher in the midfoot of corrected feet suggesting slight flattening of the arch. One patient had tendon transfers for bilateral calcaneal deformity and one patient had surgical correction of a bilateral valgus deformity. Aggressive hindfoot realignment provides definitive treatment of an equinovarus deformity, but care must be taken to avoid overcorrection.

Physical Examination of Acutely Injured Ankles: An Evidence-Based Approach

The rate of concurrent or isolated sprains to the syndesmosis and subtalar ligaments, however, is less cer- tain. When physically examining an acutely injured ankle, a practi- tioner might find him - self or herself asking routine questions such

The Role of the Flexor Hallucis Longus and Peroneus Longus in the Stabilization of the Ballet Foot

The importance of the flexor hallucis longus (FHL) and peroneus longus tendons in the stabilization of the subtalar joint and the longitudinal arch of the foot was demonstrated in 8 fresh-frozen human cadaver foot and ankle specimens. Dissection of the foot was done to transect stabilizing structures including joint capsule and periarticular ligaments of the medial side of the subtalar, talonavicular, navicular-first cuneiform, and first metatarsocuneiform joints; the subtalar ligaments in the sinus tarsi and the lateral capsule of the middle subtalar facet were also transected. The FHL and peroneus longus tendons were isolated and the specimen fixed to a frame. Without any tension on the FHL and peroneus longus tendons, the foot was supple and unstable. With tension applied to the FHL tendon alone, the bony arch of the foot became rigid, with inversion of the subtalar joint, rising of the longitudinal arch, plantar flexion of the forefoot, and slight adduction of the forefoot. With tension applied to the peroneus longus tendon alone, the bony arch of the foot became rigid, with eversion of the subtalar joint, rising of the longitudinal arch, plantar flexion of the forefoot, and abduction of the forefoot. With tension applied to both the FHL and peroneus longus tendons synchronously, the bony arch of the foot rose and became rigid, with plantar flexion and neutral abduction-adduction position of the forefoot. When additional tension was applied to the peroneus longus, the rigid foot assumed a locked position in mild hindfoot eversion and forefoot abduction. These qualitative observations are consistent with the hypothesis that the FHL and peroneus longus are important stabilizers of the foot in dance (demi-pointe and pointe) and soccer (kick), and may provide an explanation for injury of these tendons with these activities.