Coalizão da articulação talocalcaneana com Os sustentaculum - Uma coalizão incomum / Coalition of the medial portion of the talocalcaneal with the associated Os sustentaculum – An uncommon coalition

Introdução: O Os sustentaculum é um osso acessório raro localizado na extremidade posterior do sustentaculum tali. A coalizão tarsal pode ser considerada uma anomaliacongênita que pode se tornar sintomática. Frequentemente, é necessária a TC ou a RM para confirmar o diagnóstico de coalizão talo-calcânea quando os achados nas radiografiassão ambíguos. Objetivo: Relatar um caso incomum de Coalizão da articulação talocalcaneana com Os sustentaculum, diagnosticado por exames de imagem. Relatodo Caso: Mulher de 26 anos com “caroço” no tornozelo direito há 10 anos promovendo dor intermitente. Apresenta piora ao usar salto – independentemente do tempo, ao andar ou ao ficar em posição ortostática por mais de 1 hora, referindo dor a palpação e irradiação para o pé. A radiografia do tornozelo direito apresenta ossículo acessório na porção medial da articulação talo-calcânea – Os sustentaculum, confirmada pela tomografia computadorizada. A ressonância magnética diagnostica coalizão talo-calcânea extra-articular com Os ustentaculum. Conclusão: É importante ressaltar que o Os sustentaculum não é apenasum ossículo acessório ou uma fratura antiga, ele é um componente de um tipo de coalizão talo-calcânea extra-articular, o que faz com que essa condição seja geralmente sintomática. Portanto, se um paciente com Os sustentaculum apresentar sintomas na área articular talo-calcânea medial, uma coalizão talo-calcânea extra-articular com Os sustentaculum deve ser considerada. Palavras-chave: Coalizão tarsal, Tomografia computadorizada por raios X, Imagem por ressonância magnética, Radiografia ABSTRACT Introduction: The Os sustentaculum is a rare accessory bone located at the posterior end of the sustentaculum tali. The tarsal coalition can be considered a congenital anomaly that can become symptomatic. Often, CT or MRI is required to confirm the diagnosis of the talo-calcaneus coalition when the findings on radiographs are ambiguous. Objective: To report an unusual case of a coalition of the talocalcaneal joint with Os sustentaculum, diagnosed by imaging exams. Case Report: A 26-year-old woman with a “lump” in her right ankle for 10 years causing intermittent pain. She worsens when wearing heels - regardless of the time when walking or standing in an orthostatic position for more than 1 hour, referring to pain on palpation and irradiation to the foot. The right ankle radiograph shows an accessory ossicle in the medial portion of the talocalcaneal joint – Os Sustentaculum, confirmed by computed tomography. Magnetic resonance imaging diagnoses extra-articular talo-calcaneus coalition with Os sustentaculum. Conclusion: It is important to emphasize that the Os sustentaculum is not just an accessory ossicle or an old fracture, it is a component of a type of extra-articular talo-calcaneus coalition, which makes this condition generally symptomatic. Therefore, if a patient with Os sustentaculum shows symptoms in the medial talo-calcaneus joint area, an extra-articular talo-calcaneus coalition with Os sustentaculum should be considered. Keywords: Tarsal coalition, X-ray computed tomography, Magnetic resonance imaging, Radiography

Morphologic Analysis of Nonosseous Talocalcaneal Coalitions Using 3D Reconstruction

Background: Resection of talocalcaneal coalitions has generally involved osseous coalitions. We attempted to evaluate the morphology of nonosseous talocalcaneal coalitions. This study aimed to investigate if the calcaneal articular surface area of feet with talocalcaneal coalitions is different than that of normal feet. Methods: Twenty nonosseous talocalcaneal coalition cases with analyzable computed tomography (CT) scans were compared to 20 control cases. Three-dimensional models of the talus and calcaneus were constructed, and the surface areas of the posterior facet (SPF), whole talocalcaneal joint of the calcaneus (SWJ), and coalition site (SCS) of each 3D-CT model were measured. “Calibrated” values of the 2 groups were created to adjust for relative size of the tali and then compared. The preoperative and postoperative AOFAS Ankle-Hindfoot scale was calculated for 9 cases that had undergone single coalition resection. Results: The calibrated SPF and SWJ were significantly greater in the coalition group than in the control group (40% and 12%, respectively). No significant difference was detected between the calibrated (SWJ – SCS) value of the coalition group and the calibrated SWJ value of the control group. The AOFAS scale was improved postoperatively in all 9 cases analyzed. Conclusion: The calcaneal articular surface of nonosseous talocalcaneal coalition feet in our series was larger than that of the normal feet. This study indicates that the total calcaneal articular surface after coalition resection may be comparable to the calcaneal articular surface of normal feet. We suggest that the indication for coalition resection be reconsidered for nonosseous coalition. Level of Evidence: Level III, retrospective comparative study.

Does the position of a sustentacular screw influence the stability of a plate osteosynthesis of a calcaneal fracture? A biomechanical study

The purpose of the study was to compare the stability of the plate osteosyntheses of intra-articular calcaneal fractures using various types of a sustentacular screw insertions. A geometrical model of a calcaneal fracture was created. The fracture was fixed with a plate and screws with a uniform distribution. The individual models differed regarding the position of the sustentacular screw. The screw was inserted using three different variants: Model A: into the tip of sustentaculum tali, Model B: under the sustentaculum tali, and Model C: into the inferior peripherial rim of the sustentacular fragment. In all three variants, the screw was either locked into the plate via threads or unlocked. The model was loaded with force in the vertical direction. The stiffness of individual models was evaluated using the finite element method, which was expressed as the maximum force (Fmax) that the system was able to transmit and by determining the magnitude and distribution of reduced stress (σred) on the individual parts of the model of a fixed calcaneal fracture. The greatest stiffness of the system was observed in the Model B (Fmax = 335.8 N). The least stiffness was observed in Model C (Fmax = 296.3 N). This model also produced the greatest load on bone tissue was observed (σmaxred = 67.5 MPa). The least load on bone tissue was measured in Model B (σmaxred = 53.7 MPa). The load on the plate was similar in all three models (814.0–820.0 MPa). The analyses suggest that in a plate osteosynthesis of a calcaneal fracture, the insertion of a sustentacular screw under the tip of the sustentaculum tali is acceptable in terms of osteosynthesis stability. This sustentacular screw position reduces the risk of the screw penetrating into the talocalcaneal joint.

Arthroscopic Mobilization of the Ankle-subtalar Joint Complex Using a Novel “Infra-fibula-tip” Portal

Category: Arthroscopy; Hindfoot Introduction/Purpose: As a minimally invasive surgical option for posterior ankle/subtalar pathologies, the prone hindfoot endoscopy (a.k.a. Van-Dijk’s method) has been becoming the ‘gold standard’ technique. While this technique holds advantage regarding good orientation and safety handling of posteromedial pathologies, it limits access to the anterolateral part, therefore inconvenient when simultaneously dealing with anterior and posterior pathologies. Recently, we have introduced a novel ‘infra- fibula-tip (IFT)’ portal, which permits wide access to the posterior talocalcaneal joint (PTCJ), from anterolateral to posteromedial, with a patient positioned in supine or semi-lateral. The present study reviewed clinical outcomes of a case series of arthroscopic hindfoot mobilization using this new surgical technique, so as to document its clinical utility. Methods: The sequence of surgical procedures is as follows; - Create an IFT portal, from a small incision immediately distal to the fibular tip, through the peroneal tendon sheath (anterior to the tendons, but posterior to the calcanofibular ligament), toward the posterior porch of PTCJ. - Inserting a 30-deg 2.7mm scope to the posterior porch, and broadly observing posterior intraarticular findings. - Gently moving the scope to the anterolateral porch, and broadly observing anterolateral intraarticular findings. - Creating an anterolateral (AL) portal under arthroscopic guidance. - Creating a PL portal at immediately lateral to the Achilles tendon, with guidance of a blunt rod inserted from the AL portal (gently advanced posteriorly through the lateral recess and penetrated the rod toward subcutis). - Executing posterior procedures from the PL portal, while observing from the IFT portal. Executing anterolateral procedures working from the AL portal, while observing from the IFT portal. Results: A total of 7 cases underwent the procedure of interest to date. Subtalar osteoarthritis (OA) occurred in all, with accessory anterolateral talar facet (AALTF) impingement in 3. Ankle OA occurred in 3, with anterior bony impingement in 2. Preceding pathologies included peri-ankle intraarticular fractures (4), talocalcaneal coalition (2), and neurogenic varus foot (1). Mobilization procedures included lateral-to-posterior PTCJ debridement (7), coalition release (2), AALTF removal (3), sinus debridement (2), posterior ankle capsule release (2), anterior ankle debridement (2), talonavicular debridement (1), and Achilles tendon lengthening (1). The surgery duration ranged from 65 to 245 minutes. Postoperatively, of 4 cases followed more than 6 months, remarkable motion improvement (10 degrees or more) occurred in 3, and every case reported symptom relief. Conclusion: The IFT portal accesses the middle of the PTCJ, with a short skin-to-joint distance, allowing flexible exploration of both the posterior and anterior porches. Posteriorly, ability of direct intraarticular access (without extraarticular shaving) reduces surgical invasion, as well as the risk of potential neurovasucular injury. Anteriorly, it helps secure good triangulation for handling sinus pathologies. Since subtalar arthroscopy using the IFT portal is doable in a supine or semi-lateral position, anterior ankle arthroscopy could be simultaneously executed. Arthroscopic hindfoot mobilization using this technique appears to be efficient for dealing with ankle/subtalar contracture due to combined anterior and posterior pathologies.

Augmented Ligament Reconstruction Partially Restores Hindfoot and Midfoot Kinematics After Lateral Ligament Ruptures

Background: Altered kinematics and persisting ankle instability have been associated with degenerative changes and osteochondral lesions. Purpose: To study the effect of ligament reconstruction surgery with suture tape augmentation (isolated anterior talofibular ligament [ATFL] vs combined ATFL and calcaneofibular ligament [CFL]) after lateral ligament ruptures (combined ATFL and CFL) on foot-ankle kinematics during simulated gait. Study Design: Controlled laboratory study. Methods: Five fresh-frozen cadaveric specimens were tested in a custom-built gait simulator in 5 different conditions: intact, ATFL rupture, ATFL-CFL rupture, ATFL-CFL reconstruction, and ATFL reconstruction. For each condition, range of motion (ROM) and the average angle (AA) in the hindfoot and midfoot joints were calculated during the stance phase of normal and inverted gait. Results: Ligament ruptures mainly changed ROM in the hindfoot and the AA in the hindfoot and midfoot and influenced the kinematics in all 3 movement directions. Combined ligament reconstruction was able to restore ROM in inversion-eversion in 4 of the 5 joints and ROM in internal-external rotation and dorsiflexion-plantarflexion in 3 of the 5 joints. It was also able to restore the AA in inversion-eversion in 2 of the 5 joints, the AA in internal-external rotation in all joints, and the AA in dorsiflexion-plantarflexion in 1 of the joints. Isolated ATFL reconstruction was able to restore ROM in inversion-eversion and internal-external rotation in 3 of the 5 joints and ROM in dorsiflexion-plantarflexion in 2 of the 5 joints. Isolated reconstruction was also able to restore the AA in inversion-eversion and dorsiflexion-plantarflexion in 2 of the joints and the AA in internal-external rotation in 3 of the joints. Both isolated reconstruction and combined reconstruction were most successful in restoring motion in the tibiocalcaneal and talonavicular joints and least successful in restoring motion in the talocalcaneal joint. However, combined reconstruction was still better at restoring motion in the talocalcaneal joint than isolated reconstruction (1/3 for ROM and 1/3 for the AA with isolated reconstruction compared to 1/3 for ROM and 2/3 for the AA with combined reconstruction). Conclusion: Combined ATFL-CFL reconstruction showed better restored motion immediately after surgery than isolated ATFL reconstruction after a combined ATFL-CFL rupture. Clinical Relevance: This study shows that ligament reconstruction with suture tape augmentation is able to partially restore kinematics in the hindfoot and midfoot at the time of surgery. In clinical applications, where the classic Broström-Gould technique is followed by augmentation with suture tape, this procedure may protect the repaired ligament during healing by limiting excessive ROM after a ligament rupture.

Anatomy of the Tarsal Canal and Sinus in Relation to the Subtalar Joint Capsule

Background: Anatomical knowledge of the tarsal canal and sinus is still unclear owing to the complexity of the ligamentous structures within them, particularly the relationship with the capsules of the subtalar joints. The aim of this study was to examine the anatomical relationship between the fibrous tissues of the tarsal canal and sinus and the articular capsules of the subtalar joint. Methods: We conducted a descriptive anatomical study of 21 embalmed cadaveric ankles. For a macroscopic overview of the subtalar joint, we removed the talus in 18 ankles and separated the fibrous tissues from the surrounding connective tissues to analyze the layered relationship between the inferior extensor retinaculum (IER) and the subtalar joint capsule. Additionally, we histologically analyzed the tarsal canal and the medial and lateral sides of the tarsal sinus using Masson’s trichrome staining in 3 ankles. Results: The medial and intermediate roots of the IER and interosseous talocalcaneal ligament (ITCL) were located in the same layer and were connected to each other, between the capsules of the posterior talocalcaneal and talocalcaneonavicular joints. The intermediate root of the IER and the cervical ligament (CL) had adjacent attachments on the tarsal sinus, and synovial tissues originating from the joint capsules filled the remaining area in the tarsal canal and sinus. Conclusion: We determined that the tarsal canal and sinus tarsi contained 3 layered structures: the anterior capsule of the posterior talocalcaneal joint, including the anterior capsule ligament; the layer of ITCL and IER; and the posterior capsule of the talocalcaneonavicular joint, including the CL. Clinical Relevance: The results of this study may help with the understanding of the pathomechanism of subtalar instability and sinus tarsi syndrome, resulting in better treatment.

Deformity and Clinical Outcomes Following Operative Correction of Charcot Foot: A New Classification With Implications for Treatment

Background: The historic treatment of Charcot foot arthropathy has been immobilization during the active phase of the disease process, followed by accommodative bracing of the acquired deformity. Evidence derived from modern patient-reported outcomes investigations has convinced many surgeons to attempt operative correction of the acquired deformity with a goal of improving quality of life. Methods: Over a 12-year period, 214 patients (9 bilateral) underwent reconstruction of the acquired deformity associated with midtarsal Charcot foot arthropathy. Over time, 3 patterns of deformity were observed based on weight-bearing pattern, relationship of the forefoot to the hindfoot, and integrity of the talocalcaneal joint. A valgus deformity pattern was present in 138, varus in 48, and dislocation of the talocalcaneal joint in 37. A consistent operative strategy was employed. Surgery included percutaneous tendon-Achilles lengthening, resection of infection when present, attempted correction of the structural deformity by wedge resection at the apex of the deformity, and immobilization with a 3-level static circular external fixator. Additional deformity pattern-specific procedures were added over time. Clinical outcomes were based on the historic metrics of limb salvage and resolution of infection and the functional metric of the ability to walk with commercially available therapeutic footwear. Results: Seven patients died within a year of surgery, and 15 underwent partial- or whole-foot amputation. Overall, 173 of 223 feet (77.6%) achieved a favorable clinical outcome. Patients with a valgus deformity pattern were most likely to achieve a favorable clinical outcome (120 of 138, 87.0%). Patients with a dislocation pattern were less likely to achieve a favorable clinical outcome (26 of 37, 70.3%), and those with a varus deformity pattern were least likely to achieve a favorable clinical outcome (27 of 48, 56.3%). Conclusions: Operative correction of the acquired deformity of Charcot foot arthropathy was performed with a goal of improving quality of life. Stratification of patients by deformity pattern allowed alterations of the basic surgery to afford improved outcomes. In addition to achieving historic goals of resolution of infection and limb salvage, almost 80% of the patients were able to achieve the functional goal of independent ambulation with commercially available therapeutic footwear. The clinical outcomes achieved in this retrospective case series appear to support the modern paradigm of operative correction of deformity in this complex patient population. This realistic appreciation of outcome expectations should both be helpful in counseling patients on the risk-benefit ratio associated with surgery and provide a benchmark to measure newer strategies of treatment. Level of Evidence: Level IV, retrospective case series.