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In recent years, the involvement of the compensation ability of the subtalar joint in lower extremity alignment has been reported. We previously showed that hindfoot alignment angle (HAA) is an indicator of compensation ability of the subtalar joint. The abnormal compensation ability of the subtalar joint was defined by the mobility of the subtalar joint, and evaluation of the mobility of the subtalar joint may help to further clarify the pathophysiology of abnormal compensation ability of the subtalar joint. This study was performed to evaluate the mobility of the subtalar joint and clarify the pathophysiology of abnormal compensation ability of the subtalar joint in the varus knee. Seventy-two knees of 72 patients aged ≥40 years with varus knee were included in this study. Preoperative radiographs were used for measurement of this study parameters. Based on our previous study, we defined HAA of ≥15.9°as abnormal compensation ability of the subtalar joint. The patients were divided into an abnormal group (A-group) and normal group (N-group). All measurement parameters were compared between the groups, and correlations between the HAA and each measurement parameter were analyzed. The weight-bearing hindfoot angle (WBHA) (p < 0.001) and non-weight-bearing hindfoot angle (non-WBHA) (p = 0.003), were significantly greater in the A-group than in the N-group. Conversely, the ratio of change in hindfoot alignment (p = 0.006), were significantly smaller in the A-group than in the N-group. The HAA was positively correlated with WBHA (r = 0.66) and non-WBHA (r = 0.43) and negatively correlated with the ratio of change in hindfoot alignment (r = −0.32). The pathophysiology of abnormal compensation ability of the subtalar joint in the varus knee is thought to involve a state of increased valgus of hindfoot alignment and an inability to move into normal hindfoot alignment. Level Ⅲ, retrospective study. [ABSTRACT FROM AUTHOR]

Boots are widely used by many people for various purposes, but their impact on gait biomechanics and injury risk is not well understood. This study investigated the effects of boots on walking biomechanics, compared to casual footwear. The lower limb joint kinematics and kinetics of 20 healthy male participants aged 20 to 30 years old were compared during self-paced walking with boots and shoes. The results showed that walking with boots is associated with greater hip extensor (P = 0.009) and ankle dorsiflexor (P < 0.001) moments in early stance, hip power generation (P < 0.001) and knee power absorption (P < 0.001) in early swing phase, hip abductor (P < 0.001) and knee adduction (P < 0.001) moments in the entire stance, net concentric work for the hip joint in sagittal (13.9%, P = 0.001) and frontal (21.7%, P = 0.002) planes. In contrast, the subtalar supinator moment in the entire stance (P < 0.001), ankle angular velocity in late stance (P < 0.001), and net concentric (− 42.7%, P < 0.001) and eccentric (− 44.6%, P = 0.004) works of subtalar joint were significantly lower in the boot condition. The compensatory adjustments in the hip and knee joints may result from ankle restrictions. While boots may aid those with ankle disorders, lower limb loading and the risk of musculoskeletal injuries and osteoarthritis could be increased. This study offers new perspectives on the biomechanical impact of boots on gait, potential prevention and treatment strategies of related injuries, and advancing footwear design. [ABSTRACT FROM AUTHOR]

Objectives: The objectives of this study were to contribute to the limited existing knowledge about subtalar dislocations, analyze the computed tomography (CT) findings and advantages over radiography, and report the rate and potential risk factors of post-traumatic peri-talar osteoarthritis (OA). Material and Methods: A total of 23 cases of traumatic subtalar dislocation during a 15-year period at three regional hospitals were retrospectively reviewed. Results: All 23 cases were closed dislocations. Successful close reduction was performed in 17 patients (73.9%) and 6 patients (26.1%) required open reduction and internal fixation. Twenty patients (87%) had associated foot and ankle fractures. Fractures of calcaneal medial tubercle were the most common (75%), followed by talar head (30%), sinus tarsi (25%), and medial malleolus (25%). The radiograph's sensitivity for identifying fractures was 48.1%. The mean follow-up period is 30 months. Symptomatic OA affected 8 patients (36.4%). No post-trauatic talar avascular necrosis was noted. Fractures were present in all of those patients with post-traumatic OA (100%). Three out of five patients who sustained high-energy mechanism injury developed radiographic OA (66.7%). Three out of six patients (50%) treated with open reduction and internal fixation also developed radiographic OA. Conclusion: Subtalar dislocation remains a rare injury. It is strongly associated with foot and ankle fractures. Fractures of the calcaneal medial tubercle were the most common. The risk of post-traumatic symptomatic peritalar OA is high. CT is useful in detecting occult fractures and injured bony subregions. We postulated potential risk factors of post-traumatic OA (fracture, high-energy mechanism of injury, open reduction, and internal fixation); however, this requires further study. [ABSTRACT FROM AUTHOR]

Background: The use of subtalar arthroereisis as an adjunct to the surgical treatment of stage 1 flexible progressive collapsing foot deformity (PCFD) is controversial. The aim was to investigate the clinical outcomes and report the implant removal rate of subtalar arthroereisis as an adjunct for stage 1 PCFD. Methods: A retrospective study of 212 consecutive feet undergoing operative management of stage 1 PCFD with adjunctive subtalar arthroereisis between October 2010 and April 2018. The primary outcome was the Foot and Ankle Outcome Score (FAOS). Secondary outcomes included Foot and Ankle Disability Index (FADI), Euroqol-5D-5L Index and implant removal rate. Results: Post-operative clinical FAOS outcomes were collected for 153 feet (72.2%). At mean 2.5-year follow-up, the mean ± standard deviation FAOS for each domain was as follows; Pain: 81.5 ± 18.5, Symptoms: 79.5 ± 12.9, Activities of Daily Living: 82.5 ± 15.4 and Quality of Life: 64.2 ± 23.7. EQ-5D-5L Index was 0.884 ± 0.152. Pre-operative scores were available for 20 of these feet demonstrating a statistically significant improvement in all FAOS, FADI and EQ-5D-5L domains (p < 0.05). The implant removal rate for persistent sinus tarsi pain was 48.1% (n = 102). Conclusion: Use of a subtalar arthroereisis implant as an adjunct to conventional procedures in stage 1 flexible PCFD can result in significant improvement in pain and function. Patients should be counselled as to the relatively frequent rate of subsequent implant removal. Level of evidence: IV. [ABSTRACT FROM AUTHOR]

Displaced intra-articular calcaneus fractures (DIACFs) are difficult injuries to treat and are often encountered by orthopedic surgeons. For DIACFs treated nonoperatively or with open reduction internal fixation (ORIF), a common complication is painful subtalar arthritis and the need for a secondary subtalar fusion, which prolongs the overall recovery time. One treatment option to address this sequela involves ORIF with subtalar fusion as the primary treatment. We describe a reproducible, minimally invasive surgical technique for primary ORIF with subtalar fusion when the calcaneal tuberosity is amendable to cannulated screw fixation to treat these complex calcaneal fractures. Our technique offers advantages compared to other techniques in that it avoids screw traffic, allows easy bony compression of the subtalar joint, and minimizes soft tissue damage via percutaneous screw fixation. Fourteen fractured calcanei in 12 patients underwent our technique and all achieved bony union with a median time to fusion of 107.5 days (range, 54–530 days). Eight patients returned to work with the remaining 4 patients having an unknown work status at last follow-up, although 2 of these 4 patients resumed normal activities. Only 1 patient experienced a complication, which was an infection after achieving bony union, and was treated with successful hardware removal and our infection protocol. Overall, we conclude our surgical technique offers a successful option in the treatment of DIACFs when the calcaneal tuberosity is amendable to cannulated screw fixation. [ABSTRACT FROM AUTHOR]

Talocalcaneal coalitions (TCC) is the second most frequent tarsal coalition reported. Our aim was to review talocalcaneal coalition classifications and to propose a new classification emphasizing a therapeutic approach. None of the classifications described for TCC mention the presence of flatfoot or valgus hindfoot, which are the key elements when defining the optimal treatment of this disease. We defined five clinical and radiological factors that would guide the choice of surgical treatment and based on these, we proposed a new classification system. [ABSTRACT FROM AUTHOR]

Objectives: Calcaneal external shape differs among nonhuman primates relative to locomotion. Such relationships between whole‐bone calcaneal trabecular structure and locomotion, however, have yet to be studied. Here we analyze calcaneal trabecular architecture in Gorilla gorilla gorilla, Gorilla beringei beringei, and G. b. graueri to investigate general trends and fine‐grained differences among gorilla taxa relative to locomotion. Materials and methods: Calcanei were micro‐CT scanned. A three‐dimensional geometric morphometric sliding semilandmark analysis was carried out and the final landmark configurations used to position 156 volumes of interest. Trabecular thickness (Tb.Th), trabecular spacing (Tb.Sp), and bone volume fraction (BV/TV) were calculated using the BoneJ plugin for ImageJ and MATLAB. Non‐parametric MANOVAs were run to test for significant differences among taxa in parameter raw values and z‐scores. Parameter distributions were visualized using color maps and summarized using principal components analysis. Results: There are no significant differences in raw BV/TV or Tb.Th among gorillas, however G. b. beringei significantly differs in z‐scores for both parameters (p = <0.0271). All three taxa exhibit relatively lower BV/TV and Tb.Th in the posterior half of the calcaneus. This gradation is exacerbated in G. b. beringei. G. b. graueri significantly differs from other taxa in Tb.Sp z‐scores (p < 0.001) indicating a different spacing distribution. Discussion: Relatively higher Tb.Th and BV/TV in the anterior calcaneus among gorillas likely reflects higher forces associated with body mass (transmitted through the subtalar joint) relative to forces transferred through the posterior calcaneus. The different Tb.Sp pattern in G. b. graueri may reflect proposed differences in foot positioning during locomotion. [ABSTRACT FROM AUTHOR]

Advanced varus ankle osteoarthritis is a debilitating disease that can present with limited physical function, severe pain, and diminished quality of life. Weightbearing computed tomography enables submillimeter 3-dimensional visualization, computational analyses, and enhanced diagnoses in reporting complex degenerative changes more accurately. This study set to compare static posture weightbearing joint angle differences in healthy and varus ankle osteoarthritis patients (compensated and non-compensated). Our retrospective assessment included 70 individuals, 44 of whom were diagnosed with advanced varus ankle osteoarthritis, and the remaining 26 were healthy participants to serve as controls. An automatic anatomic coordinate system was applied to each patient's 3-dimensional talus and calcaneus bone reconstructions from weightbearing computed tomography scans. Subtalar and midtarsal joint angles were calculated using Euler angles. We report statistical differences between the healthy group and both advanced varus osteoarthritis groups for midtarsal inversion/eversion. Specifically, both osteoarthritis groups' midtarsal joints were more inverted and plantarflexed as compared to healthy participants. Compensated and non-compensated subtalar joints were statistically different with respect to inversion/eversion. Non-compensated ankles exhibited a similar mean to healthy ankles who were both less inverted than compensated ankles. Our study helps physicians to better understand underlying mechanisms of peritalar compensation in varus ankle osteoarthritis. Patients featuring hindfoot compensation on average had a greater subtalar joint angle indicating greater inversion than healthy and non-compensated patients. • Advanced varus ankle OA patients had more midtarsal inversion and plantarflexion. • Abnormal alignment may alter mechanics, risking cartilage damage and instability. • This 3D study aids tailored varus ankle OA treatments using weightbearing CT images. [ABSTRACT FROM AUTHOR]

The complex anatomical structure of the foot-ankle imposes challenges to accurately quantify detailed hindfoot kinematics and estimate musculoskeletal loading parameters. Most systems used to capture or estimate dynamic joint function oversimplify the anatomical structure by reducing its complexity. Can four dimensional computed tomography (4D CT) imaging in combination with an innovative foot manipulator capture in vivo hindfoot kinematics during a simulated stance phase of walking and can talocrural and subtalar articular joint mechanics be estimated based on a detailed in silico musculoskeletal foot-ankle model. A foot manipulator imposed plantar/dorsiflexion and inversion/eversion representing a healthy stance phase of gait in 12 healthy participants while simultaneously acquiring 4D CT images. Participant-specific 3D hindfoot rotations and translations were calculated based on bone-specific anatomical coordinate systems. Articular cartilage contact area and contact pressure of the talocrural and subtalar joints were estimated using an extended foot-ankle model updated with an elastic foundation contact model upon prescribing the participant-specific rotations measured in the 4D CT measurement. Plantar/dorsiflexion predominantly occurred at the talocrural joint (RoM 15.9±3.9°), while inversion/eversion (RoM 5.9±3.9°) occurred mostly at the subtalar joint, with the contact area being larger at the subtalar than at the talocrural joint. Contact pressure was evenly distributed between the talocrural and subtalar joint at the beginning of the simulated stance phase but was then redistributed from the talocrural to the subtalar joint with increasing dorsiflexion. In a clinical case study, the healthy participants were compared with four patients after surgically treaded intra-articular calcaneal fracture. The proposed workflow was able to detect small but meaningful differences in hindfoot kinematics and kinetics, indicative of remaining hindfoot pathomechanics that may influence the onset and progression of degenerative joint diseases. • 4D CT enables in vivo quantification of dynamic gait-like motion of the hindfoot. • Talocrural joint allows plantar/dorsiflexion; subtalar enables inversion/eversion. • Musculoskeletal modelling allows quantification of dynamic hindfoot loading. • Talocrural contact pressure is negatively correlated with talocrural dorsiflexion. • Detection of meaningful differences between healthy and pathological subjects. [ABSTRACT FROM AUTHOR]

Talonavicular (TN) fusion is a common treatment for TN arthritis or deformity correction. There is incongruous evidence regarding remaining motion at the talocalcaneal and calcaneocuboid joints after TN fusion. Additionally, the effects of a malaligned TN fusion are not well understood and alignment of the fusion may be important for overall foot integrity. This project assessed the kinematic and kinetic effects of neutral and malaligned TN fusions. Ten cadaveric feet were tested on a gait simulator in four conditions: unfused, fused in neutral, fused in varus, and fused in valgus. The fusions were simulated with external fixation hardware. An eight‐camera motion analysis system and a 10‐segment foot model generated kinematic data, and a pressure mat captured pressure data. Simulated TN fusion was achieved in eight feet. From unfused to fused‐neutral, range of motion (ROM) was not eliminated in the adjacent joints, but the positions of the joints changed significantly throughout stance phase. Furthermore, the ROM increased at the tibiotalar joint. Plantar pressure and center of pressure shifted laterally with neutral fusion. The malalignments marginally affected the ROM but changed joint positions throughout stance phase. Pressure patterns were shifted laterally in varus malalignment and medially in valgus malalignment. The residual motion and the altered kinematics at the joints in the triple joint complex after TN fusion may subsequently increase the incidence of arthritis. Clinical significance: This study quantifies the effects of talonavicular fusion and malalignment on the other joints of the triple joint complex. [ABSTRACT FROM AUTHOR]

Introduction: Subtalar Arthroereisis (STA) is a surgical intervention for pediatric flexible flatfoot (PFF), primarily targeting hindfoot alignment by limiting excessive subtalar eversion. However, its effects on forefoot parameters remain underexplored. This study aims to investigate radiological changes following STA in pediatric patients. Materials and Methods: A retrospective analysis was conducted on consecutive patients treated with STA for PFF. First ray-related angles, including the Hallux Valgus Angle (HVA) and the Intermetatarsal Angle (IMA), alongside hindfoot radiological parameters such as the Meary, Calcaneal Pitch, and Costa Bartani angles, were assessed. Subgroup analysis by gender was performed, and correlations between demographic and preoperative radiological parameters were examined. Results: Forty-one patients (81 feet) with an average age of 11.6 years were included, with a mean follow-up duration of 6.4 months. No significant differences were observed in first ray-related angles pre-and postoperatively, with the mean IMA changing from 7.97° to 7.18° and the mean HV angles changing from 9.51° to 8.66°. Noteworthy improvements were seen in flat foot angles, including the Meary, Calcaneal Pitch, and Costa Bartani angles, postoperatively. The age subgroup analysis revealed similar trends in IMA and HVA changes between Group A (who underwent surgery before peak growth) and Group B (who underwent surgery after peak growth). Higher preoperative angles tended to improve, while lower preoperative IMAs and HVAs tended to worsen postoperatively, all remaining within normal ranges. Conclusion: STA showed positive radiological outcomes for PFF treatment, while negligible changes in first ray-related angles were observed. The age subgroup analysis indicated similar trends regardless of operation timing. Higher preoperative angles tended to improve, while lower preoperative angles tended to worsen postoperatively, despite all falling within non-pathological ranges. Further research is warranted to confirm this correlation. [ABSTRACT FROM AUTHOR]

Background: The peroneus longus (PL) and peroneus brevis (PB) function as the primary muscles of eversion, a movement closely associated with tibial external rotation for ankle mor-tise stability. Ankle motion and tibial rotation vary based on different ankle and knee positions. Objects: This study aimed to investigate the PL, PB, and biceps femoris (BF) muscle activation and eversion strength during side-lying isometric eversion exercise based on different ankle positions (neutral [N] and plantarflexion [PF]) and knee positions (90° flexion [KF] and exten-sion [KE]). Methods: Thirty healthy adults with an Ankle Joint Functional Assessment Tool score of ≥ 22 were recruited (mean age = 24.8 ± 3.1 years). Maximal isometric eversion strength and submaximal muscle activation of the PL, PB and BF were measured during isometric eversion exercise in side-lying. A 2 × 2 repeated measures analysis of variance was performed to inves-tigate differences in muscle activation and strength. Results: The PL and PB muscle activation showed significant main effects with the knee and ankle positions (p < 0.05); activation was greater in the KE and PF positions than in the KF and N positions. The BF muscle activation showed a significant interaction effect with knee and ankle positions, which was greater in knee extension and ankle plantarflexed (KEPF) posi-tion than in knee flexion and ankle plantarflexed (KFPF) position (p < 0.05). Eversion strength showed a significant main effect only in ankle position (p < 0.05) and was greater in the N position than in the PF position. Conclusion: The results of this study indicate that the KEPF position can be recommended to facilitate contraction of the PL and PB during side-lying eversion exercise. Furthermore, the effects of the knee-ankle positions should be considered for measuring ankle eversion strength and implementing the isometric submaximal side-lying eversion exercise.

This case report presents a novel cause of rigid flatfoot caused by the entrapment of the Flexor Hallucis Longus (FHL) tendon within the subtalar joint. A 19-year-old male with chronic right ankle and foot pain diagnosed with rigid flatfoot deformity. MRI identified the FHL tendon entrapped within the subtalar joint, a condition to our knowledge never previously reported. This report highlights the importance of thorough clinical evaluation and advanced imaging techniques in diagnosing rare causes of rigid flatfoot and suggests that surgical options may still be valid for such rare presentations.

Objectives The etiology of flatfoot and cavus foot is multicausal and controversial. So far, no literature reports the relationship between the sagittal morphology of subtalar joint and the alignment of foot. The purpose of this study was to explore whether the subtalar alignment would influence the configuration of foot. Methods From January 2017 to January 2020, we included 109 feet in the flatfoot group, 95 feet in the cavus group, and 104 feet in the control group in this retrospective comparative study. The Gissane angle and calcaneal posterior articular surface inclination angle represented the sagittal morphology of the subtalar joint. Meary's angle, calcaneal pitch angle, and talar pitch angle reflected the alignment of foot. They were measured in the weightbearing foot X‐rays. The angles in different groups were compared via Mann–Whitney U test. We calculated the correlation between the sagittal alignment of subtalar joint and the alignment of foot using Spearman's correlation analysis. Interobserver and intraobserver reliability were calculated. Results The Gissane angle, calcaneal posterior articular surface inclination angle, Meary's angle, talar pitch angle, and calcaneal pitch angle were significantly different in the three groups. The Gissane angle had an excellent correlation with the Meary's angle (r = 0.850, p

Abstract Background The talocrural joint and the subtalar joint are the two major joints of the ankle-joint complex. The position and direction of the exosuit force line relative to these two joint axes can influence ankle motion. We aimed to understand the effects of different force-lines on ankle multidimensional motion. Methods In this article, three assistance force line schemes for ankle exosuits were proposed: perpendicular to the talocrural joint axis (PT), intersecting with the subtalar joint axis (IS), and parallel to the triceps surae (PTS). A theoretical model was proposed to calculate the exosuit’s assistance moment. Seven participants completed four experimental tests of ankle plantarflexion, including three passive motions assisted by the PT, PTS and IS schemes, and one active motion without exosuit assistance (Active). Results The simulation results demonstrated that all three exosuits were able to produce significant moments of ankle plantarflexion. Among these, the PT scheme exhibited the highest moments in all dimensions, followed by the PTS and IS schemes. The experimental findings confirmed the effectiveness of all three exosuit schemes in assisting ankle plantarflexion. Additionally, as the assistive force lines approached the subtalar joint, there was a decrease in ankle motion assisted by the exosuits in non-plantarflexion directions, along with a reduction in the average distance of ankle angle curves relative to active ankle motion. Furthermore, the linear correlation coefficients between inversion and plantarflexion, adduction and plantarflexion, and adduction and inversion gradually converged toward active ankle plantarflexion motion. Conclusions Our research indicates that the position of the exosuit force line to the subtalar joint has a significant impact on ankle inversion and adduction. Among all three schemes, the IS, which has the closest distance to the subtalar joint axes, has the greatest kinematic similarity to active ankle plantarflexion and might be a better choice for ankle assistance and rehabilitation.

Medial displacement calcaneal osteotomy (MDCO) is the standard procedure for flatfoot. We investigated the effect of MDCO on the foot using a finite element analysis. Foot models were created from computed tomography data of 8 patients with flat feet. MDCO was performed on each model with bone translation distance of 4, 8, and 12 mm. The morphological changes, plantar pressures, and stress percentage on the talocrural and subtalar joints were evaluated before and after surgery. Morphological evaluation showed improvement in the medial longitudinal arch. The stress percentage of plantar pressure in the medial area decreased, and the stress percentage of plantar pressure in the mid- and lateral forefoot area increased. At the talocrural joint, the medial and middle stress percentage increased, while the lateral and posterior stress percentage decreased. In the subtalar joint, the stress percentage in the middle subtalar joint increased and that in the posterior subtalar joint decreased. Within the posterior subtalar joint, the anterior and medial stress percentage increased, while the posterior and lateral stress percentage decreased. Preoperative simulation using the finite element analysis may be useful in understanding postoperative morphological changes and loading conditions to perform patient-specific surgery. [ABSTRACT FROM AUTHOR]

Objective: The treatment of talar neck and/or body fractures is known to be difficult and challenging, with significant impact on the long‐term functional outcome for the patient. The optimal management, including the choice of surgical approaches and implants, are still under constant discussion. The purpose of the study was to investigate the clinical effects of lateral mini‐plate combined with medial lag screws for the treatment of complicated central talar fractures. Methods: The data of eight patients with complex central talus fractures treated between June 2019 and January 2021 were retrospectively analyzed. There were six males and two females, ranging in age from 15 to 66 years, with an average age of 37.4 years. There were three cases on the left and five cases on the right. All fractures were comminuted, including talar neck with talar body fracture in seven cases and talar body comminuted with subluxation of subtalar joint in one case. All patients were treated with the anteromedial combined anterolateral approach, lateral talar mini‐plate fixation and medial lag screw fixation. Fracture reduction quality, union time, and complications were recorded, and functional outcomes were evaluated using the American Orthopedic Foot & Ankle Society (AOFAS) scoring system. Results: The time from injury to surgery was 1–6 days, with an average of 3.38 days. The follow‐up period was 34–53 months (mean 44.88 months). All fractures healed with a mean healing time of 16.75 weeks (13–23 weeks). Anatomical reduction was observed in six cases and near in two cases. After operation, there was no loosening or breakage of implant, loss of fracture reduction, and irritation of skin and soft tissue by internal fixation. The average AOFAS score was 87.38 (48–100), with excellent five cases, good two cases and poor one case, and the excellent and good rate was 87.5%. Superficial skin necrosis in one surgical incision healed after dressing exchange. No deep infection occurred. One case (1/8, 12.5%) developed avascular necrosis of the talus without collapse. Posttraumatic arthritis was found in four cases (4/8, 50%). Conclusion: The utilization of lateral mini‐plates in combination with medial screws for treating complex central talar fractures results in satisfactory reduction and stable fixation, mitigating complications associated with poor reduction. However, due to the absence of an anatomical mini‐plate, pre‐contouring is necessary when applying the lateral plate. This demands a surgeon's thorough familiarity with the anatomical morphology of the talus and proficiency in surgical techniques. Posttraumatic arthritis is the most common complication of complex central talar fractures. [ABSTRACT FROM AUTHOR]

Objectives: The etiology of flatfoot and cavus foot is multicausal and controversial. So far, no literature reports the relationship between the sagittal morphology of subtalar joint and the alignment of foot. The purpose of this study was to explore whether the subtalar alignment would influence the configuration of foot. Methods: From January 2017 to January 2020, we included 109 feet in the flatfoot group, 95 feet in the cavus group, and 104 feet in the control group in this retrospective comparative study. The Gissane angle and calcaneal posterior articular surface inclination angle represented the sagittal morphology of the subtalar joint. Meary's angle, calcaneal pitch angle, and talar pitch angle reflected the alignment of foot. They were measured in the weightbearing foot X‐rays. The angles in different groups were compared via Mann–Whitney U test. We calculated the correlation between the sagittal alignment of subtalar joint and the alignment of foot using Spearman's correlation analysis. Interobserver and intraobserver reliability were calculated. Results: The Gissane angle, calcaneal posterior articular surface inclination angle, Meary's angle, talar pitch angle, and calcaneal pitch angle were significantly different in the three groups. The Gissane angle had an excellent correlation with the Meary's angle (r = 0.850, p < 0.0001), and the talar pitch angle (r = −0.825, p < 0.0001), and a good correlation with the calcaneal pitch angle (r = 0.638, p < 0.0001). The calcaneal posterior articular surface inclination angle had an excellent correlation with the Meary's angle (r = −0.902, p < 0.001), and the talar pitch angle (r = 0.887, p < 0.0001), and a good correlation with the calcaneal pitch angle (r = −0.702, p < 0.0001). The interobserver and intraobserver reliability for all radiographic measurements was good to excellent. Conclusion: A subtalar joint with a larger Gissane angle and a more horizontal calcaneal posterior articular surface angle tended to have a higher foot arch and vice versa. The inspiration from this study was that the deformities of flatfoot and cavus foot may relate to the subtalar deformity. [ABSTRACT FROM AUTHOR]

Subtalar distraction arthrodesis (SDA) is a surgical procedure designed to treat hindfoot deformities associated with isolated subtalar joint arthritis. In 1996, Fitzgibbons was the first to observe that, in some cases, hindfoot fusion appeared to be associated with the development of tibiotalar valgus tilt. Since then, few studies have addressed this issue. Given that hindfoot fusion can be performed using various techniques, this study investigated the potential tibiotalar joint frontal or sagittal modifications resulting from the modified Grice–Green technique. All the consecutive patients who underwent the modified Grice–Green procedure were included. The patient records were reviewed to extract demographic data. Weight-bearing foot and ankle radiographs were assessed to measure the talar tilt angle and the tibiotalar ratio on the same picture archiving and communication system by three independent observers. A total of 69 patients met the criteria for inclusion. The mean talar tilt showed no substantial changes, since the increase from 1.46 ± 1.62 preoperatively to 1.93 ± 2.19 at a minimum of 8 months postoperatively was not statistically significant (p = 0.47). The average preoperative tibiotalar ratio significantly increased from 33.4 ± 4.4% to 35 ± 4% postoperatively (p = 0.007), although remaining within the normal range, indicating a possible realignment of the posterior facet of the subtalar joint. In conclusion, this study highlights the effectiveness of the modified Grice–Green procedure in achieving a favorable realignment without impacting the ankle joint, particularly regarding tibiotalar valgus tilt. [ABSTRACT FROM AUTHOR]

Background: Pes planovalgus is one of the most common pediatric skeletal deformities. There have been no studies to analyze in detail the spatiotemporal variables of gait following arthroereisis. Purpose of the study: The purpose of our study was to assess gait parameters in patients with symptomatic flexible flatfoot following treatment with the talus screw. Methods: This was a prospective study assessing the 22 patients treated surgically due to symptomatic flexible flatfoot with the talus screw. Patients underwent gait assessment with a G-Sensor. We analyzed the following gait parameters: gait cycle duration, step length, support phase duration, swing phase duration, double support duration, single support duration, cadence, velocity, step length. Results: The post-operative gait parameter assessment for the operated and non-operated foot showed a significant difference only in terms of step length. Cadence increased from the pre-operative mean of 82.29 steps/min to a post-operative mean of 102.94 steps/min. Gait velocity increased significantly from 0.81 m/s before to 0.96 m/s after surgery. Discussion: Arthroereisis with the talus screw helps improve gait parameters following surgery. Post-operatively, we observed increased gait velocity and cadence and decreased gait cycle duration in the operated limb. Conclusion: Short-term biomechanical outcomes of pes planovalgus treatment with the talus screw are good. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: Sinus tarsi syndrome (STS) is caused by various pathologies. However, the exact etiology of STS remains controversial. This study evaluated the imaging and arthroscopic findings of patients who underwent surgical treatment after conservative treatment for STS failed. Materials and Methods: Between December 2014 and August 2018, 20 patients (21 cases) who underwent surgical treatment for STS were included in the study. The clinical results were analyzed using the visual analog scale (VAS) and the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot functional scale. The radiographic results were analyzed using Meary's angle, calcaneal pitch angle, and hindfoot alignment angle. The pathologic conditions of sinus tarsi were confirmed by magnetic resonance imaging (MRI) and subtalar arthroscopy. Synovitis, bone edema, and accessory anterolateral talar facet (AALTF) were evaluated on MRI. Synovial thickening, cartilage damage, interosseous talocalcaneal ligament (ITCL) and cervical ligament rupture, soft tissue impingement, AALTF, and accessory talar facet impingement (ATFI) were evaluated by subtalar arthroscopy. Results: The mean duration of symptoms was 28.7 months (4~120). All patients showed significant improvement in the VAS and AOFAS ankle-hindfoot scale. Significant improvements in hindfoot alignment angle and Meary's angle postoperatively were noted in patients who underwent medial displacement calcaneal osteotomy. MRI confirmed synovitis in all patients, AALTF in 19 cases (90.5%), and ATFI with bone edema in seven cases (33.3%). In subtalar arthroscopy, pathologic conditions were observed in the following order: synovitis in 21 cases (100%), AALTF in 20 cases (95.2%), ITCL partial rupture in nine cases (42.9%), and soft tissue impingement in seven cases (33.3%). All cases had two or more pathological conditions, and 15 (71.4%) had three or more. Conclusion: In cases of STS that do not respond to conservative treatment, a comprehensive examination of the lesions of the tarsal sinus and lesions around the subtalar joint is essential. [ABSTRACT FROM AUTHOR]

Background and Objectives: Despite the established role of subtalar joint arthrodesis (SJA) for treatment of subtalar osteoarthritis, achieving bone union remains challenging, with up to 46% non-union rates. Adequate compression and stable fixation are crucial for successful outcomes, with internal screw fixation being the gold standard for SJA. The delta configuration, featuring highly divergent screws, offers stability, however, it can result in hardware irritation in 20–30% of patients. Solutions to solve this complication include cannulated compression screw (CCS) countersinking or cannulated compression headless screw (CCHS) application. The aim of this biomechanical study was to investigate the stability of a delta configuration for SJA utilizing either a combination of a posterior CCHS and an anterior CCS or a standard two-CCS combination. Materials and Methods: Twelve paired human cadaveric lower legs were assigned pairwise to two groups for SJA using either two CCSs (Group 1) or one posterior CCHS and one anterior CCS (Group 2). All specimens were tested under progressively increasing cyclic loading to failure, with monitoring of the talocalcaneal movements via motion tracking. Results: Initial stiffness did not differ significantly between the groups, p = 0.949. Talocalcaneal movements in terms of varus–valgus deformation and internal–external rotation were significantly bigger in Group 1 versus Group 2, p ≤ 0.026. Number of cycles until reaching 5° varus–valgus deformation was significantly higher in Group 2 versus Group 1, p = 0.029. Conclusions: A delta-configuration SJA utilizing a posterior CCHS and an anterior CCS is biomechanically superior versus a standard configuration with two CCSs. Clinically, the use of a posterior CCHS could prevent protrusion of the hardware in the heel, while an anterior CCS could facilitate less surgical time and thus less complication rates. [ABSTRACT FROM AUTHOR]

Background: The talocrural joint and the subtalar joint are the two major joints of the ankle-joint complex. The position and direction of the exosuit force line relative to these two joint axes can influence ankle motion. We aimed to understand the effects of different force-lines on ankle multidimensional motion. Methods: In this article, three assistance force line schemes for ankle exosuits were proposed: perpendicular to the talocrural joint axis (PT), intersecting with the subtalar joint axis (IS), and parallel to the triceps surae (PTS). A theoretical model was proposed to calculate the exosuit’s assistance moment. Seven participants completed four experimental tests of ankle plantarflexion, including three passive motions assisted by the PT, PTS and IS schemes, and one active motion without exosuit assistance (Active). Results: The simulation results demonstrated that all three exosuits were able to produce significant moments of ankle plantarflexion. Among these, the PT scheme exhibited the highest moments in all dimensions, followed by the PTS and IS schemes. The experimental findings confirmed the effectiveness of all three exosuit schemes in assisting ankle plantarflexion. Additionally, as the assistive force lines approached the subtalar joint, there was a decrease in ankle motion assisted by the exosuits in non-plantarflexion directions, along with a reduction in the average distance of ankle angle curves relative to active ankle motion. Furthermore, the linear correlation coefficients between inversion and plantarflexion, adduction and plantarflexion, and adduction and inversion gradually converged toward active ankle plantarflexion motion. Conclusions: Our research indicates that the position of the exosuit force line to the subtalar joint has a significant impact on ankle inversion and adduction. Among all three schemes, the IS, which has the closest distance to the subtalar joint axes, has the greatest kinematic similarity to active ankle plantarflexion and might be a better choice for ankle assistance and rehabilitation. [ABSTRACT FROM AUTHOR]

This paper aimed to investigate the biomechanical changes during the talus impact with the calcaneus at varying velocities. Various three-dimensional reconstruction software was utilized to construct a finite element model that consisted of the talus, calcaneus, and ligaments. The explicit dynamics method was used to explore the process of the talus impacting on the calcaneus. The velocity of impact was altered from 5 m/s to 10 m/s with a 1 m/s interval. Stress readings were collected from the posterior, intermediate, and anterior subtalar articular (PSA, ISA, ASA), calcaneocubic articular (CA), Gissane Angle (GA), calcaneal base (BC), medial wall (MW), and lateral wall (LW) of the calcaneus. The changes in the amount and distribution of stress in the different regions of the calcaneus that varied with velocity were analysed. The model was validated through comparison with findings from the existing literature. During the process of impact between the talus and calcaneus, the stress in the PSA reached its peak first. Notably, stress was concentrated mainly in the PSA, ASA, MW, and LW of the calcaneus. At varying impact velocities of the talus, the mean maximum stress of the PSA, LW, CA, BA, and MW exhibited statistically significant differences (P values were 0.024, 0.004, <0.001, <0.001, and 0.001, respectively). However, the mean maximum stress of the ISA, ASA, and GA was not statistically significant (P values were 0.289, 0.213, and 0.087, respectively). In comparison with the velocity at 5 m/s, the mean maximum stress increases in each region of the calcaneus at a velocity of 10 m/s were as follows: PSA 73.81%, ISA 7.11%, ASA 63.57%, GA 89.10%, LW 140.16%, CA 140.58%, BC 137.67%, MW 135.99%. The regions of stress concentration were altered, and the magnitude and sequence of peak stress in the calcaneus also varied according to the velocity of the talus during impact. In conclusion, the velocity of the talus during impact had a significant influence on the magnitude and distribution of stress within the calcaneus, which was a crucial factor in the development of calcaneal fractures. It was possible that the magnitude and sequence of stress peaks played a vital role in determining the emergence of fracture patterns. [ABSTRACT FROM AUTHOR]

Purpose: Planovalgus foot deformity (PVFD) is common in children with neuromuscular conditions and severe deformity may require surgical correction. This study aims to assess clinical and radiological outcomes of PVFD secondary to neuromuscular disease managed by subtalar arthroeresis (SuAE), midfoot soft tissue release and talo-navicular arthrodesis (TNA). Methods: A retrospective analysis of children with neuromuscular disease and nonreducible PVFD who underwent SuAE, midfoot soft tissue release, and TNA and with a minimum follow-up of 5 years was performed. A total of 60 patients with neuromuscular disease (108 feet) including cerebral palsy were reviewed. Mean age at surgery was 12.7 ± 4.6 years (6–17). Mean follow-up was 7 ± 2.9 years (5–10). Clinical outcomes and radiologic correction at final follow-up were compared with preoperative values. Statistical analysis was performed and significance was set at P < 0.01. Results: Statistically significant radiological improvements between pre- and postoperative values were found for all angle values. At final follow-up, there was a significant improvement in VAS score (4.8 vs. 2; P < 0.01). There was also a positive trend in the improvement of walking ability. No cases of pseudoarthrosis were reported at final follow-up. Screw removal was required in 5 out of 108 feet (4.6%) and 2 feet (3.3%) had delayed medial wound healing. Conclusions: SuAE combined with TNA and midfoot soft tissue is a safe and feasible procedure that can provide good clinical and radiologic results in patients with neuromuscular disease and nonreducible PVFD; the procedure can improve foot stability, and has a limited number of complications. Level of Evidence: IV [ABSTRACT FROM AUTHOR]

Landing from heights is a common movement for active-duty military personnel during training. And the additional load they carry while performing these tasks can affect the kinetics and ankle kinematic of the landing. Traditional motion capture techniques are limited in accurately capturing the in vivo kinematics of the talus. This study aims to investigate the effect of additional trunk load on the kinematics of the talocrural and subtalar joints during landing, using a dual fluoroscopic imaging system (DFIS). Fourteen healthy male participants were recruited. Magnetic resonance imaging was performed on the right ankle of each participant to create three-dimensional (3D) models of the talus, tibia, and calcaneus. High-speed DFIS was used to capture the images of participants performing single-leg landing jumps from a height of 40 cm. A weighted vest was used to apply additional load, with a weight of 16 kg. Fluoroscopic images were acquired with or without additional loading condition. Kinematic data were obtained by importing the DFIS data and the 3D models in virtual environment software for 2D–3D registration. The kinematics and kinetics were compared between with or without additional loading conditions. During added trunk loading condition, the medial-lateral translation range of motion (ROM) at the talocrural joint significantly increased (p < 0.05). The subtalar joint showed more extension at 44–56 ms (p < 0.05) after contact. The subtalar joint was more eversion at 40–48 ms (p < 0.05) after contact under the added trunk load condition. The peak vertical ground reaction force (vGRF) significantly increased (p < 0.05). With the added trunk load, there is a significant increase in peak vGRF during landing. The medial-lateral translation ROM of the talocrural joint increases. And the kinematics of the subtalar joint are affected. The observed biomechanical changes may be associated with the high incidence of stress fractures in training with added load. • The first fluoroscopy-based study to examine effects of additional trunk loading (ATL) on ankle. • The ATL significantly increased peak vGRF during landing. • The ATL increased the medial-lateral translation ROM of talocrural joint. • The ATL significantly effects the kinematics of the subtalar joint during landing. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to evaluate the diagnostic accuracy, inter-reader agreement, and associated pathologies on MR images of patients with confirmed TC. Methods and materials: In this retrospective study, 168 ankle MRI exams were included, consisting of 56 patients with clinically or surgically confirmed TC and 112 controls without TC, matched for age and sex. Images were analyzed independently by three radiologists blinded to clinical information. The evaluation criteria included the presence, type, and location of TC, as well as associated pathologies. After calculating diagnostic accuracy and the odds ratio of demographic data and anatomic coalition type for associated pathologies, inter-reader agreement was assessed using kappa statistics. Results: The majority of TCs were non-osseous (91.1%) and located at the calcaneonavicular (33.9%) or talocalcaneal joint (66.1%). Associated pathologies included adjacent and distant bone marrow edema (57.1% and 25.0%), osteochondral defect of the talar dome (OCD, 19.6%), and joint effusion (10.7%) and accessory anterolateral talar facet (17.9%). Talar OCD was associated with increased patient age (p = 0.03). MRI exhibited a cumulative sensitivity and specificity of 95.8% and 94.3% with almost perfect inter-reader agreement (κ = 0.895). Conclusion: MRI is a reliable method for detecting tarsal coalition and identifying commonly associated pathologies. Therefore, we recommend the routine use of MRI in the diagnostic workup of patients with foot pain and suspected tarsal coalition. Clinical relevance statement: MRI is an accurate and reliable modality for diagnosing tarsal coalitions and detecting associated pathologies, while improving patient safety compared to computed tomography by avoiding radiation exposure. Key Points: • Despite the technological progress in magnetic resonance imaging (MRI), computed tomography (CT) is still regarded as the gold standard for diagnosing tarsal coalition (TC). • MRI had a cumulative sensitivity of 95.8% and specificity of 94.3% for detecting tarsal coalition with an almost perfect inter-reader agreement. • MRI demonstrates high accuracy and reliability in diagnosing tarsal coalitions and is useful for identifying associated pathologies, while also improving patient safety by avoiding radiation exposure. [ABSTRACT FROM AUTHOR]

Background: As the anatomical variations of the foot, enlarged peroneal tubercle (EPT) and accessory anterolateral talar facet (AALTF) have attracted the attention of foot surgeons in recent years. However, EPT and AALTF have not been examined for a relationship with calcaneus spur (CS) as a common osteophyte. Methods: The subjects were 369 individuals who died in northeastern Thailand and were preserved as skeletal specimens. The authors examined for the presence of left and right EPT, AALTF, and calcaneus spur (CS). We divided the EPT (+) group with EPT and the EPT (-) group without it and also divided the AALTF (+) group with AALTF and the AALTF (-) group without it. The age at death and the presence of CS were compared statistically between the EPT (+) and EPT (-) groups and between the AATLF (+) and AALTF (-) groups. Results: Out of the total 369 cases, EPT was found in 117 cases (31.7%), AALTF was positive in 91 cases (24.7%), and CS was found in 194 cases (52.3%). In comparison between EPT (+) and EPT (-) groups, CS was significantly higher (p < 0.0001) in the EPT (+) group, but there was no significant difference in age at death. In comparison between AALTF (+) and AALTF (-) groups, there was no significant difference in age at death or CS. Conclusion: This study showed a strong relationship between EPT and CS, and the prevalence of EPT and AALTF by age in Thailand was first reported. We believe it helps to know the pathogenesis and biomechanism of EPT and AALTF. Trial registration: Not applicable. [ABSTRACT FROM AUTHOR]

Purpose: The calcaneocuboid joint is located in the lateral part of the foot and acts as a major stabilizer for the foot. Injuries to this joint often occur in association with ankle or foot injuries and are frequently overlooked, subsequently causing chronic pain or osteoarthritis. However, the relationship between ligaments surrounding the joint and joint instability remains unclear. Therefore, this study aimed to clarify the morphology and position of the ligaments surrounding the calcaneocuboid joint, and to reveal the relationship between the ligament structure. Methods: The position and morphology of the bifurcate ligament (subdivided into calcaneonavicular and calcaneocuboid ligaments), dorsal calcaneocuboid ligament, lateral calcaneocuboid ligament, long plantar ligament, and short plantar ligament were measured (N = 11 feet in 6 Japanese cadavers). The circumference of the joint was quartered, while the ligament-uncovered area and the estimated cross-sectional area of each ligament were compared between the four sides. Furthermore, the estimated cross-sectional area of each ligament was calculated as an index for the ligament strength. Results: The inferolateral side of the calcaneocuboid joint had the most uncovered area (54.63%) by the ligaments. In addition, the cross-sectional area of the ligaments on the lateral side was considerably smaller than that on the medial side. Conclusion: Our results suggest that ligament weakness on the inferolateral side may cause instability of the calcaneocuboid joint, especially after an inversion sprain injury, and may decrease the lateral longitudinal arch function, which results in chronic foot pain. [ABSTRACT FROM AUTHOR]

Tarsal coalition occurs in 1% of the population and represents a congenital failure of segmentation in two or more tarsal bones. It most commonly occurs at the talocalcaneal and calcaneonavicular joint. Although commonly asymptomatic, it may present with pain, rigidity, and pes planus. Cubonavicular, multiple synchronous, and bilateral coalitions are rare but an awareness is required to ensure accurate diagnosis and management. In this article, we presented the first reported case (to the best of our knowledge) of bilateral cubonavicular coalition with synchronous talocalcaneal coalition and stress response within the intermediate cuneiform. [ABSTRACT FROM AUTHOR]

Introduction. Calcaneus fractures are rare but potentially debilitating injuries. Most of them are displaced intraarticular fractures, whose management is among controversial issues. There is no consensus on whether to operate or not. The most often chosen surgical treatment is open reduction and internal fixation as the primary method. Failure of this surgery often needs secondary subtalar arthrodesis as definitive management, so primary subtalar arthrodesis in cases with severe comminution represents definitive treatment in one stage with good functional results. Case outline. We present a case of a 54-year-old male patient with a severely comminuted (Sanders type IV) bilateral calcaneus fracture. After the withdrawal of local swelling and disappearance of fracture blisters, the patient was operated on using one-stage bilateral subtalar arthrodesis with percutaneous screw fixation and bone grafting performed through a mini-open sinus tarsi approach. The early postoperative period was uneventful. The patient did not walk for the first seven postoperative weeks, after which rehabilitation was continued with partial weight bearing with a gradual increase of weight-bearing to full over the next five weeks, after which walking aids were completely phased out. Three years after surgery, the patient has no symptoms and has a close-to-normal gait. Conclusion. Although this type of injury has traditionally been treated with open reduction and internal fixation, we believe that primary subtalar arthrodesis with bone grafting through a mini-open sinus tarsi approach can benefit patients with severe comminution of calcaneus, allowing good functional results and patient satisfaction, with fewer postoperative complications and faster definitive recovery.

Humans have the remarkable ability to run over variable terrains. During locomotion, however, humans are unstable in the mediolateral direction and this instability must be controlled actively--a goal that could be achieved in more ways than one. Walking research indicates that the subtalar joint absorbs energy in early stance and returns it in late stance, an attribute that is credited to the tibialis posterior muscle-tendon unit. The purpose of this study was to determine how humans (n = 11) adapt to mediolateral perturbations induced by custom-made 3D-printed "footwear" that either enhanced or reduced pronation of the subtalar joint (modeled as motion in 3 planes) while running (3 m/s). In all conditions, the subtalar joint absorbed energy (ie, negative mechanical work) in early stance followed by an immediate return of energy (ie, positive mechanical work) in late stance, demonstrating a "spring-like" behavior. These effects increased and decreased in footwear conditions that enhanced or reduced pronation (P ≤ .05), respectively. Of the recorded muscles, the tibialis posterior (P ≤ .05) appeared to actively change its activation in concert with the changes in joint energetics. We suggest that the "spring-like" behavior of the subtalar joint may be an inherent function that enables the lower limb to respond to mediolateral instabilities during running. [ABSTRACT FROM AUTHOR]

Background: The biomechanics of the hindfoot in ankle osteoarthritis (OA) are not yet fully understood. Here, we aimed to identify hindfoot motion in a gait analysis using a multi-segment foot model (MFM) according to ankle OA stage and the presence of subtalar compensation defined by hindfoot alignment. Methods: We retrospectively reviewed the medical records, plain radiographs, and gait MFM data of 54 ankles admitted to our hospital for the treatment of advanced ankle OA. Spatiotemporal gait parameters and three-dimensional motions of the hindfoot segment were analyzed according to sex, age, body mass index, Takakura classification, and the presence of subtalar compensation. Twenty ankles were categorized as compensated group, and 34 ankles as decompensated group. Results: No spatiotemporal gait parameters differed significantly according to the presence of subtalar compensation or ankle OA stage. Only normalized step width differed significantly (P = 0.028). Average hindfoot motion (decompensation vs. compensation) did not differ significantly between the sagittal and transverse planes. Graphing of the coronal movement of the hindfoot revealed collapsed curves in both groups that differed significantly. Compared with Takakura stages 3a, 3b, and 4, cases of more advanced stage 3b had a smaller sagittal range of motion than those of stage 3a (P = 0.028). Coronal movement of the hindfoot in cases of Takakura stage 3a/3b/4 showed a relatively flat pattern. Conclusions: The spatiotemporal parameters were not affected by the hindfoot alignment resulting from subtalar compensation. The sagittal range of hindfoot motion decreased in patients with advanced ankle OA. Once disrupted, the coronal movement of the subtalar joint in ankle OA did not change regardless of ankle OA stage or hindfoot compensation state. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the effects of individually designed insoles on physical activity level, balance, and functional performance in patients with pes planus. Materials and Methods: 38 participants were divided into 2 groups as 3D printed (n=20) and placebo (n=18). In the 3D printed group, medial longitudinal arch support, medial wedge of the foot, medial heel wedge, and transverse arch support were given to the insoles according to the needs of the participants. The placebo group received placebo insoles. Muscle strength, range of motion, static and dynamic balance, physical and physical activity levels were measured at baseline, and eight weeks later (clinicaltrials.gov ID: NCT05306886). Results: Muscle strengths of the plantar flexion (p=0.030) and eversion increased after the use of insoles in the 3D printed and placebo groups (p=0.020). There was no change in static balance in both groups (p=0.386), but there were significant improvements in dynamic balance in 3D printed groups (p=0.019). Gait speed improved in both 3D printed (p=0.001) and placebo groups (p=0.015). There was no significant difference in the explosive power between the groups (p=0.272). The shuttle run test improved significantly in the placebo group (p=0.015), but no significant change was observed in the 3D printed group (p=0.886). While the physical activity levels in the placebo group showed a significant improvement (p=0.017), the physical activity level decreased in the 3D printed group (p=0.489). Conclusions: In this study, it was found that the use of personalized insoles is effective in improving physical activity, balance, and performance, while placebo insoles were found to be more effective in increasing muscle strength and explosive muscle strength. [ABSTRACT FROM AUTHOR]

In this study, the calcaneus and talus bones of 20 male and female adult Simmental and Angus cattle were used. The age and sex of these animals were recorded before slaughter, and carcass weights were taken after slaughter. Calcaneus and talus morphometric measurements were used to obtain multipliers that allow the estimation of the carcass weight. These multipliers were found to be mean values of 3.346 and 4.642, respectively. Thus, multipliers were obtained that can be used in the evaluation of chronological differences in archaeological cattle size and consequently carcass weight. LSM (Least Square Means) analysis of calcaneus and talus GL values revealed the effect of sex but not of breed. Proportional factors were obtained for calcaneus and talus pairings and associated bone size (GL) estimates. [ABSTRACT FROM AUTHOR]

Purpose: To determine the diagnostic value of seven injury history variables, nine clinical tests (including the combination thereof) and overall clinical suspicion for complete discontinuity of the lateral ankle ligaments in the acute (0–2 days post‐injury) and delayed setting (5–8 days post‐injury). Methods: All acute ankle injuries in adult athletes (≥18 years) presenting up to 2 days post‐injury were assessed for eligibility. Athletes were excluded if imaging studies demonstrated a frank fracture or 3 T MRI could not be acquired within 10 days post‐injury. Using standardized history variables and clinical tests, acute clinical evaluation was performed within 2 days post‐injury. Delayed clinical evaluation was performed 5–8 days post‐injury. Overall, clinical suspicion was recorded after clinical evaluation. MRI was used as the reference standard. Results: Between February 2018 and February 2020, a total of 117 acute ankle injuries were screened for eligibility, of which 43 were included in this study. Complete discontinuity of lateral ankle ligaments was observed in 23 (53%) acute ankle injuries. In the acute setting, lateral swelling had 100% (95% confidence interval [CI]: 82–100) sensitivity, haematoma had 85% (95% CI: 61–96) specificity and the anterior drawer test had 100% (95% CI: 77–100) specificity. In the delayed setting, sensitivity for the presence of haematoma improved from 43% (95% CI: 24–65) to 91% (95% CI: 70–98; p < 0.01) and the sensitivity of the anterior drawer test improved from 21% (95% CI: 7–46) to 61% (95% CI: 39–80; p = 0.02). Clinical suspicion had a positive likelihood ratio (LR) of 4.35 (95% CI: 0.55–34.17) in the acute setting and a positive LR of 6.09 (95% CI: 1.57–23.60) in the delayed setting. Conclusions: In the acute setting, clinical evaluation can exclude complete discontinuity (e.g., absent lateral swelling) and identify athletes with a high probability of complete discontinuity (e.g., positive anterior drawer test) of the lateral ankle ligaments. In the delayed setting, the sensitivity of common clinical findings increases resulting in an improved diagnostic accuracy. In clinical practice, this study underlines the importance of meticulous clinical evaluation in the acute setting. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

The patient is a 22-year-old female basketball player initially diagnosed with a calcaneal fracture. Five months after the pain began, the patient was referred to a foot and ankle surgeon and diagnosed with middle facet tarsal coalition. The patient received one X-ray-guided subtalar steroid injection and two platelet-rich plasma injections to aid in pain relief while completing her senior year of collegiate basketball. She elected to end her senior season early to have the recommended subtalar fusion surgery. The surgery ended her basketball career but provided pain-free activities of daily living. This case presents unique components compared with available literature on how injury presentation in adult populations can complicate a timely and accurate initial diagnosis. This case is also unique because despite conservative efforts, a surgical fusion was required to optimize pain and function during activities of daily living. [ABSTRACT FROM AUTHOR]

Plano-valgus foot is a common problem among children and adolescents. The problem is most often noticed in early childhood, as this is the period when the arches of the foot should achieve a normal structure through the disappearance of the fat pad that is present from birth. During this period, the child's skeletal system is very malleable and its remodelling can be considerably influenced by additional factors. This is due to the high amount of cartilage tissue present in a child's skeletal system. Plano-valgus foot can be treated with non-operative methods, such as physiotherapy or the use of orthopaedic supplies, such as suitable orthopaedic insoles. Unfortunately, non-operative treatment is not always sufficient. If physiotherapy does not achieve the expected results, a physician may opt for surgical treatment to restore a correct foot alignment. The most commonly performed plano-valgus foot procedure is subtalar arthroereisis. It is a minimally invasive procedure that takes approximately 10-30 minutes to perform. During the procedure, appropriate implants of various types and sizes are inserted into the tarsal sinus to reduce excessive foot pronation. Studies have shown that the procedure is beneficial to the patient, as it positions the foot correctly and children can return to performing physical activities without experiencing pain and/or rapid muscle fatigue in the foot area. The most commonly used measurements to assess the effects of plantar arthrodesis are those calculated from X-rays, such as Meary's angle, calcaneal inclination pitch angle (CP), talocalcaneal angle (Kite's angle), and surveys using The American Orthopaedic Foot and Ankle Society's (AOFAS's) ankle and hindfoot scoring. [ABSTRACT FROM AUTHOR]

Introduction: The COVID-19 pandemic brought about numerous changes. Access to health services was limited, and restrictions were imposed to prevent the spread of the disease. These restrictions included wearing protective masks, staying indoors, keeping distance from others in public places, quarantines, and home isolation in confirmed SARS-CoV-2 cases. Consequently physical activity of children was limited due to their increased time at home, which could result in reduced physical performance and abnormal development. Aim: This study aimed to assess the access to physiotherapy and the use of telemedicine regarding children after subtalar arthroereisis surgery during the COVID-19 pandemic. Material and methods: Seventy-nine parents/guardians of children who underwent subtalar arthroereisis surgery at Chorzow Municipal Hospital Complex between May 2019 and May 2021 participated in the study. A self-administered questionnaire designed for the study was used as the research method. Results: The results showed that some respondents perceived the wait times at the National Health Service and the cost of private services as problems during the COVID-19 pandemic. However, increased problems associated with general access or course of treatment were not confirmed. Sixty-seven percent of respondents confirmed decreased physical activity in children due to the COVID-19 pandemic. One-third of parents noticed weight gain and muscle weakness in their children, while for 56% of respondents, the weight gain was not noticeable. In addition, more than 70% of the children had no complaints of pain. The results also showed that only 36.8% of respondents used telemedicine during the pandemic. Conclusions: The constraints imposed by the COVID-19 pandemic caused a decline in children's physical activity; one-third of parents reported weight gain in their children. In addition, waiting times for physiotherapy reimbursed by the National Health Fund were long, and the cost of private physiotherapy was higher; it could not be confirmed whether more patients subsequently used telemedicine. [ABSTRACT FROM AUTHOR]

Background: Pain is a significant global public health concern, particularly among individuals aged 45 and above. Its impact on the overall lifestyle of the individuals varies depending on the affected anatomical parts. Despite its widespread impact, there is limited awareness of the attributes of pain, making effective pain management challenging, particularly in India. This study aims to estimate the prevalence and variation in pain in different anatomical sites among middle-aged and older adults in India. Methods: A cross-sectional design was employed, utilising data from the first wave of the Longitudinal Aging Study in India (LASI), 2017–2018. The age-sex adjusted prevalence of pain by anatomical sites (the back, joints, and ankles) was estimated using a multivariate logistic regression model. Results: 47% of individuals aged 45 years and above reported joint pain, 31% reported back pain and 20% suffered from ankle or foot pain. The prevalence of pain at all the anatomical sites increased with age and was reported higher among females. Relative to respondents aged 45–59 years, those aged 75 years and older exhibited a 41% higher likelihood of experiencing back pain (AOR: 1.41, 95% CI: 1.19–1.67), a 67% higher likelihood of joint pain (AOR: 1.67, 95% CI: 1.49–1.89), and a 32% higher likelihood of ankle/foot pain (AOR: 1.32, 95% CI: 1.16–1.50). In comparison to males, females had a 56% higher likelihood of encountering back pain (AOR: 1.56, 95% CI: 1.40–1.74), a 38% higher likelihood of joint pain (AOR: 1.38, 95% CI: 1.27–1.50), and a 35% higher likelihood of ankle/foot pain (AOR: 1.35, 95% CI: 1.17–1.57). We also found significant regional variations in pain prevalence, with higher rates in the mountainous regions of India. Conclusion: This research highlights the high burden of pain in major anatomical sites among middle-aged and older adults in India and emphasises the need for increased awareness and effective pain management strategies. [ABSTRACT FROM AUTHOR]

Purpose: A fracture of the posterior talar process is easily missed because of its hidden position. Inappropriate treatment is likely to result in complications, such as nonunion of the fracture and traumatic arthritis. This study evaluated the outcomes of arthroscopy-assisted reduction combined with robotic-assisted screw placement in the treatment of fractures of the posterior talar process. Methods: The clinical data for nine patients who underwent surgical treatment of a fracture of the posterior talar process at our institution between September 2017 and January 2021 were retrospectively reviewed. Arthroscopy-assisted reduction of the fracture was performed, and a cannulated screw was placed using three-dimensional orthopedic robotic-assisted navigation. Results: The patients (seven men, two women) had a mean age of 36.33 ± 9.77 years and were followed up for 21 ± 5.43 months. The operation time was 106.67 ± 24.5 min with blood loss of 47.78 ± 9.05 ml. Primary healing was obtained in all cases, and no patient sustained a nerve or tendon injury, had fracture nonunion, or developed talar osteonecrosis. One patient developed subtalar arthritis, for which subtalar joint fusion was performed; pain was markedly less severe after cleaning. Conclusion: Arthroscopy-assisted reduction and robotic-assisted screw placement have the advantages of visualization of fracture reduction, minimal injury, and precise screw placement in the treatment of fractures of the posterior talar process. [ABSTRACT FROM AUTHOR]

Introduction: Although intramedullary nailing is a popular method for tibiotalocalcaneal arthrodesis, nonunion is one of the most commonly reported complications. This study aimed to evaluate the fusion rate, improvement in functional outcomes, and occurrence of complications in tibiotalocalcaneal arthrodesis using retrograde intramedullary nailing with partial fibulectomy and onlay bone graft technique. Materials and methods: Twenty-six consecutive patients using the proposed technique were retrospectively reviewed. For radiographic outcomes, the union rate, alignment, and any related complications were assessed. Functional outcomes were evaluated using the American Orthopedic Foot and Ankle Society hindfoot scale, Foot and Ankle Outcome Score, and visual analog scale, preoperatively and at the final follow-up. Results: The mean follow-up period was 38.2 months. The tibiotalar joint achieved complete union in 80.8% at six months postoperatively, while all the cases achieved complete union at 12 months postoperatively. However, the subtalar joint achieved complete union in 26.9% at six months postoperatively, which gradually increased to 73.1% at 12 months postoperatively, and 80.8% at the final follow-up without revision surgery. A subgroup analysis showed there was a trend of higher subtalar fusion rate when an additional screw for the subtalar joint fixation was placed (86.7% vs. 54.5%). The functional outcomes significantly improved at the final follow-up. A few minor complications occurred, including surgical site infection, irritational symptoms, and metal failure; however, they eventually resolved. Conclusions: Our technique of tibiotalocalcaneal arthrodesis with partial fibulectomy and onlay bone grafting could be a good option where both the tibiotalar and subtalar joints need to be fused. [ABSTRACT FROM AUTHOR]

Introduction: The sustentaculum tali is displaced in almost half of calcaneal fractures and during surgical fixation represents one of the main reference points upon which the other bone has to be reduced. The purpose of this study was to investigate which subtalar joint fracture pattern is more frequently associated with sustentaculum tali involvement. Furthermore, correlation between postoperative clinical outcome and sustentaculum tali integrity was performed. Material and methods: Patients with isolated calcaneal fractures were analyzed. Sanders-type fracture and involvement of both sustentaculum tali and calcaneocuboid joint were detected on computed tomography imaging; postoperative AOFAS scores were analyzed according to sustentacular involvement. Results: Fifty calcaneus fractures in 47 patients were included in the final analysis. The sustentaculum tali was fractured in 18 cases (36.0%), thus contradicting its supposed constant position. Sanders type 3 and 4 fractures were more frequently associated with fractured sustentaculum than type 2 (p = 0.012). Sanders type 4 fractures were associated with displaced sustentacular fragment significantly more than type 2 and 3 (p = 0.043). Patients with intact sustentaculum tali reported significantly higher (p < 0.001) mean AOFAS scores than the uninjured group (84.4 ± 9.1 and 74.3 ± 9.5, respectively). Conclusion: Sanders type 3 and 4 fractures were more frequently associated with sustentaculum tali and/or calcaneocuboid joint involvement than simpler fractures. Injury of sustentaculum tali was related to significant worse postoperative clinical outcomes, underlying the relevance of this fragment on clinical course. [ABSTRACT FROM AUTHOR]

Powered ankle prostheses have been proven to improve the walking economy of people with transtibial amputation. All commercial powered ankle prostheses that are currently available can only perform one-degree-of-freedom motion in a limited range. However, studies have shown that the frontal plane motion during ambulation is associated with balancing. In addition, as more advanced neural interfaces have become available for people with amputation, it is possible to fully recover ankle function by combining neural signals and a robotic ankle. Accordingly, there is a need for a powered ankle prosthesis that can have active control on not only plantarflexion and dorsiflexion but also eversion and inversion. We designed, built, and evaluated a two-degree-of-freedom (2-DoF) powered ankle–foot prosthesis that is untethered and can support level-ground walking. Benchtop tests were conducted to characterize the dynamics of the system. Walking trials were performed with a 77 kg subject that has unilateral transtibial amputation to evaluate system performance under realistic conditions. Benchtop tests demonstrated a step response rise time of less than 50 milliseconds for a torque of 40 N·m on each actuator. The closed-loop torque bandwidth of the actuator is 9.74 Hz. Walking trials demonstrated torque tracking errors (root mean square) of less than 7 N·m. These results suggested that the device can perform adequate torque control and support level-ground walking. This prosthesis can serve as a platform for studying biomechanics related to balance and has the possibility of further recovering the biological function of the ankle–subtalar–foot complex beyond the existing powered ankles. [ABSTRACT FROM AUTHOR]

Purpose: The increase in ankle sprains in children is a reflection of the greater inclusion of this population in sports. This places the calcaneofibular (CFL) and the anterior talofibular (ATFL) ligaments in focus for study. In adults, the presence of arcuate fibers extending between these two ligaments suggests the existence of a new anatomical and functional complex called the lateral fibulotalocalcaneal ligament of the ankle (LFTCL), which can be associated with the persistence of instability of the talocrural joint in ankle sprains. This study aimed to verify the presence of arciform fibers between the CFL and ATFL in human fetuses and to study the topography of the lateral ankle region. Methods: Forty matched fetal ankles aged between 28 and 38 weeks, fixed in 4% formalin, were macroscopically, chemically and mesoscopically dissected and analyzed in stereoscope. Results: The ATFL was characterized as a capsular ligament consisting of two fascicles (proximal and distal). The CFL was characterized as an extracapsular ligament. The LFTCL complex was verified in all specimens, characterized by the arcuate fibers between the ATFL and the CFL. Conclusion: Such results suggest that this functional unit is congenital and that it should be taken into consideration in the treatment of persistent ankle instabilities in the pediatric population. [ABSTRACT FROM AUTHOR]

Purpose: Chronic pain can affect up to 40% of patients after ankle inversion sprains. The current hypothesis to explain this high percentage of chronic pain is a partial/total rupture of anterior talofibular ligament (ATFL) superior fascicle, a structure that has recently been described as intra‐articular and as having a different function than ATFL's inferior fascicle. This has created the need for diagnosing ATFL superior and inferior fascicles independently. Therefore, the objective of this study is to investigate if the ATFL's superior fascicle can be visualized on ultrasound, and to describe its ultrasonographic appearance. Methods: Twenty fresh‐frozen ankle specimens were used in this 4‐phases study. First, the specimens were scanned on US to identify what was believed to be ATFL's superior fascicle. Second, ATFL's superior fascicle was sutured under direct arthroscopic vision. Next, the specimens were scanned on US to obtain an image of the sutured structure. Finally, the specimens were dissected to confirm that the suture was indeed placed on ATFL's superior fascicle. Results: On the 20 specimens studied, full correlation was obtained between US, arthroscopic suture and specimen dissection. ATFL's superior fascicle US appearance is provided. Conclusion: ATFL's superior fascicle can be visualized on US, which will allow to undergo diagnosis of isolated injuries to that fascicle, a common finding in ankle microinstability. The results of this study will facilitate the diagnosis of partial or complete rupture of ATFL's superior fascicle, likely increasing the amount of ankle microinstability diagnosis, impacting clinical management of ankle sprain consequences. [ABSTRACT FROM AUTHOR]

Background: 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. Methods: 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. Results: 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]). Conclusion: 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. Clinical Relevance: 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. [ABSTRACT FROM AUTHOR]