Fracture of the lateral process of the talus (FLPT) is uncommon in clinical practice and can be easily missed or misdiagnosed. In recent years, as researchers from all over the world have further deepened their research on FLPT, there has been a breakthrough in the classification, and the methods and principles of clinical management have changed accordingly; however, there is still no standardized guideline for the diagnosis and management of FLPT, and there have been few relevant literature review articles related to this kind of fracture in the past at least 5 years. In this article, we review the clinical classification, classification-based therapeutic recommendations, and prognosis of FLPT, with the aim of providing a reference for the clinical diagnosis and management of this infrequent fracture.

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.

Objective: To investigate the clinical efficacy of simultaneous arthroscopic repair of anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) for treating chronic lateral ankle instability (CLAI) in conjunction with subtalar instability (STI). Methods: This is a retrospective case series study. The clinical data of 15 patients with ankle arthroscopic in the Department of Hand and Foot Surgery, the Second Affiliated Hospital of Soochow University from January 2019 to December 2022 were analyzed retrospectively. There were 11 male cases and 4 female cases, aged (28.6±1.5) years (range: 19 to 39 years). All the patients were evaluated by manual inversion stress X-ray and MRI before operation. Arthroscopically observing and then repairing the ATFL and CFL separately after further diagnostic confirmation. One year after operation, MRI was performed, and pain visual analogue score(VAS), American Orthopedic Foot and Ankle Society ankle hindfoot scale (AOFAS-AH) and Karlsson ankle functional scale(KAFS) were evaluated. Data were compared using paired sample t test. Results: The follow-up period was (23.6±2.3) months (range: 12 to 30 months). At last follow-up,the VAS decreased from 6.1±1.4 preoperatively to 1.4±1.2(t=9.482, P<0.01).The AOFAS-AH improved from 50.5±11.7 preoperatively to 94.2±6.1(t=-13.132, P<0.01), and the KAFS improved from preoperatively 44.3±10.8 to 90.8±6.4 (t=-12.510, P<0.01). There was no complication such as recurred instability or joint stiffness. Conclusions: Arthroscopically repairing the ATFL and CFL separately can effectively restore the stability of the ankle and subtalar joint with small trauma. Patients can recover quickly after surgery. It provides a new idea for the clinical treatment of CLAI combined with STI.
目的： 探究关节镜下修复距腓前韧带（ATFL）和跟腓韧带（CFL）治疗慢性踝关节外侧不稳（CLAI）合并距下关节不稳（STI）的临床效果。 方法： 本研究为回顾性病例系列研究。回顾性分析2019年1月至2022年12月于苏州大学附属第二医院手足外科行关节镜手术治疗的15例CLAI合并STI患者的临床资料。男性11例，女性4例，年龄（28.6±1.5）岁（范围：19~39岁）。右侧9例，左侧6例。所有患者术前拍摄踝关节内翻应力位X线片并行MRI检查，术中在关节镜下采用拉索技术分别行ATFL和CFL修复术。术后1年复查MRI，记录患肢功能恢复情况，采用疼痛视觉模拟评分（VAS）、美国足踝外科协会踝与后足评分（AOFAS-AH）及Karlsson踝关节功能评分（KAFS）评估患肢疼痛和功能情况。手术前后数据比较采用配对样本t检验。 结果： 所有患者均获随访，随访时间（23.6±2.3）个月（范围：12~30个月），切口均一期愈合，未发生血管神经损伤、感染等并发症。末次随访时，AOFAS-AH由术前的（50.5±11.7）分升至（94.2±6.1）分（t=-13.132，P<0.01）；KAFS由术前的（44.3±10.8）分升至（90.8±6.4）分（t=-12.510，P<0.01）；VAS 由术前的（6.1±1.4）分降至（1.4±1.2）分（t=9.482，P<0.01），差异均有统计学意义。 结论： 采用关节镜技术修复ATFL和CFL可恢复患者踝关节和距下关节稳定性，且操作简便、创伤小、患者术后恢复快，为临床治疗CLAI合并STI提供了一种新思路。.

OBJECTIVE: 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.
CONCLUSIONS: 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.

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.

Objective: Ankle braces can affect the kinematics of the ankle joint during landing tasks. Previous studies were primarily relied on traditional marker-based motion capture systems, which pose limitations in non-invasively capturing the motion of the talus bone. The effect of ankle braces on the in vivo kinematics of the tibiotalar and subtalar joints during landing remains unknown. This study used a high-speed dual fluoroscopic imaging system (DFIS) and magnetic resonance imaging (MRI) to investigate effect of ankle braces on the in vivo kinematics of the tibiotalar and subtalar joints during landing. Methods: Fourteen healthy participants were recruited for this study. During the experiment, static three-dimensional MRI data were collected for each participant, and 3D ankle joint models for the calcaneus, talus, and tibia were constructed. The DFIS was used to capture the images of each participant performing a single-leg landing-jump task at a height of 40 cm. The images were captured once with and without a brace in the fatigue condition, which was induced by running. The six-degree-of-freedom (6DOF) kinematic data were obtained by 2D-3D registration. Results: The flexion-extension range of motion (ROM) (42.73 ± 4.76° vs. 38.74 ± 5.43°, p = 0.049) and anterior-posterior translation ROM (16.86 ± 1.74 mm vs. 15.03 ± 1.73 mm, p = 0.009) of the tibiotalar joint were decreased. The maximum inversion angle (-3.71 ± 2.25° vs. 2.11 ± 1.83°, p = 0.047) of the subtalar joint was decreased. Conclusion: The ankle brace limited the flexion-extension ROM of the tibiotalar joints and the inversion angle of the subtalar joint during landing.

Objective: Fatigue can affect the ankle kinematic characteristics of landing movements. Traditional marker-based motion capture techniques have difficulty in accurately obtaining the kinematics of the talocrural and subtalar joints. This study aimed to investigate the effects of fatigue on the talocrural and subtalar joints during the landing using dual fluoroscopic imaging system (DFIS). Methods: This study included fourteen healthy participants. The foot of each participant was scanned using magnetic resonance imaging to create 3D models. High-speed DFIS was used to capture images of the ankle joint during participants performing a single-leg landing jump from a height of 40 cm. Fatigue was induced by running and fluoroscopic images were captured before and after fatigue. Kinematic data were obtained by 3D/2D registration in virtual environment software. The joint kinematics in six degrees of freedom and range of motion (ROM) were compared between the unfatigued and fatigued conditions. Results: During landing, after the initial contact with the ground, the main movement of the talocrural joint is extension and abduction, while the subtalar joint mainly performs extension, eversion, and abduction. Compared to unfatigued, during fatigue the maximum medial translation (1.35 ± 0.45 mm vs. 1.86 ± 0.69 mm, p = 0.032) and medial-lateral ROM (3.19 ± 0.60 mm vs. 3.89 ± 0.96 mm, p = 0.029) of the talocrural joint significantly increased, the maximum flexion angle (0.83 ± 1.24° vs. 2.11 ± 1.80°, p = 0.037) of the subtalar joint significantly increased, and the flexion-extension ROM (6.17 ± 2.21° vs. 7.97 ± 2.52°, p = 0.043) of the subtalar joint significantly increased. Conclusion: This study contributes to the quantitative understanding of the normal function of the talocrural and subtalar joints during high-demand activities. During landing, the main movement of the talocrural joint is extension and abduction, while the subtalar joint mainly performs extension, eversion, and abduction. Under fatigue conditions, the partial ROM of the talocrural and subtalar joints increases.

BACKGROUND: Osseous structures have been demonstrated as risk factors for chronic ankle instability (CAI). Previously, the researchers only focused on the osseous structures of ankle, but ignored the osseous structures of subtalar joint(STJ). Accordingly, the aim of our study was to investigate the morphological characteristics of STJ osseous structures in CAI.
METHODS: 52 patients with CAI and 52 sex- and age- matched control subjects were enrolled from The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University. The lateral radiographs of ankle in weight-bearing were used to compare the diversity of the two groups. Specifically, The Length of calcaneus, Calcaneal facet height and Absolute foot height, Böhler\'s angle, Gissane\'s angle, Calcaneal inclination angle, Talocalcaneal angle, Tibiotalar angle, Tibiocalcaneal angle, Talar-horizontal angle, talar declination angle, facet inclination angle were gauged in the two groups.
RESULTS: The Böhler\'s angle, Calcaneal inclination, Talocalcaneal angle, Tibiotalar angle, Talar-horizontal angle, Talar declination angle, Facet inclination angle and Absolute foot height of CAI group were significantly higher than normal control group (P < 0.05). There were no significant differences in Gissane\'s angle, Tibiocalcaneal angle, Length of calcaneus and Calcaneal facet height between patients with CAI and normal controls (P > 0.05).
CONCLUSIONS: The osseous structures of STJ in CAI patients are different from normal people in morphology. Therefore, we should pay more attention to the changes of STJ anatomical parameters in the diagnosis and prevention of CAI.
METHODS: Ⅲ.

BACKGROUND: The subtalar joint may compensate for tibio-talar deformity, but what would happen to the joint after the deformity was corrected is not well known. Supramalleolar osteotomy (SMOT) is an effective procedure for the treatment of varus deformity of ankle arthritis. The objective of this study was to investigate the subtalar joint alignment pre and postoperatively following SMOT, and the factors which influenced the alignment of the subtalar joint.
METHODS: Thirty-one patients with varus ankle arthritis (Takakura stage 2, 3a and 3b) who were treated using SMOT were retrospectively reviewed. The subtalar and ankle joint alignment was measured on weightbearing radiograph and weightbearing computerized tomography (WBCT).
RESULTS: The foot and ankle offset (FAO), tibial articular surface angle (TAS), tibio-talar surface angle (TTS), and subtalar vertical angle (SVA) were significantly corrected (P＜0.05). The subtalar inclination angle (SIA) decreased in 19 patients and increased in the other 12 cases after the SMOT (P＜0.001). The shift of subtalar joint (ΔSIA) showed an inverse correlation with the preoperative FAO (P＜0.001, r = -0.621).
CONCLUSIONS: The shift of subtalar joint after SMOT could maintain the neutral position of the hindfoot and showed a negative correlation with the preoperative FAO. The ΔSIA was greater in the severer preoperative hindfoot deformity.
METHODS: Level IV, case series.

BACKGROUND: Foot kinematics, such as excessive eversion and malalignment of the hindfoot, are believed to be associated with running-related injuries. The majority of studies to date show that different foot strike patterns influence these specific foot and ankle kinematics. However, technical deficiencies in traditional motion capture approaches limit knowledge of in vivo joint kinematics with respect to rearfoot and forefoot strike patterns (RFS and FFS, respectively). This study uses a high-speed dual fluoroscopic imaging system (DFIS) to determine the effects of different foot strike patterns on 3D in vivo tibiotalar and subtalar joints kinematics.
METHODS: Fifteen healthy male recreational runners underwent foot computed tomography scanning for the construction of 3-dimensional models. A high-speed DFIS (100 Hz) was used to collect 6 degrees of freedom kinematics for participants\' tibiotalar and subtalar joints when they adopted RFS and FFS in barefoot condition.
RESULTS: Compared with RFS, FFS exhibited greater internal rotation at 0%-20% of the stance phase in the tibiotalar joint. The peak internal rotation angle of the tibiotalar joint under FFS was greater than under RFS (p < 0.001, Cohen\'s d = 0.92). RFS showed more dorsiflexion at 0%-20% of the stance phase in the tibiotalar joint than FFS. RFS also presented a larger anterior translation (p < 0.001, Cohen\'s d = 1.28) in the subtalar joint at initial contact than FFS.
CONCLUSIONS: Running with acute barefoot FFS increases the internal rotation of the tibiotalar joint in the early stance. The use of high-speed DFIS to quantify the movement of the tibiotalar and subtalar joint was critical to revealing the effects of RFS and FFS during running.