Complejo ligamentoso lateral de la articulación talocrural (tobillo): biometría y patrones de división / Lateral ankle ligamentous complex: biometrics and division patterns

El complejo ligamentoso lateral de la articulación talocrural o «tobillo» (CLT) contempla básicamente tres estructuras denominadas como ligamento talofibular anterior (LTFA), ligamento calcaneofibular (LCF) y ligamento talofibular posterior (LTFP). En los últimos artículos publicados en relación con la morfología del CLT, se clasifica al LTFA en tres tipos, basada en el número de bandas o fascículos. Esta variabilidad morfológica plantea nuevos desafíos de estudios anatómicos en la biomecánica y estabilidad de la región talocrural. El objetivo de este estudio fue profundizar la anatomía de este complejo, en base a disecciones por capa que nos permitan visualizar las relaciones existentes entre estos ligamentos y estructuras aledañas. Se utilizaron 10 piezas congeladas pertenecientes al Departamento de Anatomía y Medicina Legal de la Facultad de Medicina de la Universidad de Chile, cuyos ligamentos fueron localizados y medidos en ancho y longitud. Para el LTFA se observó un patrón único en 5 muestras, bifurcado en 4, mientras que en un caso se visualizó un patrón trifurcado. El conocimiento del complejo ligamentoso lateral de tobillo, así como de su dirección, biometría y bandas o fascículos son un importante aporte para la imagenología, rehabilitación, clínica y cirugías que aborden esta región.

SUMMARY: The lateral ankle complex (LAC) basically includes three structures called anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL) and posterior talofibular ligament (PTFL). In recent works published in relation to the morphology of LAC, ATFL is classified into three types, based on the number of bands or fascicles. This morphological modification poses new challenges for anatomical studies in biomechanics and ankle stability. The objective of this is to deepen in greater detail the anatomy of this complex, based on dissections by layer that allow us to study the existing relationships between these ligaments and surrounding structures. 10 frozen pieces belonging to the Department of Anatomy and Legal Medicine of the Faculty of Medicine of the University of Chile were used; whose ligaments were located and measured in width and length. For ATFL, a single pattern was found in 5 samples, bifurcated in 4, while a trifurcated pattern was seen in one case. Knowledge of the lateral ligamentous complex of the ankle, as well as its direction, biometry and bands or fascicles, are an important contribution to imaging, rehabilitation, clinics and surgeries that address this region.

Particularities on Anatomy and Normal Postsurgical Appearances of the Ankle and Foot.

The anatomy of the ankle and foot is complex, allowing for a wide range of functionality. The movements of the joints represent a complex dynamic interaction. A solid understanding of the characteristics and actions of the anatomic elements helps explain the mechanisms and patterns of injury. This article reviews the anatomy, with special focus on concepts that are the object of recent study and the features that favor the development of symptoms. Good understanding of the surgical procedures helps in providing information to guarantee a favorable outcome. We review the commonly expected postsurgical appearances and the most common postsurgical complications.

Influencia de la fase de menstruación y de ovulación en el rango articular de extensión del tobillo y primera articulación metatarsofalángica / Influence of the menstruation and ovulation phase in the extension range of motion of the ankle and first metatarsophalangeal joint

Objetivos: Se trata de un estudio de investigación observacional prospectivo, cuyo objetivo fue valorar si existen diferencias en el rango articular de las articulaciones: tobillo, primera articulación metatarsofalángica del primer dedo durante la fase de ovulación y de menstruación. Pacientes y métodos: Se tomó como muestra a 14 mujeres de 20 a 25 años, que cumplían con los criterios de inclusión. Fueron exploradas en el Área Clínica de Podología de la Universidad de Sevilla por la investigadora del trabajo, reuniendo todos los requisitos de instalaciones y protección de datos para la paciente. Se tomaron dos medidas: durante la ovulación y durante la menstruación. Las propias pacientes informaron de su ciclo menstrual, tras firmar el previo consentimiento informado. Resultados: Tras el análisis estadístico se observó que la flexión dorsal del tobillo, con rodilla extendida y flexionada, y la extensión de la primera metatarsofalángica del primer dedo aumentaron significativamente (p < 0.001 en ambos pies) su rango articular durante la fase de ovulación. Conclusiones: Se han apreciado diferencias en el rango de extensión del tobillo y de la primera articulación metatarsofalángica del primer dedo, siendo mayor el rango en la fase ovulatoria.(AU)

Objective: This is a prospective, observational research study whose objective was to assess whether there are differences in the joint range of the joints: ankle, first metatarsophalangeal of the first toe during the ovulation and menstruation phase. Patients and methods: A sample of 14 women between the ages of 20 and 25, who met the inclusion criteria, were taken as a sample. They were explored in the Podiatry Clinical Area of the University of Seville by the researcher of the work, meeting all the facilities and data protection requirements for the patient. Two measurements were taken, during ovulation and another during menstruation. The patient themselves reported their menstrual cycle after signing the prior informed consent. Results: After the statistical analysis, it was observed that the dorsiflexion of the ankle, with the knee extended and flexed, and the extension of the first metatarsophalangeal of the first toe significantly increased (p < 0,001 in both feet) their joint range during the ovulation phase.Conclusions: Differences have been observed in the range of extensión of the ankle and of the first metatarsophalangeal joint of the first finger, the range being greater in the ovulatory phase.(AU)

Mapeo sonográfico de los nervios de la cara medial del tobillo y del pie / Sonographic mapping of the nerves of the medial side of the ankle and foot

El uso de los ultrasonidos en el examen, la identificación y el intervencionismo de las diferentes ramas nerviosas del tobillo y del pie son una herramienta de gran apoyo en el ámbito clínico. En la actualidad, la ecografía es un método que se ha ido universalizando en el mundo de la podología, bien por su mayor accesibilidad debido al abaratamiento de los costes, a los avances tecnológicos y a sus beneficios de inocuidad, fácil disponibilidad para el examen inmediato y su aplicación dinámica en la evaluación de las diferentes estructuras anatómicas. El presente trabajo trata de presentar a la comunidad podológica una descripción detallada del mapeo mediante ecografía de los nervios en cara medial del pie. Entendemos que esta descripción puede ayudar a los profesionales en el diagnóstico de las patologías de atrapamiento nervioso a dicho nivel, así como en procedimientos mínimamente invasivos guiados ecográficamente en dicha área anatómica.(AU)

The use of ultrasound in clinical practice is a great tool for the examination, identification and intervention of the different nerve branches in the foot and ankle. Nowadays, sonography is an exploratory method that has been universally expanded in podiatry because of lowering of costs associated to its use, technological progresses and its benefits of safety, disposal for the inmediate clinical exam and its dynamic application in the evaluation of different structures. The aim of the present paper is to present to the podiatry community a detailed description of sonographic mapping of the nerves in the medial side of the ankle. It is intended to help professionals involved in the management of foot ankle disorders regarding the diagnosis of entrapment neuropathies at this level and also to help with minimally invasive treatments sonographically guided.(AU)

Developmental evolution of the distal ankle in the dinosaur-bird transition.

The adult ankle of early reptiles had five distal tarsal (dt) bones, but in Dinosauria, these were reduced to only two: dt3 and dt4, articulated to metatarsals (mt) mt3 and mt4. Birds have a single distal tarsal ossification center that fuses to the proximal metatarsals to form a new adult skeletal structure: the composite tarsometatarsus. This ossification center develops within a single large embryonic cartilage, but it is unclear if this cartilage results from fusion of earlier cartilages. We studied embryos in species from four different bird orders, an alligatorid, and an iguanid. In all embryos, cartilages dt2, dt3, and dt4 are formed. In the alligatorid and the iguanid, dt2 failed to ossify: only dt3 and dt4 develop into adult bones. In birds, dt2, dt3, and dt4 fuse to form the large distal tarsal cartilage; the ossification center then develops above mt3, in cartilage presumably derived from dt3. During the entire dinosaur-bird transition, a dt2 embryonic cartilage was always formed, as inferred from the embryology of extant birds and crocodilians. We propose that in the evolution of the avian ankle, fusion of cartilages dt3 and dt2 allowed ossification from dt3 to progress into dt2, which began to contribute bone medially, while fusion of dt3 to dt4 enabled the evolutionary loss of the dt4 ossification center. As a result, a single ossification center expands into a plate-like unit covering the proximal ends of the metatarsals, that is key to the development of an integrated tarsometatarsus.

Anatomical landmarks for locations and boundary of distal tarsal tunnel at medial side of ankle with clinical implication / Puntos de referencia anatómicos para ubicaciones y límites del túnel tarsiano distal en el lado medial del tobillo con implicación clínica

SUMMARY: The tarsal tunnel (TT) is an osteofibrous tunnel that separates into proximal and distal tarsal tunnels. The most common nerve entrapment which involved tarsal tunnel was tarsal tunnel syndrome (TTS) which divided into proximal TTS and distal TTS because they had different compression areas and symptoms. We were interested in distal TT because this structure had limited studies. Therefore, we studied anatomical landmarks of locations and boundary of distal TT. We studied forty legs from fresh frozen cadavers and used two reference lines: Malleolar-calcaneal (MC) and navicular-calcaneal (NC) axes. The locations of the distal tarsal tunnel were defined by 10 located points and were recorded in X-coordinate and Y-coordinate. The lengths of boundary of the tarsal tunnel were measured from one point to the other. These results were reported as mean±SD. We found that the distal TT located deep to abductor hallucis (AbH) muscle. Medial wall of distal TT had two layers such as deep fascia of AbH muscle and deep thin layer. It showed the trapezoidal shape and was divided into two tunnels by the septum. The information of the location and boundary of the distal TT could improve knowledge and understanding of clinicians and anatomists. Additionally, this information could help surgeons improve their treatments, especially tarsal tunnel release.

RESUMEN: El túnel tarsiano (TT) es un túnel osteofibroso que se divide en túneles tarsianos proximal y distal. El atrapamiento nervioso más común del túnel tarsiano es el síndrome del túnel tarsiano (TTS), el cual se divide en TTS proximal y TTS distal debido a diferentes áreas de compresión. En este trabajo se estudiaron los puntos de referencia anatómicos de las ubicaciones y los límites del TT distal. Estudiamos cuarenta piezas de cadáveres frescos congelados y utilizamos dos líneas de referencia: ejes maleolar-calcáneo (MC) y navicular-calcáneo (NC). Las ubicaciones del túnel tarsiano distal se definieron en 10 puntos y se registraron en coordenadas X e Y. Las longitudes de los límites del túnel tarsiano se midieron desde un punto a otro. Estos resultados se informaron como media ±DE. Encontramos que el TT distal se ubicaba profundo al músculo abductor del hállux (AbH). La pared medial del TT distal tenía dos capas, la fascia profunda del músculo AbH y una capa delgada profunda. Se observó la forma trapezoidal del túnel la que se encontraba dividida por el tabique en dos túneles. La información de la ubicación y el límite del TT distal podría mejorar el conocimiento de los médicos y anatomistas. Además, esta información podría ayudar a los cirujanos durante los tratamientos, especialmente la liberación del túnel tarsiano.

Effects of human variation on foot and ankle pain in rural Madagascar.

OBJECTIVES: Foot and ankle dysfunction in barefoot/minimally shod populations remains understudied. Although factors affecting musculoskeletal pain in Western populations are well-studied, little is known about how types of work, gender, and body shape influence bone and joint health in non-Western and minimally shod communities. This study examines the effect of human variation on locomotor disability in an agrarian community in Madagascar. MATERIALS AND METHODS: Foot measurements were collected along with height, weight, age, and self-report data on daily activity and foot and ankle pain from 41 male and 48 female adults. A short form revised foot function index (FFI-R), that measures functional disability related to foot pain, was calculated. Raw and normalized foot measurements were compared by gender and used in a multiple linear regression model to determine predictors of FFI-R. RESULTS: Compared to men, women reported higher FFI-R scores (p = 0.014), spent more time on their feet (p = 0.019), and had higher BMIs (p = 0.0001). For their weight, women had significantly smaller and narrower feet than men. Bimalleolar breadth (p = 0.0005) and foot length (p = 0.0223) standardized by height, time spent on feet (p = 0.0102), ankle circumference standardized by weight (p = 0.0316), and age (p = 0.0090) were significant predictors of FFI-R score. DISCUSSION: Our findings suggest that human variation in anatomical and behavioral patterns serve as significant explanations for increased foot and ankle pain in women in this non-Western rural population. Foot and ankle pain were prevalent at similar levels to those in industrialized populations, indicating that research should continue to examine its effect on similar barefoot/minimally shod communities.

The level of bifurcation of peroneal artery and its implications for posterolateral approach to the ankle: a CT angiography study.

PURPOSE: This study aims to provide data, with the use of computed tomography angiography, regarding the level of bifurcation of the peroneal artery to the anterior perforating branch and the lateral calcaneal branch, in relation to the osseous anatomic structures of the tibial plafond, the medial malleolus and the lateral malleolus. METHODS: The study included patients who underwent diagnostic computed tomography angiography of the lower extremities. Measurements were performed in two-dimensional reconstructions and included the perpendicular distance from peroneal artery bifurcation into anterior perforating branch and lateral calcaneal branch to the lowest level of tibial plafond (D1), medial malleolus (D2) and lateral malleolus (D3). The distances were also normalized to the length of the tibia. RESULTS: Sixty patients and a total of 115 limbs were enrolled in this study. The mean distance ± standard deviation from peroneal artery bifurcation to tibial plafond (D1) was 4.33 ± 1.12 cm (normalized 0.12 ± 0.03) (range 2.54-8.26 cm), to medial malleolus (D2) was 5.53 ± 1.18 cm (normalized 0.16 ± 0.03) (range 3.27-9.5 cm) and to lateral malleolus (D3) was 6.53 ± 1.17 cm (normalized 0.18 ± 0.03) (range 4.71-10.2 cm), respectively. There was no significant difference between right and left limb measurements (p > 0.05). Females presented lower, but not statistically significant (p > 0.05), D1, D2 and D3 measurements compared to males. CONCLUSION: The bifurcation of the peroneal artery takes place at lower level compared to previously published studies and consequently extreme caution should be exercised when performing the posterolateral approach to the ankle. This study adds to the understanding of the relevant vascular anatomy of the region and assists in performing the posterolateral approach to the ankle with safety.

Neutral alignment resulting from tibial vara and opposite femoral valgus is the main morphologic pattern in healthy middle-aged patients: an exploration of a 3D-CT database.

PURPOSE: Given the goal of achieving optimal correction and alignment after knee arthroplasty or high tibial osteotomy, literature focusing on the inter-individual variability of the native knee, tibia and femur with regards to the coronal or sagittal alignment is lacking. The aim of this study was to analyse normal angular values in the healthy middle-aged population and determine differences of angular values according to inter-individual features. The first hypothesis was that common morphological patterns may be identified in the healthy middle-aged non-osteoarthritic population. The second hypothesis was that high inter-individual variability exists with regards to gender, ethnicity and alignment phenotype. METHODS: A CT scan-based modelling and analysis system was used to examine the lower limb of 758 normal healthy patients (390 men, 368 women; mean age 58.5 ± 16.4 years) with available data concerning angular values and retrieved from the SOMA database. The hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior distal femoral angle (PDFA), posterior proximal tibial angle (PPTA) and non weight-bearing joint line convergence angle (nwJLCA) were then measured for each patient. Results were analysed for the entire cohort and based on gender, ethnicity and phenotype. RESULTS: The mean HKA was 179.4° ± 2.6°, LDFA: 85.8° ± 2.0°, MPTA: 85.6° ± 2.4°, PDFA: 85.2° ± 1.5°, PPTA: 83.8° ± 2.9° and nwJLCA: 1.09° ± 0.9°. Gender was associated with higher LDFA and lower HKA for men. Ethnicity was associated with greater proximal tibial vara and distal femoral valgus for Asian patients. Patients with an overall global varus alignment had more tibia vara and less femoral valgus than patients with an overall valgus alignment. CONCLUSION: Even if significant differences were found based on subgroup analysis (gender, ethnicity or phenotype), this study demonstrated that neutral alignment is the main morphological pattern in the healthy middle-aged population. This neutrality is the result from tibia vara compensated by an ipsilateral femoral valgus. LEVEL OF CLINICAL EVIDENCE: III, retrospective cohort study.

Posterior to anterior malleolar extended lateral approach to the ankle (PAMELA): a cadaveric anatomic study.

INTRODUCTION: The posterolateral approach is used in most cases of surgical treatment of ankle fractures involving the posterior and lateral malleoli. However, this approach does not allow access to the anterolateral structures of the ankle, which represent important landmarks to allow an anatomical reduction in case of complex ankle fracture. Our objective is to propose a novel surgical approach for optimal management of injuries including both a fracture of the posterior malleolus and a complex lesion of the lateral and/or anterolateral portions of the ankle. METHODS: Cadaveric dissection, including a vascular study, was performed on eight specimens. Assessment included density of the vascular supply around the lateral malleolus, identification of the structures at risk, quality of exposure of the bony structures, and convenience of hardware fixation. RESULTS: The cutaneous flap benefits from a rich interconnected arterial supply. Structures at risk, including the superficial peroneal and sural nerves, the lesser saphenous vein, and the peroneal artery are easily identified and protected. The interval between the peroneal tendons and the flexor hallucis longus muscle provides optimal access to the posterior malleolus. The lateral malleolus is exposed by retracting the peroneal tendons medially. An anterolateral arthrotomy, respecting the anterior talofibular and tibiofibular ligaments, offers a sharp view on the talo-tibio-fibular junction. Hardware placement can be done with optimal access to any exposed surfaces. CONCLUSIONS: The PAMELA opens a new perspective in the optimal management of complex fractures of the ankle. The approach allows optimal exposure to address fractures of the posterior malleolus, of the lateral malleolus, and of the anterolateral portion of the ankle through a single incision. Application in clinical practice is the subject of a future study in our institution.

Posteroinferior tibiofibular ligament - A cadaveric study.

BACKGROUND: Ankle injuries are one of the most common musculoskeletal disorder. The purpose of this study was to analyze and describe the detailed anatomical arrangement and relationship of posterior ligaments of the ankle, especially de posteroinferior tibiofibular ligament (PITFL) and intermalleolar ligament (IML). Controversy exists in the previous literature regarding their morphology and denomination, as well as the relation with ankle injuries including posterior soft tissue impingement syndrome. METHODS: Seventeen fresh-frozen cadaveric feet were used. The origins, insertions, ligament lengths, orientations with respect to relevant bony landmarks of the PITFL were evaluated. RESULTS: PITFL was present in all anatomical specimens. It was formed by two independent components, the superficial and deep fibers. Their dimensions vary widely between specimens. The IML was located between the deep PITFL and posterior talofibular ligament. The shape varied from a thin fibrous band to a thick cordlike structure. The IML was evident in 82.4% of the ankles. In 28.6% of the cases, the posterior intermalleolar ligament was split into two bundles in the fibular insertion. In 14 ankles, three slips were found. CONCLUSION: Given the frequency of injury and increasing necessity for surgical intervention, a more comprehensive anatomic knowledge of the different ligaments is warranted, provide clinically pertinent quantitative data and improve the treatment of these lesions.

Morphological analysis of Gissane's angle utilising a statistical shape model of the calcaneus.

INTRODUCTION: Gissane's crucial angle (GA) facilitates to diagnose calcaneal fractures, and serves as an indicator of the quality of anatomical reduction after fixation. The study aimed to utilise statistical shape models (SSM) for analysing the complex 3D surface anatomy of the calcaneus represented by the simplified GA measurement on lateral radiographs. MATERIALS AND METHODS: SSMs were generated from CT scans of paired adult calcanei from 10 Japanese and 31 Thai specimens. GA measurements in 3D and 2D were obtained for the lateral, central and medial anatomy of the posterior facet and sinus tarsi. The correlation between calcaneal length and GA was analysed. Regression and principal component (PC) analyses were conducted for analysing morphological variability in calcaneal shape relating to GA. The bilateral symmetry of the obtained measurements was analysed. RESULTS: The mean GA (lateral) for the Japanese specimens was 105.1° ± 7.5 and 105.4° ± 8.5 for the Thai. The projected 2D angles of the central and medial measurements were larger (P < 0.00) than the 3D values. The medial projected 2D angles were larger (P ≤ 0.02) compared to the lateral. Despite the bilateral symmetry of GA and calcaneal length, their correlation displayed clear signs of asymmetry, which was confirmed by regression and PC analyses. CONCLUSIONS: Japanese and Thai specimens revealed lower GAs (both range and mean) compared to reported reference values of other ethnicities. As a reduced GA is generally indicative of a calcaneal fracture, our results are important to surgeons for their diagnostic assessment of Japanese and Thai patients. The results indicate that the GA measurement on a plain radiograph is a simplified representation of the lateral-to-central 3D calcaneal anatomy but significantly underestimates the angle measurement on the medial aspects of the respective surface areas.

Estudo experimental comparativo da resistência tensional da safena magna no tornozelo e na região inguinal / Experimental comparative assay of tensile resistance of greater saphenous vein from ankle and groin

Resumo Contexto A veia safena magna é usada como material de remendo em vários tipos de reconstrução arterial, incluindo no trauma e endarterectomias de carótida e femoral. Houve relatos de ruptura do remendo de safena, particularmente de veias colhidas na região do tornozelo. Há uma necessidade de medição objetiva da resistência tecidual da safena magna. Objetivos Mensurar a força tensional suportada pela veia safena magna e analisar a correlação entre resistência e diâmetro da veia. Métodos As veias foram coletadas durante operações de safenectomia por varizes dos membros inferiores. Foram analisados apenas segmentos sem refluxo. Foram analisados 10 membros de oito pacientes, com um total de 20 espécimes. Os espécimes foram submetidos a ensaio de tração em equipamento eletrônico, obtendo-se os valores de tensão máxima do material em quilogramas-força por centímetro quadrado (kgf/cm2; força máxima dividida pela área de secção transversa do segmento submetido à tração). Resultados A tensão máxima suportada pela veia safena do tornozelo variou de 74,02 a 190,10 kgf/cm2, e a tensão máxima da veia safena da crossa variou de 13,53 a 69,45 kgf/cm2 (p < 0,0001). O coeficiente de correlação de Pearson entre o diâmetro da veia distendida e a tensão máxima suportada foram iguais a -0,852 (correlação inversa moderada a forte). Conclusões A resistência tecidual da veia safena magna do tornozelo é maior do que a da crossa em mulheres submetidas a operação de varizes; há correlação negativa entre o diâmetro da veia e sua resistência tecidual nessa mesma população.

Abstract Background The great saphenous vein is used as patch material in several types of arterial reconstruction, including trauma and carotid and femoral endarterectomy. There have been reports of saphenous patch blowout, particularly of patches constructed with veins harvested from the ankle. There is a need for objective measurement of the resistance of saphenous vein tissues. Objectives To measure the tensile strength of the great saphenous vein harvested at the ankle and groin and analyze the correlation between diameter and tissue strength. Methods Venous samples were harvested during elective saphenous stripping in patients with symptomatic varicose veins. Only segments without reflux were included. Ten limbs from eight patients were studied, providing 20 samples in total. Venous segments were opened along their longitudinal axis and fitted to electronic traction assay equipment to obtain values for material maximum tension in kilograms-force per square centimeter (kgf/cm2; the maximum force resisted by the segment, divided by its cross-sectional area). Results The average maximum tension in the ankle saphenous vein group ranged from 74.02 to 190.10 kgf/cm2 and from 13.53 to 69.45 kgf/cm2 in the groin saphenous vein group (p < 0.0001). The Pearson coefficient for the correlation between vein diameter and maximum tension was -0.852 (moderate to strong inverse correlation). Conclusions Ankle saphenous vein tissue from female patients operated for varicose veins has significantly higher resistance than saphenous vein tissue from the groin and there is an inverse relation between vein diameter and resistance of tissue from the same population.

Inclination angles of the ankle and head relative to the centre of mass identify gait deviations post-stroke.

BACKGROUND: Whole-body movement adjustments during gait are common post-stroke, but comprehensive ways of quantifying and evaluating gait from a whole-body perspective are lacking. RESEARCH QUESTION: Can novel kinematic variables related to Center of Mass (CoM) position discriminate side asymmetries as well as coordination between the upper and lower body during gait within persons post-stroke and compared to non-disabled controls? METHODS: Thirty-one persons post-stroke and 41 age-matched non-disabled controls walking at their self-selected speed were recorded by 3D motion capture. The Ankle-CoM Inclination Angle (A-CoMIA) and the Head-CoM Inclination Angle (H-CoMIA) defined the angle between the CoM and the ankle and the head, respectively, in the frontal plane. These angles and their angular velocities were compared between groups, and with regard to motor impairment severity during all phases of the gait cycle (GC) using a functional interval-wise testing analysis suitable for curve data. Upper and lower body coordination was assessed using cross- correlation. RESULTS: The A-CoMIA was symmetrical between body sides in persons post-stroke but larger compared to controls. The angular velocity of A-CoMIA also differed when compared to controls. The H-CoMIA was consistently asymmetrical in persons post-stroke and larger than in controls throughout the stance phase. There were only minor group differences in the angular velocity of H-CoMIA, with some side asymmetry in persons post-stroke. The A-CoMIA of the non-affected side, and the H- CoMIA, discriminated between persons with more severe impairments compared to those with milder impairments post-stroke. The variables showed strong cross- correlations in both groups. SIGNIFICANCE: The A-CoMIA and Head-CoMIA discriminated post-stroke gait from non-disabled, as well as motor impairment severity. These variables with the advantageous curve analysis during the entire GC add valuable whole-body information to existing parameters of post-stroke gait analysis through assessment of symmetry and upper and lower body coordination.

Instrumented triple single-leg hop test: A validated method for ambulatory measurement of ankle and knee angles using inertial sensors.

BACKGROUND: Hop tests are commonly used in clinical environments to measure function after sport-related knee injuries. Joint angle measurement during hopping is feasible in research-based environments equipped with motion-capture systems. Employing these systems in clinical research settings is inefficient, given the associated cost, preparation time, and expertise required to administer and interpret the findings. Therefore, this study aimed to introduce a wearable system comprising three inertial measurement units for 3D joint angular measurement during horizontal hop tests, validate the joint angles against a camera-based system, and evaluate its applicability in clinical research environments. METHODS: Ten able-bodied participants were outfitted with three inertial measurement units during triple single-leg hop trials. 3D knee and ankle angles were calculated using the strap-down integration method, and results were compared with camera-based joint angles. Additionally, knee and ankle range of motions (RoMs) during bilateral triple single-leg hop trials were compared for 22 participants with unilateral sport-related knee injuries and 10 uninjured participants. FINDINGS: Estimated angles had root-mean-square and RoM error medians of less than 2.3 and 3.2 degrees for both joints, and correlation coefficients of above 0.92 when compared with the camera-based system, for all hop phases. Injured participants had smaller sagittal ankle RoM (P = .008) on their injured side, during the third hop. Concurrently, they demonstrated smaller knee RoM symmetry indices (P = .017) and injured knee sagittal RoMs (P = .009) compared to uninjured participants. INTERPRETATION: The introduced system had appropriate accuracy to highlight post-injury modifications in hopping kinematics and reveal noteworthy differences in RoM of clinical samples.

Functional joint center of prosthetic feet during level ground and incline walking.

Energy storage and returning prosthetic feet do not provide a well-defined articulation point compared to the human ankle. Calculation of user relevant parameters, such as ankle power, requires such a joint center point when using traditional mechanical models. However, shortcomings of current calculation methods result in some errors. The aim of this case study was to compare conventional ankle joint calculations to a functional joint center (FJC) using data collected on a roll-over test machine and in a motion lab during dissimilar walking tasks. Three prosthetic feet were evaluated on a roll-over test machine. Then, two trans-tibial amputees were each fitted with the same three prosthetic feet matching their weight and activity category. Kinematic data were collected during walking on level ground, as well as up and down a slope. The FJC during the stance phase of gait was calculated for each test method and compared with outcomes using conventional methods. The location of the FJC was generally anterior and inferior to the estimated anatomical joint position. Importantly, the FJC location varied for the different prosthetic feet and was task dependent as per the three gait conditions. This was reflected in different ankle angles and moments of FJC calculations compared to conventional methods for level ground walking. Differences in the calculated FJC between conditions represented the variations in prosthetic foot deformation, and explained how this parameter is influenced by the prosthetic's stiffness. For level ground walking, calculated FJC location between human subject testing and machine evaluation were strongly correlated. Both stiffness and task dependent demands of the prosthetic foot should be considered during testing. The FJC of elastic ankles can serve as a parameter for characterization and differentiation between various prosthetic foot designs and be an important parameter for prosthetic foot designers to consider. As the position of the FJC is dependent on the design and task, it is a more informative measure of the prosthetic foot's response to the user's needs. Furthermore, prosthetists could use this metric in clinical practice to better appreciate amputee feedback and perception. FJC provides an alternative center during calculation of ankle power using standard methods.

The posterior talocalcaneal ligament: an MRI evaluation.

PURPOSE: A wide inter-individual variability in terms of size, orientation and insertion is observed regarding ankle ligaments. The aim of this study is to identify and describe the anatomical features of the posterior talocalcaneal ligament (PTCL) observed through the use of magnetic resonance imaging (MRI) of the ankle. METHODS: The study was retrospectively carried out on 893 ankle MRI's exams. The exams have all been performed using a 1.5-T (T) MRI. The same scanning protocols and scan planes were carried out in all the exams. The first evaluated parameter was the recognition of the PTCL. Subsequently, in all those cases where the ligament was present, its features such as insertion sites, length, and thickness were evaluated. RESULTS: The PTCL identification was possible in 77 exams (8.6% of the total number). Among these, we were able to identify some variants regarding insertion sites, length, and thickness. The PTCL could be further classified into four categories based on the most common characteristics observed. CONCLUSIONS: Our study has identified different characteristics of the PTCL that allow us to further understand the characteristics of the ligament itself. In conclusion, the need for further studies focused on the biomechanical role of the PTCL in the ankle joint appears mandatory.

Functional morphology of the ankle extensor muscle-tendon units in the springhare Pedetes capensis shows convergent evolution with macropods for bipedal hopping locomotion.

This study assesses the functional morphology of the ankle extensor muscle-tendon units of the springhare Pedetes capensis, an African bipedal hopping rodent, to test for convergent evolution with the Australian bipedal hopping macropods. We dissect and measure the gastrocnemius, soleus, plantaris, and flexor digitorum longus in 10 adult springhares and compare them against similar-sized macropods using phylogenetically informed scaling analyses. We show that springhares align reasonably well with macropod predictions, being statistically indistinguishable with respect to the ankle extensor mean weighted muscle moment arm (1.63 vs. 1.65 cm, respectively), total muscle mass (41.1 vs. 29.2 g), total muscle physiological cross-sectional area (22.9 vs. 19.3 cm2 ), mean peak tendon stress (26.2 vs. 35.2 MPa), mean tendon safety factor (4.7 vs. 3.6), and total tendon strain energy return capacity (1.81 vs. 1.82 J). However, total tendon cross-sectional area is significantly larger in springhares than predicted for a similar-sized macropod (0.26 vs. 0.17 cm2 , respectively), primarily due to a greater plantaris tendon thickness (0.084 vs. 0.048 cm2 ), and secondarily because the soleus muscle-tendon unit is present in springhares but is vestigial in macropods. The overall similarities between springhares and macropods indicate that evolution has favored comparable lower hindlimb body plans for bipedal hopping locomotion in the two groups of mammals that last shared a common ancestor ~160 million years ago. The springhare's relatively thick plantaris tendon may facilitate rapid transfer of force from muscle to skeleton, enabling fast and accelerative hopping, which could help to outpace and outmaneuver predators.

A simple approach for determining tendon limb length in open Achilles lengthening: technical note.

Estimating the appropriate tendon length and associated skin incision needed to achieve a plantigrade foot without compromising function are essential steps in open Achilles tendon lengthening. Here we describe a technique using basic surgical instruments referencing anatomic landmarks without the need for radiographs. The center of ankle rotation in the sagittal plane is found referencing the tip of the medial malleolus. This point is translated to the plantar surface of the foot, and a straight instrument in line with the foot is used to make a mark at the posterior calcaneal fat pad. The straight instrument is then rotated (representing the plantar surface of the foot) as if dorsiflexing the ankle along the axis of the transposed tibiotalar joint from a plantar-flexed position to the desired final position and a second mark is made at the posterior heel. The distance between the marks is measured, representing the amount of Achilles lengthening required. The skin incision and tendon limb lengths area a sum of the operative correction and the amount of desired tendon overlap, typically 2 cm of tendon overlap is optimal to allow for suture fixation, ensure tendon healing, and maintain the integrity of the repair. A Z-type lengthening is then performed using this tendon limb length. This technique allows an accurate and simple approach to lengthening the Achilles tendon. In this way the ideal tendon limb length is selected to optimize function while minimizing incision length, associated wound complications, inadequate lengthening, and overlengthening. Level of evidence: Technical note, Level V.

Does Function Determine the Structure? Changes in Flexor Hallucis Longus Muscle and the Associated Performance Related to Dance Modality: A Cross-Sectional Study.

Background and Objectives: Flexor hallucis longus pathology is one of the most common conditions of the ankle and foot in dancers, due to the high demand of dance movements performed in an extreme plantar flexion and dorsiflexion range of motion. The objectives of this study were to determine the bilateral differences between the thickness and cross-sectional area of the flexor hallucis longus muscle in dancers, to establish possible differences between dance modalities, and to analyze whether there is a correlation between ultrasonographic parameters or performance variables and the dance modality. Material and Methods: A sample of 50 (29 classical and 21 contemporary) full-time pre-professional female dancers were included in the study. The thickness and cross-sectional area of the flexor hallucis longus muscle were evaluated for both limbs using ultrasound imaging. The range of movement of the first metatarsophalangeal joint was measured using functional extension with maximal ankle plantarflexion, balance was measured in a unilateral stance with the heel raised, endurance was evaluated through a modified heel rise fatigue test, and a counter movement jump to assess the vertical jump performance was measured bilaterally. Results: There were no significant differences recorded between the dominant and non-dominant limbs for each variable, within both groups. Contemporary dancers showed a greater thickness and cross-sectional area of the flexor hallucis longus muscle than classical dancers. However, classical dancers showed an increase of balance, endurance, range of movement of the first metatarsophalangeal joint, and counter movement jump with respect to contemporary dancers. Conclusion: Bilateral symmetry was identified in all variables for both groups. The size and performance of the flexor hallucis longus muscle may be influenced by the specific nature of dance modality.