Calculating the axes of rotation for the subtalar and talocrural joints using 3D bone reconstructions

Orientation of the subtalar joint axis dictates inversion and eversion movements of the foot and has been the focus of evolutionary and clinical studies for a number of years. Previous studies have measured the subtalar joint axis against the axis of the whole foot, the talocrural joint axis and, recently, the principal axes of the talus. The present study introduces a new method for estimating average joint axes from 3D reconstructions of bones and applies the method to the talus to calculate the subtalar and talocrural joint axes. The study also assesses the validity of the principal axes as a reference coordinate system against which to measure the subtalar joint axis. In order to define the angle of the subtalar joint axis relative to that of another axis in the talus, we suggest measuring the subtalar joint axis against the talocrural joint axis. We present corresponding 3D vector angles calculated from a modern human skeletal sample. This method is applicable to virtual 3D models acquired through surface-scanning of disarticulated 'dry' osteological samples, as well as to 3D models created from CT or MRI scans.     

Analysis of the human and ape foot during bipedal standing with implications for the evolution of the foot

The ratio of the power arm (the distance from the heel to the talocrural joint) to the load arm (that from the talocrural joint to the distal head of the metatarsals), or RPL, differs markedly between the human and ape foot. The arches are relatively higher in the human foot in comparison with those in apes. This study evaluates the effect of these two differences on biomechanical effectiveness during bipedal standing, estimating the forces acting across the talocrural and tarsometatarsal joints, and attempts to identify which type of foot is optimal for bipedal standing. A simple model of the foot musculoskeletal system was built to represent the geometric and force relationships in the foot during bipedal standing, and measurements for a variety of human and ape feet applied. The results show that: (1) an RPL of around 40% (as is the case in the human foot) minimizes required muscle force at the talocrural joint; (2) the presence of an high arch in the human foot reduces forces in the plantar musculature and aponeurosis; and (3) the human foot has a lower total of force in joints and muscles than do the ape feet. These results indicate that the proportions of the human foot, and the height of the medial arch are indeed better optimized for bipedal standing than those of apes, further suggesting that their current state is to some extent the product of positive selection for enhanced bipedal standing during the evolution of the foot.     

The Effect of the Chronic Peripheral Circulatory Deficiency on Muscle Function in Lower Extremities

The muscle strength of the lower extremities was measured in 52 subjects between 30 to 48 years of age with chronic peripheral circulatory deficiency (grade endarteritis obliterans II–IV). The dynamometry was used to record the moments of strength of the flexor and extensor muscles of the crus and the dorsal and plantar flexors of foot. The transverse stiffness of the gastrocnemic muscles and the relationship between the strength of the crural muscles and the angle of talocrural articulation were investigated. The maximum moments of strength of the femoral and crural muscles in subjects with chronic peripheral circulatory deficiency were lower than those in the age-matched healthy subjects; as the pathological process increased, this difference became more significant. In subjects with endarteritis obliterans, the functions of the femoral and crural muscles decreased to the same extent.     

In vivo tests of an improved method for functional location of the subtalar joint axis

The subtalar joint is important in frontal plane movement and posture of the hindfoot. Abnormal subtalar joint moments caused by muscle forces and the ground reaction force acting on the foot are thought to play a role in various foot deformities. Calculating joint moments typically requires knowledge of the location of the joint axis; however, location of the subtalar axis from measured movement is difficult because the talus cannot be tracked using skin-mounted markers. The accuracy of a novel technique for locating the subtalar axis was assessed in vivo using magnetic resonance imaging. The method was also tested with skin-mounted markers and video motion analysis. The technique involves applying forces to the foot that cause pure subtalar joint motion (with negligible talocrural joint motion), and then using helical axis decomposition of the resulting tibiocalcaneal motion. The resulting subtalar axis estimates differed by 6° on average from the true best-fit subtalar axes in the MRI tests. Motion was found to have been applied primarily about the subtalar joint with an average of only 3° of talocrural joint motion. The proposed method provides a potential means for obtaining subject-specific subtalar axis estimates which can then be used in inverse dynamic analyses and subject-specific musculoskeletal models.     

Roentgeno-functional study of the talocrural joint in the long-term follow-up of a fracture of the crural bone

On the basis of the results of clinicoroentgenological and tensographic investigations of 119 patients after traumas of the crural bones and ankle joint (2-36 yrs. ago) the authors showed the importance of roentgenofunctional investigation of the ankle joint, a patient being in a standing position with maximum flexion and extension of the foot. A specially designed footing was proposed. Of 77 patients after intra-articular fractures of the ankle bones various disorders in articular proportions, undetectable on routine roentgenography, were diagnosed in 29 by functional roentgenography. Articular changes on roentgenofunctional investigation were revealed in one patient only out of 42 patients with extra-articular fractures of the crural bones. Tensography showed disorders of foot biomechanics in all patients with subluxations in the ankle.     

Accuracy of a CT-based bone contour registration method to measure relative bone motions in the hindfoot

For measuring the in-vivo range of motion of the hindfoot, a CT-based bone contour registration method (CT-BCM) was developed to determine the three-dimensional position and orientation of bones. To validate this technique, we hypothesized that the range of motion in the hindfoot is equally, accurately measured by roentgen stereophotogrammetric analysis (RSA) as by the CT-BCM technique.Tantalum bone markers were placed in the distal tibia, talus and calcaneus of one cadaver specimen. With a fixed lower leg, the cadaveric foot was held in neutral and subsequently loaded in eight extreme positions. Immediately after acquiring a CT-scan with the foot in a position, RSA radiographs were made. Bone contour registration and RSA was performed. Helical axis parameters were calculated for talocrural and subtalar joint motion from neutral to extreme positions and between opposite extreme positions. Differences between CT-BCM and RSA were calculated.Compared with RSA, the CT-BCM data registered an overall root mean square difference (RMSd) of 0.21° for rotation about the helical axis, and 0.20 mm translation along the helical axis for the talocrural and subtalar joint and for all motions combined. The RMSd of the position and direction of the helical axes was 3.3 mm and 2.4°, respectively. The latter errors were larger with smaller helical rotations.The differences are similar to those reported for validated RSA and thus are not clinically relevant. Concluding, CT-BCM is an accurate and accessible alternative for studying joint motion, as it does not have the risk of infection and overlapping bone markers.     

Morphology of the facets of the proximal Tarsi bones from an ancient population

The analysis of morphological variation of tali and calcanei articular surfaces from “S'Illot des Porros” (Majorca, 2430±200 BP) has been made. It indicates the high frequency of extensions of the talocrural and subtalar surfaces, which are shown to be produced not only by a high level of stress on the bones. The presence of the sulcus tali facet in most cases could indicate, however, a greater degree of lateral movement of the foot.     

Foot mechanics during the first six years of independent walking

Recognition of the changes during gait that occur normally as a part of growth is essential to prevent mislabeling those changes from adult gait as evidence of gait pathology. Currently, in the literature, the definition of a mature age for ankle joint dynamics is controversial (i.e., between 5 and 10 years). Moreover, the mature age of the metatarsophalangeal (MP) joint, which is essential for the functioning of the foot, has not been defined in the literature. Thus, the objective of the present study explored foot mechanics (ankle and MP joints) in young children to define a mature age of foot function. Forty-two healthy children between 1 and 6 years of age and eight adults were measured during gait. The ground reaction force (GRF), the MP and ankle joint angles, moments, powers, and 3D angles between the joint moment and the joint angular velocity vectors (3D angle α(M.ω)) were processed and compared between four age groups (2, 3.5, 5 and adults). Based on statistical analysis, the MP joint biomechanical parameters were similar between children (older than 2 years) and adults, hinting at a quick maturation of this joint mechanics. The ankle joint parameters and the GRFs (except for the frontal plane) showed an adult-like pattern in 5-year-old children. Some ankle joint parameters, such as the joint power and the 3D angle α(M.ω) still evolved significantly until 3.5 years. Based on these results, it would appear that foot maturation during gait is fully achieved at 5 years.     

Changes in talocrural joint contact stress characteristics after simulated rotationplasty

In order to assess the changes in talocrural joint contact stress after rotationplasty, 10 lower-leg cadaver specimens were axially loaded with 600 N and investigated in two loading situations: (1) Normal loading with a plantigrade foot; (2) in an equinus position of a simulated rotationplasty. Joint contact stress in the talar facet of the talocrural joint was determined with Fuji Prescale film cut to size and analyzed with digital image analysis for joint contact area, mean and peak pressure, contact force, and location of the load application on the trochlea tali. The results demonstrate a significant transfer on the loading zone to the posterior part of the talus (p = 0.005), a significant reduction of the contact area (p = 0.005) and force (p = 0.005), and a significant increase of the mean (p = 0.022) and maximum pressures (p = 0.013). These results indicate that the rotationplasty causes pronounced changes in joint loading characteristics.     

Evaluating foot kinematics using magnetic resonance imaging: from maximum plantar flexion, inversion, and internal rotation to maximum dorsiflexion, eversion, and external rotation

The foot consists of many small bones with complicated joints that guide and limit motion. A variety of invasive and noninvasive means [mechanical, X-ray stereophotogrammetry, electromagnetic sensors, retro-reflective motion analysis, computer tomography (CT), and magnetic resonance imaging (MRI)] have been used to quantify foot bone motion. In the current study we used a foot plate with an electromagnetic sensor to determine an individual subject's foot end range of motion (ROM) from maximum plantar flexion, internal rotation, and inversion to maximum plantar flexion, inversion, and internal rotation to maximum dorsiflexion, eversion, and external rotation. We then used a custom built MRI-compatible device to hold each subject's foot during scanning in eight unique positions determined from the end ROM data. The scan data were processed using software that allowed the bones to be segmented with the foot in the neutral position and the bones in the other seven positions to be registered to their base positions with minimal user intervention. Bone to bone motion was quantified using finite helical axes (FHA). FHA for the talocrural, talocalcaneal, and talonavicular joints compared well to published studies, which used a variety of technologies and input motions. This study describes a method for quantifying foot bone motion from maximum plantar flexion, inversion, and internal rotation to maximum dorsiflexion, eversion, and external rotation with relatively little user processing time.     

Ecological divergence and talar morphology in gorillas

Gorillas occupy a variety of habitats from the west coast to eastern central Africa. These habitats differ considerably in altitude, which has a pronounced effect on forest ecology. Although all gorillas are obligate terrestrial knuckle‐walking quadrupeds, those that live in lowland habitats eat fruits and climb more often than do those living in highland habitats. Here we test the hypothesis that gorilla talus morphology falls along a morphocline that tracks locomotor function related to a more inverted or everted foot set. This proposed morphocline predicts that gorillas living in lowland habitats may have a talocrural joint configured to facilitate a more medially oriented foot during climbing, suggesting that they may be more adaptively committed to arboreality than gorillas living in highland habitats. To quantify the relative set of the foot in gorillas, we chose two three‐dimensional measurements of the talocrural joint: mediolateral curvature of the trochlea and relative surface area of the lateral malleolus. Our results show that, in comparison to their eastern counterparts, western gorillas have talar features that reflect a more medially directed sole of the foot. This morphology likely facilitates foot placement in a wider range of positions and minimization of shearing stresses across the joint when the foot is loaded on more curved or vertically oriented substrates as occurs during climbing and other arboreal behaviors. In contrast, eastern gorilla talar morphology is consistent with habitual placement of the foot with the sole directed more inferiorly, suggesting more effective loading during plantigrade push‐off on terrestrial substrates. Am J Phys Anthropol 153:526–541, 2014. © 2013 Wiley Periodicals, Inc.     

Skeletal kinematics of the midtarsal joint during walking: Midtarsal joint locking revisited

The kinematics of the human foot complex have been investigated to understand the weight bearing mechanism of the foot. This study aims to investigate midtarsal joint locking during walking by noninvasively measuring the movements of foot bones using a high-speed bi-planar fluoroscopic system. Eighteen healthy subjects volunteered for the study; the subjects underwent computed tomography imaging and bi-planar radiographs of the foot in order to measure the three-dimensional (3D) midtarsal joint kinematics using a 2D-to-3D registration method and anatomical coordinate system in each bone. The relative movements on bone surfaces were also calculated in the talonavicular and calcaneocuboid joints and quantified as surface relative velocity vectors on articular surfaces to understand the kinematic interactions in the midtarsal joint. The midtarsal joint performed a coupled motion in the early stance to pronate the foot to extreme pose in the range of motion during walking and maintained this pose during the mid-stance. In the terminal stance, the talonavicular joint performed plantar-flexion, inversion, and internal rotation while the calcaneocuboid joint performed mainly inversion. The midtarsal joint moved towards an extreme supinated pose, rather than a minimum motion in the terminal stance. The study provides a new perspective to understand the kinematics and kinetics of the movement of foot bones and so-called midtarsal joint locking, during walking. The midtarsal joint continuously moved towards extreme poses together with the activation of muscle forces, which would support the foot for more effective force transfer during push-off in the terminal stance.     

In vivo determination of the Achilles tendon moment arm in three-dimensions

Two-dimensional methods have been applied to determine the Achilles tendon moment arm in previous studies, although the talocrural joint rotates in three-dimension. The purpose of this study was to develop a method for determining the Achilles tendon moment arm in three-dimensions (3DMA). A series of sagittal ankle images were obtained at ankle positions of -20°, -10° (dorsiflexed position), 0° (neutral position), +10°, +20°, and +30° (plantarflexed position). The talocrural joint axis was determined as the finite helical axis of the ankle joint over 20° of displacement, and the 3DMA was determined as the shortest distance from the talocrural joint axis to the line of action of the Achilles tendon force. The corresponding 2DMA was determined with the center of rotation method using the images captured on the sagittal plane passing through the mid-point of the medio-lateral width of the tibia. The 3DMA ranged from 35 to 41 mm across various ankle positions and was, on average, 11 mm smaller than 2DMA. The difference between the two measures was attributable primarily to the deviations of the talocrural joint axis from the anatomical medio-lateral direction. The deviations on the coronal plane (21.4±20.7°) and on the transverse planes (14.8±22.6°) accounted for the errors of 1.3 mm and 3.0 mm, respectively. In addition, selecting either a medially or laterally misaligned sagittal-plane image for determining the 2DMA gave rise to error by 3.5 mm. The remaining difference was accounted for by the random measurement error.     

Inter-generation differences in foot morphology: aging or secular change?

Inter-generation differences in foot dimensions were examined using ANCOVA to determine whether aging or secular change is the more important causal factor. In examining the results, bone size was assumed not to change after the end of linear growth, while foot arches were assumed to become flatter rather than higher if there were any changes in skeletal structure. Changes in overall body build according to age were examined using statistical data collected by the government through population-follow-up. Secular changes in foot length (FL) and foot breadth, diagonal (FB) as well as the changes with age in FB were examined using data measured at ages younger than 50 years. The effects of overall body build were examined using the body mass index (BMI). Compared to the 1970 group (birth year: 1960-78) of the same FL, the 1930 group (birth year: 1909-39) had larger foot circumferences, wider breadth measurements, higher dorsal arches and ball, and greater toe 5 angle, but had shorter fibular instep lengths and shorter 5th metatarsal bones. The 1930 groups tended to have larger FB than the 1970 group of the same foot circumference. No inter-generation differences were observed in the heights at the medial and lateral malleoli, toe 1 angle, or the relationship between FB and heel breadth. These findings are discussed in terms of the effects of weight increase after the end of linear growth, changes in skeletal structure, overall body build as young adults, socioeconomic status during the growth period, as well as differential growth rates of foot bones. The conclusions are 1) changes in foot length and longitudinal arches due to aging are negligible, 2) the large circumferences, breadths, and higher dorsal arches and ball of the 1930 group for their foot length are better explained by their robust bones than by the increase in soft tissue after the end of linear growth, and 3) the larger FB of the 1930 group for their foot circumference is partly explained by their shorter fibular instep length. As a whole, factors affecting growth (secular change) are more important than changes after the end of growth (aging) in the inter-generation differences in foot morphology.     

Talocrural and talocalcaneal joint kinematics and kinetics during the stance phase of walking

The purpose of this investigation was to study the kinematics and kinetics of the joints between the leg and calcaneus during the stance phase of walking. The talocrural and talocalcaneal joints were each assumed to act as monocentric single degree of freedom hinge joints. Motion at one joint was defined by the relative rotation of a point on the opposing joint. The results, based upon the gait of three subjects, showed that the hinge joint assumption may be reasonable. A discrepancy in the kinematics was shown between the talocrural joint rotation and its commonly assumed sagittal plane representation, especially during initial flatfoot. This discrepancy is due to the fact that the sagittal plane rotation is created by the combined rotations of the talocrural and talocalcaneal joints. The talocalcaneal joint showed a peak 25-30 Nm supinatory moment at 80% of stance. The talocrural joint moment was qualitatively similar to the commonly measured sagittal plane moment, but the present results show that the sagittal plane moment overpredicted the true moment by 6-22% due to the two-dimensional assumption.     

Synostosis dynamics in human long tubular bones

More than 8,000 roentgenograms and electroroentgenograms of brachial, ulnar, radiocarpal, coxofemoral, knee, talocrural joints have been studied in persons of both sex at the age from birth up to 25 years. The synostosis degree is appreciated by the six-mark system. The roentgenological data are corroborate histologically. The method of appreciation applied makes it possible to reveal cases of initially forming synostosis long before puberty. Three stages of synostosis process are defined. The first stage--slow increase of the synostosis mark. The second--quick synostosis formation. The third--final stage. According to the stages defined, a comparative analysis of the synostosis process in all metaepiphyseal zones of all long tubular bones, peculiarities of the process depending on the sex are demonstrated. The data on the time, when the points of ossification appear, on the beginning and completion of synostosis process in all metaepiphyseal zones of the long tubular bones are presented.     

Magnetic resonance imaging of the ankle joint and foot: possible diagnostic errors

The paper deals with the visualizing study of the ankle joint and foot by MRI and with the problems in the interpretation of magnetic resonance images in health. For this, 50 healthy volunteers without diseases and lesions of the ankle joint and foot were examined. The study was performed by using flexible superficial coils and T1-, T2-, and proton-weighed pulse-sequences in the orthogonal projections. The articular surfaces and cavity of the ankle joint were evaluated. The specific features of visualization of the muscles and tendons of this area and the pattern of fluid under their membranes were explored. The typical location of the "magic corner" phenomenon was revealed. The individual specific features of identification of the ligaments of the ankle joint and foot and plantar aponeurosis were defined. The features of visualization of bones simulating abnormalities were studied. A category of normalcy in the MRI of the ankle joint and foot was formulated.     

天津蓟州区桃花园墓地明清时期缠足女性的足骨形变

本文通过量化方法,对桃花园墓地明清时期101例女性足骨形变方式、程度、对称性等进行了系统分析。研究结果表明,双侧足骨形变总体上是对称的。缠足对跗骨的影响主要在于整体尺寸缩小和关节面改变。第1跖骨除整体尺寸缩小外,还存在诸多明显的骨体形态改变;第2、3跖骨头部和底部尺寸缩小,但形变不大。第3至第5近节趾骨骨体长度和高度的侧别差异明显,特别是第3近节趾骨双侧整体不对称。该群体至少在18岁时已经缠足,25岁以后足骨已发生形变,35岁之后形变较明显。部分个体足骨形变程度较轻,其生前可能仅束足纤直,未经裹弯。足骨形变程度与陪葬品多寡并无相关性,其形变差异很可能与身体疾病、劳作需要、缠足方法或缠足观念差异有关。