Medial Ball Research Articles

Medial Ball and Socket Total Knee Arthroplasty in Indian Population: 5-Year Clinical Results.

BackgroundMedial pivot total knee arthroplasty aims to restore native knee kinematics through highly conforming medial tibiofemoral articulation with survival comparable to contemporary knee designs. The aim of this study was to report preliminary clinical results of medial pivot total knee arthroplasty in an Indian population.MethodsA retrospective analysis of 45 patients (average age, 62 years; 40 women and 5 men) with end-stage arthritis (Kellgren-Lawrence grade 4) operated with a medial pivot prosthesis was done. All patients were assessed using Knee Society Score (satisfaction, expectation, and functional scores) and Oxford Knee Score, and range of motion was recorded at the end of 5-year postoperative follow-up. In addition, all patients underwent standardized radiological assessment.ResultsAt the final follow-up, patients reported significant improvement in mean Knee Society Score (satisfaction, expectation, and functional scores) and Oxford Knee Score (p < 0.05). The mean range of motion achieved at the end of 5 years ranged from 0° (extension) to 118.4° (further flexion). There was no evidence of loosening or osteolysis at a minimum follow-up of 5 years.ConclusionsThese results demonstrated satisfactory clinical and radiological outcomes at 5 years after total knee arthroplasty with a medial pivot design, which may be related to better replication of natural knee kinematics with the medial pivot knee and inherent advantages of this design.

3차원 스캔 데이터에 의한 초등학생의 발 성장에 관한 연구

This study was about to investigate the characteristics of elementary school students' feet growth, comparing and analyzed the measured values and the index values of 3D scan data. As the results from analyzing the measured values, the all measurement items excluding 'Toe 5 angle' showed some significant differences among the age classes, knowing that the elementary school students' feet were continually grown. Although, the items of length, thickness, width, height and circumference indicate some rapid growth of feet at 11 years old, but it appears slowing growth of 'Foot width' after the age of 11 years old. The angle item didn't show any sequential differences according to ages. As the results from analyzing the index values, the children in higher grades have longer 'Toe 5', thicker ankles, wider and thicker the superior part of feet than the children in lower grades. For the superior and the middle part of feet were lowly raised, their Arch height was low and thick. The inferior part of feet showed narrow width and higher height. Giving that the Medial ball width was wide and the Toe 1 angle is high for the children in higher grades, it is expected that the Metatarsophalangeal I might be more projected than that of children in lower grades. Likewise, knowing that the male students' feet shape was bigger than female students' feet from the result that the male students' index values were higher.

Variability of footprint ridge density and its use in estimation of sex in forensic examinations.

The present study deals with a comparatively new biometric parameter of footprints called footprint ridge density. The study attempts to evaluate sex-dependent variations in ridge density in different areas of the footprint and its usefulness in discriminating sex in the young adult population of north India. The sample for the study consisted of 160 young adults (121 females) from north India. The left and right footprints were taken from each subject according to the standard procedures. The footprints were analysed using a 5 mm × 5 mm square and the ridge density was calculated in four different well-defined areas of the footprints. These were: F1 - the great toe on its proximal and medial side; F2 - the medial ball of the footprint, below the triradius (the triradius is a Y-shaped group of ridges on finger balls, palms and soles which forms the basis of ridge counting in identification); F3 - the lateral ball of the footprint, towards the most lateral part; and F4 - the heel in its central part where the maximum breadth at heel is cut by a perpendicular line drawn from the most posterior point on heel. This value represents the number of ridges in a 25 mm(2) area and reflects the ridge density value. Ridge densities analysed on different areas of footprints were compared with each other using the Friedman test for related samples. The total footprint ridge density was calculated as the sum of the ridge density in the four areas of footprints included in the study (F1 + F2 + F3 + F4). The results show that the mean footprint ridge density was higher in females than males in all the designated areas of the footprints. The sex differences in footprint ridge density were observed to be statistically significant in the analysed areas of the footprint, except for the heel region of the left footprint. The total footprint ridge density was also observed to be significantly higher among females than males. A statistically significant correlation is shown in the ridge densities among most areas of both left and right sides. Based on receiver operating characteristic (ROC) curve analysis, the sexing potential of footprint ridge density was observed to be considerably higher on the right side. The sexing potential for the four areas ranged between 69.2% and 85.3% on the right side, and between 59.2% and 69.6% on the left side. ROC analysis of the total footprint ridge density shows that the sexing potential of the right and left footprint was 91.5% and 77.7% respectively. The study concludes that footprint ridge density can be utilised in the determination of sex as a supportive parameter. The findings of the study should be utilised only on the north Indian population and may not be internationally generalisable.

Effect of Ski Mountaineering Track on Foot Sole Loading Pattern

Ski mountaineering is becoming a popular sport. The ascending techniques (tracks) can be divided into 3 different groups: flat field, direct ascent, and traversing. This study examines the relationship between different mechanical loads on the foot and the 4 different mountaineering ascending techniques. All subjects used the same pair of ski boots and the same skis while performing the 4 different ascending techniques. An in-shoe dynamic pressure measuring system was used to measure the mechanical load on the foot soles of each ski mountaineer. The foot sole was divided into 6 anatomic sections to measure the different loads in each section. Thirteen men with an average age of 29 years were enrolled in the study. The results showed small, not significant differences in the mechanical foot load in the flat field or in the direct ascent. The average mechanical foot load was highest on the valley side foot while traversing (179 kPa to 117 kPa). The higher load forces were in the medial ball of the foot and the longitudinal aspect of the foot side closer to the hill. The higher impact placed on the valley side foot and the concentration of force placed on the medial ball of the valley side foot suggested the influence of the track on the load pattern of the foot sole. This higher impact may result in upward forces that affect the force distribution in the ankle and knee joints.

Anthropometric influences on dynamic foot shape: Measurements of plantar three-dimensional foot deformation

Purpose: Advances in scanner technology enable the capture of feet during walking. Knowledge of dynamic deformation is essential for fundamental research and application-oriented improvements in terms of comfortable and functional footwear. The core hypothesis of our study is that there is a relationship between dynamic foot measures and the anthropometric dimensions age, gender and body mass index. Methods: We measured the dynamic foot shape of 129 subjects (77 female, 52 male) with a plantar dynamic scanner system. During stance phase we captured maximum values (MaxDyn) and changes (ΔDyn) of length, width, and height measures as well as angles and indices of feet. We identified relationships between foot measures and anthropometric dimensions by two statistical methods: analysis of variance (ANOVA) between matched groups and multiple regression analysis within whole sample size. Results: MaxDyn values of foot width measures are higher in overweight subjects. Most important predictors of MaxDyn are static measures and gender, regarding values that characterise the longitudinal arch as well as lateral ball length. More dynamic deformation was found in ball and arch angle as well as medial ball length and ball width of overweight subjects and in width measures of women. Multiple regression analysis detects body weight as an important predictor for changes in foot width measures as well as arch height and angle. Conclusion: The ability to collect foot measures during natural walking is the basis for the following findings. First, our study confirms that static foot measures can be used as basic design criteria for footwear. Second, our study points out the influence of factors like gender and body weight on dynamic foot morphology. Consideration of these additional factors can essentially improve design methods and particularly the fit of footwear.

Spatial summation of vibrotactile sensations at the foot

Thresholds for the perception of vibration on the hand reduce with increasing area of excitation when the thresholds are mediated by the Pacinian channel (a phenomenon known as spatial summation) but thresholds are generally independent of the area of excitation when they are mediated by non-Pacinian channels. The effect of the area of excitation on vibrotactile thresholds at the sole of the foot has not been thoroughly investigated. In the study reported in this paper, thresholds for the perception of 20Hz vibration and 160Hz vibration were determined on the foot (at the big toe (hallux), the medial (inside) ball, the lateral (outside) ball, and the heel) and on the hand (at the thenar eminence and at the fingertip) in 12 male subjects using four probe diameters: 1mm (0.19cm2 excitation area), 3mm (0.38cm2), 6mm (0.78mm2) and 10mm (1.53cm2) with a 2mm gap between the vibrating probe and a fixed surround. On both the hand and the foot, thresholds for the perception of 160Hz vibration decreased as the probe diameter increased. There was no overall consistent change in thresholds for the perception of 20Hz vibration. Thresholds for the perception of 160Hz vibration were lowest at the fingertip and highest at the big toe. Thresholds for 20Hz vibration were also lowest at the fingertip. It is concluded that on the sole of the foot there is evidence of spatial summation in the perception of 160Hz vibration, mediated by the Pacinian channel, but not in the perception of 20Hz vibration, mediated by a non-Pacinian channel. The findings show that vibrotactile thresholds at the foot obtained with different areas of excitation, or an unknown area of excitation, should not be compared. It is concluded that there is a need to standardise methods of measuring the vibrotactile thresholds at the foot that are obtained for clinical applications.

Shape spaces via medial axis transforms for segmentation of complex geometry in 3D voxel data

In this paper we construct a shape space of medial ball representations from given shape training data using methods of Computational Geometry and Statistics. The ultimate goal is to employ the shape space as prior information in supervised segmentation algorithms for complex geometries in 3D voxel data. For this purpose, a novel representation of the shape space (i.e., medial ball representation) is worked out and its implications on the whole segmentation pipeline are studied. Such algorithms have wide applications for industrial processes and medical imaging, when data are recorded under varying illumination conditions, are corrupted with high noise or are occluded.

Footprint ridge density: A new attribute for sexual dimorphism

Estimation of sex of footprints can help in establishing the biological profile of potential suspects. This research attempts to study the sex differences in the ridge density in four different areas of a footprint. The study sample comprises footprints from both feet of 106 adult subjects from India that were analysed using standardized techniques. A total of 212 footprints were studied in detail. The four areas analysed in the study included the upper portion of the medial border of the great toe (F1), the ball of the great toe (F2), the ball of the 5th toe below the triradius point (F3) and the central prominent part of the heel (F4). Male–female differences in footprint ridge density were statistically analysed for each designated area and compared between right and left sides. The mean footprint ridge density was significantly higher among females than males in all designated areas (p<0.05) in both feet. No right-left differences were apparent in the analysed areas. Variations in footprint ridge density between different areas in right and left feet were evident among males and females. This study observes that sex differences exist in footprint ridge density among humans. Maximum sex differences were observed for ridge density in medial ball area, followed by great toe, lateral ball and minimum sex differences were observed in the heel region. It is observed that sex can be estimated from footprint ridge density with reasonable accuracy. The sexing potential of total footprint ridge density was 82.6% from the right and 83.6% from the left footprints respectively.

Medial Kernels

AbstractWe introduce the medial kernel, an association measure which provides for a robust construction of volume‐aware distances defined directly on point clouds. The medial kernel is a similarity measure defined as the likelihood of two points belonging to a common interior medial ball. We use the medial kernel to construct a random walk on the point cloud, where movement in the walk is restricted to regions containing similar medial balls. Our distances are defined as the diffusion distances of this random walk, assigning low distance to points belonging to similar medial regions. These distances allow for a robust means of processing incomplete point clouds, capable of distinguishing nearby yet separate undersampled components, while also associating points which are far in Euclidean distance yet mutually share an interior volume. We leverage these distances for several applications: volumetric part segmentation, the construction of function bases, and reconstruction‐by‐parts – a surface reconstruction method which adheres to the medial kernel.

여성 농업인 발 유형에 관한 연구

This study was performed to offer the basic data for the design of farm shoes. 265 Korean female farmers aging between the 40s to the 80s volunteered for this study and we measured 40 items on each foot with the 3D foot scanner. First, the differences between farmers` feet and non-farmers` feet were analyzed. Farmers` feet were thicker in the instep areas, but had lower arch height than non-farmers` feet. In addition, farmer`s feet were tilted to the inside. Next, eight factors were extracted among the 40 measuring items, and the classification criteria of the foot shape was analyzed. The important factors were: size of foot length and volume of ankle, malleolus height and size, volume of the front part of ankle, medial & lateral ball width, and vertical size of foot. Third, three clusters according to the foot shapes were categorized by cluster analysis of eight factor scores. Foot type 1 was medium in foot length, big in thickness, large in lateral ball width, small in toe 1 angle, and tilted to the inside. Foot type 2 was long and slim, and big in toe 5 angle. Foot type 3 was short in foot length, medium in volume of the front part of ankle, large in medial ball width, and big in toe 1 angle. Despite its shortness, foot type 3 was thick and showed severe deformation in toe 1. Lastly, the frequency distributions of the foot types in each age group were analyzed. Female farmers of the forties showed high frequency in type 1 and other age groups showed high frequency in type 2. The older female farmers showed higher frequency of type 3.

The Jinniushan hominin pedal skeleton from the late Middle Pleistocene of China

Bipedalism has long been recognized as the seminal adaptation of the hominin radiation and thus used to distinguish hominins from great ape fossils. Notwithstanding preconceptions and varied interpretations, the distinctive features of the modern human foot and accompanying striding gait, appear to be recent innovations that are largely absent in the earliest facultative bipeds. These distinctive features are mainly components of fixed longitudinal and transverse pedal arches, and of a uniquely derived hallucal metatarsophalangeal joint. They enhance ankle joint plantar flexor function and accommodate localized peak plantar pressures at the medial ball during terminal stance. To date, the paleontological record has yielded very little of the hominin foot, especially of the Middle Pleistocene hominins. New specimens from this time interval should help provide insights into the timing and pattern of what appears to be a mosaic pattern of evolution of the modern human foot features. Here we describe the fossil hominin foot skeleton recovered from the Jinniushan site, Liaoning Province, People's Republic of China. It affords a singular glimpse of the pedal morphology of a late Middle Pleistocene hominin (c.f. Homo heidlebergensis). Dated to 200 ka or older, this foot offers the earliest evidence for increased stability of the medial longitudinal arch, while retaining a number of primitive features apparently characteristic of robust premodern hominins, including lower arches and a less stable hallucal metatarsophalangeal joint (medial ball) than in modern humans. These features reflect different foot capabilities and suggest the bipedal stride of the Jinniushan hominin differed subtlety from that of modern humans.

Gender differences in foot shape: a study of Chinese young adults

One important extrinsic factor that causes foot deformity and pain in women is footwear. Women's sports shoes are designed as smaller versions of men's shoes. Based on this, the current study aims to identify foot shape in 1,236 Chinese young adult men and 1,085 Chinese young adult women. Three-dimensional foot shape data were collected through video filming. Nineteen foot shape variables were measured, including girth (4 variables), length (4 variables), width (3 variables), height (7 variables), and angle (1 variable). A comparison of foot measures within the range of the common foot length (FL) categories indicates that women showed significantly smaller values of foot measures in width, height, and girth than men. Three foot types were classified, and distributions of different foot shapes within the same FL were found between women and men. Foot width, medial ball length, ball angle, and instep height showed significant differences among foot types in the same FL for both genders. There were differences in the foot shape between Chinese young women and men, which should be considered in the design of Chinese young adults’ sports shoes.

Foot shape of older people: implications for shoe design

Foot problems and deformities, which are highly prevalent in older people, may affect foot anthropometrics and result in older people having difficulty finding shoes that fit. This study aimed to characterise the dimensions and shape of the feet of older people and to determine whether foot anthropometrics were influenced by gender and/or the presence of foot problems in older people. Foot anthropometrics and foot problems were assessed in 312 community-dwelling older men and women. Men had significantly higher normalised first and fifth toe heights and a greater fifth toe angle, whereas women had a significantly longer normalised medial ball length and greater first toe and heel bone angles (p < 0.05). Older people who had moderate-to-severe hallux valgus, lesser toe deformities, swollen or flat feet exhibited different foot anthropometrics to those without foot problems. Consequently, footwear for older people should be designed to cater for the altered morphology of older feet.

Preliminary Report on Hominid and Other Vertebrate Footprints from the Late Quaternary Strata of Jeju Island, Korea

Numerous footprints attributable to hominids, artiodactyla, proboscidea, carnivores, and birds have been preserved in the Late Quarternary strata of Jeju Island, Korea, which is composed of volcaniclastic sediments deposited in a shoreline environment. The hominid footprints are 12–26 cm long and 6–12 cm wide and are characterized by impressions of medial arch, heel, and ball. These are considered to have been made by at least nine humans of different sites. The artiodactyl footprints are up to 8 cm in length and are characterized by impressions of paired hooves. The diverse range of footprint sizes indicate herds of artiodactyls, composed of juvenile, young, and adult. The footprints attributable to proboscideans are characterized by large circular tracks about 40 cm in diameter. The carnivore footprints are generally characterized by impressions of pads and toes. Diverse bird footprints are recognized on the basis of size, length/width ratio, interdigital angles, curvature of digits, and the presence or absence of web and hallux traces. Fish trails, diverse invertebrate trace fossils, and body fossils are also observed. These fossils extended the knowledge of their rarely reported geographic distribution throughout the world and also enable the paleoenvironment and paleoecology of the strata to be interpreted.

Comparison of the effects of backpack loading and of walking speed on foot-floor contact patterns

Load-bearing over variable distances at diverse speeds constitutes a major component of manual materials handling activities that persist as ergonomic concerns even in the most technologically advanced societies. The mechanisms of slipping and tripping relate in part to the way pedal segments approach or leave the walking surface. To demonstrate the kinematic effects of load and speed, as measured underfoot, i.e. at the worker-substrate interface, 45 young adult males traversed a 40 m walkway unburdened, and with 20%, 30%, 40%, 50% and 60% bodyweight backpack loads, under controlled speed conditions. The same subjects also walked unburdened at 0.83 m s-1 to 2.22 m s-1 (i.e. in 1 km h-1 increments between 3 and 8 km h-1). Telemetric footswitch technology was used to obtain temporal patterns of heel, lateral and medial ball and toe of each foot. The findings of this study, in which subjects were shoeless, help to establish ‘baseline’ descriptions of foot-floor contact patterns, unaffected by interindividual differences due to shoe or boot rigidity. From these, measured or derived data on temporal statistical parameters were obtained which show that all make- and break-contacts of pedal segments occur absolutely and relatively faster as speed increases, whereas forefoot contacts are made faster and broken slower as loads increase. Under loading the earlier phases of stance simulate an increased speed pattern, whereas the later phases of stance simulate a reduced speed pattern.