Diabetic foot infections: fate of the contralateral foot

Following an initial report urging conservative management of severe diabetic foot infections, the authors have managed 45 patients with a minimum 3-year follow-up. By using standard principles for soft-tissue infection, 78 percent of the patients healed minor amputation sites and maintained biped ambulation following the initial foot involvement. Only 22 percent required a major amputation at the time of the initial foot involvement. The 45 patients were followed and 22 (or 49 percent) developed a severe infection involving the contralateral foot within 18 months. Although 15 of the 22 patients developing contralateral infection (or 33 percent of the total series) required some type of amputation on the contralateral foot, the conservative approach allowed 64 percent of the patients with severe infections in both feet to maintain biped ambulation. This included 40 percent of the patients who required amputation of some portion of both feet.     

Natural gaits of the non-pathological flat foot and high-arched foot

There has been a controversy as to whether or not the non-pathological flat foot and high-arched foot have an effect on human walking activities. The 3D foot scanning system was employed to obtain static footprints from subjects adopting a half-weight-bearing stance. Based upon their footprints, the subjects were divided into two groups: the flat-footed and the high-arched. The plantar pressure measurement system was used to measure and record the subjects' successive natural gaits. Two indices were proposed: distribution of vertical ground reaction force (VGRF) of plantar and the rate of change of footprint areas. Using these two indices to compare the natural gaits of the two subject groups, we found that (1) in stance phase, there is a significant difference (p<0.01) in the distributions of VGRF of plantar; (2) in a stride cycle, there is also a significant difference (p<0.01) in the rate of change of footprint area. Our analysis suggests that when walking, the VGRF of the plantar brings greater muscle tension to the flat-footed while a smaller rate of change of footprint area brings greater stability to the high-arched.     

Replantation of an avulsive amputation of a foot after recovering the foot from the sea

A foot avulsion case, with the dismembered body part submerged in sea water for 1 hour, is presented. This report is unique in that it is the first to document the reattachment of a body part that had been submerged in sea water. It was not known how salt-water exposure would affect wound management. Differences in osmolarity and bacterial flora between the sea water and foot tissues have not caused any problems, and the patient has not suffered any vascular or infectious complications after replantation. Neurotization of the plantar surface by the tibial nerve, which was stripped off during amputation and replaced in its original traces, was the most critical part of convalescence. After management of such an interesting case, we conclude that exposure to sea water of the dismembered part should not be a contraindication for replantation surgery.     

Functional anatomy of the tarsier foot

Tarsiers possess a very odd musculoskeletal foot anatomy that goes beyond their acknowledged specialized leaping adaptations. Tarsius has evolved a fundamentally different method of bone rotation to achieve an inverted foot position during grasping and has developed an unusual muscular system for holding onto vertical supports. Although galagos and tarsiers possess elongated foot bones as adaptations for leaping, galagos utilize many more types of movements, have specialized osteological surface for inversion, and have a more common type of muscle development in the foot and leg than tarsiers possess. Likewise, the Omomyidae, the ancestral lineage of Tarsius, exhibit a lack of morphological similarity with Tarsius in the known foot joints.     

A biomechanical model of the foot

The foot is modeled as a statically indeterminate structure supporting its load at the heads of the five metatarsals and the tuberosity of the calcaneous. The distribution of support is determined through an analysis of the deformations caused in the structure as a result of the forces at these locations. The analysis includes the effect of the plantar aponeurosis and takes into account the deformation of the metatarsals and bending of the joints. A parametric study is presented to illustrate the behavior of the solution under a broad range of conditions.     

Surgical treatment of the cleft foot

Between 1970 and 1997, we treated a total of 32 cleft feet in 21 patients (11 male and 10 female). We classified cases of cleft foot on the basis of the number of central ray deficiencies. Fourteen patients with 22 cleft feet were followed up for more than 1 year postoperatively (9 feet had no or one central ray deficiency, and 13 feet had two or three central ray deficiencies). The mean follow-up period was 8.8 years. The objective of this study was to evaluate the results of operative treatment of cleft foot. We evaluated the results of three methods: simple closure of the cleft, application of a double-pedicled flap, and insertion of a silicone block. Cosmetic complications, including widening of the foot, hypertrophic scarring, pigmentation of the grafted skin, and overlapping of the toes, were observed in patients with two or three central ray deficiencies. Few functional complications were observed: None of the patients experienced gait disturbances, although one patient complained of pain following walking. Roentgenography showed that the distance between the first and fifth metatarsals was 86 percent of that of the contralateral foot. When treating patients with no or one central ray deficiency, satisfactory results can be expected with simple closure of the cleft. However, in patients with two or three central ray deficiencies, it is difficult to obtain satisfactory results with simple closure of the cleft or application of a double-pedicled flap. Therefore, silicone block insertion to correct the defect is recommended when there is more than one central ray deficiency.     

Energy budget of the chicken foot

1. 1.|A mathematical model predicts the energy loss from a chicken foot provided the following variables are known: body temperature, air temperature, wind velocity, blood flow to the foot, and the relative partitioning of blood flow via two distinct venous returns.

2. 2.|Chickens are capable of keeping their feet from freezing at temperatures as low as −30°C ambient, but at a high energy cost.

3. 3.|Chickens can modulate blood flow to their feet at thermoneutral temperatures enough to vary heat loss to environment by about one-fourth metabolic heat production.

Biomechanical model of the diabetic foot

In this work, a two dimensional (2D) finite element foot model was established from magnetic resonance imaging (MRI) of a male subject. The model comprises first medial planar cross-section through the foot, representing the foot in standing posture. For specified external load, the stress and strain distribution field under foot structure are determined. The material characterization of foot structure components are stronger related to diabetic phenomena. The new material model for soft tissue based on mixture theory is proposed. The linear finite element model replaced by nonlinear counterpart with segment-to-segment contact element.     

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.