Rheumatoid Arthritis and Tenosynovitis at the Metatarsophalangeal Joints: An Anatomic and MRI Study of the Forefoot Tendon Sheaths.

Background Although tenosynovitis in the hands is associated with rheumatoid arthritis (RA), it is unknown whether tenosynovitis of the forefoot is associated with RA. Purpose To determine the anatomy of tendon sheaths of the forefoot and the relationship between MRI-detected tenosynovitis at metatarsophalangeal (MTP) joints and RA. Materials and Methods Fourteen forefeet of donated bodies were examined at flexor tendons and extensor tendons for the presence and course of tendon sheaths. In the prospective study between June 2013 and March 2016, newly presenting patients with RA, patients with other early arthritides, and healthy control participants all underwent MRI of unilateral MTP joints 1-5. MRI studies were scored by two independent readers for tenosynovitis, synovitis, and bone marrow edema. The association between the presence of these features and RA was examined by using logistic regression. Results Macroscopically, all extensor and flexor tendons crossing MTP joints demonstrated sheaths surrounding tendons. Microscopically, a synovial sheath was present. MRI evaluation was performed in 634 participants: 157 newly presenting patients with RA (109 women; mean age, 59 years ± 11 [standard deviation]), 284 patients with other early arthritides (158 women; mean age, 56 years ± 17), and 193 healthy control participants (136 women; mean age, 50 years ± 16). MRI-detected tenosynovitis was associated with RA, both when compared with patients with other arthritides (odds ratio [OR], 2.5; 95% confidence interval [CI]: 1.7, 3.9; P < .001) and healthy control participants (OR, 46; 95% CI: 14, 151; P < .001). The association was OR of 2.4 (95% CI: 1.5, 3.8; P < .001) for flexor tendons and OR of 3.1 (95% CI: 1.9, 5.2; P < .001) for extensor tendons. The sensitivity of tenosynovitis in RA was 65 of 157 (41%; 95% CI: 35%, 50%). The specificity for RA was 63 of 284 (78%; 95% CI: 72%, 82%) compared with other arthritides, and three of 193 (98%; 95% CI: 96%, 99%) compared with healthy control participants. Conclusion Tendons at metatarsophalangeal joints are surrounded by tenosynovium. MRI-detected tenosynovitis at metatarsophalangeal joints was specific for rheumatoid arthritis when compared with findings in patients with other arthritides and findings in healthy control participants. © RSNA, 2020 Online supplemental material is available for this article.

Impact of first metatarsal shortening on forefoot loading pattern: a finite element model study.

BACKGROUNDS: There has long been a consensus that shortening of the first metatarsal during hallux valgus reconstruction could lead to postoperative transfer metatarsalgia. However, appropriate shortening is sometimes beneficial for correcting severe deformities or relieving stiff joints. This study is to investigate, from the biomechanical perspective, whether and how much shortening of the first metatarsal could be allowed. METHODS: A finite element model of the human foot simulating the push-off phase of the gait was established. Progressive shortening of the first metatarsal from 2 to 8 mm at an increment of 2 mm were sequentially applied to the model, and the corresponding changes in forefoot loading pattern during push-off phase, especially the loading ratio at the central rays, was calculated. The effect of depressing the first metatarsal head was also investigated. RESULTS: With increasing shortening level of the first metatarsal, the plantar pressure of the first ray decreased, while that of the lateral rays continued to rise. When the shortening reaches 6 mm, the load ratio of the central rays exceeds a critical threshold of 55%, which was considered risky; but it could still be manipulated to normal if the distal end of the first metatarsal displaced to the plantar side by 3 mm. CONCLUSIONS: During the first metatarsal osteotomy, a maximum of 6 mm shortening length is considered to be within the safe range. Whenever a higher level of shortening is necessary, pushing down the distal metatarsal segment could be a compensatory procedure to maintain normal plantar force distributions.

Anatomic basis and clinical application of the distally based medialis pedis flaps.

BACKGROUND: Soft-tissue defects of the forefoot are difficult to cover adequately, particularly, although multiple options for reconstruction are available. This study especially focused on the vascularization of the medial side of the foot and the determination of the contribution of the nutrient vessels to medialis pedis flap viability. METHODS: Thirty cadavers were available for this anatomical study. Microdissection was conducted under a microscope, and details of the course and distribution and the communication of the first plantar metatarsal artery with the fascial vascular network of the medial side of the foot were recorded. Clinically, six cases of soft-tissue defects at the forefoot region were reconstructed with distally based medialis pedis flap. RESULTS: The perforator of the first plantar metatarsal artery pierces in the superficial fascia of the medial aspect of the foot 2.2 ± 0.7 cm proximal to the first metatarsophalangeal joint, vascularize the skin of the medial plantar region. The anatomical study showed that the vasculature pattern could roughly be classified into two types. In terms of clinical application, all flaps completely survived, and one patient had partial loss of skin graft. CONCLUSION: The perforators of the medialis pedis flap are presented constant. The forefoot region can be repaired by the distally based medialis pedis flap on the perforator of the medial plantar artery of the hallux or the first plantar metatarsal artery perforator with medial plantar vein, medial plantar cutaneous nerve and nutrient vessels.

Fore- and rearfoot kinematics in high- and low-arched individuals during running.

BACKGROUND: Differences in the location and incidence of lower extremity injuries have been reported between high and low arched individuals. These differences might be related to functional differences between the two foot types. In particular, the characteristics of the medial longitudinal arch may influence foot function. The purpose of this study was to investigate forefoot and rearfoot kinematics as well as tibial shock in participants with both high and low arches. MATERIALS AND METHODS: Fifteen high arched and 15 low arched males were recruited. Tibial acceleration as well as forefoot, rearfoot and shank kinematic data were collected as participants ran at 3.5 m/s wearing gait sandals. Variables of interest included peak tibial acceleration in addition to rearfoot eversion excursion, forefoot eversion excursion, forefoot eversion velocity, forefoot abduction excursion and forefoot abduction velocity. MANOVA and effect sizes were used to investigate kinematic differences between groups. RESULTS: Multivariate analysis revealed that foot type had an effect on the kinematic variables of interest (p = 0.04). Forefoot abduction excursion (High arched = 4.7 +/- 1.3 degrees, Low arched 3.8 +/- 1.0 degrees) and forefoot abduction velocity (High arched = 96.0 +/- 24.8 degrees/s, Low arched = 69.3 +/- 13.3 degrees/s) were greater in the high arched group. Tibial shock (p = 0.24) and other kinematic variables were similar between groups. CONCLUSION: Clear evidence of forefoot and rearfoot motion as a shock attenuation mechanism was not found. Differences in the foot kinematics during early stance were highlighted by a smaller forefoot abduction excursion and reduced forefoot abduction velocity in low arched compared to high arched individuals. It is suggested that low arched feet may have a reduced available range of motion through which the forefoot can pass before reaching the end range of motion point. CLINICAL RELEVANCE: Foot kinematics during early stance warrant further investigation to establish a specific link to injury risk.

Analysis of the proximal phalanx size as a guide for an Akin closing wedge osteotomy.

BACKGROUND: The Akin closing wedge osteotomy for correction of hallux valgus interphalangeus has experienced a resurgence in popularity. Commonly, the size of the osteotomy is visually judged intraoperatively. We present a means of performing the osteotomy more objectively. MATERIALS AND METHODS: Radiographs of 101 feet were studied to derive mean values for dimensions of the hallux proximal phalanx in the general population. Based on these we calculated the size of osteotomy required for given corrections. RESULTS: The mean hallux width 5 mm distal to the apex of the articular surface differed between males and females. In males the mean width was 18 mm (95% CI 17.5 to 18.8) and in females 15 mm (95% CI 14.5 to 15.5). For a 10 degree correction, an osteotomy with a 3 mm base would be required. CONCLUSION: Although the Akin osteotomy dimensions are commonly estimated, a more objective method of planning the osteotomy is presented. The method can also be applied to any closing wedge osteotomy. CLINICAL RELEVANCE: We believe this method of the Akin osteotomy can improve the accuracy of the surgery.

Comparative in vivo forefoot kinematics of Homo sapiens and Pan paniscus.

The human metatarsophalangeal joints play a key role in weight transmission and propulsion during bipedal gait, but at present, the identification of when a habitual, human-like metatarsi-fulcrimating mechanism first appeared in the fossil record is debated. Part of this debate can be attributed to the absence of certain detailed quantitative data distinguishing human and great ape forefoot form and function. The aim of this study is to quantitatively test previous observations that human metatarsophalangeal joints exhibit greater amounts of dorsal excursion (i.e., dorsiflexion) than those of Pan at the terminal stance phase of terrestrial locomotion. Video recordings were made in order to measure sagittal excursions of the medial metatarsophalangeal joints in habitually shod/unshod adult humans and adult bonobos (Pan paniscus). Results indicate that the human first and second metatarsophalangeal joints usually dorsiflex more than those of bonobos. When timing of maximum excursion of the first metatarsophalangeal joint is coupled with existing plantar pressure data, the unique role of the human forefoot as a key site of leverage and weight transmission is highlighted. These results support hypotheses that significant joint functional differences between great apes and humans during gait underlie taxonomic distinctions in trabecular bone architecture of the forefoot.

Articular to diaphyseal proportions of human and great ape metatarsals.

This study proposes a new way to use metatarsals to identify locomotor behavior of fossil hominins. Metatarsal head articular dimensions and diaphyseal strength in a sample of chimpanzees, gorillas, orangutans, and humans (n = 76) are used to explore the relationships of these parameters with different locomotor modes. Results show that ratios between metatarsal head articular proportions and diaphyseal strength of the hallucal and fifth metatarsal discriminate among extant great apes and humans based on their different locomotor modes. In particular, the hallucal and fifth metatarsal characteristics of humans are functionally related to the different ranges of motion and load patterns during stance phase in the forefoot of humans in bipedal locomotion. This method may be applicable to isolated fossil hominin metatarsals to provide new information relevant to debates regarding the evolution of human bipedal locomotion. The second to fourth metatarsals are not useful in distinguishing among hominoids. Further studies should concentrate on measuring other important qualitative and quantitative differences in the shape of the metatarsal head of hominoids that are not reflected in simple geometric reconstructions of the articulation, and gathering more forefoot kinematic data on great apes to better understand differences in range of motion and loading patterns of the metatarsals.

Analysis of foot structure in athletes sustaining proximal fifth metatarsal stress fracture.

BACKGROUND: In the past, several studies provided anecdotal descriptions of high-arched feet in individuals sustaining proximal fifth metatarsal stress fractures. This relationship has never been supported by scientific evidence. Our objective was to examine whether athletes who sustained this injury had an exceptional static foot structure or dynamic loading pattern. MATERIALS AND METHODS: Ten injured professional soccer players who regained full professional activity following a unilateral proximal fifth metatarsal stress fracture and ten control soccer players were examined. Independent variables included static evaluation of foot and arch structure, followed by dynamic plantar foot pressure evaluation. Each variable was compared between injured, contra-lateral uninjured, and control feet. RESULTS: Static measurements of foot and arch structure did not reveal differences among the groups. However, plantar pressure evaluation revealed relative unloading of the fourth metatarsal in injured and uninjured limbs of injured athletes compared with control, while the fifth metatarsal revealed pressure reduction only in the injured limbs of injured athletes. CONCLUSION: Athletes who sustained proximal fifth metatarsal stress fracture were not characterized by an exceptional static foot structure. Dynamically, lateral metatarsal unloading during stance may either play a role in the pathogenesis of the injury, or alternately represent an adaptive process. CLINICAL RELEVANCE: Footwear fabrication for previously injured athletes should not categorically address cushioning properties designed for high-arch feet, but rather focus on individual dynamic evaluation of forefoot loading, with less attention applied to static foot and arch characteristics.

Reliability of the Maestro radiographic measuring tool.

INTRODUCTION: Maestro et al. presented a detailed preoperative measuring and classification technique for the forefoot. The purpose of this paper was to determine if the PACS system will allow the Maestro measuring technique and classification system to be reliable and precise. MATERIALS AND METHODS: This radiographic study was conducted on 73 subjects (36 females, 37 males, age 30.4 ± 9.9) who had given informed consent. The geometrical progression was measured for each foot of each subject by the two observers according to the measuring methodology of Maestro. The intraclass correlation coefficient (ICC), and the 95% lower confidence limit (95% LCL) were calculated for the geometrical progression variables of the lesser metatarsals. Once the feet were classified by each observer, the accordance in classification of the feet was analyzed between the two observers. RESULTS: The radiographic measuring technique of Maestro was a reliable method for analyzing the mathematical progression of the lesser metatarsals through the use of the PACS system. A 92.6% concordance in the classification of the radiological forefoot morphotypes was found between the two observers. CONCLUSION: We found Maestro et al.'s measuring technique and classification system precise and reproducible using PACS digital radiographs. It is hoped that utilization of this technique will lead to better forefoot outcomes and patient satisfaction.

Mode of insertion of the abductor hallucis muscle in human feet and its arterial supply.

The abductor hallucis flap is commonly used as a pedicled flap (distally or proximally based) in the management of ankle, heel, and mid-foot lesions, where it is ideally used for closing defects. This study investigates the anatomical details of this muscle regarding its various forms of insertion and its arterial supply in 15 cadaveric feet. Four types of insertion could be distinguished: type A, insertion at the proximal phalanx of the big toe (46.7%); type B, insertion by two slips into the base of the proximal phalanx and the sesamoid bone (33.3%); type C, insertion at the sesamoid bone (6.7%); And type D, the insertion is divided into superficial tendinous and deep fleshy parts which are attached to the base of the proximal phalanx and to the metatarsophalangeal joint capsule of the big toe, respectively (13.3%). As regards the arterial supply, three patterns were noticed: pattern A (40%) where the medial plantar artery (MPA) is divided into superficial and deep branches that supplied the muscle; pattern B (53.3%) where the MPA failed to produce a deep branch but instead continued as the superficial branch supplying the two ends of the muscle; and pattern C (6.6%) where the MPA continued as a deep branch supplying the muscle. A superficial branch of MPA provided a branch to the abductor hallucis muscle from its proximal part. In two specimens (13.3%), the lateral plantar artery shared in the supply of the most proximal part of the muscle. These results can be useful in determining the appropriate flap design based on the abductor hallucis type of insertion and the pattern of its arterial supply in the patients.

Normal radiographic values of the forefoot in the Thai women population.

BACKGROUND: Diseases of the forefeet are common problems in orthopedics. Evaluation of forefoot radiography has played an important role to determine the forefoot deformity. Previous studies have shown that normal radiographic values of the western population were different from the Asian population values. OBJECTIVE: To examine the normal range of radiologic values of forefoot in Thai women. MATERIAL AND METHOD: The data collected at out-patient division of the hospital for screening 100 women (200 feet). All patients have been radiographed in the AP standing position (to measure the HVA, 1st IMA, DMAA, sesamoid AP and 1st metatarsal length) and weight bearing tangential view to determine the SRA angle. RESULTS: The average results of the right and the left foot HVA = 10.75 degrees, 9.39 degrees/1st IMA = 10.24 degrees, 9.20 degrees/DMAA = 3.72 degrees, 3.32 degrees/sesamoid AP grade 0-1 = 85 percent, 82 percent/ SRA = 9.14 degrees, 8 degrees respectively, 1st metatarsal length was shorter than the 2nd metatarsal length in most cases (70%) and when comparing between the right and the left foot, no statistical significant difference were found (p > 0.05). CONCLUSION: Study found that the values of HVA, DMAA and the 1st metatarsal length in Thai women were less than the values found in the foreign literatures but it was similar to the Asian population figures.

The transverse forefoot arch demonstrated by a novel X-ray projection.

OBJECTIVE: Metatarsalgia is often treated by metatarsal osteotomy. Exact knowledge of the normal anatomy of the forefoot is essential for pre-operative planning. The objective of this study was to investigate the forefoot arch during maximal loading in a randomly selected population sample. METHODS: Two hundred subjects randomly selected from a municipality representative of Denmark were invited to interview and forefoot X-ray examination, including a novel horizontal X-ray projection by which the height of each metatarsal from the floor can be measured under maximal loading. RESULTS: One hundred and thirty-four subjects (79%) presented themselves for interview and X-ray examination. The study group was representative of the randomly selected population sample in terms of age, sex and incidence of metatarsalgia. The study verified that the interrelated geometry of the metatarsal heads in the AP plane corresponds to a parabola as suggested previously (Le Lièvre's parabola). Also in the horizontal plane, the metatarsal heads generally form an arch, the transverse forefoot arch (TFA). Mean height was 3.91mm (S.E.=0.10). The individual height of the TFA varied from -1 to 10mm and was dependent on the width of the forefoot. The relative height of the arch (arch height divided by forefoot width) was independent of age and sex. A non-significant tendency towards a lower arch among subjects with metatarsalgia was observed. CONCLUSION: This population study demonstrated that the metatarsal heads constitute arches in both planes (Le Lièvre's parabola in the AP plane and the transverse forefoot arch in the horizontal plane). This knowledge is essential for pre-operative planning in metatarsal osteotomy for metatarsalgia. Formulae for calculating the individual location of each metatarsal head were obtained.

Tarsometatarsal joint complex injuries: A study of injury pattern in complete homolateral lesions.

INTRODUCTION: Tarsometatarsal joint complex (TMC) is the anatomical structure of midfoot composed by metatarsals, tarsometatarsal (TMT) joints, cuneiforms, cuboid and navicular. TMC lesion are rare but critical since they cause severe disability if misdiagnosed. The knowledge of anatomic pattern of the lesion and biomechanics of the midfoot is the key for a successful diagnosis and treatment. The aim of this study was to review a consecutive series of TMC injuries analyzing preoperative radiograph and CT scan to accurately define the pattern of ligament and bone injuries. MATERIAL AND METHODS: We reviewed a series of 24 complete TMC injuries with homolateral dorsolateral dislocation. The total TMT joints involved were 120. We observed if the lesions were pure ligamentous or fracture-dislocation detecting the extent and the location of fractures. Twenty-nine lesions (24%) were pure dislocations and they were mainly localized in the first and fifth ray. The fracture-dislocations were 91 (76%) and 25 were fractures of the proximal row (cuneiforms and cuboid), 39 of the distal row (metatarsals), 27 of both the distal and proximal row. RESULTS: Proximal fracture had a homogeneous distribution and they were more frequently simple than comminuted. Comminuted fractures were more frequent in the cuboid. In the proximal row, majority of partial articular fractures were localized in the dorsal side. Fracture-dislocations of the distal row were more frequent in the second metatarsal base (100%) and the partial articular fractures were always placed in the plantar side. In TMC injuries fracture-dislocations are more frequent than pure dislocations. Pure dislocations occur more often in the marginal rays that are characterized by weaker ligaments and larger mobility. The second ray, where there is the more stable joint of TMC, was never dislocated with a pure ligamentous lesion. CONCLUSIONS: We suppose that plantar avulsion from the distal row and dorsal compression fracture of the proximal row is consistent with a direct force applied to the forefoot and direct dorsolaterally. The direction of the forces may explain why some fractures occur in the distal row, some in the proximal and some in both rows. The thickness of plantar ligaments may explain the frequency of plantar bone fragment avulsion.

Arch height and first metatarsal joint axis orientation as related variables in foot structure and function.

BACKGROUND: This study investigated the association of arch height combined with first metatarsal joint axis vertical (V) orientation to the size of the 1-2 intermetatarsal angle (IMA) and first metatarsal adduction/abduction position simulating foot postures during gait, kinematics commonly affected by bunion. MATERIALS AND METHODS: Nine cadaver specimens were mounted in a loading frame. Measures of arch height ratio and IMA were made. With the foot placed in positions seen during normal gait cycle an electromagnetic device measured displacement of the relative angle of rotations between the first metatarsal and navicular, and helical axis (HA) parameters. Canonical correlation analysis assessed the relationship among the variables. RESULTS: A negative relationship (r = -0.73) was found between arch height and first metatarsal HA V-orientation. When considered as combined variables, arch height and metatarsal HA V-orientation accounted for 69% of the variance of IMA and change in first metatarsal adduction/abduction position. CONCLUSION: Orientation of the first metatarsal joint axis was highly variable between specimens but correlated with arch height. The conjoined factors of arch height and first metatarsal HA V-orientation accounted for most of the variance of IMA and change in first metatarsal adduction/abduction position during the sequence of foot position during simulated gait. CLINICAL RELEVANCE: These findings suggest that orthotic arch support could reorient the metatarsal joint axis out-of-vertical and in effect, limit the first metatarsal from displacing into an adducted bunion deformity. These findings could help to explain the pathogenesis of bunions.

Differences in sprinting performance and kinematics between preadolescent boys who are fore/mid and rear foot strikers.

The purpose of this study was to clarify whether foot strike patterns are associated with different sprint performance and kinematics in preadolescent boys. The study enrolled 24 healthy 10-11-year-old boys in the fifth grade at public elementary schools in Japan. The participants performed the 50-m sprint with maximum effort. Sprint motion was recorded using a high-speed video camera (120 fps) placed in the sagittal plane on the left side of a line drawn at 35-m from the start line. Kinematic variables were calculated based on manually digitized body landmark coordinates. The participants were categorized into two groups according to their foot strike pattern (rearfoot strikers, RF group, n = 12; forefoot or midfoot strikers, FF/MF group, n = 12). The time taken to complete the 50-m sprint in the FF/MF group (9.08±0.52 s) was faster than that in the RF group (9.63±0.51 s). The FF/MF group had greater sprint speed, higher step frequency, and shorter foot contact time than the RF group. Regarding the association between foot strike pattern and sprint kinematics, we found that the RF group had a greater range of knee flexion during the support-leg phase, whereas the FF/MF group had shorter horizontal distance from the heel of the support leg to the centre of mass at the touchdown, greater maximal knee flexion velocity during the swing-leg phase, and higher the maximum hip extension velocity during the support-leg phase. The current results suggested that, in preadolescent boys, forefoot or midfoot strike (rather than rearfoot strike) is effective for obtaining a higher step frequency and sprint speed through greater magnitude of knee flexion and hip extension movement velocities during the swing and support phases, respectively. The current findings will be useful for understanding the characteristics of the development of sprinting performance in preadolescent children.

Management of Bunionette Deformity.

Bunionette deformity, historically known as tailor's bunion, is a forefoot protuberance laterally, dorsolaterally, or plantarlaterally along the fifth metatarsal head. Although bunionette deformity has been compared to hallux valgus deformity, it is likely due to a multifactorial, anatomic interplay between fifth metatarsal bony morphology and forefoot soft-tissue imbalance. Friction generated between the bony prominence, soft tissue, and associated constrictive footwear can result in keratosis, inflammation, pain, and ulceration. Symptomatic bunionettes are usually responsive to nonsurgical management. Surgical options are available based on the underlying bony deformity when nonsurgical treatment fails.

Forefoot-rearfoot coupling patterns and tibial internal rotation during stance phase of barefoot versus shod running.

BACKGROUND: Based on twisted plate and mitered hinge models of the foot and ankle, forefoot-rearfoot coupling motion patterns can contribute to the amount of tibial rotation. The present study determined the differences of forefoot-rearfoot coupling patterns as well as excessive excursion of tibial internal rotation in shod versus barefoot conditions during running. METHODS: Sixteen male subjects ran 10 times at 170 steps per minute under the barefoot and shod conditions. Forefoot-rearfoot coupling motions were assessed by measuring mean relative phase angle during five intervals of stance phase for the main effect of five time intervals and two conditions (ANOVA, P<0.05). Tibial internal rotation excursion was compared between the shod and barefoot conditions over the first 50% of stance phase using paired t-test, (P<0.05). FINDINGS: Forefoot adduction/abduction and rearfoot eversion/inversion coupling motion patterns were significantly different between the conditions and among the intervals (P<0.05; effect size=0.47). The mean absolute relative angle was significantly modified to 37 degrees in-phase relationship at the heel-strike of running with shoe wears. No significant differences were noted in the tibial internal rotation excursion between shod and barefoot conditions. INTERPRETATION: Significant variations in the forefoot adduction/abduction and rearfoot eversion/inversion coupling patterns could have little effect on the amount of tibial internal rotation excursion. Yet it remains to be determined whether changes in the frontal plane forefoot-rearfoot coupling patterns influence the tibia kinematics for different shoe wears or foot orthotic interventions. The findings question the rational for the prophylactic use of forefoot posting in foot orthoses.

Altered energy dissipation ratio of the plantar soft tissues under the metatarsal heads in patients with type 2 diabetes mellitus: a pilot study.

BACKGROUND: Foot ulceration occurs frequently on the plantar aspect of the metatarsal head region, in which the altered foot biomechanics has been mentioned as a contributor. This study attempted to compare the energy dissipation in the plantar soft tissue under the metatarsal head between type 2 diabetic patients and age-matched healthy subjects in vivo. METHODS: The plantar soft tissues under the metatarsal heads in each left foot of 13 patients with type 2 diabetes mellitus and eight age-matched healthy subjects were measured with a loading-unloading device. The system comprised a 5-12 MHz linear-array ultrasound transducer and a load cell that operated at an impact velocity of about 5 cm/s. The stress-strain plot was derived by simultaneously recording the stress response and tissue deformation during a loading-unloading cycle. The energy dissipation ratio in all subjects could then be analyzed. FINDINGS: Although only the plantar soft tissue under the fourth metatarsal head in the diabetic patients endured significantly greater energy (P=0.035) than the healthy subjects, a trend of an increased energy dissipation ratio for the metatarsals in the diabetic patients was observed. INTERPRETATION: The plantar soft tissue under the metatarsal head in the diabetic patients endures high dissipated energy during a simulating walking status in the study. The increased dissipated energy in the tissue may be responsible for the tissue breakdown in the diabetic patients.

Assessment of the influence of jogging on the shape of female foot arches.

INTRODUCTION: Both walking and its faster, running, consist of cyclical subsequent phases of swing and support; however, they differ in their time proportions as well as magnitude of acting forces. There is a lack of studies concerning the long-term consequences of repeated jogging cycles on the function of feet and, above all, on their permanent impact on the shape of foot arches. OBJECTIVES: The objective of this study was to answer the question whether regular jogging changes the shape of the transverse and medial longitudinal arches of the feet. MATERIAL AND METHODS: The research material consisted of 96 women with an average age of 26.57, and included 50 actively jogging women, and 46 of non-joggers. The study was performed with the use of EMED-SF force platform. The plantar surface of the foot was divided into 10 regions according to Cavanagh, for which peak pressure and contact time were established. Two indicators were defined: metatarsal bone pressure distribution pattern acc. to Kantali, and longitudinal arch index acc. to Cavanagh. RESULTS: The data obtained revealed more frequent occurrence of the greatest pressure under the centrally located metatarsal heads (lack of functional foot transverse arch) among the female joggers, compared with the non-joggers. Moreover, the findings indicate the higher frequency of medial longitudinal foot arch flattening among female runners, with a great deal of consistency between both feet, whereas results for the control group show asymmetrical medial arch shapes with right foot propensity to normal arch shape and left foot tendency for excessive arch. CONCLUSIONS: The observed differences in feet arch shapes between female joggers and non-joggers indicate the influence of jogging on feet functional adaptations.