The Influence of Gender, Age, and Body Mass Index on Arch Height and Arch Stiffness

Biomechanical variations in patients with flatfoot deformity: Impact of gender, age, and BMI on foot kinetics and kinematics

Background

Flatfoot is considered by the collapse of the foot arch, altered biomechanics and impacting functional abilities. The biomechanical gait alteration of foot kinematics and kinetics in individuals with flatfoot, based on gender, age and Body mass index (BMI) in each cohort is unclear. This study explores how gender, age, and body mass index (BMI) impact distinct foot biomechanical characteristics, including ankle joint angle (Jc°), Ground force reaction angle (GFR°), Achilles tendon force (T), Ankle joint force (Jc) and vertical ground reaction force (VGRF) during the gait stance phase, in flatfoot versus normal-foot individuals on Indian Population.

Method

A foot pressure test and sagittal plane motion analysis were performed on 142 individuals with normal-foot arches and 102 with flatfoot, stratified by gender, age, and BMI. Calculations of the magnitude and direction of forces in ankle joint equilibrants relied on inverse dynamic analysis, vertical ground force reaction and mapping motion data of the gait stance phases.

Result

In the midstance phase, females with high BMI (HBMI) in the middle and older age group (p = 0.029 and p = 0.014), and males with HBMI in the older age group (p = 0.039) demonstrate significantly higher V G R F . Females and males with HBMI in middle and older age groups, along with males with normal BMI in the older age cohort, show positive and negative ranges of GFR°, indicating gait instability. In the push-off phase, females with HBMI in a middle-aged group exhibit significantly lower T a n d J c (p = 0.023 and p = 0.026) respectively.

Conclusion

The biomechanical issues in individuals with flatfoot, while accounting for the influence of gender, age and BMI, are crucial for tailored interventions and precise solutions to biomechanical issues, thereby enhancing foot function and reducing discomfort.

Pes planus level affects counter movement jump performance: A study on amateur male and female volleyball players

The aim of this study was to investigate the effect of pes planus level on counter movement jump (CMJ) performance parameters in amateur female and male volleyball players. In this context, amateur volleyball players aged between 18 and 23 years actively playing in the university school volleyball team were included in the study. Pes planus levels of the participants were analyzed using the navicular drop test (NDT). My Jump Lab application was used for CMJ measurement. Within the scope of CMJ, the participants' jump height, force, relative force, power, relative power, average speed, take-off speed, impulse, and flying time were analyzed. According to the linear regression results between NDT and CMJ parameters, force in males (t = 12.93, P = .049) and average speed in females (t = -3.52, P = .017) were significantly associated with NDT. NDT was similar in men and women (P > .05). However, all CMJ parameters were highly different between genders (P < .001). In the correlation analysis between sport age and physical characteristics and CMJ parameters; height (r = .386, P = .046), weight (r = .569, P = .002), leg length (r = .389, P = .045), foot length (r =. 558, P = .005), foot width (r = .478, P = .018), force (r = .407, P = .039), impulse (r = .460, P = .018) parameters, and sport age. The results suggest that the average speed in females and force in males both significantly influenced NDT, highlighting the significance of both factors in predicting NDT scores. Moreover, all CMJ measures showed significant variations between genders, although the NDT scores did not. Furthermore, the correlation analysis demonstrated a strong correlation between a number of physical attributes and CMJ parameters, highlighting the multifaceted nature of athletic performance and indicating the possible impact of these attributes on CMJ results.

Contribution of various forefoot areas to push-off peak at different speeds and slopes during walking

BACKGROUND

Push-off during the terminal stance phase has a major impact on forward progression during walking. During this phase, the ground reaction force is applied to a small area under the forefoot. A better understanding of how single forefoot areas contribute to push-off peak in healthy subjects is needed to develop biomimetic orthopedic devices for forefoot amputees.

RESEARCH QUESTION

What is the contribution of different forefoot sole areas to push-off peak as a function of speed and slope?

METHODS

In this analytical study, 15 healthy subjects walked on a treadmill at different speeds (0.8 m/s; 1.2 m/s; 1.6 m/s; max. gait speed) without de-/inclination and on different slopes (-10°; -5°; 0°; 5°; 10°) with normal walking speed. The Novel Pedar-X System was used to measure vertical sole force. Push-off peak of the entire sole was determined and relative contributions of the areas under the hallux, first ray, and toes (I-V) were calculated and analyzed using separate repeated-measures ANOVA (α = 0.05).

RESULTS

Push-off peak increases with faster walking speeds as well as with 10° inclination. Downhill walking is associated with a reduced push-off peak. The contribution of all forefoot areas increases with faster walking speeds and at a declination of -10°. Push-off contribution of the area under the hallux increases by about 64.6% at fast walking compared to slow walking and this increase is higher than that of the area under the first ray and toes (p < 0.05).

SIGNIFICANCE

These findings indicate the major role of the hallux in speed generation and the importance of the forefoot during downhill walking. The results show the need for an adequate assistive device even in hallux amputation cases to compensate for deficits in the push-off phase.

Relationship between foot morphologic characteristic and postural control after jump-landing in youth competitive athletes

BACKGROUND

Foot arch dynamics play an important role in dynamic postural control. Association between foot arch dynamics and postural control among adolescent athletes remains poorly explored.

OBJECTIVE

To examine the relationship between foot arch dynamics, intrinsic foot muscle (IFM) morphology, and toe flexor strength and dynamic postural stability after jump landing and repetitive rebound jump performance in competitive adolescent athletes.

METHODS

Based on foot arch dynamics, evaluated from relative change in the foot arch height in sitting and standing positions, 50 adolescent athletes were classified as stiff, normal, or flexible. IFM morphology was evaluated by ultrasonography. Dynamic postural stability index (DPSI) was measured as participants jumped and landed with the right leg onto a force plate, whereas repetitive rebound jumping performance was assessed using the jump height and reactive jump index.

RESULTS

The stiff group had a significantly worse DPSI and vertical stability index than the normal group (p= 0.26, p= 0.44, respectively), and worse anteroposterior stability index (APSI) values than the flexible group (p= 0.005). Multivariate regression models of the relationship between the APSI and foot arch dynamics showed adequate power (probability of error = 0.912).

CONCLUSIONS

Increased foot arch stiffness negatively affects dynamic balance during jump-landing, which may deteriorate their performance.

Effects of plantar fascia stiffness on the internal mechanics of idiopathic pes cavus by finite element analysis: implications for metatarsalgia

Metatarsalgia occurring in individuals with pes cavus is typically associated with abnormal loading patterns in the forefoot resulting from structural alterations. Simultaneously, the frequent overstress of the plantar fascia (PF) caused by the persistence of this foot deformity may further exacerbate the chronic pain induced by metatarsal overload. We aimed to investigate and quantify the effects of PF stiffness on the internal biomechanics of pes cavus using a computational modelling approach. A patient-specific finite element model of the foot-ankle complex using the actual three-dimensional geometry of idiopathic pes cavus bones and soft tissues was reconstructed. A sensitivity study was conducted to evaluate the effects of varying elastic modulus (0-700 MPa) of the PF on the metatarsal stress distribution, and force transmission through the metatarsophalangeal (MTP) and tarsometatarsal (TMT) joints in the pes cavus. The results indicated that variations in PF stiffness led to stress redistribution in the metatarsal region. Peak stress gradually reduced with decreasing stiffness until the PF was released, eventually resulting in a reduction of 22.39% compared to the reference value of 350 MPa. Furthermore, adjusting the PF stiffness to twice the reference value (700 MPa) increased the contact forces through the TMT and MTP joints by up to 23% and 116%, respectively. The reduction of PF stiffness alleviated focal metatarsal loading, and therefore, surgical fascia release can be considered to alleviate metatarsalgia in patients with pes cavus.

Methodological and statistical approaches for the assessment of foot shape using three-dimensional foot scanning: a scoping review

OBJECTIVE

The objectives of this study were to: (i) review and provide a narrative synthesis of three-dimensional (3D) foot surface scanning methodological and statistical analysis protocols, and (ii) develop a set of recommendations for standardising the reporting of 3D foot scanning approaches.

METHODS

A systematic search of the SCOPUS, ProQuest, and Web of Science databases were conducted to identify papers reporting 3D foot scanning protocols and analysis techniques. To be included, studies were required to be published in English, have more than ten participants, and involve the use of static 3D surface scans of the foot. Papers were excluded if they reported two-dimensional footprints only, 3D scans that did not include the medial arch, dynamic scans, or derived foot data from a full body scan.

RESULTS

The search yielded 78 relevant studies from 17 different countries. The available evidence showed a large variation in scanning protocols. The subcategories displaying the most variation included scanner specifications (model, type, accuracy, resolution, capture duration), scanning conditions (markers, weightbearing, number of scans), foot measurements and definitions used, and statistical analysis approaches. A 16-item checklist was developed to improve the consistency of reporting of future 3D scanning studies.

CONCLUSION

3D foot scanning methodological and statistical analysis protocol consistency and reporting has been lacking in the literature to date. Improved reporting of the included subcategories could assist in data pooling and facilitate collaboration between researchers. As a result, larger sample sizes and diversification of population groups could be obtained to vastly improve the quantification of foot shape and inform the development of orthotic and footwear interventions and products.

Contributions of age, gender, body mass index, and normalized arch height to hallux valgus: a decision tree approach

BACKGROUND

Hallux valgus (HV) is a common toe deformity with various contributory factors. The interactions between intrinsic risk factors of HV, such as arch height, sex, age, and body mass index (BMI) should be considered. The present study aimed to establish a predictive model for HV using intrinsic factors, such as sex, age, BMI, and arch height based on decision tree (DT) model.

METHODS

This is retrospective study. The study data were based on the fifth Size Korea survey, of the Korea Technology Standard Institute. Among 5,185 patients, 645 were excluded due to unsuitable age or missing data, and 4,540 (males = 2,236 and females = 2,304) were selected for inclusion in the study. Seven variables (i.e., sex, age, BMI, and four normalized arch height variables) were used to develop the prediction model for the presence of HV using a DT model.

RESULTS

The DT model correctly classified 68.79% (95% confidence interval [CI] = 67.25-70.29%) of the training data set (3,633 cases). The predicted presence of HV based on the DT was verified against the testing data set (907 cases) and showed an accuracy of 69.57% (95% CI = 66.46-72.55%).

CONCLUSIONS

The DT model predicted the presence of HV on the basis of sex, age, and normalized arch height. According to our model, women aged over 50 years and those with lower normalized arch height were at high risk of HV.

Techniques and Applications of Lower Extremity Feminization and Masculinization

Background

Significant differences exist between feminine and masculine lower extremities, and this region contributes to gender dysphoria in transgender and nonbinary individuals.

Methods

A systematic review was conducted for primary literature on lower extremity (LE) gender affirmation techniques as well as anthropometric differences between male and female lower extremities, which could guide surgical planning. Multiple databases were searched for articles before June 2, 2021 using Medical Subject Headings. Data on techniques, outcomes, complications, and anthropometrics were collected.

Results

A total of 852 unique articles were identified: 17 met criteria for male and female anthropometrics and 1 met criteria for LE surgical techniques potentially applicable to gender affirmation. None met criteria for LE gender affirmation techniques specifically. Therefore, this review was expanded to discuss surgical techniques for the LE, targeting masculine and feminine anthropometric ideals. LE masculinization can target feminine qualities, such as mid-lateral gluteal fullness and excess subcutaneous fat in the thigh and hips. Feminization can target masculine qualities like a low waist-to-hip ratio, mid-lateral gluteal concavity, calf hypertrophy, and body hair. Cultural differences and patient body habitus, which influence what is considered "ideal" for both sexes, should be discussed. Applicable techniques include hormone therapy, lipo-contouring, fat grafting, implant placement, and botulinum toxin injection, among others.

Conclusions

Due to lack of existing outcomes-based literature, gender affirmation of the lower extremities will rely on application of an array of existing plastic surgery techniques. However, quality outcomes data for these procedures is required to determine best practices.

Relationship between specific leisure activities and successful aging among older adults

Background/Objectives

This study was designed to investigate the association between specific leisure activities and successful aging among older adults, using data from the Chinese Longitudinal Healthy Longevity Survey.

Methods

A total of 7689 older adults were involved in this study and categorized as successful aging group (n = 3989; 51.8%) or non-successful aging group (n = 3703; 48.2%). Participants were identified as successful aging if they had a score of more than 3 points, or as non-successful aging. The points were based on the following five items and each item was assigned 1 point: self-rated health, self-rated psychological status or mood, cognitive function, activities of daily life, and physical activity. Six activities including gardening work, reading newspapers or books, raising domestic animals or pets, playing cards or mahjong, watching TV or listening to radio, and participating in social activities were collected to reflect leisure activities. Chi-square tests, independent sample t-test, and logistic regression analyses were employed to explore the association between specific leisure activities and successful aging.

Results

The prevalence of successful aging was 51.8% among Chinese older adults. A significant positive relationship was found between the frequency of participation in specific leisure activities and successful aging (p < 0.05). Older adults who usually participated in leisure activities had greater odds for successful aging compared to those who never participated in leisure activities (adjusted odds ratio (OR): 1.31 (95% CI: 1.15-1.49) to 1.88 (95% CI: 1.62-2.19)). Older adults participating in one or more leisure activities had greater odds for successful aging compared to those who did not participate in leisure activities (adjusted OR: 1.51 (95% CI: 1.30-1.76) to 4.10 (95% CI: 2.44-6.89)).

Conclusions

The findings provide evidence that participating more frequently and in more leisure activities was associated with a greater probability of successful aging among Chinese older adults. Encouraging older people to participate frequently in a larger number of leisure activities may be a key to promote successful aging. Therefore, the frequency and number of participation in leisure activities should be highlighted and targeted for promoting successful aging.

The Effect of Arch Stiffness on the Foot-Ankle Temporal Kinematics during Gait Termination: A Statistical Nonparametric Mapping Study

This study compares foot-ankle temporal kinematics characteristics during planned and unplanned gait termination (PGT and UGT) in subjects with different arch stiffnesses (ASs) based on the statistical nonparametric mapping (SnPM) method. By measuring three-dimensional arch morphological parameters under different loading conditions, 28 healthy male subjects were classified and participated in gait termination (GT) tests to collect metatarsophalangeal (MTP) and ankle-joint kinematics data. The two-way repeated-measures ANOVA using SnPM was employed to assess the impacts of AS on foot-ankle kinematics during PGT and UGT. Our results show that joint angles (MTP and ankle joints) were altered owing to AS and GT factors. The flexible arches hahadve periods of significantly greater MTP and ankle joint angles than those of stiff arches during the stance phase of GT, whereas subjects exhibited significantly smaller ankle and MTP joint angles during UGT. These results add additional insights into the morphological arch biomechanical function, and the comprehensive compensatory adjustment of lower-limb joints during gait stopping caused by unplanned stimulation.

Association between intraoperative plantar regional oxygen saturation and acute kidney injury after cardiac surgery

Acute kidney injury (AKI) is one of the most common complications after cardiac surgery, associated with increased mortality and morbidity. Near-infrared spectroscopy (NIRS) continuously measures regional oxygen saturation(rSO₂) in real-time. This exploratory retrospective study aimed to investigate the association between intraoperative plantar rSO₂ and postoperative AKI in cardiac surgery patients. Between August 2019 and March 2021, 394 patients were included. Plantar and cerebral rSO₂ were monitored using NIRS intraoperatively. The primary outcome was AKI within 7 postoperative days. The nonlinear association between plantar rSO₂, cerebral rSO₂, and mean arterial blood pressure (MBP) and AKI was assessed, and plantar rSO₂<45% was related to an increased risk of AKI. Multivariable logistic regression analyses revealed that longer duration and higher area under the curve below plantar rSO₂<45% and MBP<65 mmHg were more likely to be associated with increased odds of AKI. In additional multivariable regression analyses, association between plantar rSO₂<45% and AKI was still maintained after adjusting the duration or AUC of MBP<65 mmHg as a covariate. Cerebral rSO₂ levels were not associated with AKI. Independent of MAP, intraoperative plantar rSO₂ was associated with AKI after cardiac surgery. However, intraoperative cerebral rSO₂ was not associated with AKI. Intraoperative plantar rSO₂ monitoring may be helpful in preventing AKI.

Associations of muscle volume of individual human plantar intrinsic foot muscles with morphological profiles of the foot

Human plantar intrinsic foot muscles consist of 10 muscles that originate and insert within the sole of the foot. It is known that the anatomical cross‐sectional area (ACSA) and muscle thickness of two plantar intrinsic foot muscles, the flexor hallucis brevis (FHB) and abductor hallucis (ABH), associate with morphological parameters of the foot, such as total and truncated foot length and navicular height. However, it is unclear how the size for each of the plantar intrinsic foot muscles associates with various morphological profiles of the foot. This study aimed to elucidate this subject. By using magnetic resonance imaging (MRI), serial images of the right foot were obtained in 13 young adult men without foot deformities. From the obtained MR images, ACSA for each of the individual plantar intrinsic foot muscles was analyzed along the foot length, and then its muscle volume (MV) was calculated. The analyzed muscles were the abductor digiti minimi (ABDM), ABH, adductor hallucis oblique head (ADDH‐OH), adductor hallucis transverse head (ADDH‐TH), flexor digitorum brevis (FDB), FHB, and quadratus plantae (QP). Furthermore, MV of the whole plantar intrinsic foot muscle (WHOLE) was defined as the total MVs of all the analyzed muscles. As morphological parameters, total foot length, truncated foot length, forefoot width, ball circumference, instep circumference, navicular height, great toe eversion angle, and little toe inversion angle were measured using a laser three‐dimensional foot scanner in standing and sitting conditions. In addition, navicular drop (ND) and normalized truncated navicular height (NTNH) were also calculated as medial longitudinal arch (MLA) height indices. The MV of WHOLE was significantly associated with the forefoot width, ball circumference, and instep circumference (r = 0.647–0.711, p = 0.006–0.013). Positive correlations were found between the forefoot width and MV of FHB, FDB, and QP (r = 0.564–0.653, p = 0.015–0.045), between the ball circumference and MV of QP (r = 0.559, p = 0.047), between the instep circumference and MV of FHB (r = 0.609, p = 0.027), and between the little toe inversion angle and MV of QP (r = 0.570, p = 0.042). The MVs of ABH, ABDM, and ADDH‐OH were not significantly correlated with any morphological parameters of the foot. Similarly, no significant correlations were found between MV of each muscle and either of the MLA height indices (ND and NTNH). Thus, the current results indicate that forefoot width and circumferential parameters (instep and ball circumference), not MLA height, associate with the size of the whole plantar intrinsic foot muscles, especially those specialized in toe flexion (FHB, FDB, and QP).

Assessing the relationship between hearing impairment and falls in older adults

Falls and fall-related injuries are the major sources of mortality, disability, and dysfunction among older people. The study aimed to examine the association between hearing impairment and falls in Chinese older adults, using data from the Chinese Longitudinal Healthy Longevity Survey. The outcome variable was experienced falls in the past year, and the exposure variable was hearing impairment. The odds ratio (OR) of falls was 1.51 and 1.47 for men and women with hearing impairment than those without hearing impairment after adjusting for covariates. For participants aged 60-69 years, 70-79 years, 80-89 years, and ≥ 90 years, the OR of risk of falls associated with hearing impairment was 2.80, 1.41, 1.50 and 1.44, respectively. These results suggested that there was an association between hearing impairment and falls. Older adults with hearing impairment had a higher risk of falls than those without hearing impairment in the Chinese older population.

Do Arch Height and Arch Stiffness Relate to Physical Performance in Adult Men?

Foot arch plays an important role in bearing body weight, absorbing ground reaction forces and maintaining balance, and its structure and function are bound to have a profound effect on physical activities and sports. Arch height and arch stiffness are 2 factors that represent the structure and function of the arch. Therefore, the purpose of this study was to explore the associations of arch height and arch stiffness with physical performance. A total of 56 men (aged 49.00 ± 7.95 years, mean body mass index [BMI] 26.80 ± 3.75 kg/m²) participated in this study. A 3-dimensional laser scanner was employed to obtain foot structure information of each participant, from which the arch height index (AHI) and arch stiffness index (ASI) were computed. Physical performance measures including agility, power, and proprioception were tested in a random order. The results indicated that the stepping forward and backward and vertical jump that represent agility and force respectively were negatively and significantly associated with AHI (r = -0.27, p = .045; r = -0.35, p = .009). When adjusted for age and BMI, only height of vertical jump was found to be correlated significantly with AHI (r = -0.29, p = .040); while no significant relationships were observed between physical performance measures and ASI. Multivariate linear regression analysis showed that AHI, age, and BMI can effectively predict the height of vertical jump. This study demonstrates that there is a negative correlation between arch height and muscle power of lower limbs in adult men.

Arch Height Index, Arch Rigidity Index, and Arch Stiffness Values in a Symptomatic Population

BACKGROUND

Studies of arch height index (AHI), arch rigidity index (ARI), and arch stiffness have primarily focused on healthy populations. Normative values of the aforementioned measurements in a pathologic sample may be useful in identifying relationships between arch structure and pathology.

METHODS

AHI was obtained bilaterally at 10% and 90% weightbearing conditions using the AHI measurement system. ARI and arch stiffness were calculated using AHI measurements. Dependent t tests compared right and left, dominant and nondominant, and injured and noninjured limbs. Dominant feet were compared between sexes using independent t tests. Relationships between arch stiffness and subcategories were examined using the coefficient of determination (R2). One-way analyses of variance determined differences between arch structure and number of pathologies or body mass index (BMI).

RESULTS

A total of 110 participants reported one (n = 55), two (n = 38), or three or more (n = 17) pathologies. Plantar fasciitis (n = 31) and hallux valgus (n = 28) were the most common. AHI, ARI, and arch stiffness did not differ between limbs or sexes for any comparisons. Between subgroups of BMI and number of pathologies, BMI influenced AHI (10% weightbearing) and arch stiffness (P < .05). Arch stiffness showed a weak relationship to AHI, where a higher AHI was associated with a stiffer arch (R2 = 0.06).

CONCLUSIONS

Normative arch structure values were established in a pathologic sample with a large incidence of plantar fasciitis and hallux valgus. Understanding relationships between arch structure and pathology is helpful for clinicians and researchers.

The influence of the windlass mechanism on kinematic and kinetic foot joint coupling

Background

Previous research shows kinematic and kinetic coupling between the metatarsophalangeal (MTP) and midtarsal joints during gait. Studying the effects of MTP position as well as foot structure on this coupling may help determine to what extent foot coupling during dynamic and active movement is due to the windlass mechanism. This study’s purpose was to investigate the kinematic and kinetic foot coupling during controlled passive, active, and dynamic movements.

Methods

After arch height and flexibility were measured, participants performed four conditions: Seated Passive MTP Extension, Seated Active MTP Extension, Standing Passive MTP Extension, and Standing Active MTP Extension. Next, participants performed three heel raise conditions that manipulated the starting position of the MTP joint: Neutral, Toe Extension, and Toe Flexion. A multisegment foot model was created in Visual 3D and used to calculate ankle, midtarsal, and MTP joint kinematics and kinetics.

Results

Kinematic coupling (ratio of midtarsal to MTP angular displacement) was approximately six times greater in Neutral heel raises compared to Seated Passive MTP Extension, suggesting that the windlass only plays a small kinematic role in dynamic tasks. As the starting position of the MTP joint became increasingly extended during heel raises, the amount of negative work at the MTP joint and positive work at the midtarsal joint increased proportionally, while distal-to-hindfoot work remained unchanged. Correlations suggest that there is not a strong relationship between static arch height/flexibility and kinematic foot coupling.

Conclusions

Our results show that there is kinematic and kinetic coupling within the distal foot, but this coupling is attributed only in small measure to the windlass mechanism. Additional sources of coupling include foot muscles and elastic energy storage and return within ligaments and tendons. Furthermore, our results suggest that the plantar aponeurosis does not function as a rigid cable but likely has extensibility that affects the effectiveness of the windlass mechanism. Arch structure did not affect foot coupling, suggesting that static arch height or arch flexibility alone may not be adequate predictors of dynamic foot function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-022-00520-z.

Increase in foot arch asymmetry after full marathon completion

Long-distance running results in lowering of the foot medial longitudinal arch, but it is unknown whether the left and right arches decrease equally. This study aimed to determine whether foot arch asymmetry increases upon completion of a full marathon and to identify factors capable of explaining the degree of asymmetry of navicular height and navicular height displacement. The three-dimensional foot posture data of 74 collegiate runners were obtained using an optical foot scanner system before (PRE) and immediately after (POST) a full marathon. The navicular height and arch height ratio (normalised navicular height by foot length) of both feet significantly decreased from PRE to POST full marathon completion (44.3 ± 6.3 mm versus 40.8 ± 6.5 mm, 17.8 ± 2.5 versus 16.6 ± 2.7, respectively; p < 0.001, both). The asymmetry of the arch height ratio was significantly greater POST than PRE marathon. Multiple linear regression analysis indicated that the POST-race Asymmetry Index (AI) of navicular height was significantly predicted by the PRE-race AI of navicular height; navicular height displacement was predicted by PRE-race navicular height and the marathon time. Full marathon running induced increasing asymmetry and lowering of the medial longitudinal arch in runners.

A Comparative Biomechanical Analysis during Planned and Unplanned Gait Termination in Individuals with Different Arch Stiffnesses

Although values of arch stiffness index (ASI) have been used to evaluate arch structure and injury susceptibility, investigations are limited regarding the influence of ASI on biomechanical characteristics during gait termination, which involves a challenging balance transition from walking to standing. This study aimed to explore plantar pressure distribution and lower extremity joint kinematic differences between individuals with both a stiff and flexible arch (SA and FA, respectively) during planned and unplanned gait termination (PGT and UGT, respectively). Following the calculation of ASI, sixty-five asymptomatic male subjects were classified and participated in two types of gait termination tests to acquire kinematic and plantar pressure data. Parameters were compared between SA and FA using a two-way ANOVA during PGT and UGT, respectively. UGT was found to have a larger range of motion on the hip joint in the sagittal plane and the knee joint in the transverse plane when compared with PGT. The differences in the kinematic characteristics of the lower limb joints caused by the difference in arch stiffness are mainly concentrated in the ankle and metatarsophalangeal joints. Plantar pressure data, represented by the maximum pressure, showed significant differences in the forefoot and rearfoot areas. These results suggest that ASI could change freedom of motion of the lower limb joints, and UGT tends to conduct a compensatory adjustment for the lower extremity kinetic chain. An understanding of the biomechanical characteristics of arch structures may provide additional insights into foot function and injury prediction during gait termination.

[Ankle fractures in older patients : What should we do differently?]

As a result of the demographic developments ankle fractures in older patients are part of routine trauma surgery. Due to comorbidities, such as diabetes mellitus, reduced bone quality and limited compliance in follow-up treatment, these fractures are prone to complications. The primary goal in the treatment of older patients with ankle fractures is to maintain mobility. In contrast to young patients most fractures are unstable pronation-abduction injuries. In the diagnostics the recognition and optimization of factors influencing the outcome, such as the blood perfusion and the generous use of computed tomography (CT) are recommended. As in the case of younger patients, conservative treatment is reserved for stable fracture forms and, if there are contraindications, should also be initiated in the case of unstable injuries. The choice of approaches is different for surgical treatment, which is adapted to the soft tissues, if necessary minimally invasive and increasingly carried out by a posterolateral approach. The initial transfixation can reduce soft tissue problems. Special surgical techniques and implants that provide a high level of stability, such as dorsal plate positioning, hook plates, angular stable plate systems and intramedullary systems as well as additional options, such as tibia pro fibula constructs are used. Primary retrograde nail arthrodesis is reserved as a salvage procedure only for exceptional cases. As part of the follow-up treatment, an interdisciplinary approach with respect for and optimization of concomitant diseases seems to make sense.