Foot medial longitudinal-arch deformation during quiet standing and gait in subjects with medial tibial stress syndrome

Prognostic Power of Foot Mobility in Identifying the Risk of Musculoskeletal Injuries: A Cross-Sectional Study of Male Volleyball Players at Different Competitive Levels

(1) Background: The arch structure and mobility of the foot are considered injury risk factors in volleyball. However, there are limited studies presenting differences in injury prevalence and the risk of lower limb injuries in relation to the competitive level in male volleyball. Therefore, the main aim of the current study was to evaluate foot mobility (through navicular drop test) as an injury risk factor in volleyball players from different competitive levels. (2) Methods: The reliability and usefulness of navicular drop testing were initially assessed in test-retest procedures (based on a sample of eight participants and 16 feet measurements), with primary analyses conducted using foot measurements of the twelve top-level volleyball players (24 feet) and eighteen academic-level volleyball players (36 feet). The modified navicular drop test was conducted, and the feet were classified based on arch height, and injury prevalence was retrospectively assessed with a previously validated questionnaire. Chi-squared tests, receiver operating curves, and logistic regression were used as statistical methods. The navicular drop test was verified as a reliable tool by intraclass correlation coefficient (ICC) (3.1) analysis. (3) Results: There were no significant differences in injury prevalence between academic- and top-level volleyball players, though there was a significant relationship between pronated foot and injury risk independent of competitive level. Generally, for both groups, thresholds above 10 mm of the navicular drop were predictors of lower limb injuries. The risk of injury if the foot was pronated ranged from 70% (academic level) to over 90% (top-level players). However, no statistically significant effect of competitive level on the chance of injury was observed. (4) Conclusions: Our study found a high prevalence of foot injuries independently of competitive level. There was a relationship between pronation of the foot and the risk of injury. However, the risk of lower limb injury was higher in pronated top-level players. Also, a navicular drop greater than 10 mm was an excellent predictor of injuries at both competitive levels.

The interaction effect of different footwear types and static navicular drop or dynamic ankle pronation on the joint stiffness of the lower limb during running

BACKGROUND

Although the effects of footwear type on joint stiffness have previously been investigated, researchers did not consider foot flexibility. Thus, the present investigation aimed to determine the interaction effects of footwear type, static navicular drop and dynamic ankle pronation on dynamic joint stiffness in running.

RESEARCH QUESTION

Does the footwear types in interaction with the foot posture affect the stiffness of the joints of the lower limb?

METHODS

Forty-seven male individuals participated in this study. Firstly, they were divided into the high navicular, low navicular, and normal navicular drop. Secondly, they were divided into the high dynamic ankle pronation, low dynamic ankle pronation, and normal dynamic ankle pronation groups. Participants performed three running trials at 3 ± 0.2 m/s at minimalist footwear, conventional footwear, and barefoot conditions. We collected the ground reaction forces and three-dimensional kinematic data and calculated joint stiffness over the stance phase.

RESULTS

There was no significant main effect of navicular drop or dynamic ankle pronation on dynamic joint stiffness for the ankle, knee, and hip (p > 0.05). However, footwear type significantly affected dynamic joint stiffness. The pairwise comparison revealed that the ankle and hip dynamic joint stiffness magnitudes in the conventional footwear condition were greater than in the barefoot and minimalist footwear conditions (p 0.001). In contrast, the knee dynamic joint stiffness magnitude in the conventional footwear condition was lesser than in barefoot and minimalist footwear conditions (p 0.001).

SIGNIFICANCE

The navicular drop or dynamic ankle pronation did not influence lower limb joint stiffness, and there was no significant interaction between navicular drop or dynamic ankle pronation and footwear on lower limb dynamic joint stiffness. However, conventional footwear increased the ankle and hip dynamic joint stiffness while reducing knee dynamic joint stiffness, leading to changes in transfer energy, which could have implications for relative injury risk.

Runners with a history of shank and foot injury: Interactions among local musculoskeletal factors, age, and running experience

OBJECTIVE

To identify subgroups of runners' profiles who had or did not have a History of Running-Related Injury in the Shank and Foot (HRRI-SF).

DESIGN

Cross-sectional.

METHODS

Clinical measures of passive ankle stiffness (measured as ankle position (compliance) to index passive joint stiffness), forefoot-shank alignment, peak torque of ankle plantar flexors, years of running experience, and age were analyzed through Classification and Regression Tree (CART).

RESULTS

The CART identified four subgroups of runners with a greater prevalence of HRRI-SF: (1) ankle stiffness ≤0.42°; (2) ankle stiffness >0.42°, age ≤23.5 years, and forefoot varus >19,64°; (3) ankle stiffness >0.42°, age >62.5 years, and forefoot varus ≤19.70°; (4) ankle stiffness >42°, age >62.5 years, forefoot varus >19.70°, and running experience ≤7 years. Three subgroups had a lower prevalence of HRRI-SF: (1) ankle stiffness >0.42° and age between 23.5 and 62.5 years; (2) ankle stiffness >0.42°, age ≤23.5 years, and forefoot varus ≤14.64°; (3) ankle stiffness >0.42°, age >62.5 years, forefoot varus >19.7°, and running experience >7 years.

CONCLUSION

One runner profile subgroup showed that higher ankle stiffness could predict HRRI-SF without association with other variables. Distinct interactions among variables characterized the other subgroups' profiles. The identified interactions among the predictors used to characterize the runners' profiles could be used in clinical decision-making.

Effects of Barefoot and Shod on the In Vivo Kinematics of Medial Longitudinal Arch During Running Based on a High-Speed Dual Fluoroscopic Imaging System

Shoes affect the biomechanical properties of the medial longitudinal arch (MLA) and further influence the foot’s overall function. Most previous studies on the MLA were based on traditional skin-marker motion capture, and the observation of real foot motion inside the shoes is difficult. Thus, the effect of shoe parameters on the natural MLA movement during running remains in question. Therefore, this study aimed to investigate the differences in the MLA’s kinematics between shod and barefoot running by using a high-speed dual fluoroscopic imaging system (DFIS). Fifteen healthy habitual rearfoot runners were recruited. All participants ran at a speed of 3 m/s ± 5% along with an elevated runway in barefoot and shod conditions. High-speed DFIS was used to acquire the radiographic images of MLA movements in the whole stance phase, and the kinematics of the MLA were calculated. Paired sample t-tests were used to compare the kinematic characteristics of the MLA during the stance phase between shod and barefoot conditions. Compared with barefoot, shoe-wearing showed significant changes (p < 0.05) as follows: 1) the first metatarsal moved with less lateral direction at 80%, less anterior translation at 20%, and less superiority at 10–70% of the stance phase; 2) the first metatarsal moved with less inversion amounting to 20–60%, less dorsiflexion at 0–10% of the stance phase; 3) the inversion/eversion range of motion (ROM) of the first metatarsal relative to calcaneus was reduced; 4) the MLA angles at 0–70% of the stance phase were reduced; 5) the maximum MLA angle and MLA angle ROM were reduced in the shod condition. Based on high-speed DFIS, the above results indicated that shoe-wearing limited the movement of MLA, especially reducing the MLA angles, suggesting that shoes restricted the compression and recoil of the MLA, which further affected the spring-like function of the MLA.

A influência de calçados no arco longitudinal medial do pé e na cinemática dos membros inferiores de crianças no início da fase de aquisição de marcha

Objective  To evaluate the biomechanical behavior of the medial longitudinal arch (MLA) of the foot and the kinematic parameters of the lower limbs with biomimetic footwear (BF) and non-biomimetic (NB1, NB2, NB3 and NB4) footwear in children at the beginning of the gait acquisition phase.

Methods  Four toddlers were evaluated at the beginning of the gait acquisition phase under the following conditions: walking barefoot, ambulation with BF and NB1, NB2, NB3 and NB4 footwear in hard floor. BF is described as biomimetic because of its property of emulating natural and irregular floors through a dynamic internal insole. The MLA and kinematics of the hip, knee, and ankle during gait were evaluated by three-dimensional motion analysis system. The similarity between the kinematic curves of barefoot and footwear conditions was analyzed by root mean square error (RMSE).

Results  The use of BF presented the highest magnitude of MLA and the greatest difference in relation to barefoot condition (higher RMSE). The BF showed less difference in the kinematics of the knee and ankle joints during gait when compared to barefoot condition (lower RMSE). NB2 footwear presented hip kinematics more similar to barefoot condition (lower RMSE).

Conclusion Biomimetics footwear and NB2 shoes (both with wider forefoot region) generated smaller differences in lower limbs compared to barefoot. In addition, the MLA was higher in the BF, probably because different design from other shoes.

Stature estimation using foot dimensions via 3D scanning in Taiwanese male adults

In forensic identification, the use of foot dimensions to predict stature is a requisite. For Taiwanese male stature prediction, available information about stature estimation using foot dimensions is still lacking. Therefore, the primary purpose of this study was to establish Taiwanese adult male stature prediction models for various foot dimensions. A total of 2,072 male 3D foot models were collected and the subjects' ages ranged from 18 to 59 years old. Thirteen foot dimensions for each foot were utilized in this study. Bilateral differences were tested using pairedt-tests. Stature predictions based on different foot dimensions were conducted using simple linear and stepwise regression methods. The results showed significant bilateral differences in the majority of the selected foot dimensions (p < 0.001). Foot length had the highest positive correlation with stature in the right and left foot. Using length-related dimensions generated better prediction accuracy (0.356 < R² < 0.533, 4.193 < SEE < 4.928), whereas the worst accuracy was observed with angle-related dimensions (0.001 < R² < 0.023; 6.072 < SEE < 6.137) when employing a single foot dimension to estimate Taiwanese male stature. Stepwise regression analysis results indicated that the coefficient of determination was improved to 0.590 and 0.593 by applying five and six foot parameters to predict stature, respectively. The findings of the present study suggest that these stature estimation equations can be applied to predict Taiwanese male stature in the forensic science field.

Accuracy and correlation between skin-marker based and radiographic measurements of medial longitudinal arch deformation

Static and dynamic measurements of the medial longitudinal arch (MLA) in the foot are critical across different clinical and biomechanical research fields. While MLA deformation can be estimated using skin-markers for gait analysis, the current understanding of the correlates between skin-marker based models and radiographic measures of the MLA is limited. This study aimed at assessing the correlation and accuracy of skin-marker based measures of MLA deformation with respect to standard clinical X-ray based measures, used as reference. 20 asymptomatic subjects without morphological alterations of the foot volunteered in the study. A lateral X-ray of the right foot of each subject was taken in monopodalic upright posture with and without a metatarsophalangeal-joint dorsiflexing wedge. MLA angle was estimated in the two foot postures and during gait using 16 skin-marker based models, which were established according to the marker set of a validated multi-segment foot kinematic protocol. The error of each model in tracking MLA deformation was assessed and correlated with respect to standard radiographic measurements. Estimation of MLA deformation was highly affected by the skin-marker models. Skin-marker models using the marker on the navicular tuberosity as apex of the MLA angle showed the smallest errors (about 2 deg) and the largest correlations (R = 0.64-0.65; p < 0.05) with respect to the radiographic measurements. According to the outcome of this study, skin-marker based definitions of the MLA angle using the navicular tuberosity as apex of the arch may provide a more accurate estimation of MLA deformation with respect to that from radiographic measures.

The Effects of a Medial Heel Wedge on the Weight-Bearing Response of Hindfoot Valgus and the Total Weight-Bearing Responses of the Navicular and Talus Bones

OBJECTIVES Medial heel wedges are commonly prescribed to manage the weight-bearing response of hindfoot valgus and the total weight-bearing responses of the navicular and talus bones. Previous studies have reported that a medial heel wedge is effective in the management of musculoskeletal injuries. However, it remains unclear the effect of a medial heel wedge on the weight-bearing responses of footarch bones in vivo. To clarify the effects of a medial heel wedge on the weight-bearing response of hindfoot valgus and the total weight-bearing responses of the navicular and talus bones is necessary to understand how best to treat musculoskeletal injuries clinically. The purpose of our study was to clarify the effects of a medial heel wedge on the weight-bearing response of hindfoot valgus and the total weight-bearing responses of the navicular and talus bones.METHODS Twenty-five healthy males were analyzed. We obtained MRI scanning of the right foot under non-loading (NL) and full weight-bearing (FW) conditions. Participants wore two insole types, a flat insole and a medial heel wedge. To evaluate the weight-bearing response in hindfoot valgus, the hindfoot alignment view (HAV) was measured. We also measured navicular and talus bone positions and calculated the total positional changes of the navicular and talus bones (ΔTPCN, ΔTPCT) from the vertical and medial displacements using the Pythagorean theorem.RESULTS Significant interactions were observed with the HAV. Under both NL and FW conditions, the HAV was smaller on the medial heel wedge than on the flat insole. In addition, the ΔTPCN was significantly smaller on the medial heel wedge than on the flat insole. However, no significant differences were observed for ΔTPCT.CONCLUSIONS Our results suggest that use of a medial heel wedge decreases hindfoot valgus values under both NL and FW conditions and stabilizes the total weight-bearing response of the navicular bone.

Effect of dynamic guidance-tubing short foot gait exercise on muscle activity and navicular movement in people with flexible flatfeet

BACKGROUND

Navicular drop is a common plantar deformity which makes the plantar medial longitudinal arch (MLA) collapse and leads to other deformities in lower extremities. Active structures are from intrinsic and extrinsic foot muscle activities such as abductor hallucis (AbdH), tibialis anterior (TA), tibialis posterior, flexor hallucis brevis, flexor digitorum brevis during dynamic situations. As AbdH plays a role as a dynamic elevator of MLA, the importance of AbdH has been emphasized and the proper recruitment of both intrinsic and extrinsic muscle is crucial for stabilization of MLA during dynamic weight bearing condition. Because the short foot (SF) exercise is difficult to perform and tends to activate the intrinsic muscles concentrically rather than a natural coordination of concentric-isometric-eccentric activation, we have developed the guidance-tubing SF gait (GFG) exercise.

OBJECTIVE

We investigated the effect of GFG exercise on muscle activity, AbdH:TA activity ratio, MLA angle, and foot pressure distribution during walking compared to SF gait (SFG) exercise.

METHODS

Thirty-two subjects with flexible flat feet were divided into two groups and performed SFG exercise with (GFG) and without guidance-tubing (SFG) for seven serial days.

RESULTS

AbdH muscle activity significantly increased from foot flat to heel rise in the GFG group (p = 0.006). The AbdH:TA activity ratio significantly increased in both the SFG (p = 0.015) group and GFG group (p = 0.006). MLA angles significantly decreased in both the SFG group (p = 0.001) and GFG group (p = 0.000), and the decrement was significantly higher in the GFG group (p = 0.001). The foot pressure distribution did not show any statistically significant change.

CONCLUSIONS

The result of this study provides a clinical implication for training MLA supporter muscles in individuals with flat feet. The overactive muscle must be inhibited first, then facilitation and strengthening are followed respectively.

The effect of toe-tap exercise on abductor hallucis activity and medial longitudinal arch angle in individuals with pes planus

BACKGROUND: Active interventions for pes planus, including short-foot exercises (SF) and toe-spread-out exercises (TSO), aim to continuously support the medial longitudinal arch (MLA) by activating the abductor hallucis (AbdH) muscle. However, compensatory movements, such as ankle supination and/or plantar flexion, often occur during these exercises. OBJECTIVE: To examine the effects of a novel exercise, i.e., the toe-tap (TT) exercise on AbdH activity and MLA angle. METHODS: A total of 16 participants with pes planus participated in this study. Participants performed SF, TSO, and TT exercises. Electromyographic activity of the AbdH and MLA angle during three AbdH contraction exercises were recorded using surface EMG system and digital image analysis program, respectively. The differences in outcome measures among the three exercises were analyzed using one-way repeated-measures analysis of variance. RESULTS: The EMG activity of the AbdH was significantly greater during the TT exercise compared to the SF and TSO exercises. The MLA angle was significantly smaller during the TT exercise compared with the SF and TSO exercises. CONCLUSIONS: These findings suggest that the TT exercise could be effective in activating the AbdH and increasing height of the MLA, as part of a sports rehabilitation program for individuals with pes planus.

The effect of pads on foot morphology in athletes with medial tibial stress syndrome

BACKGROUND

Evaluation of the effect of a pad on foot morphologies in patients with medial tibial stress syndrome (MTSS) requires more reliable and objective methods, rather than conventional subjective observations.

OBJECTIVE

The objective of this study was to investigate the effect of pads on foot morphologies during quiet standing in athletes with MTSS.

METHODS

We measured three-dimensional foot morphologies in 30 feet with MTSS and 40 healthy feet.

RESULTS

The analysis showed that Hallux valgus degree, calcaneal angle, arch height, and arch height ratio differed significantly as a result of the pad support, compared to no pad support in the MTSS group. The pad support only resulted in significant differences in arch height, compared to no support in the control group. Furthermore, thumb side angle, calcaneal angle, and arch height ratio were significantly different between the MTSS and control groups.

CONCLUSIONS

Our study results suggest that changes in foot morphologies because of the use of a pad can be measured objectively in patients with MTSS.

Effect of Isometric Hip Abduction on Foot and Ankle Muscle Activity and Medial Longitudinal Arch During Short-Foot Exercise in Individuals With Pes Planus

CONTEXT

The improvement of hip joint stability can significantly impact knee and rearfoot mechanics. Individuals with pes planus have a weak abductor hallucis (AbdH), and the tibialis anterior (TA) may activate to compensate for this. As yet, no studies have applied isometric hip abduction (IHA) for hip stability during short-foot exercise (SFE).

OBJECTIVE

To compare the effects of IHA on the muscle activity of the AbdH, TA, peroneus longus (PL), and gluteus medius (Gmed), as well as the medial longitudinal arch (MLA) angle during sitting and standing SFE.

DESIGN

Two-way repeated analyses of variance were used to determine the statistical significance of AbdH, TA, PL, and Gmed electromyography activity, as well as the change in MLA angle.

SETTING

University research laboratory.

PARTICIPANTS

Thirty-two participants with pes planus.

INTERVENTION(S)

The participants performed SFE with and without isometric hip abduction in sitting and standing positions.

MAIN OUTCOME MEASURES

Surface electromyography was used to measure the activity of the AbdH, TA, PL, and Gmed muscles, and Image J was used to measure the MLA angle.

RESULTS

Significant interactions between exercise type and position were observed in terms of the PL muscle activity and in the change in MLA angle only, while other muscles showed significant main effects. The IHA during SFE significantly increased the AbdH muscle activity, while the TA muscle activity was significantly lower. The muscle activity of Gmed and PL was significantly increased in the standing position compared with sitting, but there was no significant difference with or without IHA. The change in the MLA angle was significantly greater in SFE with IHA in a standing position than in the other SFE conditions.

CONCLUSIONS

IHA may be an effective method for reducing compensatory TA activity and increasing AbdH muscle activity during SFE for individuals with pes planus.

The Relationship Between Foot Feature Parameters and Postural Stability in Healthy Subjects

OBJECTIVE

Little has been explored about the disparate contribution of medial longitudinal arch (MLA) and lateral longitudinal arch (LLA) to human gait and postural stability. This study aims to investigate the correlation of foot feature parameters including both MLA and LLA with postural stability.

METHOD

Thirteen young and healthy subjects participated in this study. The newly developed FFMS extracted foot feature parameters in nonweight-bearing (NWB) and weight-bearing (WB) conditions along with postural stability parameters in single-leg-standing (SLS) condition. A bivariate correlation analysis was carried out to investigate the correlation between the foot characteristics and the postural stability parameters.

RESULTS

The foot length and width showed negative correlation with center of pressure (CoP) distance in medio-lateral (ML) and total direction, whereas the foot length in NWB and WB conditions, and the foot width in WB condition showed positive correlation with CoP distance in anterior-posterior (AP) direction. The height of the LLA curve and the area of the MLA were correlated with the postural stability parameters in AP direction. The ratios of the LLA height and area showed moderate correlation with the CoP distance in ML direction and total direction.

CONCLUSION

The size of a foot, such as the length and width, is correlated with postural stability. Whereas the MLA features are associated with postural stability in AP direction, the LLA features are associated with that in ML and total direction.

APPLICATION

The findings suggest that the roles and contributions of the MLA and LLA features in and to the postural control are different.

Relationships between the foot posture Index and static as well as dynamic rear foot and arch variables

Clinicians, podiatrists and researchers have been quantifying foot posture and movement in various speed conditions and populations. Common variables to assess foot posture/movement are the Foot Posture Index (FPI-6), Achilles tendon angle (β), rear foot angle (γ) and longitudinal arch angle (LAA). These variables were frequently used in clinical and biomechanical settings. This study aimed to determine the relationship between the biomechanical variables (β, γ & LAA) in static and dynamic conditions and the clinically used FPI-6 and their redundancy. Forty participants performed bipedal standing, over ground walking and running trials. Manual assessment data (FPI-6), kinematic data and ground reaction forces were collected. Discrete biomechanical variables (β, γ & LAA) were calculated at various time points (e.g. heel strike). A Principal Component Analysis (PCA) was performed to quantify the contribution of each variable to the overall variance in the data set. Spearman correlations were used to assess the relationship between the sub-measures of the FPI-6 and the biomechanical variables. Two major components were found that explained 85.2% of the overall variance, consisting of LAA and β variables, respectively. Only LAA variables showed significant, but moderate correlations (r < -0.6) with the fifth sub-measurement of the FPI-6. The LAA and β describe independent movements, which dominate foot posture/movement in static and dynamic conditions. The FPI-6 sub-measurements did not closely reflect static nor dynamic behavior of the rear and mid foot. The FPI-6 and biomechanical variables may not be used interchangeably for screening or grouping individuals according to their foot posture/movement.

In Vivo Measurement of Plantar Tissue Characteristics and Its Indication for Foot Modeling

Plantar heel pain is one of the most common musculoskeletal disorders and generally causing long term discomfort of the patients. The objective of the present study is to combine in vivo experimental measurements and finite element modelling of the foot to investigate the influences of stiffness and thickness variation of individual plantar tissues especially the heel pad on deformation behaviours of the human foot. The stiffness and thickness variance of individuals were measured through supersonic shear wave elastography considering detailed heel pad layers refered to in literature as: dermis, stiffer micro-chamber layer, softer macro-chamber layer. A corresponding foot model with separated heel pad layers was established and used to a sensitivity analysis related to the variance of above-mentioned tissue characteristics. The experimental results show that the average stiffness of the micro-chamber layer ranged from 24.7 (SD 2.4) kPa to 18.8 (SD 3.5) kPa with the age group increasing from 20-29 years old to 60-69 years old, while the average macro-chamber stiffness is 10.6 (SD 1.5) kPa that appears to slightly decrease with the increasing age. Both plantar soft tissue stiffness and thickness of male were generally larger than that of female. The numerical simulation results show that the variance of heel pad strain level can reach 27.5% due to the effects of stiffness and thickness change of the plantar tissues. Their influences on the calcaneus stress and plantar pressure were also significant. This indicates that the most appreciate way to establish a personalized foot model needs to consider the difference of both individual foot anatomic geometry and plantar soft tissue material properties.

Adaptation to Coriolis force perturbations of postural sway requires an asymmetric two-leg model

In the companion paper (Bakshi A, DiZio P, Lackner JR. J Neurophysiol. In press, 2019), we reported how voluntary forward-backward sway in a rotating room generated medial-lateral Coriolis forces that initially deviated intended body sway paths. Pure fore-aft sway was gradually restored over per-rotation trials, and a negative aftereffect occurred during postrotation sway. Force plate recordings showed that subjects learned to compensate for the Coriolis forces by executing a bimodal torque, the distribution of which was asymmetric across the two legs and of opposite sign for forward vs. backward sway. To explain these results, we have developed an asymmetric, nonparallel-leg, inverted pendulum model to characterize upright balance control in two dimensions. Fore-aft and medial-lateral sway amplitudes can be biomechanically coupled or independent. Biomechanical coupling occurs when Coriolis forces orthogonal to the direction of movement perturb sway about the ankles. The model includes a mechanism for alternating engagement/disengagement of each leg and for asymmetric drive to the ankles to achieve adaptation to Coriolis force-induced two-dimensional sway. The model predicts the adaptive control underlying the adaptation of voluntary postural sway to Coriolis forces. A stability analysis of the model generates parameter values that match those measured experimentally, and the parameterized model simulations reproduce the experimentally observed sway trajectories. NEW & NOTEWORTHY This paper presents a novel nonparallel leg model of postural control that correctly predicts the perturbations of voluntary sway that occur in a rotating environment and the adaptive changes that occur to restore faithful movement trajectories. This engaged leg model (ELM) predicts the asymmetries in force distribution and their patterns between the two legs to restore accurate movement trajectories. ELM has clinical relevance for pathologies that generate postural asymmetries and for altered gravitoinertial force conditions.

Forefoot and hindfoot kinematics in subjects with medial tibial stress syndrome during walking and running

Excessive foot pronation during static standing, walking and running has been reported as a contributing factor for the development of medial tibial stress syndrome (MTSS). The motion of foot pronation consists of hindfoot and forefoot motion. However, no previous studies have investigated forefoot and hindfoot kinematics during walking and running in subjects with MTSS. The current study sought to compare hindfoot and forefoot kinematics between subjects with and without MTSS while walking and running. Eleven subjects with MTSS and 11 healthy controls (each group containing 10 males and one female) participated in the current study. Segment angles of the hindfoot and forefoot during walking and running barefoot on a treadmill were recorded using three-dimensional kinematic analysis. An independent t-test was used to compare kinematic data between groups. Subjects with MTSS exhibited significantly greater hindfoot eversion and abduction (p < 0.05) during walking and running than subjects without MTSS, significantly greater forefoot eversion and abduction (p < 0.05) during walking, and significantly greater forefoot abduction during running (p < 0.05). Hindfoot and forefoot kinematics during walking and running were significantly different between subjects with and without MTSS. For prevention and rehabilitation of MTSS, it may be important to focus on not only hindfoot but also forefoot kinematics during both running and walking. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Reliability of medial-longitudinal-arch measures for skin-markers based kinematic analysis

The medial-longitudinal arch (MLA) is perhaps the most important feature characterizing foot morphology. While current skin-markers based models of the MLA angle used in stereophotogrammetry allow to estimate foot arch shape and deformation, these do not always appear consistent with foot anatomy and with standard clinical definitions. The aim of this study was to propose novel skin-markers based measures of MLA angle and investigate their reliability during common motor tasks. Markers on the calcaneus, navicular tuberosity, first metatarsal head and base, and on the two malleoli were exploited to test eight definitions of MLA angle consistent with foot anatomy, both as angles between two 3-dimensional vectors and as corresponding projections on the sagittal plane of the foot. The inter-trial, inter-session and inter-examiner reliability of each definition was assessed in multiple walking and running trials of two volunteers, tested by four examiners in three sessions. Inter-trial variability in walking was in the range 0.7-1.2 deg, the inter-session 2.8-7.5 deg, and the inter-examiner in the range 3.7-9.3 deg across all MLA definitions. The Rizzoli Foot Model definition showed the lowest inter-session and inter-examiner variability. MLA measures presented similar variability in walking and running. This study provides preliminary information on the reliability of MLA measurements based on skin-markers. According to the present study, angles between 3-dimensional vectors and minimal marker sets should be preferred over sagittal-plane projections. Further studies should be sought to investigate which definition is more accurate with respect to the real MLA deformation in different loading conditions.

Supplementary Motor Area and Superior Parietal Lobule Restore Sensory Facilitation Prior to Stepping When a Decrease of Afferent Inputs Occurs

The weighting of the sensory inputs is not uniform during movement preparation and execution. For instance, a transient increase in the transmission to the cortical level of cutaneous input ~700 ms was observed before participants initiated a step forward. The sensory facilitation occurred at a time when feet cutaneous information is critical for setting the forces to be exerted onto the ground to shift the center of mass toward the supporting side prior to foot-off. Despite clear evidence of task-dependent modulation of the early somatosensory signal transmission, the neural mechanisms are mainly unknown. One hypothesis suggests that during movement preparation the premotor cortex and specifically the supplementary motor area (SMA) can be the source of an efferent signal that facilitates the somatosensory processes irrespectively of the amount of sensory inputs arriving at the somatosensory areas. Here, we depressed mechanically the plantar sole cutaneous transmission by increasing pressure under the feet by adding an extra body weight to test whether the task-dependent modulation is present during step preparation. Results showed upregulation of the neural response to tactile stimulation in the extra-weight condition during the stepping preparation whereas depressed neural response was still observed in standing condition. Source localization indicated the SMA and to a lesser extent the superior parietal lobule (SPL) areas as the likely origin of the response modulation. Upregulating cutaneous inputs (when mechanically depressed) at an early stage by efferent signals from the motor system could be an attempt to restore the level of sensory afferents to make it suitable for setting the anticipatory adjustments prior to step initiation.

A protocol to prospectively assess risk factors for medial tibial stress syndrome in distance runners

Background

Medial tibial stress syndrome (MTSS) is a lower leg injury with a reported incidence rate of up to 35% in active individuals. Although numerous prospective studies have tried to identify risk factors for developing MTSS, managing the syndrome remains difficult. One risk factor yet to be extensively explored in MTSS development is reduced lower leg girth. Further investigation of reduced lower leg girth is required due to the important role lower leg musculature plays in attenuating ground reaction forces during the gait cycle. Therefore, the primary aim of this study is to ascertain whether lower leg muscle morphology and function contribute to the development of MTSS. Our ultimate aim is to identify potential risk factors for MTSS that can be targeted in future studies to better manage the injury or, preferably, prevent individuals developing MTSS.

Methods

This study will be prospective in design and will recruit asymptomatic distance runners. All participants will be tested at base line and participants will have their training data longitudinally tracked over the following 12 months to assess any individuals who develop MTSS symptoms. At base line, outcome measures will include bilateral measures of lower limb anthropometry; cross sectional area (CSA) and thickness of the tibialis anterior, peroneals, flexor digitorum longus, flexor hallucis longus and thickness of soleus, medial and lateral head of gastrocnemius. Tibial bone speed of sound, ankle dorsiflexion range of motion, strength of the six previously described muscles, foot alignment and ankle plantar flexor endurance will also be assessed. Participants will also complete a treadmill running protocol where three-dimensional kinematics, plantar pressure distribution and electromyography data will be collected.

Discussion

This study will aim to identify characteristics of individuals who develop MTSS and, in turn, identify modifiable risk factors that can be targeted to prevent individuals developing this injury.

The influence of gait and speed on the dynamic navicular drop - A cross sectional study on healthy subjects

INTRODUCTION

Variations of gait speed influence kinematic variables that may have an effect on dynamic foot deformation. The influence of gait speed on the navicular drop has not yet been investigated.

METHODS

The navicular drop was evaluated in static and dynamic conditions using a 3D-motion capture system. The dynamic navicular drop was evaluated on a treadmill while walking and running at three different speeds. A repeated measures ANOVA and post-hoc tests were conducted to evaluate the differences in dynamic navicular drop, corresponding unloaded navicular height at foot strike and loaded navicular height during stance.

RESULTS

Higher walking speed led to a significant decrease in navicular height at foot strike and a subsequent decrease of dynamic navicular drop (p=0.006). Across increasing running speeds, minimum navicular height was significantly decreased which in consequence led to an increased dynamic navicular drop (p=0.015). For walking and running at the same speed, there was a large effect of gait style with an increase of dynamic navicular drop by 3.5mm (p<0.001) during running.

DISCUSSION

The change of gait from walking to running at the same speed had a large effect on dynamic navicular drop. The values of navicular height at foot strike and minimum navicular height during stance should be taken into account for the interpretation of dynamic navicular drop measures. Static and dynamic navicular drop measures differ substantially.

Gender difference in factors affecting the medial longitudinal arch height of the foot in healthy young adults

[Purpose] Medial longitudinal arch (MLA) height is associated with various injuries and diseases and gender differences, if any. This study aimed to examine factors affecting the MLA height associated with gender differences in healthy subjects with no orthopedic disorders. [Subjects and Methods] This study included 36 healthy adults (19 males, 17 females; mean age, 21.8 ± 3.6 years; body mass index, 21.1 ± 2.0 kg/m²). Their height, body weight, foot length, muscle strength of the tibialis posterior muscle (TPM), toe-gripping strength, hallux valgus angle, inversion microdactylia angle, angle of leg-heel alignment, femoro-tibial angle, and navicular height were measured. Correlation between the ratio of arch height and other measurement parameters was examined. [Results] In females, the ratio of arch height was significantly positively correlated with muscle strength of the TPM and toe-gripping strength and negatively correlated with the hallux valgus angle and the leg-heel alignment, whereas in males, only a positive correlation between the ratio of arch height and muscle strength of the TPM was observed. [Conclusion] These results reveal that etiological mechanisms determining MLA height are different between males and females. Overall, the present results indicate that further studies identifying causes of MLA height variation must include gender-based analysis.

Comprehensive biomechanical characterization of feet in USMA cadets: Comparison across race, gender, arch flexibility, and foot types

Lower extremity musculoskeletal injuries are common, complex, and costly problems. Literature supports associations between static foot structure and dynamic foot function, as well as between overuse injury and demographic characteristics. Previous studies failed to provide a comprehensive biomechanical foot characteristics of at-risk military personnel. In this study, foot structure, function, and arch height flexibility (AHF) were objectively measured in 1090 incoming cadets (16.3% female, mean age of 18.5years and BMI of 24.5kg/m²) of the United States Military Academy at the start of their training. A Generalized Linear Model with an identity link function was used to examine the effects of race, gender, foot types, and AHF while accounting for potential dependence in bilateral data. Planus and flexible feet independently demonstrated over-pronation, as measured by reduced Center of Pressure Excursion Index (CPEI). When comparing across race, Black participants showed a significantly lower arch height index (AHI), a larger malleolar valgus index (MVI), and a higher prevalence of pes planus (91.7% versus 73.3% overall). However, Asian participants with flexible arches, rather than Black with low arch, displayed over-pronation in gait. Females showed no significant difference in standing AHI and MVI but demonstrated a significantly greater AHF and a reduced CPEI than male participants. This was the first large scale investigation that comprehensively characterized biomechanical foot in a cohort of young at-risk individuals with lower limb musculoskeletal injuries. Long-term goal is to examine the relationship between these biomechanical features and injuries, ultimately to develop effective preventive measures.

Biomechanical Factors Associated With Achilles Tendinopathy and Medial Tibial Stress Syndrome in Runners

BACKGROUND

There is disagreement in the literature regarding whether the excessive excursion or velocity of rearfoot eversion is related to the development of 2 common running injuries: Achilles tendinopathy (AT) and medial tibial stress syndrome (MTSS). An alternative hypothesis suggests that the duration of rearfoot eversion may be an important factor. However, the duration of eversion has received relatively little attention in the biomechanics literature.

HYPOTHESIS

Runners with AT or MTSS will demonstrate a longer duration of eversion but not greater excursion or velocity of eversion compared with healthy controls.

STUDY DESIGN

Controlled laboratory study.

METHODS

Forty-two runners participated in this study (13 with AT, 8 with MTSS, and 21 matched controls). Participants were evaluated for lower extremity alignment and flexibility, after which a 3-dimensional kinematic and kinetic running gait analysis was performed. Differences between the 2 injuries and between injured and control participants were evaluated for flexibility and alignment, rearfoot kinematics, and 3 ground-reaction force metrics. Binary logistic regression was used to evaluate which variables best predicted membership in the injured group.

RESULTS

Injured participants, compared with controls, demonstrated higher standing tibia varus angles (8.67° ± 1.79° vs 6.76° ± 1.75°, respectively; P = .002), reduced static dorsiflexion range of motion (6.14° ± 5.04° vs 11.19° ± 5.10°, respectively; P = .002), more rearfoot eversion at heel-off (-6.47° ± 5.58° vs 1.07° ± 2.26°, respectively; P < .001), and a longer duration of eversion (86.02% ± 15.65% stance vs 59.12% ± 16.50% stance, respectively; P < .001). There were no differences in the excursion or velocity of eversion. The logistic regression (χ² = 20.84, P < .001) revealed that every 1% increase in the duration of eversion during the stance phase increased the odds of being in the injured group by 1.08 (95% CI, 1.023-1.141; P = .006).

CONCLUSION

Compared with healthy controls, runners currently symptomatic with AT or MTSS have a longer duration of eversion but not greater excursion or velocity of eversion.

CLINICAL RELEVANCE

Static measures of the tibia varus angle and dorsiflexion range of motion, along with dynamic measures of the duration of eversion, may be useful for identifying runners at risk of sustaining AT or MTSS.

Prevalence of Flexible Flat Foot in Adults: A Cross-sectional Study

INTRODUCTION

Flat foot (pes planus) is a commonly observed disorder in clinical practice. The height of Medial Longitudinal Arch (MLA) determines the degree of pes planus. Majority of the previous studies on prevalence of flexible flat foot were done among children.

AIM

The present study was undertaken to determine the prevalence of flexible flat foot among 18-21-year-old Indian adults using Navicular Drop Test (NDT) which is regarded as reliable and valid method to characterise MLA.

MATERIALS AND METHODS

The present study was a cross-sectional study in which Brody's Navicular Drop Test was performed in five hundred healthy subjects (250 males and 250 females) aged 18-21-year-old. Navicular Drop (ND) of ≥ 10 mm was regarded as flexible flat foot. Statistical analysis was done using SPSS version 23.0.

RESULTS

The prevalence of flexible flat foot was 13.6% (for males-12.8%; for females-14.4%). The median with Inter Quartile Range (IQR) for ND among males was 6 mm (4-8) and 6 mm (4-9) for right and left foot respectively. The median with IQR for ND among females was 6mm (4-10) and 7mm (3-8) for right & left respectively. The correlation of Right Side Navicular Drop (RND) with height and weight was significant, but insignificant correlation was found between RND and BMI. The correlation of Left Side Navicular Drop (LND) with height, weight and BMI of individuals was statistically not significant. The difference between the ND of males and female group was statistically not significant.

CONCLUSION

The present study quantified the prevalence of flexible flat foot and gender wise normative values of ND among 18-21-year-old Indian adults. The information obtained by this study will be useful in the field of orthopaedics.

Plantar Sole Unweighting Alters the Sensory Transmission to the Cortical Areas

It is well established that somatosensory inputs to the cortex undergo an early and a later stage of processing. The later has been shown to be enhanced when the earlier transmission decreased. In this framework, mechanical factors such as the mechanical stress to which sensors are subjected when wearing a loaded vest are associated with a decrease in sensory transmission. This decrease is in turn associated with an increase in the late sensory processes originating from cortical areas. We hypothesized that unweighting the plantar sole should lead to a facilitation of the sensory transmission. To test this hypothesis, we recorded cortical somatosensory evoked potentials (SEPs) of individuals following cutaneous stimulation (by mean of an electrical stimulation of the foot sole) in different conditions of unweighting when standing still with eyes closed. To this end, the effective bodyweight (BW) was reduced from 100% BW to 40% BW. Contrary to what was expected, we found an attenuation of sensory information when the BW was unweighted to 41% which was not compensated by an increase of the late SEP component. Overall these results suggested that the attenuation of sensory transmission observed in 40 BW condition was not solely due to the absence of forces acting on the sole of the feet but rather to the current relevance of the afferent signals related to the balance constraints of the task.

Relationship between the mobility of medial longitudinal arch and postural control

OBJECTIVE

The aim of this study was to analyze the relationship between the medial longitudinal arch mobility and static and dynamic balance.

METHODS

A total of 50 subjects (25 female, and 25 male; Mean age: 22.2 ± 1.3 years; BMI: 22.8 ± 3.8 kg/m²) were included in this study. The relative arch deformity (RAD) was calculated with both 10% and 90% weight bearing (WB). Static balance was evaluated with Single Leg Stance Test and dynamic balance with TechnoBody PK 200WL computerized balance device. Subjects were evaluated for goniometric measurements of lower extremity joints, leg dominance and leg-length discrepancy.

RESULTS

Bipedal dynamic balance was correlated with both feet length at 10% WB and 90% WB. There was a correlation between the dynamic balance on dominant foot and RAD value on the aspect of Medium Speed (r = -0.32, p = 0.02), Perimeter Length (r = -0.32, p = 0.02) and Anterior-Posterior Sway (r = 0.36, p = 0.01). Static balance was unaffected by RAD value when the visual system was eliminated.

CONCLUSION

Our results suggest that decrease of arch mobility on the dominant foot is associated with posterior sway by causing knee or hip strategy and preventing ankle strategy even in small perturbations. The rate of deviation from the equilibrium point and the degree of total swaying increase when arch mobility decreases.

The assessment of three-dimensional foot pronation using a principal component analysis method in the stance phase of running

Foot pronation has not been quantified dynamically in three planes of movement in an in-vivo study. The aims of this study were to determine foot pronation through using Principal Component Analysis (PCA) method and to compare it among barefoot, shod and shod with 6° lateral wedge during the stance phase of running. In this method, three-dimension of foot movements were measured and each of these components represents a percentage of foot pronation. These components were derived based on eigenvalues and vectors of covariance matrix of primary variables. The first (PC1), second (PC2) and third (PC3) components explained about (82.5%, 79.1%), (14%, 15.8%) and (3.5%, 5.1%) the foot pronation for barefoot and shod conditions, respectively. These components were mutually independent and the components set had the same information as the primary variables. Foot pronation index and eversion angles were calculated and compared among barefoot, shod and shod with wedge insole (6° lateral wedge insole) conditions in the four phases of stance. Statistical analysis showed that there was no foot conditions effect for foot eversion in four phases (p=0.72), while this effect was significant for PC1 (p=0.001). This finding shows that PC1 index could discriminate footwear effect among each phase of stance. Specifically, pronation was reduced in shoe condition as compared to barefoot condition (p=0.02) from 5 to 50% of stance phase. It has been suggested that the PCA method provides more accurate criteria for investigating effects of footwear interventions on simultaneous three-dimensional foot motion.

Differences in the angle of the medial longitudinal arch and muscle activity of the abductor hallucis and tibialis anterior during sitting short-foot exercises between subjects with pes planus and subjects with neutral foot

BACKGROUND AND OBJECTIVES

Excessive activity of the tibialis anterior muscle may be a causal mechanism in overuse injuries such as stress fracture in pes planus patients. However, information about this relationship is limited. In this study, we compared the angle of the medial longitudinal arch, the activities of the abductor hallucis and tibialis anterior muscles, and the activity ratio of tibialis anterior/abductor hallucis in individuals with pes planus and those with a neutral foot position during short-foot exercises conducted while sitting.

METHODS

Differences between the groups were analyzed using an independent t-test. In all, 28 university students participated in this study (14 subjects in each group).

RESULTS

The activity of the abductor hallucis muscle was significantly lower (p < 0.001), and the activity ratio of tibialis anterior/abductor hallucis was significantly greater (p = 0.012) in the pes planus group than in the neutral foot group during the exercise.

CONCLUSIONS

Clinicians should recognize that pes planus patients may compensate for reduced activation of the abductor hallucis to maintain the angle of the medial longitudinal arch during the sitting short-foot exercise.

Medial Tibial Stress Syndrome in Active Individuals: A Systematic Review and Meta-analysis of Risk Factors

CONTEXT

Medial tibial stress syndrome (MTSS) is a common condition in active individuals and presents as diffuse pain along the posteromedial border of the tibia.

OBJECTIVE

To use cross-sectional, case-control, and cohort studies to identify significant MTSS risk factors.

DATA SOURCES

Bibliographic databases (PubMed, Scopus, CINAHL, SPORTDiscus, EMBASE, EBM Reviews, PEDRo), grey literature, electronic search of full text of journals, manual review of reference lists, and automatically executed PubMed MTSS searches were utilized. All searches were conducted between 2011 and 2015.

STUDY SELECTION

Inclusion criteria were determined a priori and included original research with participants' pain diffuse, located in the posterior medial tibial region, and activity related.

STUDY DESIGN

Systematic review with meta-analysis.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Titles and abstracts were reviewed to eliminate citations that did not meet the criteria for inclusion. Study characteristics identified a priori were extracted for data analysis. Statistical heterogeneity was examined using the I2 index and Cochran Q test, and a random-effects model was used to calculate the meta-analysis when 2 or more studies examined a risk factor. Two authors independently assessed study quality.

RESULTS

Eighty-three articles met the inclusion criteria, and 22 articles included risk factor data. Of the 27 risk factors that were in 2 or more studies, 5 risk factors showed a significant pooled effect and low statistical heterogeneity, including female sex (odds ratio [OR], 2.35; CI, 1.58-3.50), increased weight (standardized mean difference [SMD], 0.24; CI, 0.03-0.45), higher navicular drop (SMD, 0.44; CI, 0.21-0.67), previous running injury (OR, 2.18; CI, 1.00-4.72), and greater hip external rotation with the hip in flexion (SMD, 0.44; CI, 0.23-0.65). The remaining risk factors had a nonsignificant pooled effect or significant pooled effect with high statistical heterogeneity.

CONCLUSION

Female sex, increased weight, higher navicular drop, previous running injury, and greater hip external rotation with the hip in flexion are risk factors for the development of MTSS.

Can positional MRI predict dynamic changes in the medial plantar arch? An exploratory pilot study

BACKGROUND

Positional MRI (pMRI) allows for three-dimensional visual assessment of navicular position. In this exploratory pilot study pMRI was validated against a stretch sensor device, which measures movement of the medial plantar arch. We hypothesized that a combined pMRI measure incorporating both vertical and medial displacement of the navicular bone induced by loading would be correlated with corresponding stretch sensor measurements.

METHODS

10 voluntary participants were included in the study. Both pMRI and subsequent stretch sensor measurements were performed in a) supine, b) standing and c) standing position with addition of 10 % body weight during static loading of the foot. Stretch sensor measurements were also performed during barefoot walking.

RESULTS

The total change in navicular position measured by pMRI was 10.3 mm (CI: 7.0 to 13.5 mm). No further displacement occurred when adding 10 % bodyweight (mean difference: 0.7 mm (CI: -0.7 to 2.0 mm), P = 0.29). The total navicular displacement correlated with stretch sensor measurement under static loading conditions (Spearman's rho = 0.66, P = 0.04) but not with measurements during walking (Spearman's rho = 0.58, P = 0.08).

CONCLUSIONS

Total navicular bone displacements determined by pMRI showed concurrent validity with stretch sensor measurements but only so under static loading conditions. Although assessment of total navicular displacement by combining concomitant vertical and medial navicular bone movements would appear advantageous compared to monoplanar measurement the combined measure did not seem to predict dynamic changes of the medial foot arch during walking, which are among several possible factors depending on different walking patterns.

Neural Consequences of Increasing Body Weight: Evidence from Somatosensory Evoked Potentials and the Frequency-Specificity of Brain Oscillations

Previous studies on the control of human balance suggested that increased pressure under the feet, leading to reduced plantar sole mechanoreceptors sensitivity, increases body sway. Although this suggestion is attracting, it is unclear whether increased plantar sole pressure simply reduces the transmission of plantar sole afferent to the cortex or also alters the sensorimotor integrative mechanisms. Here we used electrical stimulation applied under the sole of the foot to probe the sensorimotor mechanisms processing foot mechanoreceptors. Balance control of healthy individuals was assessed either when wearing a loaded vest or in normal-weight condition. In the Loaded condition, we observed decreased cortical activity over the primary somatosensory cortex (SI) for both an early P₅₀-N₉₀ somatosensory evoked potential (SEP) and for oscillatory brain activity within the gamma band (30–80 Hz). These reductions were interpreted as a disrupted early sensory transmission (i.e., decreased early SEP) leading to a decreased perception of plantar sole sensory information (i.e., decreased gamma band power). These early sensory mechanisms for the Loaded condition were associated with an increase in the late P₁₇₀-N₂₁₀ SEP and oscillatory brain activity within the beta band (19–24 Hz). These neural signatures involved areas which are engaged in sensorimotor integrative processes (secondary somatosensory cortex (SII) and right temporoparietal junction). Altered early and late sensory processes may result from the increase pressure on the mechanoreceptors of the foot sole and not from postural instability per se. Indeed, postural instability with normal weight condition did not lead to SEP changes.

Forefoot flexibility and medial tibial stress syndrome

PURPOSE

To investigate the association between medial tibial stress syndrome (MTSS) and morphology and flexibility of the foot arches.

METHODS

131 feet from 74 healthy subjects and 31 feet from 27 patients with MTSS were classified as normal feet (n=78 in 40 subjects), flat feet (n=53 in 34 subjects), or MTSS feet (n=31 in 27 patients). The medial longitudinal arch (MLA) ratio and the transverse arch length (TAL) were measured in both rearfoot and forefoot loading positions. The difference between the 2 positions indicated the flexibility of the MLA (diff-MLA ratio) and the transverse arch (diff- TAL).

RESULTS

The MLA ratio was higher in normal feet than MTSS feet or flat feet (15.1% vs. 12.8% vs. 12.3%, p<0.001). The diff-TAL was lower in MTSS feet than normal feet or flat feet (0.4% vs. 0.8% vs. 0.9%, p<0.001]). The 3 groups were comparable in terms of the diff-MLA ratio and the TAL. Respectively for the MLA ratio and the diff-TAL, the cut-off value was 11.9% and 0.61% based on the Youden index. The sensitivity, specificity, and odds ratio of the cut-off value were 0.4, 0.9, and 4.8 for the MLA ratio, and 0.6, 0.7, and 9.8 for the diff-TAL, respectively.

CONCLUSION

Decreased flexibility of the transverse arch and decreased MLA ratio are risk factors for MTSS. In contrast, the flexibility of the MLA and the height of the transverse arch were not risk factors for MTSS.

Studying the Relation Between Medial Tibial Stress Syndrome and Anatomic and Anthropometric Characteristics of Military Male Personnel

BACKGROUND

Medial Tibial Stress Syndrome (MTSS) is common among military recruits and to our knowledge; the factors that might put the military recruits at higher risk of incidence of MTSS are not well known.

OBJECTIVES

This study was done to investigate the association between some anthropometric and anatomical factors and the prevalence of MTSS among military recruits.

PATIENTS AND METHODS

One hundred and eighty one randomly selected military recruits were included in this cross sectional study. Using history taking and physical examinations they were tested for MTSS. Accordingly the subjects were assigned to the case (those with MTSS) and control groups (normal healthy subjects). Using standard guidelines, the anthropometric and anatomical criteria of the subjects were measured. The correlation between the measurements and the prevalence of MTSS was tested using statistical analysis.

RESULTS

Data of all the 181 subjects with the mean age of 30.7 ± 4.68 years were Included in the final analysis. The prevalence of MTSS was found to be 16.6% (30 people). Internal and external rotation range of motion, iliospinale height, the score of navicular drop test, and the trochanteric tibial lateral length were significantly different between healthy subjects and patients with MTSS (P < 0.05).

DISCUSSION

The prevalence of MTSS was relatively lower in this study comparing to other studies on military personnel. It was not probably due to type of military shoes or exercise area surface (none of them were standardized); it could be due to low intensity trainings and the long intervals between training sessions.

Non-surgical treatment of pain associated with posterior tibial tendon dysfunction: study protocol for a randomised clinical trial

Background

Symptoms associated with pes planovalgus or flatfeet occur frequently, even though some people with a flatfoot deformity remain asymptomatic. Pes planovalgus is proposed to be associated with foot/ankle pain and poor function. Concurrently, the multifactorial weakness of the tibialis posterior muscle and its tendon can lead to a flattening of the longitudinal arch of the foot. Those affected can experience functional impairment and pain. Less severe cases at an early stage are eligible for non-surgical treatment and foot orthoses are considered to be the first line approach. Furthermore, strengthening of arch and ankle stabilising muscles are thought to contribute to active compensation of the deformity leading to stress relief of soft tissue structures. There is only limited evidence concerning the numerous therapy approaches, and so far, no data are available showing functional benefits that accompany these interventions.

Methods

After clinical diagnosis and clarification of inclusion criteria (e.g., age 40–70, current complaint of foot and ankle pain more than three months, posterior tibial tendon dysfunction stage I & II, longitudinal arch flattening verified by radiography), sixty participants with posterior tibial tendon dysfunction associated complaints will be included in the study and will be randomly assigned to one of three different intervention groups: (i) foot orthoses only (FOO), (ii) foot orthoses and eccentric exercise (FOE), or (iii) sham foot orthoses only (FOS). Participants in the FOO and FOE groups will be allocated individualised foot orthoses, the latter combined with eccentric exercise for ankle stabilisation and strengthening of the tibialis posterior muscle. Participants in the FOS group will be allocated sham foot orthoses only. During the intervention period of 12 weeks, all participants will be encouraged to follow an educational program for dosed foot load management (e.g., to stop activity if they experience increasing pain). Functional impairment will be evaluated pre- and post-intervention by the Foot Function Index. Further outcome measures include the Pain Disability Index, Visual Analogue Scale for pain, SF-12, kinematic data from 3D-movement analysis and neuromuscular activity during level and downstairs walking. Measuring outcomes pre- and post-intervention will allow the calculation of intervention effects by 3×3 Analysis of Variance (ANOVA) with repeated measures.

Discussion

The purpose of this randomised trial is to evaluate the therapeutic benefit of three different non-surgical treatment regimens in participants with posterior tibial tendon dysfunction and accompanying pes planovalgus. Furthermore, the analysis of changes in gait mechanics and neuromuscular control will contribute to an enhanced understanding of functional changes and eventually optimise conservative management strategies for these patients.

Trial registration

ClinicalTrials.gov Protocol Registration System: ClinicalTrials.gov ID NCT01839669

Foot posture as a risk factor for lower limb overuse injury: a systematic review and meta-analysis

Background

Static measures of foot posture are regularly used as part of a clinical examination to determine the need for foot level interventions. This is based on the premise that pronated and supinated foot postures may be risk factors for or associated with lower limb injury. This systematic review and meta-analysis investigates foot posture (measured statically) as a potential risk factor for lower limb overuse injuries.

Methods

A systematic search was performed using Medline, CINAHL, Embase, SportDiscus in April 2014, to identify prospective cohort studies that investigated foot posture and function as a risk factor for lower limb overuse injury. Eligible studies were classified based on the method of foot assessment: (i) static foot posture assessment; and/or (ii) dynamic foot function assessment. This review presents studies evaluating static foot posture. The methodological quality of included studies was evaluated by two independent reviewers, using an adapted version of the Epidemiological Appraisal Instrument (EAI). Where possible, effects were expressed as standardised mean differences (SMD) for continuous scaled data, and risk ratios (RR) for nominal scaled data. Meta-analysis was performed where injuries and outcomes were considered homogenous.

Results

Twenty-one studies were included (total n = 6,228; EAI 0.8 to 1.7 out of 2.0). There was strong evidence that a pronated foot posture was a risk factor for medial tibial stress syndrome (MTSS) development and very limited evidence that a pronated foot posture was a risk factor for patellofemoral pain development, although associated effect sizes were small (0.28 to 0.33). No relationship was identified between a pronated foot posture and any other evaluated pathology (i.e. foot/ankle injury, bone stress reactions and non-specific lower limb overuse injury).

Conclusion

This systematic review identified strong and very limited evidence of small effect that a pronated foot posture is a risk factor for MTSS and patellofemoral pain respectively. Evaluation of static foot posture should be included in a multifactorial assessment for both MTSS and patellofemoral pain, although only as a part of the potential injury risk profile. Whilst the included measures are clinically applicable, further studies are required to determine their relationship with dynamic foot function.

Electronic supplementary material

The online version of this article (doi:10.1186/s13047-014-0055-4) contains supplementary material, which is available to authorized users.

Treatment of medial tibial stress syndrome according to the fascial distortion model: a prospective case control study

Medial tibial stress syndrome (MTSS) is a common problem among athletes and soldiers. There is no proven theory that could explain the pathophysiology of shin splints. The therapies described so far are time-consuming and involve a high risk of relapse. The method according to the fascial distortion model (FDM) addresses local changes in the area of the lower leg fascia. It is suited to reduce pain and functional impairments associated with this symptom complex by applying targeted manual techniques. 32 patients (male: 30; female: 2) participated in this study. Visual analogue scale (VAS) was used for the quantification of pain. Scores were also given to rate the maximum painless exercise tolerance of the patients. Subsequently treatment of the crural fascia was performed. Patients retested ability of running and jumping. Therapy was continued until full exercise tolerance or painlessness was reached. A significant reduction of the VAS pain score from 5.2 to 1.1 could be achieved (P < 0.001). The impairment of exercise tolerance could be reduced from 7 to 2 points (P < 0.001). The duration of treatment was 6.3 (SD: 4.3) days on average. The FDM therapy is a potential effective method for acute treatment of MTSS.

Effect of graft shape in lateral column lengthening on tarsal bone position and subtalar and talonavicular contact pressure in a cadaveric flatfoot model

BACKGROUND

Lateral column lengthening (LCL) has been used for correction of flatfoot deformity. The purpose of this study was to determine the effect of LCL graft shape on tarsal bone position and talonavicular and subtalar joint pressure.

METHODS

A flatfoot model was created in 6 cadaveric specimens. Corrective LCL was performed using a rectangular graft or a trapezoidal graft with the broad surface oriented dorsally, laterally, or plantarly. Bony surface markers were digitized to calculate angular parameters used in the evaluation of flatfoot deformity. Contact pressure and area in the subtalar and talonavicular joints were also recorded. All measurements were carried out under multiple axial loads in the intact and flatfoot conditions, and following LCL with each graft shape.

RESULTS

Flatfoot creation resulted in significant changes in arch collapse and forefoot abduction. LCL with a rectangular graft best corrected these parameters, while a laterally oriented trapezoidal graft provided some correction. Talonavicular contact pressure was unchanged after flatfoot creation, and was significantly less than intact after LCL. Subtalar contact pressure decreased in some conditions after flatfoot creation, and decreased further after LCL.

CONCLUSION

LCL with a rectangular graft best restored tarsal bone orientation in a cadaveric flatfoot model. The decreases in talonavicular pressure likely represent redistribution of force from the medial to lateral foot.

CLINICAL RELEVANCE

When performing LCL for flatfoot deformity, increased bone graft volume medially better restores tarsal bone position. One way of achieving this is through the use of a rectangular graft as opposed to a trapezoidal graft.

Comparing 3D foot scanning with conventional measurement methods

BACKGROUND

Foot dimension information on different user groups is important for footwear design and clinical applications. Foot dimension data collected using different measurement methods presents accuracy problems. This study compared the precision and accuracy of the 3D foot scanning method with conventional foot dimension measurement methods including the digital caliper, ink footprint and digital footprint.

METHODS

Six commonly used foot dimensions, i.e. foot length, ball of foot length, outside ball of foot length, foot breadth diagonal, foot breadth horizontal and heel breadth were measured from 130 males and females using four foot measurement methods. Two-way ANOVA was performed to evaluate the sex and method effect on the measured foot dimensions. In addition, the mean absolute difference values and intra-class correlation coefficients (ICCs) were used for precision and accuracy evaluation. The results were also compared with the ISO 20685 criteria.

RESULTS

The participant's sex and the measurement method were found (p < 0.05) to exert significant effects on the measured six foot dimensions. The precision of the 3D scanning measurement method with mean absolute difference values between 0.73 to 1.50 mm showed the best performance among the four measurement methods. The 3D scanning measurements showed better measurement accuracy performance than the other methods (mean absolute difference was 0.6 to 4.3 mm), except for measuring outside ball of foot length and foot breadth horizontal. The ICCs for all six foot dimension measurements among the four measurement methods were within the 0.61 to 0.98 range.

CONCLUSIONS

Overall, the 3D foot scanner is recommended for collecting foot anthropometric data because it has relatively higher precision, accuracy and robustness. This finding suggests that when comparing foot anthropometric data among different references, it is important to consider the differences caused by the different measurement methods.

Motion analysis to track navicular displacements in the pediatric foot: relationship with foot posture, body mass index, and flexibility

BACKGROUND

Increased navicular drop (NDro) and navicular drift (NDri) are associated with musculoskeletal pathology in adults. The aim of this study was to investigate navicular motion in children, with respect to foot posture, and identify altered patterns of motion that demonstrate midfoot dysfunction. Navicular motion in different activities was evaluated as well as the role of flexibility and body mass index (BMI).

METHODS

Twenty-five children with flatfeet and 26 with neutral feet (age range, 8-15) underwent gait analysis using a 12-camera Vicon MX system (Vicon, UK). Navicular motion indices were calculated from marker coordinates. Student t tests and Pearson's correlation coefficient (R) were used to investigate navicular motion differences between groups. The relationship between NDRo, NDRi, and their dynamic counterparts was also assessed.

RESULTS

Normalized NDri (NNDri) and normalized NDro (NNDro) correlated strongly in neutral feet (R = 0.56, P = .003) but not in flatfeet (R = 0.18, P > .05). Flatfeet demonstrated reduced NNDri compared to neutral footed children (0.7 vs 1.6, P = .007). No difference was observed in NNDro between groups. Standard and dynamic measures of NDri and NDRo were highly correlated. Navicular motion correlated poorly with BMI and flexibility.

CONCLUSION

Motion of the navicular in the transverse and the sagittal plane is important when investigating foot function. Uncoupling of this motion in flatfeet may indicate impaired midfoot function. Reduced navicular medial translation in flatfeet may indicate altered alignment of the talonavicular joint.

CLINICAL RELEVANCE

The measurement of dynamic navicular motion indices did not add information about dynamic foot function compared to measurement of static indices.

Medial longitudinal arch mechanics before and after a 45-minute run

BACKGROUND

Medial longitudinal arch integrity after prolonged running has yet to be well documented. We sought to quantify changes in medial longitudinal arch kinematics before and after a 45-min run in healthy recreational runners.

METHODS

Thirty runners performed barefoot seated, standing, and running trials before and after a 45-min shod treadmill run. Navicular displacement, arch lengthening, and the arch height index were used to quantify arch deformation, and the arch rigidity index was used to quantify arch stiffness.

RESULTS

There were no statistically significant differences in mean (95% confidence interval) values for navicular displacement (5.6 mm [4.7-6.4 mm]), arch lengthening (3.2 mm [2.6-3.9 mm]), change in arch height index (0.015 [0.012-0.018]), or arch rigidity index (0.95 [0.94-0.96]) after the 45-min run (all multivariate analyses of variance P ≥ .065).

CONCLUSIONS

Because there were no statistically significant changes in arch deformation or rigidity, the structures of a healthy, intact medial longitudinal arch are capable of either adapting to cyclical loading or withstanding a 45-min run without compromise.

Risk factors associated with medial tibial stress syndrome in runners: a systematic review and meta-analysis

Background

Medial tibial stress syndrome (MTSS) affects 5%–35% of runners. Research over the last 40 years investigating a range of interventions has not established any clearly effective management for MTSS that is better than prolonged rest. At the present time, understanding of the risk factors and potential causative factors for MTSS is inconclusive. The purpose of this review is to evaluate studies that have investigated various risk factors and their association with the development of MTSS in runners.

Methods

Medical research databases were searched for relevant literature, using the terms “MTSS AND prevention OR risk OR prediction OR incidence”.

Results

A systematic review of the literature identified ten papers suitable for inclusion in a meta-analysis. Measures with sufficient data for meta-analysis included dichotomous and continuous variables of body mass index (BMI), ankle dorsiflexion range of motion, navicular drop, orthotic use, foot type, previous history of MTSS, female gender, hip range of motion, and years of running experience. The following factors were found to have a statistically significant association with MTSS: increased hip external rotation in males (standard mean difference [SMD] 0.67, 95% confidence interval [CI] 0.29–1.04, P<0.001); prior use of orthotics (risk ratio [RR] 2.31, 95% CI 1.56–3.43, P<0.001); fewer years of running experience (SMD −0.74, 95% CI −1.26 to −0.23, P=0.005); female gender (RR 1.71, 95% CI 1.15–2.54, P=0.008); previous history of MTSS (RR 3.74, 95% CI 1.17–11.91, P=0.03); increased body mass index (SMD 0.24, 95% CI 0.08–0.41, P=0.003); navicular drop (SMD 0.26, 95% CI 0.02–0.50, P=0.03); and navicular drop >10 mm (RR 1.99, 95% CI 1.00–3.96, P=0.05).

Conclusion

Female gender, previous history of MTSS, fewer years of running experience, orthotic use, increased body mass index, increased navicular drop, and increased external rotation hip range of motion in males are all significantly associated with an increased risk of developing MTSS. Future studies should analyze males and females separately because risk factors vary by gender. A continuum model of the development of MTSS that links the identified risk factors and known processes is proposed. These data can inform both screening and countermeasures for the prevention of MTSS in runners.

Osteopathic Manipulative Treatment in Tarsal Somatic Dysfunction: A Case Study

The authors present a case of a 24-year-old woman with left foot pain that began after an inversion injury obtained while running. The pain minimally improved with nonsteroidal anti-inflammatory medications. Clinical examination revealed a relatively normal foot with palpable changes in the bony structures at the midfoot consistent with a tarsal subluxation. Cuboid reduction was performed using high-velocity, low-amplitude manipulation, after which the patient reported immediate and near-complete pain relief. The authors also review mechanisms of injury, clinical findings, and treatment modalities for patients with tarsal subluxation.

Exercise therapy and custom-made insoles are effective in patients with excessive pronation and chronic foot pain--a randomized controlled trial

BACKGROUND

Excessive foot pronation is a causal mechanisms described in relation to injuries of the lower extremities. Evidence to support an effective treatment is insufficient.

OBJECTIVE

To investigate the effect of exercise and custom-made insoles to patients with excessive pronation and chronic pain conditions in the foot at short and long term follow-up.

METHODS

Single blinded Randomized Controlled Trial with 80 subjects randomized: (1) Standard Intervention, (2) Insole, (3) Exercise, and (4) Insole+Exercise. Exercise - 12 week supervised program. Insoles - individually molded and posted. Pain was measured during walking, resting and running. Static and dynamic foot postures were measured as calcaneal angle, navicular drift, drop and height.

RESULTS

The average duration of foot pain was 7.3 years. There was a significant pain reduction during walking within all groups at 4 and 12 months follow-up. No differences were seen between groups in any of the pain parameters. Weak correlations between changes in pain and foot postures were observed at baseline and one-year follow-up.

CONCLUSION

A significant pain reduction was seen in all groups, none of the treatment modalities seem to be superior with the number of patients included. Compliance in the standard intervention group was a concern at 12 months.

Dynamic midfoot kinematics in subjects with medial tibial stress syndrome

BACKGROUND

Medial tibial stress syndrome (MTSS) is a common diagnosis. Several studies have demonstrated that excessive static navicular drop (ND) is related to the diagnosis. However, no studies have yet investigated ND and the velocity of ND during dynamic conditions. The aim of this study was to evaluate ND characteristics in patients with MTSS in dynamic and static conditions.

METHODS

In a case-control study, 14 patients diagnosed as having MTSS were included from an orthopedic outpatient clinic. A control group consisting of 14 healthy participants was matched regarding age, sex, and typical sporting activity. Navicular drop was evaluated during treadmill walking by a two-dimensional video analysis. Static foot posture, static ND, dynamic ND (dND), and velocity of dND were compared.

RESULTS

The two groups were comparable in relation to age, sex, height, weight, and foot size. No significant difference was found in static foot posture. Static ND showed a mean difference of 1.7 mm between the groups (P = .08). During treadmill walking, patients with MTSS had, on average, a 1.5-mm-larger dND (P =.004) and a 2.4-mm/sec-larger mean velocity of dND (P = .03).

CONCLUSIONS

Patients with MTSS display a larger ND and a higher ND velocity during treadmill walking. Increased ND velocity may be important to this condition. Future studies should include velocity of dND to investigate the mechanisms of dND in relation to overuse injuries.