The influence of foot orthoses on foot mobility magnitude and arch height index in adults with flexible flat feet

A Method-Comparison Study Highlighting the Disparity between Osseous- and Skin-Based Measures of Foot Mobility

PURPOSE

This study examined the validity of standard clinical measures of arch height mobility, midfoot width mobility (MWM), and foot mobility magnitude (FMM) relative to skin-based and osseous measures derived from radiographs.

METHODS

Skin-based clinical indices of foot mobility were calculated from standard, caliper-based measures of foot length, midfoot width, and dorsal arch height of the left limb of 20 healthy participants (8-71 yr) during non-weight-bearing and weight-bearing. Skin-based radiographic and osseous indices were derived from concurrent anteroposterior and lateral radiographs. Agreement between skin-based clinical and skin-based radiographic measures of foot mobility with those of osseous measures was investigated using the Bland and Altman approach.

RESULTS

Foot mobility indices derived from clinical measures were significantly higher (20%-50%) than skin-based radiographic measures ( P < 0.01), which were, in turn, significantly higher (200%-250%) than osseous measures ( P < 0.01). Clinical measures demonstrated significant levels of proportional bias compared with radiographic measures of foot mobility ( P < 0.01). The contribution of osseous movement to skin-based clinical measures of mobility was highly variable between individuals, ranging between 19% and 81% for arch height mobility, between 4% and 87% for MWM, and between 14% and 75% for FMM. The limits of tolerance for clinical measures of foot mobility ranged from ±3.2 mm for MWM to ±6.6 mm for measures of FMM. The limits of tolerance for skin-based clinical and skin-based radiographic measures were generally larger than osseous movement with weight-bearing.

CONCLUSIONS

Skin-based measures of foot mobility, whether clinical or radiographic methods, are not interchangeable and are poor indicators of osseous mobility. Although further research regarding the utility of osseous measures is warranted, these findings strongly caution against the use of skin-based clinical measures of foot mobility in clinical and research settings.

Capitalizing on skin in orthotics design: the effects of texture on plantar intrinsic foot muscles during locomotion

Foot orthoses (FO) are a commonly prescribed intervention to alter foot function during walking although their effects have been primarily studied in the extrinsic muscles of the foot. Furthermore, enhancing sensory feedback under the foot sole has been recently shown to alter extrinsic muscle activity during gait; however, the effects of FOs with enhanced sensory feedback on plantar intrinsic foot muscles (PIFMs) remain unknown. Thus, the purpose of this study was to investigate the effect of FOs with and without sensory facilitation on PIFM activity during locomotion. Forty healthy adults completed a series of gait trials in non-textured and textured FOs when walking over hard and soft flooring. Outcome measures included bilateral joint kinematics and electromyography (EMG) of four PIFMs. Results of this study highlight the distinct onset and cessations of each PIFM throughout the stance phase of gait. PIFMs remained active during mid-stance when wearing FOs and textured FOs facilitated muscle activity across the stance phase of gait. Increasing cutaneous input from foot sole skin, via the addition of texture under the foot sole, appears to alter motor-neuron pool excitation of PIFMs. Future academics are encouraged to increase our understanding on which pathologies, diseases, and/or medical conditions would best benefit from textured FOs.

Comparing the effects of University of California Biomechanics Laboratory and custom-made semi-rigid insole on pedobarographic parameters in pediatric flexible flat foot

BACKGROUND

Pediatric flexible flat foot (PFFF) is often associated with pain along the medial longitudinal arch and potential disability. There are several conservative treatment options for PFFF, ranging from intrinsic muscle exercises to orthosis, including University of California Biomechanics Laboratory (UCBL) and custom-made semi-rigid insoles.

OBJECTIVES

To investigate and compare the effect of UCBL and custom-made semi-rigid insoles on pedobarographic and radiologic parameters in PFFF.

STUDY DESIGN

This study prepared a retrospective chart review of 143 children diagnosed with PFFF between the age of 4 and 12 years.

METHODS

Data of twenty-seven children with PFFF who were prescribed foot orthoses between the age of 4 and 12 years were retrospectively reviewed. Medical charts were retrospectively reviewed, and pedobarographic and radiological parameters assessed before and 1 year after application of orthoses were reviewed.

RESULTS

The difference in the calcaneal pitch angle and the center of pressure excursion index (CPEI) were significantly improved in the custom-made semi-rigid insole group compared to that in the UCBL group. The contact area ratio of the midfoot and toe and CPEI at 1 year after wearing the insole was significantly improved in the custom-made semi-rigid insole group compared to that in the UCBL group. Moreover, the calcaneal pitch angle and CPEI were significantly improved 1 year after application of the insole in the custom-made semi-rigid insole group.

CONCLUSIONS

This result showed that the custom-made semi-rigid insole is more effective in improving the deviation of the center pressure curve and calcaneal pitch angle than the UCBL. The custom-made semi-rigid insole may help relieve foot instability during gait and improve the medial longitudinal arch in children with PFFF.

The Soft Prefabricated Orthopedic Insole Decreases Plantar Pressure during Uphill Walking with Heavy Load Carriage

This study aimed to investigate the effect of varying the hardness of prefabricated orthopedic insoles on plantar pressure and muscle fatigue during uphill walking with a heavy backpack. Fifteen healthy male recreational athletes (age: 20.4 ± 1.0 years, height: 176.9 ± 5.7 cm, weight: 76.5 ± 9.0 kg) wore prefabricated orthopedic insoles with foot arch support; a heel cup with medium (MI), hard (HI), and soft (SI) relative hardnesses; and flat insoles (FI). They performed treadmill walking on uphill gradients with 25 kg backpacks. The plantar pressure and surface electromyographic activity were recorded separately, in 30 s and 6 min uphill treadmill walking trials, respectively. The HI, MI, and SI significantly decreased peak plantar pressure in the lateral heel compared to FI. The MI and SI significantly decreased the peak plantar pressure in the fifth metatarsal compared to FI. The MI significantly reduced the pressure–time integral in the lateral heel compared to FI. The HI significantly increased the peak plantar pressure and pressure–time integral in the toes compared to other insoles, and decreased the contact area in the metatarsal compared to SI. In conclusion, a prefabricated orthopedic insole made of soft material at the fore- and rearfoot, with midfoot arch support and a heel cup, may augment the advantages of plantar pressure distribution during uphill weighted walking.

Hard, soft and off-the-shelf foot orthoses and their effect on the angle of the medial longitudinal arch: A biplane fluoroscopy study

BACKGROUND

Foot orthoses have proven to be effective for conservative management of various pathologies. Pathologies of the lower limb can be caused by abnormal biomechanics such as irregular foot structure and alignment, leading to inadequate support.

OBJECTIVES

To compare biomechanical effects of different foot orthoses on the medial longitudinal arch during dynamic gait using skeletal kinematics.

STUDY DESIGN

This study follows a prospective, cross-sectional study design.

METHODS

The medial longitudinal arch angle was measured for 12 participants among three groups: pes planus, pes cavus and normal arch. Five conditions were compared: three orthotic devices (hard custom foot orthosis, soft custom foot orthosis and off-the-shelf Barefoot Science©), barefoot and shod. An innovative method, markerless fluoroscopic radiostereometric analysis, was used to measure the medial longitudinal arch angle.

RESULTS

Mean medial longitudinal arch angles for both custom foot orthosis conditions were significantly different from the barefoot and shod conditions ( p < 0.05). There was no significant difference between the off-the-shelf device and the barefoot or shod conditions ( p > 0.05). In addition, the differences between hard and soft custom foot orthoses were not statistically significant. All foot types showed a medial longitudinal arch angle decrease with both the hard and soft custom foot orthoses.

CONCLUSION

These results suggest that custom foot orthoses can reduce motion of the medial longitudinal arch for a range of foot types during dynamic gait.

LEVEL OF EVIDENCE

Therapeutic study, Level 2.

CLINICAL RELEVANCE

Custom foot orthoses support and alter the position of the foot during weightbearing. The goal is to eliminate compensation of the foot for a structural deformity or malalignment and redistribute abnormal plantar pressures. By optimizing the position of the foot, the medial longitudinal arch (MLA) will also change and quantifying this change is of interest to clinicians.

The effect of hydrodynamic insole on foot kinematics in individuals with flexible flatfoot: Case series using a single-subject design

The medial longitudinal arch of the foot is a dynamic structure while walking. The mobility of this structure in people with flexible flatfoot is partially or completely absent. The aim of this study was to investigate the efficacy of an insole that was designed to retrieve the medial longitudinal arch mobility in people with flatfoot. The study was a case series using a single-subject design. This single-subject design study was based on three subjects with flexible flatfoot. This study was designed in two phases: the baseline phase and the intervention phase. Each phase included five measurement sessions that were done in 5 consecutive weeks. We used the celeration-line method to detect the significant differences between the phases. Significant differences were recorded in the walking velocity, step length, and medial longitudinal arch mobility parameters when using the hydrodynamic insole. The results of this study showed that using the hydrodynamic insole may have a positive effect on the foot kinematics and gait parameters in people with flexible flatfoot.

The transverse arch collapse correction as a path to foot toes alignment

The study presents a fragment of pilot studies showing the reconstruction of the transverse arch of the foot using a specially constructed orthosis for this purpose. It involves the mechanical reinforcement of the effect by an orthosis, which pushes down the I, IV, and V metatarsal bones while elevating or blocking the fall of the near-immobile II and III metatarsal bones according to the “three-force” rule. The correction of the transverse arch of the foot runs simultaneously with the correction of hallux valgus (HV). As a result, the significant correction of HV and associated toe deformities was achieved. In stage I foot deformity, the reduction of HV was reduced from 19.1° before to 15.1° after putting on orthosis (p = 0.024). In stage II, the reduction was from 20.1° (before) to 16.2° (after; p = 0.032). Equally satisfactory results were obtained for the remaining angles of the metatarsal bones. In the future, the method can be suitable for patients undergoing preparation for corrective HV surgery and for maintaining postoperative HV results. It can be used preventively, for example, by women who frequently wear high-heeled shoes and by those who need to remain standing for prolonged periods of time.

Effect of total-contact orthosis on medial longitudinal arch and lower extremities in flexible flatfoot subjects during walking

BACKGROUND

Total-contact orthosis (TCO) is one kind of foot orthosis (FO) that is used to adjust biomechanics in flexible flatfoot.

OBJECTIVE

To determine the effects of a TCO on the MLA moment, MLA deformation angle and lower limb biomechanics.

STUDY DESIGN

Cross-sectional study.

METHODS

Seven-flatfoot and thirteen-normal foot subjects were recruited by footprint and radiographs. The biomechanics of subjects with normal foot (NF), flatfoot with shoe only (FWOT) and flatfoot with TCO (FWT) were collected in a 3D motion analysis laboratory and force plates. The MLA and lower limb biomechanics in each condition during specific sub-phases of stance were analyzed.

RESULTS

The NF had larger MLA eversion moment after shod walking ( p = 0.001). The FWT condition compared with the FWOT condition had a significantly larger peak MLA upward moment ( p = 0.035) during pre-swing, larger peak knee external rotation angle ( p = 0.040) during mid stance, smaller peak knee extension moment during terminal stance ( p = 0.035) and a larger ground reaction force in the anterior-posterior direction during early stance ( p < 0.05).

CONCLUSION

Our study found positive effects from the customized TCOs which included an increased TCO angle that led to a decreased peak MLA moment in the frontal plane in flexible flatfoot subjects during walking. Clinical relevance Lower limb biomechanics is different from normal in subjects with flexible flatfoot. The design of a TCO affects MLA, ankle and knee biomechanics and may be used to clinically correct biomechanical changes in flexible flatfoot.