Effect of foot orthoses on rearfoot complex kinematics during walking gait

Can a shoe-mounted IMU identify the effects of orthotics in ways comparable to gait laboratory measurements?

BACKGROUND

Footwear and orthotic research has traditionally been conducted within laboratories. With increasing prevalence of wearable sensors for foot and ankle biomechanics measurement, transitioning experiments into the real-world is realistic. However wearable systems must effectively detect the direction and magnitude of response to interventions to be considered for future usage.

METHODS

RunScribe IMU was used simultaneously with motion capture, accelerometers, and force plates during straight-line walking. Three orthotics (A, B, C) were used to change lower limb biomechanics from a control (SHOE) including: Ground reaction force (GRF) loading rate (A), pronation excursion (A and B), maximum pronation velocity (A and B), and impact shock (C) to test whether RunScribe detected effects consistent with laboratory measurements. Sensitivity was evaluated by assessing: 1. Significant differences (t-test) and effect sizes (Cohen's d) between measurement systems for the same orthotic, 2. Statistical significance (t-test and ANOVA) and effect size (Cohen's d & f) for orthotic effect across measurement systems 3. Direction of orthotic effect across measurement systems.

RESULTS

GRF loading rate (SHOE: p = 0.138 d = 0.403, A: p = 0.541 d = 0.165), impact shock (SHOE: p = 0.177 d = 0.405, C: p = 0.668 d = 0.132), pronation excursion (A: p = 0.623 d = 0.10, B: p = 0.986 d = 0.00) did not significantly differ between measurement systems with low effect size. Significant differences and high effect sizes existed between systems in the control condition for pronation excursion (p = 0.005 d = 0.68), and all conditions for pronation velocity (SHOE: p < 0.001 d = 1.24, A: p = 0.001 p = 1.21, B: p = 0.050 d = 0.64). RunScribe (RS) and Laboratory (LM) recorded the same significant effect of orthotic but inconsistent effect sizes for GRF loading rate (LM: p = 0.020 d = 0.54, RS: p = 0.042 d = 0.27), pronation excursion (LM: p < 0.001 f = 0.31, RS: p = 0.042 f = 0.15), and non-significant effect of orthotic for impact shock (LM: p = 0.182 d = 0.08, RS: p = 0.457 d = 0.24). Statistical significance was different between systems for effect of orthotic on pronation velocity (LM: p = 0.010 f = 0.18, RS: p = 0.093 f = 0.25). RunScribe and Laboratory agreed on the direction of change of the biomechanics variables for 69% (GRF loading rate), 40%-70% (pronation excursion), 47%-65% (pronation velocity), and 58% (impact shock) of participants.

CONCLUSION

The RunScribe shows sensitivity to orthotic effect consistent with the laboratory at the group level for GRF loading rate, pronation excursion, and impact shock during walking. There were however large discrepancies between measurements in individuals. Application of the RunScribe for group analysis may be appropriate, however implementation of RunScribe for individual assessment and those including pronation may lead to erroneous interpretation.

Changes in the Kinematics of Midfoot and Rearfoot Joints with the Use of Lateral Wedge Insoles

The lateral wedge insole (LWI) is a typical orthopedic treatment for medial knee osteoarthritis pain, chronic ankle instability, and peroneal tendon disorders. It is still unknown what the effects are in the most important joints of the foot when using LWIs as a treatment for knee and ankle pathologies. Objectives: The aim of this study was to determine the influence of LWIs on the position of the midfoot and rearfoot joints by measuring the changes using a tracking device. Methods: The study was carried out with a total of 69 subjects. Movement measurements for the midfoot were made on the navicular bone, and for the rearfoot on the calcaneus bone. The Polhemus system was used, with two motion sensors fixed to each bone. Subjects were compared by having them use LWIs versus being barefoot. Results: There were statistically significant differences in the varus movement when wearing a 4 mm LWI (1.23 ± 2.08°, p < 0.001) versus the barefoot condition (0.35 ± 0.95°), and in the plantarflexion movement when wearing a 4 mm LWI (3.02 ± 4.58°, p < 0.001) versus the barefoot condition (0.68 ± 1.34°), in the midfoot. There were also statistically significant differences in the valgus movement when wearing a 7 mm LWI (1.74 ± 2.61°, p < 0.001) versus the barefoot condition (0.40 ± 0.90°), and in the plantar flexion movement when wearing a 4 mm LWI (2.88 ± 4.31°, p < 0.001) versus the barefoot condition (0.35 ± 0.90°), in the rearfoot. Conclusions: In the navicular bone, a varus, an abduction, and plantar flexion movements were generated. In the calcaneus, a valgus, an adduction, and plantar flexion movements were generated with the use of LWIs.

Kinematic Effect on the Navicular Bone with the Use of Rearfoot Varus Wedge

BACKGROUND

The rearfoot varus wedge (RVW) is a common treatment for foot pain and valgus deformity. There is research on its effects in the calcaneus, but there is little research on the navicular. More research is needed with the use of RVW due to the relationship that exists between the position of the navicular and the risk of suffering an injury.

OBJECTIVES

this study sought to understand how RVW can influence the kinematics of the navicular bone, measuring their movement with the 6 SpaceFastrak system.

METHODS

a total of 60 subjects participated in the study. Two sensors were used to measure the movement of the calcaneus and navicular using RVWs as compared in the barefoot position in a static way.

RESULTS

there were statistically significant differences, the use of RVWs caused changes in the navicular bone, with subjects reaching the maximum varus movement with the use of RVW 7 mm of 1.35 ± 2.41° (p < 0.001), the maximum plantar movement flexion with the use of RVW 10 mm of 3.93 ± 4.44° (p < 0.001).

CONCLUSIONS

when RVWs were placed under the calcaneus bone, the navicular bone response was in varus movement too; thus, the use of rearfoot varus wedge can influence the movement of the navicular bone.

The immediate effects of sensorimotor foot orthoses on foot kinematics in healthy adults

BACKGROUND

Sensorimotor foot orthoses is an alternative concept, which in addition to mechanical effects, are designed to change muscle activation by altering sensory input to the plantar surface of the foot. However, there is little evidence of how these affect the kinematics of the foot during gait.

RESEARCH QUESTION

The aim of the study was to explore the immediate effect of calcaneal medial heel bars and retrocapital bars on foot kinematics during the stance phase of gait.

METHODS

Kinematic data were collected from 32 healthy individuals using an eight camera motion capture system and a six-degrees-of-freedom multi-segment foot model in three different orthotic conditions; calcaneal medial heel bar, retrocapital bar, and no orthosis. Vector field statistical analysis was performed to explore the effect of the orthotic conditions over the kinematic time series curves during stance phase. Peak median and interquartile ranges were also reported during the different phases of stance.

RESULTS

The calcaneal medial bar significantly decreased rearfoot eversion for the majority of the stance phase and compensatory increased midfoot eversion during the entire stance phase compared to the no orthosis condition. The retrocapital bar rotated the foot externally significantly abducting the rearfoot for the entire stance phase and the midfoot for the majority of stance phase.

SIGNIFICANCE

The calcaneal medial heel bar and retrocapital bar significantly altered the foot kinematics in a way that may benefit patients with abnormal pronation and intoeing gait.

Immediate effect of individual bars of insoles and their combination on gait parameters in asymptomatic healthy adults

Objective: The way how individual bars of sensorimotor insoles influence the gait kinematics is not fully understood yet. Therefore, this study aimed to explore the effect of three sensorimotor orthotic conditions (the medial calcaneal and retrocapital lateral bars and their combination) on the gait parameters in healthy adults during the stance phase of gait cycle.Materials and methods: Twenty-six young adults performed 20 gait cycles in each condition using their self-selected cadence and provided standardised shoes with the base-sole and the three types of orthotics. A three-dimensional motion analysis system (8 cameras; 200 Hz) was used and a six-degrees of freedom model was applied. The cadence, the stride length, the first peaks of foot external rotation, eversion and dorsal flexion as well as the first peak of hip adduction were analysed.Results: Significant differences (p < 0.05) were found for all parameters between the orthotic conditions, except the cadence. Significant difference in the first peak of hip adduction (p = 0.008) was found between the dominant and non-dominant leg. There were no significant interactions between the factors of condition and leg dominance (p > 0.05).Conclusions: There seems to be overall tendencies in immediate changes in ankle joint kinematics caused by all three sensorimotor orthotic conditions and besides the mechanical principles, also 'proprioceptive mechanism' seems to play a role. However, maximum observed average angular change was 2° and some variability in reactions to each orthotic condition exists among the individuals. Therefore, clinical relevance of such changes remains unclear and careful analysis of expected outcomes should be the common part of every orthotic intervention.

Can foot orthoses impose different gait features based on geometrical design in healthy subjects? A systematic review and meta-analysis

OBJECTIVE

Foot orthoses (FOs) are popular treatment to alleviate several abnormalities of lower extremity. FO designs might alter lower extremity biomechanics differently, but the association is not yet known. This review aimed to evaluate how different FO designs, namely FO with medial posting, lateral posting, arch support, or arch & heel support, change lower limb kinematics and kinetics during walking.

LITERATURE SURVEY

Electronic database search were conducted from inception to March 2019, and 25 papers passed the inclusion criteria. Two independent reviewers checked the quality using a modified Downs and Black checklist (73.7±5.5%) and a biomechanical quality checklist (71.4±17.1%). Effect sizes for differences between with- and without- FO walking were calculated, and meta-analysis was performed whenever at least two studies reported the same variable.

RESULTS

Medial posting reduced peak ankle eversion moment. Lateral posting brought about higher peak ankle dorsiflexion and peak ankle eversion for kinematics, as well as higher peak ankle abduction moment, lower peak knee adduction moment, and higher peak mediolateral ground reaction force (GRF) for kinetics. FOs with either arch support or arch & heel support tended to decrease vertical ground reaction force, but it was not significant.

CONCLUSION

The findings of this review reveal that medial or lateral posting work efficiently to change foot and knee kinematics and kinetics. However, the impact force is just slightly decreased by arch-supported and heel supported FOs. Due to the small number of available studies, and heterogeneity in meta-analysis findings, further research with more standardized biomechanical approach are required.

Effect of Different Insole Materials on Kinetic and Kinematic Variables of the Walking Gait in Healthy People

BACKGROUND

There is a lack of data that could address the effects of off-the-shelf insoles on gait variables in healthy people.

METHODS

Thirty-three healthy volunteers ranging in age from 18 to 35 years were included to this study. Kinematic and kinetic data were obtained in barefoot, shoe-only, steel insole, silicone insole, and polyurethane insole conditions using an optoelectronic three-dimensional motion analysis system. A repeated measures analysis of variance test was used to identify statistically significant differences between insole conditions. The alpha level was set at P < .05.

RESULTS

Maximum knee flexion was higher in the steel insole condition (P < .0001) compared with the silicone insole (P = .001) and shoe-only conditions (P = .032). Reduced maximum knee flexion was recorded in the polyurethane insole condition compared with the shoe-only condition (P = .031). Maximum knee flexion measured in the steel insole condition was higher compared to the barefoot condition (P = .020). Higher maximum ankle dorsiflexion was observed in the barefoot condition, and there were significant differences between the polyurethane insole (P < .0001), silicone insole (P = .001), steel insole (P = .002), and shoe conditions (P = .004). Least and highest maximum ankle plantarflexion were detected in the steel insole and silicone insole conditions, respectively. Maximum ankle plantarflexion in the barefoot and steel insole conditions (P = .014) and the barefoot and polyurethane insole conditions (P = .035) were significant. There was no significant difference between conditions for ground reaction force or joint moments.

CONCLUSIONS

Insoles made by different materials affect maximum knee flexion, maximum ankle dorsiflexion, and maximum ankle plantarflexion. This may be helpful during the decision-making process when selecting the insole material for any pathological conditions that require insole prescription.

Workflow assessing the effect of gait alterations on stresses in the medial tibial cartilage - combined musculoskeletal modelling and finite element analysis

Knee osteoarthritis (KOA) is most common in the medial tibial compartment. We present a novel method to study the effect of gait modifications and lateral wedge insoles (LWIs) on the stresses in the medial tibial cartilage by combining musculoskeletal (MS) modelling with finite element (FE) analysis. Subject's gait was recorded in a gait laboratory, walking normally, with 5° and 10° LWIs, toes inward ('Toe in'), and toes outward ('Toe out wide'). A full lower extremity MRI and a detailed knee MRI were taken. Bones and most soft tissues were segmented from images, and the generic bone architecture of the MS model was morphed into the segmented bones. The output forces from the MS model were then used as an input in the FE model of the subject's knee. During stance, LWIs failed to reduce medial peak pressures apart from Insole 10° during the second peak. Toe in reduced peak pressures by -11% during the first peak but increased them by 12% during the second. Toe out wide reduced peak pressures by -15% during the first and increased them by 7% during the second. The results show that the work flow can assess the effect of interventions on an individual level. In the future, this method can be applied to patients with KOA.

Effects of foot and ankle devices on balance, gait and falls in adults with sensory perception loss: a systematic review

BACKGROUND

Foot and ankle devices are being developed as a method of preventing people with sensory perception loss sustaining a fall. Such devices are believed to work by reducing the likelihood of a fall by improving the balance and gait of the user.

OBJECTIVES

The objective of the review was to evaluate the effectiveness of foot and ankle devices for the prevention of falls and the improvement of balance and gait in adults with sensory perception loss.

INCLUSION CRITERIA TYPES OF PARTICIPANTS

Participants were community-dwelling adults with bilateral pathological sensory perception loss.

TYPES OF INTERVENTION(S)/PHENOMENA OF INTEREST

The current review evaluated any foot or ankle device, including but not restricted to, all types of footwear (therapeutic and retail), insoles (customized and prefabricated) and ankle-foot orthoses (AFOs).

TYPES OF STUDIES

In the absence of randomized controlled trials (RCT), the review considered experimental and epidemiological study designs, except case series, individual case reports and descriptive cross-sectional studies.

OUTCOMES

The primary outcome was number of falls. Secondary outcome measures were clinical or laboratory measures of balance or gait.

SEARCH STRATEGY

A search for published and unpublished literature from inception to March 2015 written in the English language was conducted across a number of major electronic databases. A three-step search strategy was developed using MeSH terminology and keywords to ensure all that relevant materials are captured.

METHODOLOGICAL QUALITY

Methodological quality of included studies was assessed by two reviewers, who appraised each study independently, using standardized Joanna Briggs Institute (JBI) critical appraisal tools.

DATA EXTRACTION

Quantitative data were extracted from the studies that were identified as meeting the criteria for methodological quality using the standardized JBI data extraction tools.

DATA SYNTHESIS

Due to the heterogeneity of populations, interventions and outcome measures, meta-analyses were not possible and results are presented in narrative form.

RESULTS

Nine trials (from 10 papers) involving 238 participants, (14 with multiple sclerosis and 16 with idiopathic peripheral neuropathy, 150 with diabetic neuropathy) and 58 controls were included in the review. No study reported falls as an outcome measure. The results of the included studies found that in people with sensory perception loss, postural sway improved with vibrating insoles and AFO, altering the softness and texture of the top cover had no effect on postural sway, wearing footwear over long distances or AFOs improved step-to-step consistency, and no foot and ankle device was reported to have a negative effect on the balance or gait of people with sensory perception loss. The methodological quality of the included studies was poor. No study used a randomized controlled trial (RCT) methodology. No study incorporated a follow-up period or tested the intervention within the context of the intended clinical environment.

CONCLUSION

There is limited evidence to suggest that footwear and insole devices can artificially alter postural stability and may reduce the step-to-step variability in adults with sensory perception loss. Varying the material properties of an insole does not notably affect static balance or gait.

Randomized clinical trial into the impact of rigid foot orthoses on balance parameters in excessively pronated feet

Objective: To evaluate the effect of rigid foot orthoses on balance parameters in participants with clinically diagnosed excessively pronated feet.

Design: Randomized clinical trial.

Setting: University biomechanics laboratory.

Participants: Thirty female and 20 male healthy participants (mean 23.89 ± 2.2 years old) with excessively pronated feet, according to a validated foot classification system were randomly assigned to either a control or intervention group.

Interventions: Balance testing was performed using the Balance Performance Monitor with an over-the-counter rigid foot orthoses.

Main outcome measures: Standing balance in the form of mean balance (measures the participants ability to stand with an even load), medial–lateral sway and anterior–posterior sway. All participants were measured while standing bipedally.

Results: There was no significant mean difference in balance scores between the control and intervention group at baseline. After four weeks the results demonstrated no significant differences between mean) balance ( p > 0.05) and anterior–posterior sway ( p > 0.05). However, there was a reduction with the intervention group in medial–lateral sway ( p > 0.02).

Conclusion: The use of foot orthoses in the current study may have improved postural control by stabilizing the rear foot and thus maintaining balance. By the same argument, the benefits of limiting excessive foot pronation may contribute to effective control of internal rotation of the tibia and thereby reduce counter-rotatory motion at the knee and lower leg and maintain balance.

The relationship of foot and ankle mobility to the frontal plane projection angle in asymptomatic adults

Background

The frontal plane projection angle (FPPA) is frequently used as a measure of dynamic knee valgus during functional tasks, such as the single leg squat. Increased dynamic knee valgus is observed in people with knee pathologies including patellofemoral pain and anterior cruciate injury. As the foot is the primary interface with the support surface, foot and ankle mobility may affect the FPPA. This study investigated the relationship between foot and ankle mobility and the FPPA in asymptomatic adults.

Methods

Thirty healthy people (aged 18–50 years) performed 5 single leg squats. Peak FPPA and FPPA excursion were determined from digital video recordings. Foot mobility was quantified as the difference in dorsal midfoot height or midfoot width, between non-weightbearing and bilateral weightbearing positions. Ankle joint dorsiflexion range was measured as the maximum distance in centimetres between the longest toe and the wall during a knee-to-wall lunge. Linear regressions with generalised estimating equations were used to examine relationships between variables.

Results

Higher midfoot width mobility was associated with greater peak FPPA (β 0.90, p < 0.001, odds ratio [OR] 2.5), and FPPA excursion (β 0.67, p < 0.001, OR 1.9). Lower midfoot height mobility was associated with greater peak FPPA (β 0.37, p = 0.030, OR 1.4) and FPPA excursion (β 0.30, p = 0.020, OR 1.3). Lower ankle joint dorsiflexion was also associated with greater peak FPPA (β 0.61, p = 0.008, OR 1.8) and greater FPPA excursion (β 0.56, p < 0.001, OR 1.7).

Conclusions

Foot and ankle mobility was significantly related to the FPPA during the single leg squat in healthy individuals. Specifically, higher midfoot width mobility, or lower ankle joint dorsiflexion range and midfoot height mobility, were associated with a greater FPPA. These foot mobility factors should be considered in the clinical management of knee-related disorders that are associated with a high FPPA.

Reliability of a new supination resistance measurement device and validation of the manual supination resistance test

BACKGROUND

Kinematic observations are inconsistent in predicting lower-extremity injury risk, and research suggests that kinetic variables may be more important in this regard. Before kinetics can be prospectively investigated, we need reliable ways of measuring them clinically. A measurement instrument was manufactured that closely mirrors a manual test used to clinically estimate supination resistance force. The reliability of the instrument and the validity of the clinical test were investigated.

METHODS

The left feet of 26 healthy individuals (17 men and 9 women; mean ± SD age, 25.9 ± 9.2 years; mean ± SD weight, 77.7 ± 13.3 kg) were assessed. Foot Posture Index (FPI-6), manual supination resistance, and machine supination resistance were measured. Intrarater and interrater reliability of all of the measurements were calculated. Correlations of the supination resistance measured by the device with FPI-6, the manual supination resistance test, and body weight were investigated.

RESULTS

Interrater reliability of all of the measurements was generally poor. The supination resistance machine correlated highly with the manual supination test for the rater experienced with its use. Supination resistance measurements correlated poorly with the FPI-6 and weakly with body weight.

CONCLUSIONS

The supination resistance machine was shown to have sufficient limits of agreement for the study, but improvements need to be made for more meaningful research going forward. In this study, the force required to supinate a foot was independent of its posture, and approximately 12% of it was explained by body weight. Further work is required with a much larger sample size to build regression models that sufficiently predict supination resistance force and that will be of clinical use. The manual supination test is a valid clinical test for clinicians experienced in its use.

The relationship between foot motion and lumbopelvic-hip function: a review of the literature

Excessive pronation has been implicated in the development of numerous overuse injuries of the lower limb and is suggested to cause more proximal biomechanical dysfunction. Functional foot orthoses (FFO) are frequently prescribed for lower limb injury associated with excessive foot pronation and have been demonstrated to have efficacy with specific conditions. However, the mechanism of action of FFO is largely unknown. Research investigating the kinematic and kinetic changes associated with FFO use is inconclusive. Furthermore there is a growing body of evidence suggesting that changes to muscle activity patterns in response to FFO may be responsible for their therapeutic effect. Additionally, current research suggests dysfunction of musculature of the lumbopelvic-hip complex is involved in lower extremity functional changes and is related to the development some pathologies traditionally attributed to excessive foot pronation. Evidence of temporal coupling between the hip and the foot and changes in hip muscle activity associated with FFO use further suggest a relationship between proximal and distal lower limb function. The aim of this review is to discuss the association between foot and lumbopelvic-hip complex dysfunction and injury, assess the evidence for functional changes to lower limb and lumbopelvic-hip function with FFO use and finally to discuss the potential for changes to hip musculature activation with FFO use to influence distal mechanics and produce a therapeutic benefit.

The effects of railroad ballast surface and slope on rearfoot motion in walking

The purpose of this study was to investigate the effects of transversely sloped ballasted walking surface on gait and rearfoot motion (RFM) parameters. Motion analysis was performed with 20 healthy participants (15 male and 5 female) walking in six surface-slope conditions: two surfaces (solid and ballasted) by three slopes (0, 5, and 10 degrees). The gait parameters (walking velocity, step length, step rate, step width, stance time, and toe-out angle) showed significant surface effect (p = .004) and surface-slope interaction (p = .017). The RFM motion parameters (peak everted/inverted position, eversion/inversion velocity, and acceleration) revealed significant surface (p = .004) and slope (p = .024) effects. The ballasted conditions showed more cautious gait patterns with lower walk velocity, step length, and step rate and longer stance time. In the RFM parameters, the slope effect was more notable in the solid conditions due to the gait adaptations in the ballasted conditions. Ballast conditions showed reduced inversion and increased eversion and RFM range. The RFM data were comparable to other typical walking conditions but smaller than those from running.

Comparison of changes in posterior tibialis muscle length between subjects with posterior tibial tendon dysfunction and healthy controls during walking

STUDY DESIGN

Case control study.

OBJECTIVE

To compare posterior tibialis (PT) length between subjects with stage II posterior tibial tendon dysfunction (PTTD) and healthy controls during the stance phase of gait.

BACKGROUND

The abnormal kinematics demonstrated by subjects with stage II PTTD are presumed to be associated with a lengthened PT musculotendon, but this relationship has not been fully explored.

METHODS

Seventeen subjects with stage II PTTD and 10 healthy controls volunteered for this study. Subject-specific foot kinematics were collected using 3-D motion analysis techniques for input into a general model of PT musculotendon length (PTLength). The kinematic inputs included hindfoot eversion/inversion (HF Ev/lnv), forefoot abduction/adduction (FF Ab/Add), forefoot plantar flexion/dorsiflexion (FF Pf/Df), and ankle plantar flexion/dorsiflexion (Ankle Pf/Df). To estimate the change in PTLength from neutral the following model was used: PTLength = 0.401(HF Ev/lnv) + 0,270(FF Ab/Add) + 0.137(FF Pf/Df) + 0.057(Ankle Pf/Df). Positive values indicated lengthening from the subtalar neutral (STN) position, while negative values indicated shortening relative to the STN position. A 2-way analysis of variance (ANOVA) model was used to compare PTLength between groups across the stance phases of walking (loading response, midstance, terminal stance, and preswing). Also, a 2-way ANOVA was used to assess the foot kinematics that contributed to alterations in PTLength. The Short Musculoskeletal Functional Assessment Index and Mobility subscale were used to compare function and mobility.

RESULTS

PTLength was significantly greater (lengthened) relative to the STN position in the PTTD group compared to the control group across all phases of stance, with the greatest between-group difference in PTLength occurring during preswing. The greater PTLength in subjects with PTTD compared to controls was principally attributed to significantly greater HF Ev/lnv during loading response (P = .014) and midstance (P = .015). During terminal stance and preswing, each kinematic input to estimate PTLength contributed to lengthening (main effect, P = .03 and P = .01, respectively). Subjects with PTTD with abnormally greater PTLength reported significantly lower function (P = .04) and mobility (P = .03) compared to subjects with PTTD with normal PTLength during walking.

CONCLUSIONS

The greater PTLength, as determined from foot kinematics, suggests that the PT musculotendon is lengthened in subjects with stage II PTTD, compared to healthy controls. The amount of lengthening is not dependent on the phase of gait; however, different foot kinematics contribute to PTLength across the stance phase. Targeting these foot kinematics may limit lengthening of the PT musculotendon. Subjects with excessive PT lengthening experience a decrease in function.

Management of acute ligament injuries of the ankle

Ligament injuries of the ankle are common and troublesome. Management may seem easy, but residual symptoms ae common. Grade III injuries still generate controversy in terms of the best management available, and more studies are needed when it comes to early mobilization, cast immobilization, or surgery. Even the three Cohrane reviews published to date are not conclusive.

Effects of Ankle-Foot Orthoses on Ankle and Foot Kinematics in Patients With Subtalar Osteoarthritis

OBJECTIVE

To determine whether different foot orthoses have a similar effect on foot kinematics in subjects with subtalar osteoarthritis (OA) when walking on various ground conditions.

DESIGN

Within-subject comparison study.

SETTING

Biomechanics research laboratory.

PARTICIPANTS

Ten subjects with unilateral subtalar OA.

INTERVENTIONS

Custom-made ankle foot orthosis (AFO), rigid hindfoot orthosis (HFO-R), and articulated hindfoot orthosis (HFO-A) were used by subjects walking on level, ascending, and descending ramp, and side slope conditions.

MAIN OUTCOME MEASURES

The triplanar range of motion of the calcaneus relative to tibia (hindfoot) and metatarsal relative to calcaneus (forefoot) was measured using an 8-camera motion analysis system when subjects with subtalar OA wore different foot orthoses.

RESULTS

Braces tended to perform similarly in reducing motion of the forefoot and hindfoot for all ground conditions when compared with unbraced but wearing shoes. The AFO significantly restricted frontal plane hindfoot motion during ramp descent (P<.01) and on a side slope when the arthritic subtalar joint was higher than the unaffected side (P=.02). The HFO-A provided significant frontal plane hindfoot motion restriction during ramp descent (P<.01) and on a side slope when the arthritic subtalar joint was lower than the unaffected side (P=.03). The HFO-R significantly restricted frontal plane hindfoot motion in all ground conditions except ramp ascent (P<.05).

CONCLUSIONS

The HFO-R provides significant subtalar joint motion restriction while walking. The HFO-R may be considered an optimal orthosis for patients with subtalar OA pain arising from subtalar motion.

Effects of Ankle-Foot Orthoses on Ankle and Foot Kinematics in Patient With Ankle Osteoarthritis

OBJECTIVE

To determine if different foot orthoses have a similar effect on foot kinematics in subjects with ankle osteoarthritis (OA) when walking on various ground conditions.

DESIGN

Within-subject comparisons study.

SETTING

Biomechanics research laboratory.

PARTICIPANTS

Thirteen subjects with unilateral ankle OA.

INTERVENTIONS

Custom-made ankle-foot orthosis (AFO), rigid hindfoot orthosis (HFO-R), and articulated hindfoot orthosis (HFO-A) were used by subjects when walking on level, ascending and descending ramp, and side-slope conditions.

MAIN OUTCOME MEASURES

The range of motion of the hindfoot (calcaneus relative to tibia) and forefoot (metatarsal relative to calcaneus) was measured using an 8-camera motion analysis system.

RESULTS

The AFO and HFO-R provided the best sagittal plane hindfoot motion restriction over all ground conditions (P<.001). The HFO-R allowed the greatest sagittal plane forefoot motion when walking over level (P=.01) and side-slope (P<.02) conditions, the greatest frontal plane forefoot motion walking down the ramp (P=.003), and the greatest transverse plane forefoot motion when walking over level (P=.011) and ramp-ascending conditions (P=.005). The HFO-A restricted motion of the unaffected joint and did not effectively restrict hindfoot motion.

CONCLUSIONS

The HFO-R not only provides selective restriction to the ankle-hindfoot motion, but also allows sufficient forefoot motion compared with the AFO. We consider the HFO-R to be the best option of all tested orthoses for treating patients with ankle OA pain arising from ankle motion.

The relationship between hallux dorsiflexion and ankle joint complex frontal plane kinematics: a preliminary study

BACKGROUND

It has been suggested that the function of the first metatarsophalangeal joint may be related to the motion of the ankle joint complex.

OBJECTIVE

This study explored the relationship between ankle joint complex and first metatarsophalangeal joint motion during gait in a group of 14 who demonstrated clinically limited passive hallux dorsiflexion in quiet standing (cases), and 15 matched controls.

METHOD

An electromagnetic tracking system was used to measure the ankle joint complex frontal plane motion and first metatarsophalangeal joint sagittal plane motion during gait, in both cases and controls. The case group was then evaluated further to investigate the effect of an orthosis on first metatarsophalangeal joint motion.

FINDINGS

The correlation between maximum ankle joint complex eversion and maximum first metatarsophalangeal joint dorsiflexion during gait was r=0.471. Within the case group, maximum rearfoot eversion was reduced following the application of the orthoses, but there was no change in sagittal first metatarsophalangeal joint rotations.

INTERPRETATION

The relationship between maximum ankle joint complex eversion and first metatarsophalangeal joint dorsiflexion kinematics found in this study was moderate, and decreasing maximum ankle joint complex eversion with an orthosis did not result in any increase in first metatarsophalangeal joint dorsiflexion during gait in patients with functional first metatarsophalangeal joint limitation. These results do not support the assumption that ankle joint complex eversion influences first metatarsophalangeal joint motion substantially.

Effect of inverted orthoses on lower-extremity mechanics in runners

INTRODUCTION

Foot orthoses are recommended for individuals with injuries associated with abnormal lower-extremity mechanics. However, the biomechanical effect of these devices is not completely understood. Most clinicians and researchers believe that foot orthoses are effective in reducing some aspect of rearfoot motion. This is important as many injuries are suggested to be the result of increased pronation. Inverted orthoses are a more aggressive treatment in those whose symptoms do not respond to standard orthotics. They are likely to alter motion in all planes. However, no three-dimensional studies have assessed lower-extremity mechanics in individuals wearing inverted orthotics.

PURPOSE

The purpose of this study was to compare the three-dimensional kinematics and kinetics of the rearfoot and knee during running while varying orthotic intervention.

METHODS

Eleven subjects were initially fitted with standard foot orthoses and then with inverted orthoses. Three-dimensional kinematic and kinetic data were collected for conditions of no orthoses, standard orthoses, and inverted orthoses.

RESULTS

There were no differences between conditions in peak rearfoot eversion or rearfoot eversion excursion. Peak rearfoot inversion moment and work were significantly reduced (P = 0.045 and P < 0.001, respectively) in the inverted orthotic condition suggesting a decreased demand on the soft tissue structures that control eversion. Significant differences were seen in tibial rotation (P = 0.043), knee adduction (P = 0.035), and knee abduction moment (P < 0.001) in the inverted orthotic condition, suggesting alterations were made further up the kinetic chain.

CONCLUSIONS

The differences in kinetic parameters at the rearfoot may result in fewer injuries of the rearfoot soft tissue structures when using inverted orthotics. These alterations in lower-extremity mechanics associated with inverted orthoses provide clinicians some evidence for prescribing this device.

Foot orthoses in rehabilitation—what's new

Foot orthoses have been effective in the treatment of a variety of sport-related foot conditions. Although their use is well-established in clinical practice, many of the orthoses have not been evaluated in experimental conditions. Of the clinical studies that have examined the biomechanical changes associated with their use, many do not have predictable results. The failure of some studies to find trends for a particular variable does not preclude this variable being affected by the orthoses in an individual patient; rather, it may speak to the highly subject-specific responses with orthotic use. It is important to recognize that foot orthoses cannot be considered independent of a rehabilitation protocol that includes stretching and strengthening-specific therapies, as well as a consideration of training surfaces and training regimes. Additionally, foot orthoses must be considered in concert with the foot-wear recommendation.

Rehabilitation of ligamentous ankle injuries: a review of recent studies

There are many treatment modalities for ankle rehabilitation. These are reviewed, and the most effective training programme for rapid restoration of ankle movement, strength, endurance, and proprioception is selected.