Use of computerized insole sensor system to evaluate the efficacy of a modified ankle-foot orthosis for redistributing heel pressures

Tissue Augmentation with Allograft Adipose Matrix For the Diabetic Foot in Remission

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Background:

Repetitive stress on the neuropathic plantar foot is the primary cause of diabetic foot ulcers. After healing, recurrence is common. Modulating plantar pressure has been associated with extension of ulcer free days. Therefore, the goal of this study was to determine the effects of an injectable allograft adipose matrix in providing a protective padding and reducing the pressure in the plantar foot.

Methods:

After healing his recurrent ulcer using total contact casting, a 71-year-old man with a 9-year history of recurrent diabetic foot ulcers was treated with injection of allograft adipose matrix, procured from donated human tissue. This was delivered under postulcerative callus on the weight-bearing surface of the distal end of the first ray resection. As is standard in our clinic for tissue augmentation procedures, our patient underwent serial plantar pressure mapping using an in-shoe pressure monitoring system.

Results:

There was a 76.8% decrease in the mean peak pressure due to the fat matrix injected into the second metatarsal region and a 70.1% decrease in mean peak pressure for the first ray resection at the site of the postulcerative callus. By 2 months postoperatively, there was no evidence of residual callus. This extended out to the end of clinical follow-up at 4 months.

Conclusion:

The results from this preliminary experience suggest that allograft adipose matrix delivered to the high risk diabetic foot may have promise in reducing tissue stress over pre- and postulcerative lesions. This may ultimately assist the clinician in extending ulcer-free days for patients in diabetic foot remission.

Influence of casting method on effectiveness of foot orthoses using plantar pressure distribution: a preliminary study

BACKGROUND

Existing techniques of taking foot impressions for producing foot orthoses are static, while walking is a dynamic process.

OBJECTIVES

The aim of the study was to evaluate a newly developed dynamic casting method for foot orthoses in comparison with static casts.

STUDY DESIGN

Double-blind, randomized two-period cross-over trial.

METHODS

Twelve healthy volunteers (six women, six men) were randomly assigned within gender to two groups. The first group wore orthoses made from static casts for two weeks and then orthoses made from dynamic casts for two weeks, and the second group vice versa. The orthoses were worn during work in sports shoes. The outcome measure was coefficient of variation (CV, defined as standard deviation/mean) over seven measurement spots on each foot.

RESULTS

Foot orthoses produced by a dynamic casting system redistributed plantar pressure (reduced CV) more effectively in the first period on both feet. In the second period, carry-over effect and/or treatment wearing off was observed.

CONCLUSION

The dynamic casting procedure is simple, low-cost and appears promising, but further research is needed to introduce it into clinical practice.

In-shoe plantar pressure measurements for patients with knee osteoarthritis: Reliability and effects of lateral heel wedges

Although plantar pressure measurement systems are being used increasingly during gait analyses to investigate foot orthotics, there is limited information describing test-retest reliability of such measurements. Objectives of this study were to (1) examine the test-retest reliability of lateral heel pressure (LHP) and centre of pressure (COP) during walking with and without lateral heel wedges, and (2) evaluate the effects of 4° and 8° lateral heel wedges on the magnitude of LHP, the pathway of the COP and the peak external knee adduction moment (KAM) in subjects with and without knee osteoarthritis (OA). Twenty-six subjects, 12 patients with knee OA and 14 healthy subjects, were evaluated during three lateral heel wedge conditions (control, 4° and 8°) with standardized footwear. Three-dimensional analyses of gait with optical motion capture, floor-mounted force plate and in-shoe plantar pressure were completed on two occasions. Intraclass correlation coefficients (ICC(2, 1)) for LHP were excellent (0.79-0.83) while ICCs for COP in the medial-lateral and anterior-posterior directions were more variable (0.66-0.86). Reliability was slightly diminished when using heel wedges. Standard errors of measurement suggested considerable day-to-day variability in an individual's measures. Lateral heel wedges significantly (p<0.001) increased LHP, shifted COP anteriorly and laterally, and decreased the KAM. No significant differences were observed between subjects with and without OA. Although the day-to-day variability appears too large to confidently evaluate changes in individual patients, and decreases in reliability with increases in wedge size indicate caution, these results suggest in-shoe measurement of LHP and COP are appropriate for use in studies evaluating biomechanical effects of foot orthoses for knee OA.

Effect of ankle orientation on heel loading and knee stability for post-stroke individuals wearing ankle-foot orthoses

BACKGROUND

Those who experience lower extremity weakness or paralysis following a stroke often exhibit gait deviations caused by the inability to completely lift their foot during swing. An ankle-foot orthosis (AFO) is commonly prescribed for individuals post stroke with this mobility impairment.

STUDY DESIGN

Randomized controlled trial.

OBJECTIVES

To determine whether significant differences could be observed in post-stroke individuals ambulating with an experimental AFO set at three different ankle orientations.

METHODS

Gait analysis was conducted for eight post-stroke individuals ambulating with an experimental AFO set in three different randomly selected ankle orientations: 5° dorsiflexion, 5° plantarflexion, and neutral alignment. Temporospatial (velocity, cadence, stride length and step length), kinematic (knee angle), kinetic (external knee moment), and plantar force (heel) data were assessed. Within-subject statistical analysis was conducted using the repeated measures ANOVA to determine whether observed differences between the three orientations were significant.

RESULTS

Post-stroke individuals generally exhibited less knee flexion during loading response when their AFO was aligned at 5° plantarflexion. Six of the eight subjects demonstrated increased knee flexion moment during loading response with the plantarflexed versus dorsiflexed alignment. The plantarflexed ankle orientation also resulted in greater peak heel contact force during loading response.

CONCLUSIONS

Post stroke individuals may demonstrate less knee flexion during loading response and increased knee flexion moment (with respect to a dorsiflexed orientation) when their AFO is aligned in 5° plantarflexion. The fixed plantarflexed ankle orientation consistently resulted in greater peak heel contact force during loading response.

CLINICAL RELEVANCE

Plantarflexed AFOs are contraindicated for individuals with prior history of pressure sores on their heels. Post stroke individuals placed in 5° dorsiflexion may demonstrate increased knee flexion, enhanced shock absorption, decreased knee flexion moment, and decreased heel pressure (with respect to a plantarflexed orientation) during loading response.

Ground reaction force and 3D biomechanical characteristics of walking in short-leg walkers

Short-leg walking boots offer several advantages over traditional casts. However, their effects on ground reaction forces (GRF) and three-dimensional (3D) biomechanics are not fully understood. The purpose of the study was to examine 3D lower extremity kinematics and joint dynamics during walking in two different short-leg walking boots. Eleven (five females and six males) healthy subjects performed five level walking trials in each of three conditions: two testing boot conditions, Gait Walker (DeRoyal Industries, Inc.) and Equalizer (Royce Medical Co.), and one pair of laboratory shoes (Noveto, Adidas). A force platform and a 6-camera Vicon motion analysis system were used to collect GRFs and 3D kinematic data during the testing session. A one-way repeated measures analysis of variance (ANOVA) was used to evaluate selected kinematic, GRF, and joint kinetic variables (p<0.05). The results revealed that both short-leg walking boots were effective in minimizing ankle eversion and hip adduction. Neither walker increased the bimodal vertical GRF peaks typically observed in normal walking. However, they did impose a small initial peak (<1BW) earlier in the stance phase. The Gait Walker also exhibited a slightly increased vertical GRF during midstance. These characteristics may be related to the sole materials/design, the restriction of ankle movements, and/or the elevated heel heights of the tested walkers. Both walkers appeared to increase the demand on the knee extensors while they decreased the demand of the knee and hip abductors based on the joint kinetic results.

Automatic postural responses in individuals with peripheral neuropathy and ankle-foot orthoses

Eleven individuals with sensory neuropathy participated in static and dynamic balance tests with and without ankle-foot orthoses (AFOs). During the tests the subjects were required to stand on a fixed or moving computer-controlled platform with their eyes open or closed. Equilibrium scores, response latency, and strength scores were obtained. For all tests equilibrium scores were significantly larger in experiments with AFOs in comparison to conditions without AFOs (P<0.01). Decreased latency of responses with AFOs were recorded for medium and large magnitudes of movements of the platform in forward and backward directions. In addition, increased strength scores were observed when AFOs were used. The results indicate that AFOs could contribute significantly to postural control in individuals with peripheral neuropathy by providing auxiliary sensory cues to intact tissues of the lower extremities. These results have clinical implications that primarily aid in the understanding of how individuals with peripheral neuropathy benefit from the use of AFOs for postural stability.

A pilot study of the reaction forces at the heel during walking with the application of four different wound dressings

A laboratory investigation was conducted to ascertain the shock-absorbing properties of four wound dressings applied to the heel area of a convenience sample of volunteers. Four subjects walked across a force plate. Data were recorded for each subject barefoot, and then while the subject had a wound care dressing stuck to the plantar aspect of their heel. Eight trials were undertaken in the five different conditions resulting in 40 trials per subject. The results suggest that one dressing, Allevyn (Smith and Nephew Healthcare Ltd, Hull, UK), when compared to other dressing materials, exhibits similar reaction forces to the normal barefoot walking data for all subjects. However, results from the anterior posterior force show no major differences across the dressings when compared to barefoot walking. Wound care dressings that have an inherent shock-attenuating property may be advantageous when dealing with areas of the foot that come under excessive force.

Orthotic devices. Degenerative disorders of the foot and ankle

Orthotic devices are an effective method of treating degenerative arthrosis of the foot and ankle. When combined with appropriate medications and activity modifications, operative intervention may be postponed or rendered unnecessary. A thorough comprehension of relevant anatomy, biomechanics, and available devices is crucial to maximize the benefits of this modality.