Measurement of pressure walking in footwear used in leprosy

Design feature combinations effects of running shoe on plantar pressure during heel landing: A finite element analysis with Taguchi optimization approach

Large and repeated impacts on the heel during running are among the primary reasons behind runners’ injuries. Reducing plantar pressure can be conducive to reducing running injury and improving running performance and is primarily achieved by modifying the design parameters of running shoes. This study examines the effect of design parameters of running shoes (i.e., heel-cup, insole material, midsole material, and insole thickness) on landing peak plantar pressure and determines the combination of different parameters that optimize cushion effects by employing the Taguchi method. We developed the foot–shoe finite element (FE) model through reverse engineering. Model assembly with different design parameters was generated in accordance with the Taguchi method orthogonal table. The effectiveness of the model was verified using the static standing model in Ansys. The significance and contribution of different design parameters, and the optimal design to reduce plantar pressure during landing, were determined using the Taguchi method. In the descending order of percentage contribution was a conforming heel-cup (53.18%), insole material (25.89%), midsole material (7.81%), and insole thickness (2.69%). The more conforming heel-cup (p < 0.001) and softer insole (p = 0.001) reduced the heel pressure during landing impact. The optimal design of running shoe in this study was achieved with a latex insole, a 6 mm insole thickness, an Asker C-45 hardness midsole, and a 100% conforming heel-cup. The conforming heel-cup and the insole material significantly affected the peak plantar pressure during heel landing. The implementation of a custom conforming heel-cup is imperative for relieving high plantar pressure for long-distance heel-strike runners.

Relationship between Plantar Pressure and Sensory Disturbance in Patients with Hansen's Disease-Preliminary Research and Review of the Literature

Orthoses and insoles are among the primary treatments and prevention methods of refractory plantar ulcers in patients with Hansen’s disease. While dynamic plantar pressure and tactile sensory disturbance are the critical pathological factors, few studies have investigated whether a relationship exists between these two factors. In this study, dynamic pressure measured using F-scan system and tactile sensory threshold evaluated with monofilament testing were determined for 12 areas of 20 feet in patients with chronic Hansen’s disease. The correlation between these two factors was calculated for each foot, for each clinical category of the foot (0–IV) and across all feet. A significant correlation was found between dynamic pressure and tactile sensation in Category II feet (n = 8, p = 0.016, r² = 0.246, Spearman’s rank test). In contrast, no significant correlation was detected for the entire foot or within the subgroups for the remainder of the clinical categories. However, the clinical manifestation of lesion areas showed high variability: (1) pressure concentrated, sensation lost; (2) margin of pressure concentration, sensation lost; (3) pressure concentrated, sensation severely disturbed but not lost; and (4) tip of the toe. These results may indicate that, even though there was a weak relationship between dynamic pressure and tactile sensation, it is important to assess both, in addition to the basics of orthotic treatment in patients with Hansen’s disease presenting with refractory plantar ulceration.

Plantar ulcer occurrence among leprosy patients in Northern Nigeria: A study of contributing factors

Background:

The study was conducted in three major leprosy referral hospitals in Northern Nigeria, which are NKST Rehabilitation Hospital, Benue State, Yadakunya Leprosy Hospital, Kano, and National Tuberculosis/Leprosy Training Hospital, Zaria. The main objective of the study was to investigate factors responsible for the occurrence of ulcers among leprosy patients reporting to the leprosy referral hospitals.

Materials and Methods:

An analytic study of case–control design was used, with patients having plantar ulcers as cases and those without as control. Semi-structured was administered to all cases and controls.

Results:

A total of 242 patients were studied; 124 patients (51.2%) had plantar ulcers whereas 118 (48.8%) had no ulcers (controls). A Chi-square test was used in the analysis to compare cases and controls. The study found differences between cases and controls with respect to patients release from treatment (RFT), gender, availability and utilization of footwear, age, occupation, and educational status. Footwears were provided to most patients, i.e. 60.8% late (i.e., after developing plantar ulcers); however, there was very good utilization of the footwears among those who had the footwears, 65.3%. Knowledge of self-care was higher among 64.5% of cases compared to only 28.1% of the controls.

Conclusion:

Ulcer still remains a major problem among leprosy patients, especially RFT (76.6%) and most cases are provided with footwear late. Self-care knowledge is higher among cases than controls.

Plantar pressure and daily cumulative stress in persons affected by leprosy with current, previous and no previous foot ulceration

Not only plantar pressure but also weight-bearing activity affects accumulated mechanical stress to the foot and may be related to foot ulceration. To date, activity has not been accounted for in leprosy. The purpose was to compare barefoot pressure, in-shoe pressure and daily cumulative stress between persons affected by leprosy with and without previous or current foot ulceration. Nine persons with current plantar ulceration were compared to 15 with previous and 15 without previous ulceration. Barefoot peak pressure (EMED-X), in-shoe peak pressure (Pedar-X) and daily cumulative stress (in-shoe forefoot pressure time integral×mean daily strides (Stepwatch™ Activity Monitor)) were measured. Barefoot peak pressure was increased in persons with current and previous compared to no previous foot ulceration (mean±SD=888±222 and 763±335 vs 465±262kPa, p<0.05). In-shoe peak pressure was only increased in persons with current compared to without previous ulceration (mean±SD=412±145 vs 269±70kPa, p<0.05). Daily cumulative stress was not different between groups, although persons with current and previous foot ulceration were less active. Although barefoot peak pressure was increased in people with current and previous plantar ulceration, it did not discriminate between these groups. While in-shoe peak pressure was increased in persons with current ulceration, they were less active, resulting in no difference in daily cumulative stress. Increased in-shoe peak pressure suggests insufficient pressure reducing footwear in persons with current ulceration, highlighting the importance of pressure reducing qualities of footwear.

Dressing plantar wounds with foam dressings, is it too much pressure?

Diabetes and its associated complications have become a major concern locally, nationally and internationally. One such complication is lower extremity amputation, commonly preceded by chronic ulceration. The cause of this tissue breakdown is multi-faceted, but includes an increase in pressure, particularly plantar pressure. As such, the choice of dressing to be applied to a plantar wound should ideally not increase this pressure further. A commonly used and possibly more bulky dressing is the foam dressing. This pilot study investigates the plantar pressures associated with three common foam dressings (Allevyn(®), Lyofoam(®) and Mepilex(®)) compared with a control dressing (Melolin(®)). Twelve healthy males and 19 females [SD] age 36.6 [10.4] were measured using the F-scan plantar pressure measurement system. Substantial variations in individual pressure changes occurred across the foot. No significant differences were identified, once a Bonferroni correction was applied. In healthy adults, it could be concluded that foam dressings do not have any effect on the plantar pressures of the foot. However, the need remains for a robust trial on a pathological population.

novel Award First Prize Paper. Orthotic management of plantar pressure and pain in rheumatoid arthritis

OBJECTIVE

To investigate the effectiveness of foot orthoses in the management of plantar pressure and pain in subjects with rheumatoid arthritis.

DESIGN

A repeated measures study in which the independent variable was orthosis design. Dependent variables, including pressure, gait and pain parameters, were examined using analysis of variance and correlation statistics.

BACKGROUND

The aim of orthotic management of the rheumatoid foot is to relieve metatarsalgia through the reduction of metatarsal head pressure. Few studies have investigated the relative effectiveness of different orthosis designs. To date, no studies have examined the relationship between plantar pressure and second metatarsal head pain in rheumatoid arthritis subjects.

METHODS

Twelve rheumatoid arthritis subjects with foot involvement and second metatarsal head pain were tested. Four styles of foot orthosis (prefabricated, standard custom moulded, custom with metatarsal bar, custom with metatarsal dome) were compared to a shoe only control. An EMED Pedar system was used to measure plantar pressure during repeated trials of comfortable cadence walking and quiet standing. Reports of subjective pain were recorded for each orthosis as were orthosis preferences.

RESULTS

All orthoses significantly reduced pressure beneath the first and second metatarsal heads compared to the shoes only control. The custom moulded orthosis with metatarsal dome was the most effective orthosis for reducing subjective ratings of pain. A significant correlation (r=0.562) was found between ratings of pain and average pressure beneath the second metatarsal head.

CONCLUSIONS

Results from this study suggest that average pressure measurement may be a useful indicator in the management of metatarsalgia in RA. Further study is required to improve understanding of the relationship between rheumatoid foot mechanics and pain.

RELEVANCE

Appropriate foot orthosis design can substantially improve comfort in RA patients with symptomatic feet. A custom moulded foot orthosis incorporating a metatarsal dome was the most effective design for subjects with painful second metatarsal heads. Foot pressure measurement technology can be a useful adjunct to research and clinical management of the painful rheumatoid foot.