Roelof Waaijman

Effect of Custom-made Footwear on Foot Ulcer Recurrence in Diabetes: A multicenter randomized controlled trial

OBJECTIVE Custom-made footwear is the treatment of choice to prevent foot ulcer recurrence in diabetes. This footwear primarily aims to offload plantar regions at high ulcer risk. However, ulcer recurrence rates are high. We assessed the effect of offloading-improved custom-made footwear and the role of footwear adherence on plantar foot ulcer recurrence. RESEARCH DESIGN AND METHODS We randomly assigned 171 neuropathic diabetic patients with a recently healed plantar foot ulcer to custom-made footwear with improved and subsequently preserved offloading (∼20% peak pressure relief by modifying the footwear) or to usual care (i.e., nonimproved custom-made footwear). Primary outcome was plantar foot ulcer recurrence in 18 months. Secondary outcome was ulcer recurrence in patients with an objectively measured adherence of ≥80% of steps taken. RESULTS On the basis of intention-to-treat, 33 of 85 patients (38.8%) with improved footwear and 38 of 86 patients (44.2%) with usual care had a recurrent ulcer (relative risk −11%, odds ratio 0.80 [95% CI 0.44–1.47], P = 0.48). Ulcer-free survival curves were not significantly different between groups (P = 0.40). In the 79 patients (46% of total group) with high adherence, 9 of 35 (25.7%) with improved footwear and 21 of 44 (47.8%) with usual care had a recurrent ulcer (relative risk −46%, odds ratio 0.38 [0.15–0.99], P = 0.045). CONCLUSIONS Offloading-improved custom-made footwear does not significantly reduce the incidence of plantar foot ulcer recurrence in diabetes compared with custom-made footwear that does not undergo such improvement, unless it is worn as recommended.

Risk Factors for Plantar Foot Ulcer Recurrence in Neuropathic Diabetic Patients

OBJECTIVE Recurrence of plantar foot ulcers is a common and major problem in diabetes but not well understood. Foot biomechanics and patient behavior may be important. The aim was to identify risk factors for ulcer recurrence and to establish targets for ulcer prevention. RESEARCH DESIGN AND METHODS As part of a footwear trial, 171 neuropathic diabetic patients with a recently healed plantar foot ulcer and custom-made footwear were followed for 18 months or until ulceration. Demographic data, disease-related parameters, presence of minor lesions, barefoot and in-shoe plantar peak pressures, footwear adherence, and daily stride count were entered in a multivariate multilevel logistic regression model of plantar foot ulcer recurrence. RESULTS A total of 71 patients had a recurrent ulcer. Significant independent predictors were presence of minor lesions (odds ratio 9.06 [95% CI 2.98–27.57]), day-to-day variation in stride count (0.93 [0.89–0.99]), and cumulative duration of past foot ulcers (1.03 [1.00–1.06]). Significant independent predictors for those 41 recurrences suggested to be the result of unrecognized repetitive trauma were presence of minor lesions (10.95 [5.01–23.96]), in-shoe peak pressure <200 kPa with footwear adherence >80% (0.43 [0.20–0.94]), barefoot peak pressure (1.11 [1.00–1.22]), and day-to-day variation in stride count (0.91 [0.86–0.96]). CONCLUSIONS The presence of a minor lesion was clearly the strongest predictor, while recommended use of adequately offloading footwear was a strong protector against ulcer recurrence from unrecognized repetitive trauma. These outcomes define clear targets for diabetic foot screening and ulcer prevention.

Adherence to Wearing Prescription Custom-Made Footwear in Patients With Diabetes at High Risk for Plantar Foot Ulceration

OBJECTIVE Prescription custom-made footwear can only be effective in preventing diabetic foot ulcers if worn by the patient. Particularly, the high prevalence of recurrent foot ulcers focuses the attention on adherence, for which objective data are nonexisting. We objectively assessed adherence in patients with high risk of ulcer recurrence and evaluated what determines adherence. RESEARCH DESIGN AND METHODS In 107 patients with diabetes, neuropathy, a recently healed plantar foot ulcer, and custom-made footwear, footwear use was measured during 7 consecutive days using a shoe-worn, temperature-based monitor. Daily step count was measured simultaneously using an ankle-worn activity monitor. Patients logged time away from home. Adherence was calculated as the percentage of steps that prescription footwear was worn. Determinants of adherence were evaluated in multivariate linear regression analysis. RESULTS Mean ± SD adherence was 71 ± 25%. Adherence at home was 61 ± 32%, over 3,959 ± 2,594 steps, and away from home 87 ± 26%, over 2,604 ± 2,507 steps. In 35 patients with low adherence (<60%), adherence at home was 28 ± 24%. Lower BMI, more severe foot deformity, and more appealing footwear were significantly associated with higher adherence. CONCLUSIONS The results show that adherence to wearing custom-made footwear is insufficient, particularly at home where patients exhibit their largest walking activity. This low adherence is a major threat for reulceration. These objective findings provide directions for improvement in adherence, which could include prescribing specific off-loading footwear for indoors, and they set a reference for future comparative research on footwear adherence in diabetes.

The interdependency of peak pressure and pressure–time integral in pressure studies on diabetic footwear: No need to report both parameters

BACKGROUND In plantar pressure studies on diabetic footwear, both the maximum peak pressure (MPP) and peak pressure-time integral (PTI) are often reported. However, specific conclusions for each parameter are not commonly reported, suggesting these parameters may be interchangeable. The aim was to explore the interdependency of MPP and PTI in diabetic patients wearing different types of footwear. METHODS In-shoe plantar pressure was measured in 69 neuropathic diabetic patients who walked in custom made footwear, forefoot offloading shoes, cast shoes, and/or standard footwear. For each of six anatomical foot regions, correlation coefficients were calculated between MPP and PTI. To assess parameter congruency, the percentage of patients showing correlation coefficients >0.7 or coefficients of variation for both MPP and PTI <10%, was calculated. RESULTS Across all footwear conditions, MPP and PTI were highly correlated in the forefoot and midfoot (r>0.78 in all but one foot region in one footwear condition). Lower correlations coefficients were found in the rearfoot (r=0.43-0.45). Across regions, between 46% and 87% of patients (mean 72%) showed parameter congruency in the forefoot and midfoot. CONCLUSIONS The results showed that the MPP and PTI are highly interdependent in those foot regions most at risk for plantar ulceration in patients wearing commonly prescribed footwear. Since MPP has been shown to date to be the clinically more relevant parameter of the two, these results suggest that the value of reporting PTI in addition to MPP in the same diabetic footwear study is small.

Pressure-reduction and preservation in custom-made footwear of patients with diabetes and a history of plantar ulceration

Diabet. Med. 29, 1542–1549 (2012)

Offloading effect of therapeutic footwear in patients with diabetic neuropathy at high risk for plantar foot ulceration

Diabet. Med. 29, 1534–1541 (2012)

Predictors of Barefoot Plantar Pressure during Walking in Patients with Diabetes, Peripheral Neuropathy and a History of Ulceration

Objective Elevated dynamic plantar foot pressures significantly increase the risk of foot ulceration in diabetes mellitus. The aim was to determine which factors predict plantar pressures in a population of diabetic patients who are at high-risk of foot ulceration. Methods Patients with diabetes, peripheral neuropathy and a history of ulceration were eligible for inclusion in this cross sectional study. Demographic data, foot structure and function, and disease-related factors were recorded and used as potential predictor variables in the analyses. Barefoot peak pressures during walking were calculated for the heel, midfoot, forefoot, lesser toes, and hallux regions. Potential predictors were investigated using multivariate linear regression analyses. 167 participants with mean age of 63 years contributed 329 feet to the analyses. Results The regression models were able to predict between 6% (heel) and 41% (midfoot) of the variation in peak plantar pressures. The largest contributing factor in the heel model was glycosylated haemoglobin concentration, in the midfoot Charcot deformity, in the forefoot prominent metatarsal heads, in the lesser toes hammer toe deformity and in the hallux previous ulceration. Variables with local effects (e.g. foot deformity) were stronger predictors of plantar pressure than global features (e.g. body mass, age, gender, or diabetes duration). Conclusion The presence of local deformity was the largest contributing factor to barefoot dynamic plantar pressure in high-risk diabetic patients and should therefore be adequately managed to reduce plantar pressure and ulcer risk. However, a significant amount of variance is unexplained by the models, which advocates the quantitative measurement of plantar pressures in the clinical risk assessment of the patient.

The value of reporting pressure-time integral data in addition to peak pressure data in studies on the diabetic foot: A systematic review

BACKGROUND In plantar pressure studies on the diabetic foot, pressure-time integral data is often analyzed and reported next to peak pressure data, mostly because of its assumed additional value. The aim was to assess this additional value by systematically reviewing the relevant literature. METHODS The MEDLINE database was searched for original articles that report both pressure-time integral and peak pressure data measured in the diabetic foot. Eligible articles were assessed according to differences in reported results between both parameters, the quality of discussion and specific conclusions drawn on pressure-time integral data, and the added value of the pressure-time integral data. FINDINGS All 35 eligible papers described studies on gait. Differences in reported results between parameters were found to be clear, minimal, or absent in 15, 8, and 12 papers, respectively. In 15 papers, the pressure-time integral results were discussed with respect to the peak pressure results, but in only 5 papers the explanation given for reported differences was considered meaningful. Specific conclusions were drawn in 11 papers. Some added value was found in 10 papers, but in all papers one or more limitations to this value applied. INTERPRETATION The study findings suggest that the added value of reporting pressure-time integral data is limited. Unless clear benefit can be shown such, as that ulceration can be better predicted using pressure-time integral than using peak pressure data, the reporting of pressure-time integral data seems redundant to express the plantar loading in the diabetic foot.

The efficacy of a removable vacuum-cushioned cast replacement system in reducing plantar forefoot pressures in diabetic patients

BACKGROUND The purpose of this study was to determine the plantar forefoot offloading efficacy of a new prefabricated vacuum-cushioned cast replacement system designed for foot ulcer treatment in neuropathic diabetic patients. METHODS Fifteen diabetic subjects with peripheral neuropathy underwent in-shoe plantar pressure assessment while walking in five different footwear types: a standard vacuum-cushioned system with instantly moldable vacuum cushion and roller outsole, two modified vacuum-cushioned systems, one with flat surface vacuum cushion and one with flat outsole, a forefoot offloading shoe, and a control shoe. Regional peak pressures, pressure-time integrals, and inter-regional load transfers were calculated to determine the mechanical action of the footwear. Perceived walking comfort was tested using a 10-point visual analogue scale. FINDINGS Forefoot peak pressures and pressure-time integrals were significantly lower (by 41-56%) in the vacuum-cushioned system compared to control. Compared to the forefoot offloading shoe, the vacuum-cushioned system showed significantly higher metatarsal head peak pressures, similar metatarsal head pressure-time integrals, and significantly lower hallux peak pressures and pressure-time integrals. A major transfer of forefoot load to the midfoot explained the offloading efficacy of the vacuum-cushioned system. Few significant differences were present between the modified and standard vacuum-cushioned systems. Perceived walking comfort was significantly higher in the vacuum-cushioned system (score 6.6) than in the forefoot offloading shoe (score 3.4). INTERPRETATION The results showed that the vacuum-cushioned cast replacement system was effective in offloading the plantar forefoot of diabetic patients at risk for ulceration, although the contribution of the instantly moldable vacuum cushion and roller outsole were relatively small. The combined peak pressure, pressure-time integral and walking comfort results indicate that the vacuum-cushioned system may be a useful alternative for the forefoot offloading shoe in offloading the plantar diabetic forefoot.

Data‐driven directions for effective footwear provision for the high‐risk diabetic foot

Custom‐made footwear is used to offload the diabetic foot to prevent plantar foot ulcers. This prospective study evaluates the offloading effects of modifying custom‐made footwear and aims to provide data‐driven directions for the provision of effectively offloading footwear in clinical practice.