SLR - March 2012 - Quinn T. Charbonneau
Reference: Bus SA, Haspels R, Busch-Westbroek TE. (2011). Evaluation and Optimization of Therapeutic Footwear for Neuropathic Diabetic Foot Patients Using In-Shoe Plantar Pressure Analysis. Diabetes Care. 34: 1595-1600.
Scientific Literature Review
Reviewed by: Quinn T. Charbonneau, DPM
Residency Program: Massachusetts General Hospital, Boston, MA
Podiatric Relevance:
Custom shoes and insoles are commonly prescribed by podiatrists for both prevention and treatment of diabetic neuropathic ulceration. However, the degree to which these devices reduce plantar foot pressures is typically not measured quantitatively after the shoes (or insoles) are dispensed. In clinical practice, diabetic shoe or insole modification is largely performed on a trial and error basis or from relying on patient feedback. The authors of this study assessed objective in-shoe plantar pressure and its value in evaluation and optimization of plantar pressure-reducing effects of therapeutic footwear in diabetic patients with peripheral sensory neuropathy.
Methods:
Twenty three diabetic patients (17 male & 6 female) wearing either fully custom-molded shoes or custom molded insoles with extra-depth shoes were included in this study. Eighteen patients had a history of previous plantar ulceration. Each patient had a least one foot deformity. Plantar sensory neuropathy was confirmed using Semmes-Weinstein 10-gm monofilament. Baseline assessment peak pressures areas > 200 kPa, identified as regions of interest (ROIs), were assessed as the subjects walked along a 12-m walkway, wearing dynamic pressure-sensing insoles (Pedar-X system). No more than three ROIs per foot were selected. Subsequent modification of shoes or insoles was aimed to reduce peak pressure by at least 25 percent from baseline or achieve reduction in pressure below an absolute 200 kPa in ROIs. Up to three phases of modification, followed by in-shoe pressure measurements, were performed if the first or second did not meet pressure-reducing objectives. Inability to meet pressure reduction criteria within three rounds of modification was considered a failure to optimize the device (shoe or insole).
Results:
Thirty five plantar foot ROIs were identified in the subject study population, occurring beneath metatarsal heads and hallux more so than midfoot. One-half (50 percent) of those areas with history of plantar ulcer had peak pressures at the site of the previous ulcer. Within 1.6 rounds of shoe modification, peak pressures were reduced to a mean of 208 kPa. Using in-shoe pressure sensors, all shoes or insoles were effectively modified within three (3) attempts. Sixteen plantar foot ROIs were reduced in peak pressure by at least 25 percent, seven were reduced below the threshold of 200 kPa and twelve satisfied both criteria. Shoe or insole modification averaged less than one hour.
Conclusion:
The use of in-shoe pressure sensor devices provides an objective method for evaluating high plantar foot pressure locations, which may lead to ulceration in diabetic patients with peripheral sensory neuropathy. These sensor devices provide a tool to guide prompt and effective modification of custom footwear and insoles.