The Analysis and Applications of Dynamic Impression Insole

The Effect of Dynamic Impression Insoles on Plantar Pressure and Pain in Persons With Metatarsal Pain

The aim of the study was to investigate the effectiveness of dynamic impression insoles on plantar pressure and pain reduction. A dynamic impression insole was made by sequential padding with Plastazote and P-cell under daily walking compression. The pain levels and plantar pressure with the use of dynamic impression insole were assessed and compared with 7-mm Ethylene Vinyl Acetate (EVA) control, 9-mm uncompressed Plastazote and custom molded insoles. Plantar pressure was measured by a Pedar-X mobile system, and pain level was assessed using a Visual Analog Scales.

Toe deformities may cause prominence of the metatarsal heads (MTH) and distal displacement of fat-pad cushion beneath the MTH, resulting in the metatarsal pain. Foot pain frequently leads to limitation of activities of daily life and deterioration of life quality. Foot orthoses have been commonly used in clinical practice to reduce plantar pressure and subsequent pain. However, the therapeutic efficacies of custom molded insoles with a metatarsal support vary widely with their designs and materials. We designed a simple and effective method that a dynamic impression insole was made by sequential padding of foams with different compressibility under successive dynamic impression in daily walking. A piece of metatarsal pad and arch support made of EVA was attached to the bottom of impressed insole just proximal to the first, second, and third MTH according to the foot impression. Fifty participants with metatarsal pain were recruited from the podiatry outpatient clinic of Taipei Veteran General Hospital. The plantar pressure measurements were carried out under a comfortable and stable walking speed preferred by the participants one month after the dynamic impression and custom molded insoles were well fabricated. All pressure data were processed with the Novel-Win Multimask analysis software. The purposes of this study were to investigate the biomechanics of dynamic impression insole in plantar pressure and pain reduction.

We sequentially padded P-cell, Ethylene Vinyl Acetate, and Multiform on the 9-mm thick plastazote under daily walking compression to make dynamic impression insole.

The custom molded insole was made by sequentially padded Multiform, P-cell, EVA, and cork on the positive plaster cast impressed by an impression box while holding the subtalar joint at a neutral position.

We sequentially padded (1)a 6.5-mm thick P-cell (21 Shore A hardness, Acor orthopedic Inc. Cleveland, Ohio, USA), and (2)a piece of metatarsal pad and arch support made of Ethylene Vinyl Acetate (EVA) (40 Shore A hardness, Schein orthopadie service KG. Remscheid, Germany) to the bottom of the impressed 9-mm thick plastazote (15 Shore A hardness, Schein orthopadie service KG. Remscheid, Germany) with double-sided adhesive tape in the forefoot region and just proximal to the first, second, and third metatarsal head region. We additionally padded a 2-mm thick Multiform (30 Shore A hardness, Schein orthopadie service KG. Remscheid, Germany) on the top of the impressed insole with double-sided adhesive tape.

The custom molded insole was made by sequentially padded Multiform (30 Shore A hardness, Schein orthopadie service KG. Remscheid, Germany), P-cell (21 Shore A hardness, Acor orthopedic Inc. Cleveland, Ohio, USA), Ethylene Vinyl Acetate (EVA)(40 Shore A hardness, Schein orthopadie service KG. Remscheid, Germany), and cork (50 Shore A hardness, Schein orthopadie service KG. Remscheid, Germany) on the positive plaster cast impressed by an impression box while holding the subtalar joint at a neutral position.

We used 9-mm flat Plastazote(15 Shore A hardness, Schein orthopadie service KG. Remscheid, Germany) as an insole

We used 7-mm flat Ethylene Vinyl Acetate (EVA) (40 Shore A hardness, Schein orthopadie service KG. Remscheid, Germany) as an insole

We measure peak pressure (in unit of kPa) under forefoot, midfoot, and rearfoot when using different kinds of insoles by Pedar-X mobile in-shoe system (Novel gmbh, Munich, Germany), and data were processed with the Novel-Win Multimask analysis software (Novel gmbh, Munich, Germany) after using dynamic impression insole for four weeks.

We measure pain levels when using different kinds of insoles by Visual Analog Scales after using dynamic impression insole for four weeks.

Inclusion Criteria: Adults with metatarsal pain Active in walking without any walking aids Exclusion Criteria: People with flexible flat foot Any acute inflammation

Chang BC, Liu DH, Chang JL, Lee SH, Wang JY. Plantar pressure analysis of accommodative insole in older people with metatarsalgia. Gait Posture. 2014;39(1):449-54. doi: 10.1016/j.gaitpost.2013.08.027. Epub 2013 Aug 31.