Use of 3D-Printed Heel Support Insoles Based on Arch Lift Improves Foot Pressure Distribution in Healthy People

Abstract

BACKGROUND 3D-printed insoles are widely used. This study was conducted to test a customized three-dimensional (3D)-printed heel support insole based on arch lift and to investigate whether the pressure distribution on the sole was improved while maintaining foot function. MATERIAL AND METHODS The design was based on a 3D plantar contour scanning modeling technique. Thirty healthy male participants walked along a 10-m track under 3 self-controlled interventions. A customized 3D-printed heel support insole based on arch lift was inserted into the socks for the experimental condition A. For condition B, a customized 3D-printed heel-supporting insole was inserted into the socks, and a standardized pre-made heel-supporting insole was inserted into the socks as a control (condition C). We used the Footscan® pressure plate to measure the plantar parameters in the forefoot contact and foot flange phases in each condition. RESULTS Compared with condition B and the control condition, the peak pressure under the heel was significantly lower in condition A (P<0.05), and the peak pressure in the midfoot region was not significantly increased (P>0.05). CONCLUSIONS The biomechanical properties of the customized 3D-printed heel support are better than those of the traditional heel support insole, especially when there is a need for an additional increase in heel height. Patients do not decrease midfoot motion function while using this customized insole.

Figure 1

(A) The Footscan^® plantar pressure system divides the sole into 10 areas: the big toe (T1), toes 2–5 (T2–T5), from the 1^st to the 5^th metatarsal (M1, M2, M3, M4, and M5), midfoot (MF), medial heel (H1), and lateral heel (H2). For the convenience of analysis, in addition to the toes, the sole was divided into 3 areas: the forefoot area (FF), the midfoot area (MF), and the rear foot (RF) area. (B) The plantar movement has 4 phases: initial contact phase (ICP), forefoot contact phase (FFCP), foot flange phase (FFP) and forefoot push-out phase (FFPOP). (C) The center of pressure (COP) varies and this range is shown on the x-axis. (D) Customized 3D printed heel support and midfoot lift insole for experimental condition A.

Figure 2

Contact area (CA) of the 3 plantar areas in experimental conditions A and B and the control condition.

Figure 3

Peak pressure (PP) of the 3 plantar areas in experimental conditions A and B and the control condition.

Figure 4

Percentage of force-time integral (FTI) in the 3 plantar areas in experimental conditions A and B and the control condition.

Figure 5

The range of medial-lateral center of pressure (ML-COP) during the forefoot contact phase (FFCP) and foot flange phase (FFP) in experimental conditions A and B and the control condition.

Figure 6

The velocity of the medial-lateral center of pressure (ML-COP) during forefoot contact phase (FFCP) and foot flange phase (FFP) in experimental conditions A and B and the control condition.