Testing Orthoses & Footwear

In Short

Mechanical test method for evaluating the stabilizing function and durability of ankle orthoses, even in the early prototype phase, without risking injury to test persons. For this purpose, an artificial foot dummy based on the human anatomy and biomechanics was developed and equipped with integrated sensor technology.

In Detail

Background:

To improve the evidence-based development of ankle orthoses, their mechanical properties need to be better understood. Interindividual differences are the main reason for different results in clinical studies. For ethical reasons, it is very difficult to test the main function of an ankle brace, i.e. protection against sprains, using human subjects. Since comprehensive clinical studies on orthopedic devices are too expensive, only standardized laboratory testing methods can ensure a high product quality. Our vision is to realize a standardized test procedure for evaluating the function of orthoses. The challenges here are to define an adequate but at the same time representative model of individual human characteristics. At Fraunhofer IPA, a mechanical test method has been developed for testing the stabilizing effect of various ankle braces, even in the early prototype phase, without subjects. This method can be used to assure the quality of products based on objective data. In this way, orthoses can be tested during daily activities as well as under critical load conditions, without risking injury to test persons.

Test engineering:

A new artificial test foot with integrated sensor technology has been developed to characterize the mechanical properties of ankle braces, taking into account the anatomy and biomechanics of the human foot. The artificial foot model contains multiple axes:

• One axis for the talocrural joint
• One axis for the subtalar joint
• Combined axis for the metatarsal joint
• Combined axis for toe movements

This foot is used in combination with an actuator to dynamically test orthotic devices and mimic traumatic ankle motion. The integrated sensor system measures the position of the talocrural and subtalar joints as well as movements in the midfoot area. The stabilizing function of the orthosis is evaluated via a 6DoF force-torque sensor.

Applications:

• Ankle braces and ankle foot orthoses
• Soft ankle supports
• Footwear