Mechanical testing of hip protectors

Abstract

A novel hip protector has been designed to reduce the likelihood of hip fracture. The major design criteria were to improve patient compliance by making the protector small, comfortable to wear, and low maintenance. This has been achieved by designing the protector so that it can be worn continuously for periods of 5–7 days without need for replacement. Nursing staff are required to accurately position the device on the skin using an adhesive skin occlusive film (Opsite ®). There is no need for special underclothing and the pad can be made smaller since it is unable to slip out of place. Unlike other hip protectors currently available in the market, this protector is waterproof and can be worn at times when there is a high risk of falling such as when bathing or showering. The purpose of this work was to compare the new combination hip protector design with existing designs. A mechanical test rig was designed and built to simulate a person falling with sufficient impact energy to fracture the greater trochanter if unprotected. Essentially the test rig is a drop test machine using dead weights that can be dropped from predetermined heights. The test rig accounts for the shape of the hip and simulates a layer of flesh with skin. Carpet with different types of underlay was placed between the striker mass and the test samples to simulate the floor. For each hip protector, the weight of the striker mass was adjusted to obtain an impact energy of 120 J. Results from the new hip protector have been compared with that from existing hip protector designs.