Shock Attenuation of Various Protective Devices for Prevention of Fall-Related Injuries of the Forearm/Hand Complex

Abstract

Background Attenuation of the peak impact force is essential in any protective devices for prevention of fall-related injuries. Hypothesis Common wrist guards have limited effectiveness because of the multifaceted nature of wrist injury mechanisms, and other modalities may provide enhanced shock-absorbing functions. Study Design Controlled laboratory study. Methods A free-fall device was constructed using a mechanical surrogate to simulate falling impact. At 4 different falling heights, 5 different hand conditions were tested: bare hand, a generic-brand wrist guard, a Sorbothane glove, an air cell, and an air bladder condition. The impact force from the ground and the transmitted impact force to the forearm/hand complex were simultaneously measured. Results The falling height and hand condition significantly modulated the impact responses. The padded conditions always had significantly smaller peak impact forces compared with the bare-hand condition. The wrist guard became ineffective in impact force attenuation beyond the falling height of 51 cm. On the other hand, the air bladder condition maintained less than 45% of the peak impact force of the bare-hand condition and remained below the critical value, whereas other conditions were all ineffective. Conclusion It was reconfirmed that common wrist guard design could provide limited impact force attenuation, whereas damped pneumatic springs would provide substantially enhanced shock-absorbing functions. Clinical Relevance A wrist guard incorporating volar padding with the pneumatic spring design principle might be more effective at preventing injuries than are currently available designs.