A Magnetic Emergency Release System for Halo Traction

A magnetic emergency release system was developed for use in halo traction systems.  Commercially available rare earth mounting magnets, with selected weight-carrying capacities, along with ferromagnetic receptacles, were used in line between halos and overhead pulleys to both carry the prescribed traction force and provide an emergency release in the event of excessive applied force due to a transportation accident and/or sudden application of full body weight when using overhead walkers equipped with traction systems. The magnet–receptacle pairs were calibrated with an in-line digital scale. Load rate dependencies were noted, indicating that prescribed magnet–receptacle pairs should be chosen to carry at least 110% body weight. This weight capacity is reduced to approximately 88% of body weight during higher loading rates, such as transportation accidents and accidental falls. (Journal of Surgical Orthopaedic Advances 19(4):214–217, 2010)