SHAPE MEMORY LOCKING DEVICE FOR ORTHOPEDIC IMPLANTS

Abstract

A mechanism to connect the supporting portions of orthopaedic implants such as in the head, spine, upper limb and lower limb and thereby prevent loosening and fretting at the implant interface of an orthopaedic implant construct has been developed based on shape memory effect and super-elasticity of shape memory materials such as nickel-titanium (nitinol or NiTi) shape-memory-alloy, without the use of typical threaded fastening technique. Advantages are conferred by making the entire device, not just connecting pieces, out of shape memory alloy and having shape memory effect and super-elasticity. Heating the memory head of the device will compress the connection portion without the use of an auxiliary device (e.g. coupling member) so that the connection portion can be completely clamped down by the memory head. Further advantages are provided through the use of a two-way shape memory effect in which the memory device can be closed or tightened by heating up the ambient temperature, and re-opened by cooling down the temperature.