HEATED BOLT FOR MODULAR HIP STEM

摘要

During hip replacement surgery, a practitioner can attach a distal stem to a femur of the patient and can then fixedly attach a proximal body to the distal stem using a bolt. Prior to tightening, the bolt can be heated to an elevated temperature greater than average human core body temperature. The practitioner can tighten the bolt to a specified torque while the bolt is at the elevated temperature. After tightening, the bolt cools to average human core body temperature and experiences a tensile stress due to the effects of thermal expansion. The tensile stress in the bolt produces a compressive force between the distal stem and the proximal body. The compressive force can increase the attachment strength of the bolt to the distal stem and the proximal body, beyond what can be achieved by solely torquing the bolt to the specified level during surgery without first heating the bolt.

主权项

1. A modular hip stem, comprising:
a distal stem configured to be implanted within a femur of a patient; a proximal body configured to attach to a proximal end of the distal stem; a bolt configured to secure the proximal body to the distal stem; and an electrical resistive heater, disposed within or around the bolt, configured to heat the bolt to a temperature greater than average human core body temperature.