Removal of a 'cold-welded' femoral head lag screw in a nail combination.

We present a case of a femoral head lag screw 'cold welded' to an intramedullary nail (IMN) in a female in her 20s during exchange femoral nailing of a subtrochanteric femoral osteotomy non-union. We subsequently developed a reverse spiral-fluted bolt extraction socket, designed to engage the outer wall of a bolt or screw. The lag screw was removed from the Smith and Nephew Meta-Tan IMN, 1 week later, and exchange nailing was successfully completed. This case report describes a technically challenging situation of a cold-welded femoral head lag screw during a complex revision. This report introduces a novel removal device and technique for such cases.