Fracture of a spline of the femoral stem in an ingrown modular hip implant.

Abstract

Physiologic strain patterns of the femur are altered by the bending stiffness of the implant as well as the loading pattern of the implant itself. The Savish Range of Motion (S-ROM) femoral stem has been designed with flutes (to decrease distal material) and with a coronal slot (to decrease stiffness). The purpose of this case report is to briefly discuss design characteristics of femoral stems and their relationship to thigh pain as well as to describe the only report in the literature of a fracture of the anterior spline of a S-ROM prosthesis at the coronal slot. The femoral stem fractured at the coronal slot due to multiple bending moments in a small diameter stem. The proximal metaphyseal sleeve remains well fixed and the patient is functioning well without pain nearly a year after the identification of the fracture on routine follow-up.