A Comparison of Two Hip Stem Styles: Subsidence, Failure Load, and Bone Density

Abstract

The design of the femoral components used in hip arthroplasty has evolved from a concept to a standard construct with a few variations. Attempts to remove less bone have become more important as revision surgery many years after primary implantation has become more common. The Mayo Conservative Hip Prosthesis (Zimmer, Inc., Warsaw, IN) was designed to preserve bone and to use broaches that do not require strict superior/inferior access to the femoral canal. The shape of the stem was intended to reduce the amount of subsidence following implantation. The taper in both the anterior-posterior and medial-lateral directions offered an interference fit to ensure rigidity. The VerSys Fiber Metal Taper (FMT) implant (Zimmer, Inc., Warsaw, IN) is a tapered, collarless implant that is coated proximally with fiber metal and has a polished distal tip. It is intended to be inserted without cement and has a successful history of clinical use. Preparation of the canal requires more superior/inferior access for broaching and preparation of the femur.