Fracture of a Cemented, Highly Polished, Collarless, Triple-Tapered, High-Nitrogen Stainless Steel Femoral Stem

Early cemented forged stainless steel and casted cobalt-chromium femoral components were susceptible to gross material failure1-7. Proposed risk factors include type of implant, surgical technique, and patient variables1-16. Advances in implant materials and design as well as surgical and cementing techniques have rendered implant fracture increasingly rare8. Modern high-nitrogen stainless steel (HNSS) alloys, such as ORTRON 90 (DePuy International, Leeds, United Kingdom), which is used in the C-STEM (DePuy, Warsaw, Indiana), are mechanically superior to previously used stainless steel alloys17. Although HNSS femoral stems are weaker than forged cobalt-chromium stems, they are widely used because of excellent clinical results and a dramatically lower cost16. Fractures of both types of stems are extremely rare but have recently been reported in the literature10,16. To our knowledge, this is the second reported case of a stem fracture in a C-STEM, a collarless, triple-tapered, highly polished cemented HNSS femoral stem16. The patient was informed that data concerning the case would be submitted for publication, and he provided consent. A sixty-nine-year-old man presented to one of the senior authors (A.S.) with pain in the left hip and thigh. Eleven years prior to presentation, he had undergone left total hip arthroplasty with a Duraloc 100 series (DePuy) titanium cementless acetabular shell (60-mm outer diameter) with an Enduron (DePuy) polyethylene liner (28-mm inner diameter, neutral, +4 mm offset) and a cemented C-STEM (size 6) femoral stem with an Elite (DePuy) zirconia head (28 mm, standard offset). A cement restrictor as well as an end cap and centralizer for the C-STEM had been used (Fig. 1). The patient also had undergone right total hip arthroplasty with a similar prosthesis ten years prior to this presentation. He was 5′10′′ …