Fracture of the modular femoral neck component in total hip arthroplasty.

The use of modularity, specifically dual modular femoral stems, in total hip arthroplasty has increased in popularity over the past 2 decades. While offering several distinct advantages intraoperatively, the long-term success of adding a second modular junction has yet to be established. One potential complication of increasing modularity is component fracture. We present a case of modular femoral neck prosthesis fracture necessitating revision surgery to treat this complication. Careful preoperative planning during revision of these failures is essential to avoid morbidity and unnecessary subsequent revision surgeries, as demonstrated in this case. The combined effects of crevice and fretting corrosion, large-diameter femoral head, long modular neck, metal-on-metal articulation, patient size, and activity level may have all played integral roles in creating an environment susceptible to this classic pattern of fatigue fracture.