Fracture of an 18-mm Diameter Extensively Porous-Coated Femoral Stem 17.9 Years After Primary Total Hip Arthroplasty

CASE: A 79-year-old man presented with progressive right thigh pain over 6 months and reliance on a cane. He had undergone primary total hip arthroplasty (THA) with a metal-on-metal bearing in 2007. In 2025, radiographs revealed a fracture of his 18-mm diameter extensively porous-coated, cobalt-chrome alloy femoral stem (Prodigy, DePuy Orthopaedics), prompting revision THA. To the best of our knowledge, this case represents the largest diameter fracture of this type of component reported to date. CONCLUSION: While fractures of smaller diameter stems are well-documented, clinicians should be aware that fatigue fractures can also occur in very large diameter components with a cylindrical distal geometry.