Total hip replacement (THR) is a common procedure used in veterinary medicine to treat hip joint diseases, particularly in medium- and large-sized dogs. Although cementless techniques have become the standard owing to concerns regarding the aseptic loosening of cemented implants, complications such as stem fractures can still occur. This study reports a case of a 1-year-old, 2.8 kg Toy Poodle that underwent cementless THR using the Zurich mini-cementless hip system to treat Legg–Calvé–Perthes disease. Six months post-surgery, the dog developed a fractured stem, and a second surgery was performed using the “window technique” to replace the broken stem. The procedure involved creating a small window in the femoral cortex to remove the damaged stem and insert a new one. The dog recovered successfully with no further lameness. This case highlights the effectiveness of the window technique for stem replacement in small dogs and emphasizes the importance of optimal stem selection and positioning during the initial THR
