Catastrophic Early Hemorrhage During Total Knee Arthroplasty in a Patient With Klippel-Trénaunay Syndrome: A Case Report

Klippel-Trénaunay syndrome (KTS) is associated with complex venous malformations and a risk of massive intraoperative bleeding. We report a young woman with KTS who developed 2,710 mL of intraoperative bleeding during total knee arthroplasty despite prior sclerotherapy and tourniquet use, requiring postoperative ICU management for coagulopathy. Preoperative MRI demonstrated both extensive vascular involvement and intra-articular venous malformations. This case highlights the importance of preoperative risk assessment based on lesion extent and intra-articular involvement and suggests that hybrid operating room strategies may be considered in selected high-risk cases.