A 3-year-old boy developed a serious fungal bone and joint infection caused by Lomentospora prolificans after surgery to fix a broken elbow. This fungus is extremely resistant to most antifungal medications. The infection was successfully treated using multiple approaches: aggressive surgical cleaning, several different antifungal drugs used together, special antibiotic-loaded bone cement, and antiseptic rinses. After two months of intensive treatment, the infection cleared and the child’s arm was saved from amputation.