Management of Methicillin-Resistant Staphylococcus aureus-infected femoral nonunion during lengthening in achondroplasia using circular external fixator: a case report

• Published in: BMC musculoskeletal disorders 2024-12, Vol.25 (1), p.1062-7, Article 1062
• Main Authors: Nozaka, Koji, Shirahata, Tsuyoshi, Yuasa, Yusuke, Miyakoshi, Naohisa
• Format: Article
• Language: English
• Subjects: Achondroplasia; Achondroplasia - complications; Achondroplasia - surgery; Adolescent; Anti-Bacterial Agents - therapeutic use; Bone lengthening; Bone Lengthening - instrumentation; Bone Lengthening - methods; Bone Transplantation - methods; Care and treatment; Case Report; Case studies; Circular external fixator; Complications and side effects; Debridement; External Fixators; Femoral Fractures - surgery; Femur - microbiology; Femur - surgery; Fractures, Ununited; Fractures, Ununited - microbiology; Fractures, Ununited - surgery; Humans; Infected femoral nonunion; Infectious bone diseases; Male; Methicillin-Resistant Staphylococcus aureus - isolation & purification; MRSA; Staphylococcal Infections - surgery; Staphylococcus aureus infections; Surgical Wound Infection - diagnosis; Surgical Wound Infection - etiology; Surgical Wound Infection - microbiology; Surgical Wound Infection - surgery; Surgical Wound Infection - therapy; Treatment Outcome; Vancomycin - administration & dosage; Vancomycin - therapeutic use
• ISSN: 1471-2474; 1471-2474
• DOI: 10.1186/s12891-024-08224-0

Achondroplasia, the most common form of rhizomelic dwarfism, occurs in approximately 1 in 25,000 individuals. Clinical features include attenuated growth, rhizomelic limb shortening, and craniofacial abnormalities. Limb-lengthening surgery is widely employed to improve quality of life. However, reports on Methicillin-Resistant Staphylococcus aureus (MRSA) infections in femoral nonunions at lengthening sites are scarce. A 15-year-old boy with achondroplasia presented with MRSA-infected femoral nonunion. Bilateral femoral lengthening had been performed at age 13 using unilateral external fixators. Following a 7 cm lengthening of the right femur, surgical site infection occurred, with MRSA detected on postoperative day 127. Despite debridement and autologous iliac bone graft with non-locking screws, nonunion persisted. Referred to our hospital at age 15, the patient underwent radical debridement until punctate bleeding appeared, and vancomycin-loaded cement beads were implanted. A circular external fixator, effective even with bone weakened by prolonged non-weight bearing, was applied. Six weeks later, further debridement and vancomycin bead replacement were performed. Final fixation included refreshing the nonunion site and placing a cancellous bone graft from the contralateral iliac bone. Bone fusion progressed, and the ring was removed 9 months post-surgery. After seven years, no recurrence of infection was noted. Although slight knee flexion limitation persisted, the patient experiences no pain while walking and has become a healthy working adult. This case highlights the effectiveness of radical debridement, antibiotic-loaded cement beads, autologous bone grafting, and circular external fixation in treating MRSA-induced nonunion at femoral lengthening sites in achondroplasia. Circular external fixators provide stable fixation even in cases of prolonged bone weakness.