Outcomes of Surgical Interventions in Children With Fibrous Dysplasia/McCune-Albright Syndrome

Background: Fibrous dysplasia/McCune-Albright (FD/MAS) is a rare bone disorder with an increased risk of skeletal deformities and fractures. Data on surgical indications, techniques, outcomes, and complications remain limited. Methods: An observational retrospective cohort study was conducted on children with FD/MAS who underwent FD-related orthopaedic surgery before the age of 18 years. Time-to-event analyses were performed, with the event defined as (re)fracture or second surgery after the first surgery. Results: A total of 45 children with FD/MAS were included (57.8% boys), with a median age of 10 years at diagnosis and 13 years at first surgery. In total, 64 surgical sites were included, and the median follow-up was 10 years (range 0.8 to 25.3). Surgery was performed for (impending) fractures in most cases (n=45, 70.3%), involving the proximal femur in 50.0%. Most frequently performed were osteosynthesis with hardware/implants (56.3%), followed by cortical strut grafting (21.9%). (Re)Fractures were the most common complication, often adjacent to the surgical site of the previous surgery. The probability of remaining free from an event was 70.3% at 1 year and 41.9% at 5 years. Increased risk of an event was associated with female sex (HR 2.2, 95% CI: 1.1-4.5, P =0.02) and lower age at index surgery (HR 0.93 per year increase, 95% CI: 0.86-0.99, P =0.04). Conclusion: In this largest series of children with orthopaedic surgery for FD/MAS, the proximal femur was the most common surgical site, typically for (impending) fractures. Risk of an event ((re)fracture or second surgery) was higher in females and those operated at a younger age. Level of Evidence: Level III.