Biodegradable versus titanium osteosynthesis in maxillofacial surgery: a randomized controlled trial with 15 years of follow-up.

Studies on long-term outcomes of biodegradable versus titanium osteosynthesis in maxillofacial surgery are lacking. This multicentre randomized controlled trial was performed to compare the long-term clinical performance of titanium versus biodegradable osteosynthesis systems at ≥15 years of follow-up. Patients undergoing bilateral sagittal split and/or Le Fort I osteotomies, or treatment for mandible, maxilla, or zygoma fractures at four hospitals were included. Eligible participants (n = 230) were randomly assigned to receive titanium (KLS Martin) or biodegradable (Inion CPS) plates and screws (1:1). The primary outcome was symptomatic osteosynthesis removal. Secondary outcomes included malocclusion, plate palpability, swelling, mandibular function, pain scores, and patient satisfaction. Median follow-up was 16.3 years. Osteosynthesis removal at 15 years was 17.4% in the titanium group and 29.5% in the biodegradable group (hazard ratio 1.88, 95% confidence interval 1.07-3.31, P = 0.028). Notably, 4.5% of titanium group patients required symptomatic removal between 5 years and the latest follow-up, whereas no such removals were needed in the biodegradable group (P = 0.045). Plate palpability was higher in the titanium group (P = 0.004), but no significant difference was found in malocclusion, swelling, pain, or mandibular function scores. Both groups reported high patient satisfaction and excellent function without pain. The intention-to-treat results showed a significantly higher risk of symptomatic osteosynthesis removal after long-term follow-up in the biodegradable group, while the per-protocol analysis revealed a non-significant difference between the groups. There is a lifetime risk of symptomatic titanium plate removal (5% of patients at >5 years of follow-up).