Clinical outcomes of the induced membrane technique for ultra-large (>12 cm) segmental bone defects caused by osteomyelitis: a retrospective cohort study

Abstract Background The length of the bone defect is an important factor affecting surgical methods and treatment strategies for osteomyelitis. However, specialized research on the induced membrane technique (IMT) for the treatment of ultra-large bone segmental defects > 12.0 cm is still lacking. This study aims to evaluate clinical outcomes of ultra-large bone defects due to osteomyelitis treated using IMT. Methods This retrospective observational study included patients with ultra-large bone segmental defects (> 12.0 cm) due to osteomyelitis who underwent staged treatment with IMT at our hospital between January 2018 and March 2024. Data were collected for subsequent analyses, including the Self-rated Anxiety Scale (SAS) score, radiographic bone healing time, full weight-bearing time, Hospital for Special Surgery (HSS) Knee Score, and American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hind Foot Score. Results Thirty-eight patients were included in the study (30 men and 8 women; age, 52.6 ± 12.9 years). They had an average bone defect length of 16.0 ± 4.1 cm. The mean radiological healing and full weight-bearing times were 4.8 ± 2.1 and 5.2 ± 1.8 months, respectively. The radiographic union rates were 57.8% at 4 months and 86.8% at 6 months. The mean AOFAS and HSS scores were 85.2 ± 7.7 and 85.1 ± 6.3, respectively. A total of six complications were observed in four cases, and good outcomes were obtained with proper intervention. Conclusions IMT demonstrated reliable clinical efficacy in treating ultra-large bone segmental defects > 12.0 cm, consistently achieving both bone healing and functional joint recovery. Level of Evidence: Therapeutic Level Ⅳ. Trial registration: This retrospective study has been registered with the Chinese Clinical Trial Registry (registration number: ChiCTR2500109019; registration date: 2025-09-10).