Promoting bone generation through the accordion technique in critical-sized bone defects: a review

Critical-sized bone defects caused by trauma, infection, tumor resection, or congenital malformation pose formidable challenges in orthopedic reconstruction. Distraction osteogenesis (DO) has been extensively applied due to its dual capacity for bone and soft tissue regeneration. However, delayed consolidation often leads to prolonged external fixation, increasing the risk of complications. The accordion technique (AT), also known as cyclic distraction-compression, has emerged as a promising mechanical stimulation strategy to enhance bone regeneration by modulating axial micromotion at the osteotomy site. Nevertheless, the optimal parameters (timing, amplitude, and frequency) remain undefined, and the AT's underlying mechanisms are still under investigation. This review systematically summarizes experimental and clinical evidence concerning the AT within DO, with a focus on its biomechanical principles, operational strategies, and biological effects. We further highlight key challenges and future directions for translating this approach into standardized clinical protocols, aiming to provide theoretical and practical references for the treatment of complex bone defects.