Computer-assisted surgery in acetabular fractures: Virtual reduction of acetabular fracture using the first patient-specific biomechanical model simulator.

Preoperative planning for the management of acetabular fracture is founded on geometric models allowing virtual repositioning of the bone fragments, but not taking account of soft tissue and the realities of the surgical procedure. The present technical note reports results using the first simulator to be based on a patient-specific biomechanical model, simulating the action of forces on the fragments and also the interactions between soft issue and bone: muscles, capsules, ligaments, and bone contacts. In all 14 cases, biomechanical simulation faithfully reproduced the intraoperative behavior of the various bone fragments and reduction quality. On Matta's criteria, anatomic reduction was achieved in 12 of the 14 patients (86%; 0.25mm±0.45 [range: 0-1]) and in the 12 corresponding simulations (86%; 0.42mm±0.51 [range: 0-1]). Mean semi-automatic segmentation time was 156min±37.9 [range: 120-180]. Mean simulation time was 23min±9 [range: 16-38]. The model needs larger-scale prospective validation, but offers a new tool suitable for teaching purposes and for assessment of surgical results in acetabular fracture. LEVEL OF EVIDENCE: IV: retrospective study.