Anterior subcutaneous internal fixation for a complex vertical shear pelvic fracture with Morel-Lavallée lesion: a case report.

A 32-year-old male sustained a complex vertical shear pelvic fracture after a motor vehicle accident, associated with hemodynamic instability and a large Morel-Lavallée lesion involving the anterior pelvis and right thigh. Initial management included external fixation and percutaneous sacroiliac screw placement as part of damage-control orthopedics. Two weeks later, anterior subcutaneous internal fixation (INFIX) was performed to provide anterior pelvic stability while limiting further soft-tissue dissection. Postoperative imaging showed satisfactory reduction and implant positioning. The INFIX component was removed four months later after healing, with preserved pelvic stability. At 18 months, the patient was able to walk with a cane and had regained urinary continence, although bilateral foot drop persisted. This case highlights the role of soft-tissue condition in surgical decision-making for complex pelvic trauma.