Treatment of distal femur fractures using the Less Invasive Stabilization System: Surgical experience and early clinical results in 103 fractures

Objective: To summarize the complications and early clinical results of 123 distal femur fractures treated with the Less Invasive Stabilization System (LISS; Synthes, Paoli, PA). Design: Retrospective analysis of prospectively enrolled patients. Setting: Two academic level I trauma centers. Subjects and Participants: One hundred nineteen consecutive patients with 123 distal femur fractures (OTA type 33 and distal type 32 fractures) treated by 3 surgeons. One hundred three fractures (68 closed fractures and 35 open fractures) in 99 patients were followed up at least until union (mean follow-up = 14 months, range: 3-50 months). Intervention: Surgical reduction and fixation of distal femur fractures. Main Outcome Measurements: Perioperative complications, radiographic union, infection rate, loss of fixation, alignment, and range of motion. Results: Ninety-six (93%) of 103 fractures healed without bone grafting. All fractures eventually healed with secondary procedures, including bone grafting (1 of 68 closed fractures and 6 of 35 open fractures). There were 5 losses of proximal fixation, 2 nonunions, and 3 acute infections. No cases of varus collapse or screw loosening in the distal femoral fragment were observed. Malreductions of the femoral fracture were seen in 6 fractures (6%). The mean range of knee motion was 1° to 109°. Conclusions: Treatment of distal femur fractures with the LISS is associated with high union rates without autogenous bone grafting (93%), a low incidence of infection (3%), and maintenance of distal femoral fixation (100%). No loss of fixation in the distal femoral condyles was observed despite the treatment of 30 patients older than 65 years. The LISS is an acceptable surgical option for treatment of distal femoral fractures.