Internal Fixation of Distal Femur Fractures with the Less Invasive Stabilizing System (LISS)

Objective Stable internal fixation of distal femur with an implant resisting angular forces. The technique is minimally invasive, relies on a monocortical screw fixation and obviates the need for bone grafting. Indications Distal femur fractures of types A and C according to the AO classification. Periprosthetic femur fractures after total knee and hip arthroplasty. Contraindications Local infection, osteitis. Surgical Technique For intraarticular fractures: anterolateral parapatellar approach to the knee joint, anatomic reduction and temporary fixation of the articular fragments with Kirschner wires. Closed reduction aligning the block of articular fragments with the shaft. Submuscular introduction of the LISS plate with the help of an aiming device and its adaptation of the femur. Through stab incisions the screws are inserted leading to a stable anochorage of the plate. For extraarticular fractures: stab incisions over the lateral femoral condyle. Results In a prospective study, results of 54 fresh fractures of the distal femur in 51 patients (28 men, 23 women) operated between February 1997 and February 2000 could be assessed. The patients' average age at the time of infury was 53 (20-93) years. 48 patients suffered from type 33 fractures. Six type 32 fractures were encountered. Ten fractures were open. Six patients fractured their femur above or below a total joint replacement. We noted the following complications: one heterotopic ossification, two deep thrombophlebites with lung embolism and three infections. A loosening of the proximal screws occurred in four patients. 40 patients could be followed up clinically and radiologically, of these 32 after more than 6 months and 27 after more than 1 year. The Neer score of the 27 patients examined after >1 year amounted to an average of 73.9 (33-88) points, with six excellent, 14 satisfactory, six unsatisfactory results and one poor result. The Lysholm score amounted to 80.5 (40-100) points.