Radiological assessment of the safe zone for medial minimally invasive plate osteosynthesis in the distal femur with computed tomography angiography

Abstract Introduction Surgical treatment options for distal femur fractures include intramedullary nailing or plating using a lateral or lateral parapatellar approach. However, medial plating is required for additional stability in some fractures such as severely comminuted fractures and periprosthetic fractures, and in those for which use of a lateral plate or nail is not appropriate. This study aimed to explore the safe zone for medial minimally invasive plate osteosynthesis of the distal femur with computed tomography angiography. Material and methods In a series of 30 patients, the region of interest between the lesser trochanter (LT) to the adductor tubercle (AT) was divided into six levels (I to VI), and the distance from the femur to the femoral artery (FA) was measured. At each level, the medial half of the femur was divided into eight sections that were assigned ‘A to H’ from anteromedial to posteromedial, and the position of the FA and the deep femoral artery (DFA) was recorded. Results The average length from the LT to AT was 295.0 mm. The average distance to FA was 38.0 mm, 29.9 mm, 26.9 mm, 27.0 mm, 21.8 mm, and 12.2 mm from level I to VI, respectively. The FA was positioned posteromedially below level IV and positioned at C–H below level II, which was out of the anterior aspect of the femur. The DFA was in the same location as the FA between levels II and III. Conclusion The anteromedial aspect of the distal half of the femur is the safe zone, and a long plate can be positioned safely in this zone at the anterior aspect up to the level of 8 cm below the LT.