Introduction:The purpose of this study was to evaluate the indications, surgical technique, investigate the incidence and severity of knee pain after retrograde intramedullary nailing of femur fractures and thus better understand the functional results using osteosynthesis with retrograde nails in femoral shaft fractures.

Methods: All patients undergoing retrograde intramedullary nailing for femoral shaft fractures between June 2017 and August 2023 at a level 1 trauma center were reviewed. One year of follow-up or documented fracture healing were required. Records were reviewed for documentation of septic arthritis of the ipsilateral knee during the follow-up period.

Results: The fractures were classified, according to AO/OTA, as: 80 type 32A (42 - 32A1, 20 - 32A2 and 18 - 32A3); 60 type 32B (33 - 32B2, 27 - 32B3) and 56 type 32C (29 - 32AC2 and 27 - 32AC3). The average time to union was 19,5 weeks. There was one case of delayed union. The average knee range of motion was 130º of flexion (minimum 100º and maximum 150º). Eight patients (4,08%) reported knee pain.

Conclusions: The retrograde nail for the treatment of femur diaphyseal fractures achieves consolidation results similar to those of the antegrade femur nail.

Keywords: Femur shaft fracture, retrograde nailing, results.