BackgroundThis retrospective study aimed to evaluate the long-term functional outcomes of BIFOLD osteosynthesis, employing retrograde nailing and distal femoral locked plating, in patients with distal femoral fractures and metaphyseal comminution. MethodsA retrospective analysis was conducted on patients treated for distal femur fractures with metaphyseal comminution between 2012 and 2022, with a minimum follow-up of 2 years. Inclusion criteria encompassed distal femur fractures with metaphyseal comminution, excluding specific conditions. BIFOLD osteosynthesis was employed in all 33 cases, utilizing retrograde SIGN (Surgical Implant Generation Network Nail) and distal femoral locking plates. Primary outcome measures included radiographic and functional outcomes assessed through the Sanders functional evaluation score, with secondary outcomes focusing on perioperative or postoperative complications. ResultsA total of 33 patients (21 male, 12 female) were included, with an average age of 51.4 years. BIFOLD osteosynthesis exhibited an average radiographic fracture healing time of 6.2 ± 2.5 months. The procedure's average operative time was 100 ± 15 min, and blood loss averaged 420 ± 50 ml. According to Sanders criteria, 28 patients (84.84 %) demonstrated well-to-excellent functional outcomes, while 3 patients (9.09 %) reported fair outcomes, and 2 patients (6.06 %) reported poor outcomes. No significant shortening or implant failure occurred, and all patients achieved over 90 degrees of knee range of motion within 8 weeks. One patient experienced superficial infection, and two patients exhibited insignificant coronal plane deformity. ConclusionBIFOLD osteosynthesis, combining intra and extra medullary fixation principles, offers a stable construct for distal femoral fractures with metaphyseal comminution. This approach facilitates faster ambulation, pain relief, early knee joint mobilization, and significant early union, resulting in improved functional outcomes. Additionally, BIFOLD osteosynthesis helps prevent collapse, translational and rotational deformities, as well as shortening.