Outcomes after Retrograde Intramedullary Nailing of 33C Femur Fractures

OBJECTIVES: To assess the outcomes of patients with complete articular distal femur fractures treated with open reduction and retrograde intramedullary nailing. METHODS: Design: Retrospective cohort analysis. SETTING: Single-center, Level 1 academic trauma center. PATIENT SELECTION CRITERIA: Patients treated between January 1, 2016, and January 1, 2023, with complete articular distal femur fractures (AO/OTA 33 C1-3) who underwent independent articular reduction and retrograde intramedullary nailing were included. Patients were included who had a minimum of 3 months of follow-up or until fracture union. OUTCOME MEASURES AND COMPARISONS: Patient data pertaining to demographics, surgical details, and radiographic outcomes were systematically collected and analyzed. Coronal and sagittal alignments were evaluated using the anatomic lateral distal femur angle (aLDFA) and anatomic posterior distal femoral angle (aPDFA), respectively. Reoperations were stratified into planned and unplanned categories and further classified as major or minor. RESULTS: The study cohort comprised 127 patients (52% males) with 130 complete articular distal femur fractures (3 patients with bilateral fractures) with a mean age of 49.9 years (range, 12-95 years). Mean clinical follow-up was 254.1 days (range 90-1882 days). Postoperative mean aLDFA was 83.4 degrees, and aPDFA was 1.2 degrees apex posterior. Articular reductions were anatomic (0mm residual displacement, 93.8%) or near anatomic (between 0mm and 2mm residual displacement, 6.2%) in all cases. All reductions were maintained at final follow up. The reoperation rate was 15.4%, with 3.8% of cases classified as major unplanned operations. The majority of minor unplanned reoperations (8% of cases) were for implant irritation or knee arthrofibrosis. The rate of osseous union was high, with only one case of nonunion observed, yielding an aseptic nonunion rate of 0% and an infected nonunion rate of 0.8%. CONCLUSIONS: Independent articular reduction and retrograde intramedullary nailing of AO/OTA 33C femur fractures resulted in an overall reoperation rate of 15.4%, major unplanned reoperation rate of 3.8%, an osseous union rate of 99%, and maintained articular and metaphyseal reductions at final follow up. The study's findings support this technique as an effective treatment option for managing these injuries. LEVEL OF EVIDENCE: Level 3, Retrospective cohort study.