Comparative Analysis of Nail Plate Combination over Alternative Fixation Constructs in Low Energy Distal Femur Fractures: Recovery of Ambulatory Status and Outcomes

OBJECTIVES: To compare ambulatory status, union, mortality, and operative complications in distal femur fracture patients treated with the Nail Plate Combination and alternative fixation constructs. METHODS: Design: Retrospective Cohort Study. SETTING: Single Level 1, tertiary referral Academic center. PATIENT SELECTION CRITERIA: This study included adults with a low-energy distal femur fracture (OTA/AO33A/C and Su 1-3) that received ORIF within 2018-2024. Exclusions were pathologic fractures, antegrade intramedullary devices, and baseline nonambulators (from ambulatory status evaluation only). OUTCOME MEASURES AND COMPARISONS: The primary outcome was ambulatory status at postoperative intervals utilizing Koval-Walking-Score. Secondary outcomes included radiographic union, mortality, and reoperation. RESULTS: 404 patients with a low energy distal femur fracture were included, with 342 included for mobility analysis. Fixation constructs included 189 Nail-Plate-Combination (NPC) (mean age 75.0 ± 10.2, 83.1% female), 118 Lateral Locking Plate (LLP) (mean age 73.4 ± 10.2;, 76.3% female), 79 Retrograde Intramedullary Nail (rIMN) (mean age 73.7 ± 11.1, 74.7% female), and 18 Dual-Plate-Combination (DPC) (mean age 74.6 ± 10.9, 83.3% female) (Age p=0.567, Sex p=0.701). NPC was more frequently selected for Su 2 (56.2%) and Su 3 (65.9%) (p=0.001). NPC demonstrated lower average ambulatory impairment score over LLP: 3-week (-0.8; p=0.002), 6-week (-1.1; p<0.001), and both LLP and rIMN at 3-month (-0.9/-0.8; p=0.049/0.013) and 6-month (-0.9/-0.8; p=0.043/0.021). After Bonferroni correction to account for multiple testing, post hoc pairwise comparisons showed that NPC ambulation scores remained lower at 3 and 6 weeks (-0.8, p=0.024; -1.1, p<0.001). Six-month mortality was lower in NPC than rIMN (9% vs. 19%; p=0.04). DPC showed higher infection (22.2%; p=0.012), wound dehiscence (11.1%; p=0.013), and drainage (5.6%; p<0.001); though sample size limited analysis. Radiographic union was comparable (36.3% vs 52.9% vs 39.6% vs 54.5%, p=0.104). CONCLUSIONS: In this study, NPC was associated with superior ambulatory recovery rates to preinjury status over single implant constructs and improved mortality rates over rIMN. Thus, NPC represented a reliable construct for early ambulation and recovery in these injuries. LEVEL OF EVIDENCE: III.