Effect of plate geometry on femoral nonunion treated with augmentative plating while retaining the intramedullary nail: a comparison of wavy and straight plates

Aseptic atrophic nonunion of the femoral shaft after intramedullary nailing is a common but difficult problem in orthopedic practice. Many surgeons turn to plate fixation with autogenous bone grafting because it can help both stabilize the bone and support healing. In this study, we looked at how wavy plates perform compared with traditional straight plates in patients with this type of nonunion. This retrospective study reviewed 43 patients diagnosed with aseptic atrophic nonunion of the femoral shaft who were treated with plate fixation combined with autologous iliac bone grafting between January 2017 and January 2022. Depending on the plate design selected at surgery, patients were assigned to either a straight plate group (24 cases) or a wave-shaped plate group (19 cases). The main focus was bone healing, assessed by both the time to union and the proportion of patients achieving union within 12 months. Secondary outcomes included the plate-to-cortex distance, early lateral callus formation, sub-plate cortical bone resorption, perioperative parameters, and complications. Radiographic findings and clinical outcomes were systematically compared between the two groups. Baseline characteristics were similar between the groups. The wave-shaped plate group had a significantly larger plate-to-cortex distance than the straight plate group (5.6 ± 1.4 mm vs. 1.8 ± 0.6 mm, P = 0.030) and a shorter mean time to union (5.3 ± 1.4 months vs. 6.9 ± 1.7 months, P = 0.010). No significant differences were observed in 12-month union rates, perioperative outcomes, or complication rates between the groups. Early lateral callus formation and sub-plate cortical resorption were also comparable. Wave-shaped plate augmentation combined with autologous bone grafting is a feasible treatment option for aseptic atrophic femoral shaft nonunion following intramedullary nailing. Compared with conventional straight plates, wave-shaped plates created a larger plate-to-cortex distance and were associated with a shorter radiographic union time, while no significant differences were observed in the 12-month union rate, perioperative outcomes, or complication rates. Further studies incorporating functional outcomes are needed to determine whether this radiographic advantage translates into meaningful clinical benefits.