Medial Buttress Plate and Allograft Bone-Assisted Cannulated Screw Fixation for Unstable Femoral Neck Fracture with Posteromedial Comminution: A Retrospective Controlled Study

Objective To investigate the outcomes of open reduction and internal fixation combined with medial buttress plate (MBP) and allograft bone-assisted cannulated screw (CS) fixation for patients with unstable femoral neck fracture with comminuted posteromedial cortex. Methods In a retrospective study of patients operated on for unstable femoral neck fractures with comminuted posteromedial cortex from March 2016 to August 2020, the clinical and radiographic outcomes of 48 patients treated with CS + MBP were compared with the outcomes of 54 patients treated with CS only. All patients in the CS + MBP group were fixed by three CS and MBP (one-third tubular plates or reconstructive plates) with bone allografts. The surgery-related outcomes and complications were evaluated, including operative time, blood loss, union time, femoral head necrosis, femoral neck shortening, and other complications after the operation. The Harris score was evaluated at 12 months after the operation. Results All patients were followed up for 12-40 months. The average age of patients in the CS-only group (54 cases, 22 females) and CS + MBP group (48 cases, 20 females) was 48.46 +/- 7.26 and 48.73 +/- 6.38 years, respectively. More intraoperative blood loss was observed in the CS + MBP group than that of patients in CS-only group (153.45 +/- 64.27 vs 21.86 +/- 18.19 ml, t = 4.058, P = 0.015). The average operative time for patients in the CS + MBP group (75.35 +/- 27.67 min) was almost double than that of patients in the CS-only group (36.87 +/- 15.39 min) (t = 2.455, P < 0.001). The Garden alignment index of patients treated by CS + MBP from type I to type IV was 79%, 19%, 2%, and 0%, respectively. On the contrary, they were 31%, 43%, 24% and 2% for those in the CS-only group, respectively. The average healing times for the CS-only and CS + MBP groups were 4.34 +/- 1.46 and 3.65 +/- 1.85 months (t = 1.650, P = 0.102), respectively. Femoral neck shortening was better in the CS + MBP group (1.40 +/- 1.73 mm, 9/19) than that in the CS-only group (4.33 +/- 3.32 mm, 24/44). Significantly higher hip function was found in the CS + MBP group (85.60 +/- 4.36 vs 82.47 +/- 6.33, t = 1.899, P = 0.06). There was no statistical difference between femoral head necrosis (4% vs 11%, chi(2) = 1.695, P = 0.193) and nonunion (6% vs 9%, chi(2) = 0.318, P = 0.719). Conclusion For unstable femoral neck fractures with comminuted posteromedial cortex, additional MBP combined with bone allografts showed better reduction quality and neck length control than CS fixation only, with longer operative time and more blood loss.