Configuration of short- and long-threaded cannulated screws in proximal femoral plating decreases varus collapse of femoral neck fractures: A retrospective cohort study

Objectives: Proximal femoral plating serves as a good alternative for the fixation of femoral neck fractures, but fixation loss still occurs. This study aimed to evaluate the effect of a hybrid configuration of short- and long-threaded cannulated screws in proximal femoral plating in terms of decreasing varus collapse of femoral neck fractures. Materials and Methods: We retrospectively analyzed 86 patients with femoral neck fractures who were fixed by proximal femoral plating from January 2015 to June 2019. These patients were divided into two groups according to screw configuration: short- and long-threaded cannulated screws (SLTS, n = 38) and short-threaded cannulated screws (STS, n = 48). Radiological and clinical outcomes including screw withdraw, nonunion, avascular necrosis, caput-collum-diaphysis (CCD) angle, amount of femoral neck shortening (FNS), and Harris Hip Score (HHS) were compared between the groups. Results: Preoperative characteristics including age, gender, Garden type, duration of surgery, and reduction quality were not significantly different between the two groups ( p > 0.05). Less decreased CCD angle was observed in the SLTS group (-0.4 degrees (-1.4 - 1.8)) compared with that in the STS group (7.9 degrees (6.3 - 11.0)) ( p < 0.001). The SLTS group also presented with fewer amount of FNS (3.2 (2.7 - 3.8) mm vs. 5.1 (4.2 - 5.9) mm, p < 0.001). Bone union was achieved in all patients and no avascular necrosis was observed during the follow-up. The HHS was higher in the SLTS group (86.4 +/- 5.1) than that in the STS group (81.5 +/- 4.5) ( p < 0.001). Conclusion: The hybrid configuration of shortand long-threaded screws in proximal femoral plating offers better resistance against varus collapse and yields better functional outcomes in femoral neck fractures. (C) 2021 Elsevier Ltd. All rights reserved.