Outcomes for an Alternative Technique of In-situ Screw Fixation for Garden I and II Femoral Neck Fractures.

Abstract

To assess if a fully threaded inferior positioning screw in screw fixation of geriatric femoral neck fractures had lower varus collapse and failure than an all partially threaded screw construct. Single institution retrospective cohort study. Level II trauma center, community hospital health system. Included were all patients age 50 and older treated with in-situ inverted triangular screw fixation with a fully threaded (FT) inferior screw for Garden I and II femoral neck fractures (OTA/AO 31B1.1, 31B1.2, and 31B2.1) from 2015-2021, age and gender matched 2:1 with an all partially threaded screw group (PT) identified from the same period. In-situ screw fixation with a fully threaded inferior positioning screw. Reoperation rates and radiographic outcomes were compared between the FT and PT constructs. 24 patients were treated with a FT inferior screw (67% female, mean age 80.0 years (58-97)) and matched with 48 patients with an all PT construct (67% female, mean age 79.3 years (56-99)). There were no differences in age (p=0.89) or sex (p=1.0). In the FT group, one patient (4.2%) required revision surgery vs 11 (22.9%) in the PT group (p=0.03). Multivariate analysis demonstrated a protective effect of the FT construct, when controlling for trained traumatologist, Garden classification, and time to OR > 24 hours [OR (95% CI), p-value] [0.08 (0.006, 0.91), p=0.04]. Seven patients (58%) required revision due to femoral neck shortening and varus collapse. The lone FT reoperation was due to persistent nonunion without collapse (4.2%). There was no varus collapse in the FT group at final follow up. This study found a lower reoperation rate due to varus collapse in femoral neck fracture patients treated with an inferior fully threaded screw. With an inferior fully threaded screw, no case of varus displacement or collapse was observed and the only revision was due to a fracture nonunion without collapse. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.