Non-parallel screw fixation for femoral neck fractures in young adults

Current literature shows divergence of views regarding screws positioning in femoral neck fractures fixation. The goal of this study is to evaluate the efficiency of divergent screw fixation for fracture neck of femur (NOF).

The study was conducted at an academic Level 1 Trauma Center. This is a retrospective study conducted from October 2013 to October 2016. The study included 41 patients (33 males, 8 females) suffering from fracture NOF who were fixed using BDSF technique (26 within 24 h. & 15 after 24 h.). The average age was 41.5 y (23-49 y). According to Garden classification; 17 patients (41.5%) were type 4, 24 patients (58.5%) were type 3. According to Pauwel's classification; 8 cases (19.5%) were type III, 25 cases (61%) were type II & 8 cases (19.5%) were Type I. Thirty-six cases (88%) were trans-cervical, 4 Sub-capital (9.5%) and 1 (2.5%) Basi-cervical. Six patients had comminution at the fracture site. We evaluated radiographic outcomes of union, femoral neck shortening, screws back-out & femoral head avascular necrosis (AVN). We also evaluated functional outcome using the Harris hip score. Follow-up was 24 months on average (ranging from 20 to 29 months).

One patient was lost during the follow up, the remaining 40 cases gave the following results regarding union: 38 united (within 3-4 months), 2 patients were un-united & one of them developed AVN. Twenty-seven patients (71%) had femoral neck shortening <5 mm, 8 patients (21%) had shortening 5-10 & 3 patients (8%) had shortening >10 mm. Shortening was on average 3 mm (0-15). Screws back-out distance was on average 4 mm (0 to16). Patients with mild femoral neck shortening had Harris hip score of 96 on average (92-100), those with moderate shortening had a score of 75 on average (72-79), those with severe shortening had a score of 62 on average (56-68).

The Authors believes this method provides better union rate & less incidence of femoral neck shortening than that of the conventional inverted triangle screws configuration reported in literature. However multi-center studies & long term follow-up is needed to fully evaluate this method.