Parallel versus non-parallel cannulated screw fixation for femoral neck fractures: a systematic review and...

Femoral neck fracture (FNF) is a common type of hip fracture, for which cannulated screw fixation is a primary internal fixation method. The optimal configuration for cannulated screw fixation remains controversial, with debate primarily focused on two approaches: parallel fixation configuration (PFC) versus non-parallel fixation configuration (NFC). The objective of this study was to compare the efficacy and safety of two configurations in the treatment of femoral neck fractures.

Following PRISMA guidelines, we systematically searched PubMed, Embase, the Cochrane Library, and CNKI for studies comparing PFC and NFC in FNF fixation. Study quality was assessed using the Cochrane risk-of-bias tool and MINORS scale. Outcomes included femoral head necrosis, nonunion, femoral neck shortening, and fixation failure. Meta-analysis was conducted in RevMan 5.3, employing a fixed-effects model unless heterogeneity (I² > 50%) warranted an alternative approach.

A total of 20 studies involving 1,508 patients were included in the meta-analysis. The meta-analysis showed that the NFC group had significantly better outcomes, including lower rates of femoral head necrosis (OR 0.50, 95% CI 0.34-0.74, P = 0.0005), nonunion (OR 0.41, 95% CI 0.26-0.65, P = 0.0001), femoral neck shortening (OR 0.40, 95% CI 0.28-0.57, P < 0.00001), and internal fixation failure (OR 0.34, 95% CI 0.22-0.52, P < 0.00001).

Our findings indicate that NFC is more effective than traditional PFC for internal fixation of FNFs. Level of evidence Level III.