Does the Helical Blade Lead to Higher Rates of Fixation Failure as Compared to Lag Screw in the Cephalomedullary Nailing Treatment of Hip Fractures? A Systematic Review and Meta-Analysis

Recently, several studies have suggested that blade-type cephalomedullary nails (CMNs) have a higher risk of fixation failure than that of lag screws, but no clinical consensus exists. This study compared fixation failure between helical blade-type and lag screw-type CMNs with cut-out and cut-through rates as primary outcomes and degree of sliding length, time to union, and nonunion rate as secondary outcomes.MEDLINE, Embase, and Cochrane Library were systematically searched for studies published before March 4, 2020, using the PRISMA guidelines.Studies were included if they directly compared helical blade and lag screw for treating hip fractures. Data could be extracted for CMN alone to avoid mixing CMN and extramedullary plate devices, such as the dynamic hip screw.Two board-certified orthopaedic surgeons specializing in hip surgery independently extracted data from the selected studies, and the data collected were compared to verify agreement.All data were pooled using a random-effects model. For all comparisons, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated as dichotomous data, whereas continuous data were analyzed using mean differences with 95% CIs.Fixation failure (OR = 1.88, 95% CI: 1.09-3.23, P = 0.02), especially cut-through (OR = 5.33; 95% CI, 2.09-13.56; P < 0.01), was more common with helical blades than with lag screws, although the cut-out rate was not significantly different between both the 2 groups (OR = 0.87, 95% CI: 0.38-1.96, P = 0.73). Surgeons should carefully select a blade-type CMN when treating hip fractures.Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.