Efficacy of the femoral neck system in femoral neck fracture treatment in adults: A systematic review and meta-analysis

Controversy remains around the available choices for the internal fixation of a femoral neck fracture. The femoral neck system (FNS) was developed in 2018 and has been widely applied since then as it can provide rigid fixation stability with less damage to the bone mass around the fracture. However, no systematic reviews and meta-analyses have investigated the efficacy of the FNS in comparison with that of traditional internal fixation in the treatment of femoral fractures.To assess the efficacy of the FNS in comparison with that of cannulated compression screws (CCS) in the treatment of femoral fractures through systematic review and meta-analysis.Five electronic databases (PubMed, Embase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, and Wanfang) were searched from the earliest publication date to December 31, 2021. Reference Citation Analysis (https://www.referencecitationanalysis.com/) was used to check the results and further analyze the related articles. Controlled trials were included if the FNS was applied for the femoral neck fracture in adults and if it was compared with CCS for the achievement of internal fixation. The measurement outcomes included the required operation time, observed patient's blood loss, extent of fracture healing, patient's Harris Hip score (HHS) at the last follow-up, and records of any complications (such as failure of internal fixation, femoral neck shortness, avascular necrosis of the femoral head, and delayed union or nonunion).Ten retrospective controlled studies (involving 711 participants) were included in this meta-analysis. The meta-analysis showed that compared with CCS, use of the FNS could not decrease the operation time [standardized mean difference (SMD): -0.38, 95% confidence interval (CI): -0.98 to 0.22, P = 0.21, I2 = 93%), but it could increase the intraoperative blood loss (SMD: 0.59, 95%CI: 0.15 to 1.03, P = 0.009, I2 = 81%). The pooled results also showed that compared with CCS, the FNS could better promote fracture healing (SMD: -0.97, 95%CI: -1.65 to -0.30, P = 0.005, I2 = 91%), improve the HHS at the last follow-up (SMD: 0.76, 95%CI: 0.31 to 1.21, P = 0.0009, I2 = 84%), and reduce the chances of developing femoral neck shortness (OR: 0.29, 95%CI: 0.14 to 0.61, P = 0.001, I2 = 0%) and delayed union or nonunion (OR: 0.47, 95%CI: 0.30 to 0.73, P = 0.001; I2 = 0%) in adult patients with femoral neck fractures. However, there was no statistically significant difference between the FNS and CCS in terms of failure of internal fixation (OR: 0.49, 95%CI: 0.23 to 1.06, P = 0.07, I2 = 0%) and avascular necrosis of the femoral head (OR: 0.46, 95%CI: 0.20 to 1.10, P = 0.08, I2 = 0%).Compared with CCS, the FNS could decrease the chances of developing femoral neck shortness and delayed union or nonunion in adults with femoral neck fractures. Simultaneously, it could accelerate fracture healing and improve the HHS in these patients.