Dynamic hip screw vs femoral neck system for adult femoral neck fractures: A comparative meta-analysis

This study aimed to systematically evaluate and compare the outcomes of the Dynamic Hip Screw (DHS) and the Femoral Neck System (FNS) in managing adult femoral neck fractures through a meta-analysis. A comprehensive search of databases (WANFANG, VIP, CNKI, PubMed, The Cochrane Library, Embase, Medline, and SinoMed) was conducted to identify eligible studies up to October 2023, to identify clinical controlled studies comparing FNS and DHS for femoral neck fracture treatment. After screening, quality appraisal, and data extraction, statistical analyses were performed using RevMan 5.4 software. A total of eight studies met the inclusion criteria, consisting of one randomized controlled trial and seven cohort studies, covering 294 patients treated with FNS and 299 with DHS. Five studies originated from China, two from Germany, and one from Switzerland. Compared with DHS, the FNS group had shorter operative duration (MD = −20.13, 95% CI: −27.02 to −13.23, df = 6, P < 0.00001), reduced intraoperative blood loss (MD = −19.77, 95% CI: −28.72 to −10.81, df = 3, P < 0.0001), smaller incision length (MD = −0.59, 95% CI: −1.24 to −0.06, df = 2, P = 0.08), and higher Harris Hip Scores at the final follow-up (MD = 2.27, 95% CI: 0.89 to 3.65, df = 3, P = 0.001). No significant differences were observed between the two fixation methods in fluoroscopy usage (MD = −5.79, 95% CI: −14.71 to 3.13, df = 1, P = 0.20), perioperative hemoglobin reduction (MD = −0.36, 95% CI: −0.87 to 0.15, df = 1, P = 0.16), hospital stay duration (MD = −0.41, 95% CI: −1.35 to 0.52, df = 4, P = 0.39), internal fixation failure rate (RR = 0.73, 95% CI: 0.41 to 1.28, df = 5, P = 0.27), femoral neck shortening (MD = 0.42, 95% CI: −0.06 to 0.90, df = 2, P = 0.09), fracture nonunion rate (RR = 0.81, 95% CI: 0.37 to 1.76, df = 4, P = 0.59), or femoral head necrosis rate (RR = 0.77, 95% CI: 0.31 to 1.90, df = 3, P = 0.57). Compared to DHS, FNS demonstrates advantages in treating femoral neck fractures, including smaller incision length, shorter operative time, reduced intraoperative blood loss, and improved hip joint function. However, no significant differences were found in intraoperative fluoroscopy frequency, perioperative hemoglobin reduction, hospital stay duration, or long-term complications such as fixation failure, femoral neck shortening, nonunion, and avascular necrosis.