Femoral neck system vs. cannulated screws for Pauwels type III femoral neck fracture in non-elderly patients: a systematic review and meta-analysis

Background The optimal fixation strategy for Pauwels type III femoral neck fractures in non-elderly adults remains controversial because of the high risk of postoperative complications. The femoral neck system (FNS) has been developed to improve angular and rotational stability, but its clinical advantages over cannulated screws (CS) in this unstable fracture pattern remain unclear. This study aimed to compare the safety and effectiveness of FNS and CS in non-elderly patients with Pauwels type III femoral neck fractures. Methods A systematic search of PubMed, Embase, Web of Science, the Cochrane Library, Scopus, the Korean database (RISS), and Chinese databases (CNKI and Wanfang) was conducted to identify comparative studies evaluating FNS vs. CS in non-elderly adults with Pauwels type III femoral neck fractures. Fracture healing time, weight-bearing time, postoperative complications, and Harris Hip Score (HHS) were analyzed. Pooled results were expressed as mean differences (MD), standard mean differences (SMD), or odds ratios (OR) with 95% confidence intervals (CI). Meta-analyses were performed using RevMan 5.4. Results A total of ten studies were included, with a collective count of 557 non-elderly patients suffering from Pauwels type III femoral neck fractures. Among these patients, 276 patients underwent FNS treatment, whereas 281 patients were treated with CS. The findings indicated that FNS performed significantly better than did CS in terms of fracture healing time [standard mean difference (SMD) = −0.90; 95% CI (−1.30, −0.49); P < 0.0001], weight-bearing time [SMD = −1.17; 95% CI (−1.61, −0.74); P < 0.00001], total complications [OR = 0.16; 95% CI (0.08, 0.33); P < 0.00001] and the Harris Hip Score (HHS) [MD = 2.07; 95% CI (1.16, 2.97); P < 0.00001]. Nonetheless, the intraoperative blood loss in the CS group was less than that in the FNS group [MD = 21.88; 95% CI (12.48, 31.29); P < 0.00001]. Conclusion Despite increased intraoperative blood loss, FNS was associated with faster fracture healing, earlier mobilization, fewer postoperative complications, and superior hip function compared with CS. These findings suggest that FNS may be a more effective and safer fixation option for Pauwels type III femoral neck fractures in non-elderly adults. Systematic Review Registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420251111561 , PROSPERO CRD420251111561.