BackgroundWe performed an updated systematic review and meta-analysis to compare the outcomes of CHA and UCHA in patients with FNFs.MethodsWe searched 6 English databases (Cochrane Library, ScienceDirect, PubMed, Embase, Medline, and Web of Science) and 4 Chinese databases (CNKI, VIP, Wang Fang, and Sino Med) in July 2020. The quality of each study was assessed according to the Cochrane handbook of systematic reviews. Data were pooled as risk ratios (RRs) and weighted mean differences (WMDs) with 95% confidence intervals (95% CIs). We used the random-effects model despite the heterogeneity among the studies. Data regarding baseline characteristics, hip function, complications both prosthetic-related and common, and operative outcomes are reported. ResultsA total of 24 RCTs based on 22 trials involving 3119 patients (CHA, 1575; UCHA, 1544) were included. Patients in CHA group show better hip function with HHS within 6 weeks (WMD=9.097, 95% CI, 3.034-15.161; P<0.003), 3 months (WMD=3.347, 95% CI, 1.478-5.216; P<0.001), 12 months (WMD=2.183, 95% CI, 0.161-4.205; P=0.034). The pooled results show that CHA had lower rates of refracture (RR=0.227, 95% CI, 0.135-0.381; P<0.0001), subsidence or loosening (RR=0.295, 95% CI, 0.112,0.778; P<0.014) and revision (RR=0.468, 95% CI, 0.279-0.786; P=0.004). Furthermore, CHA group tend to have lower pain(VAS score) (WMD=-0.568, 95% CI, -0.897 to -0.239; P=0.001), lower rate of pressure injury(RR=0.432, 95% CI, 0.221-0.846; P=0.014) and mortality at 1 year after surgery(RR=0.852, 95% CI, 0.727-0.998; P=0.047). UCHA showed a shorter operative duration(WMD=8.739, 95% CI, 6.354-11.124; P<0.0001).ConclusionsThis meta-analysis demonstrates that CHA has better hip function, lower rates of refracture, subsidence or loosening, revision, pressure ulcer, pain and one-year mortality than UCHA, while UCHA has shorter operative duration.