Abstract: Objective To investigate the effects of different surgical methods on hip joint range of motion(ROM), immune inflammatory response and coagulation-fibrinolysis system in patients with displaced femoral neck fractures. 
Methods A total of 92 patients with displaced femoral neck fractures in our hospital were prospectively selected as the research subjects and were divided intototal hip arthroplasty(THA)group(n=48) and hemiarthroplasty(HA)group(n=44). The perioperative indicators, postoperative complication rate, surgical efficacy, total cost, functional recovery scale(FRS) score and cost-effectiveness ratio(CER), hip joint ROM score before and after surgery, immune inflammatory indexes ［interleukin-6(IL-6), tumor necrosis factor-α(TNF-α), interleukin -1β(IL-1β)］, coagulation-fibrinolytic system indicators ［kaolin partial thromboplastin time(KPTT), prothrombin time(PT), plasminogen activator inhibitor(PAI), D-dimer(D-D)］ before and after surgery were statistically compared between two groups. 
Results The duration of operation, intraoperative blood loss and length of hospital stay in THA group were longer or more than those in HA group(P＜0.05). The scores of hip joint ROM were increased, and the scores were higher in THA group than in HA group. There was significant difference in the interaction between groups, time points and time points between groups(P＜0.05). The excellent and good rate of THA group was higher than that of HA group, while the incidence of postoperative complications was lower than that of HA group(P＜0.05). The levels of IL-6, TNF-α, IL-1β, KPTT, PT, PAI and D-D increased initially and then decreased in both groups, which were higher in THA group than in HA group; there were significant differences in the interaction between groups, time points and time points between groups(P＜0.05). The total cost and CER within 2 years in THA group were higher than those in HA group(P＜0.05). There was no significant difference in FRS score between two groups(P＞0.05). 
Conclusion Compared with HA, the application of THA in the treatment of patients with displaced femoral neck fractures has greater surgical trauma and higher overall costs, but the hip function is improved more significantly. If the patient′s age, life expectancy, physical condition and economic conditions are appropriate, THA is recommended. 

Key words: femoral neck fractures, arthroplasty, replacement, hip, hemiarthroplasty