[Value of procalcitonin in the diagnosis of perioperative infection in patients undergoing primary hip replacement].

OBJECTIVE: To analyze the value of procalcitonin (PCT) in the diagnosis of perioperative infection associated with implants in patients with primary hip arthroplasty.

METHODS: A retrospective study was conducted on 150 patients who underwent primary hip arthroplasty from June 2018 to June 2020, including 86 males and 64 females, aged from 47 to 77 years old with an average of (57.04±7.43) years. All patients with primary hip arthroplasty were divided into infection group and non infection group according to whether there was infection after operation. Blood samples were collected from the elbow vein before operation (D0) and on the 4, 6, 8 days after operation(D4, D6 and D8) respectively to detect the serum PCT level and white blood cell count (WBC) level.

RESULTS: Among 150 patients with primary hip arthroplasty, 34 patients with postoperative infection were in the infection group, and 116 patients without postoperative infection were in the noninfection group. In the infection group, there were 19 cases of superficial surgical site infection(55.88%, 19/34), 9 cases of urinary tract infection (26.47%, 9/34), and 6 cases of pneumonia(17.65%, 6/34). After bacterial culture in the infection group, there were 9 cases of Staphylococcus aureus, 3 cases of Escherichia coli, 3 cases of Staphylococcus epidermidis, 3 cases of Streptococcus constellation, 3 cases of Candida albicans, 6 cases of Klebsiella pneumoniae, 2 cases of Escherichia coli and Streptococcus agalactis, 3 cases of coagulase invisible staphylococcus and Burkholderia cepacia, 2 cases of Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa. There was no significant difference in PCT levels between two groups in D0( P =0.081), D4( P =0.069) and D6( P =0.093), but there was significant difference in D8( P =0.007). There was no significant difference in WBC between two groups at any time point( P >0.05). The results of receiver operating characteristic curve(ROC) showed that the AUC of PCT diagnosis was 0.978[95% CI (0.933, 1.022)] and that of WBC was 0.562[95% CI (0.398, 0.726)], PCT was an important predictor of infection after primary hip arthroplasty(AUC>0.9). When the critical value was 0.526 ng/ml, the sensitivity and specificity of PCT diagnosis are 36% and 100%, respectively, WBC was not a significant predictor of infection after primary hip arthroplasty (0.5<AUC<0.7) . When the critical value was 7.05×109 /L, the sensitivity and specificity were 64% and 44%, respectively.

CONCLUSION: PCT has a high specificity for perioperative infection in patients with primary hip replacement, and it is a promising diagnostic index for infection.