BACKGROUND: Hidden blood loss, a frequent occurrence following artificial joint replacement, greatly affects the recovery from total hip arthroplasty. Many factors have been shown to have a correlation with the hidden blood loss, but the specific mechanism is not yet clear.
OBJECTIVE: To investigate the correlation of patients’ baseline (sex, age, underlying disease, obesity), prosthesis types, surgical time with hidden blood loss following total hip arthroplasty, as well as the association between hidden blood loss and prognosis.
METHODS: Ninety patients undergoing total hip arthroplasty were enrolled in this study. Using Gross formula, we calculated the total blood loss according to height, weight, and pre- and post-operative hematocrit, and subtracted the dominant loss of blood to get the quantitative value of hidden blood loss. According to the criterion, the 90 patients were divided to two groups: group I: volume of hidden blood loss > 480 mL, group II: volume of hidden blood loss < 480 mL. Then we analyze the difference in the gender, age, underlying disease, type of prosthesis, surgical time between the two groups, and whether there was a correlation between these factors and hidden blood loss. All the patients were followed for 1 year. Perioperative complications and survival curves were observed and monitored in the two groups.
RESULTS AND CONCLUSION: There were 39 patients in the group I, including 64.1% males, 64.1% hypertension patients, 35.9% diabetic patients, 7.7% patients receiving cement prosthesis; while, there were 51 patients in the group II, including 37.3% males, 25.5% hypertension patients, 5.9% diabetic patients, 35.3% patients receiving cemented prosthesis, showing a significant difference between the two groups. Based on these experimental findings, age, hypertension, diabetes mellitus, type of prosthesis were shown to be factors independently associated with hidden blood loss; however, obesity and smoking exhibited no correlation with hidden blood loss. In addition, a statistical difference in the survival rate was found at admission and during the 1-year follow-up.