[Case-control study on effects of vacuum drainage on perioperative blood loss after total hip arthroplasty for the treatment of femoral neck fractures].

Objective: To compare postoperative blood loss under different negative pressures of drainage after total hip arthroplasty for the treatment of femoral neck fractures.

Methods: From January 1st to December 30th 2013, 74 patients with femoral neck fractures treated with total hip arthroplasty were randomly divided into two groups: high negative pressure drainage group and low negative pressure drainage group. In high negative pressure drainage group, there were 34 cases including 10 males and 24 females, with a mean age of (75.94 ± 9.02) years old, and the patients were treated with 60 kPa negative pressure of drainage. In the low negative pressure drainage group, there were 40 cases including 13 males and 27 females, with an average age of (74.93 ± 8.90) years old, and the patients were treated with 30 kPa negative pressure of drainage. The amount of total drainage, total blood loss, and hemoglobin change were compared between these two groups.

Results: All the patients got primary healing without infections. In high negative pressure drainage group,the change of hemoglobin was (41.74 ± 15.69) g/L, total blood loss was (1,217.73 ± 459.50) ml and the drainage volume was (312.94 ± 103.44) ml; while in low negative pressure drainage group,the results were (34.90 ± 12.90) g/L, (904.01 ± 381.58) ml and (129.25 ± 44.25) ml separately. All the results in high negative pressure drainage group were higher than those in the other group. Three days after operation, the change of hemoglobin was (46.00 ± 13.29) g/L and total blood loss was (1,304.72 ± 421.75) ml; while in low negative pressure drainage group, the changes of hemoglobin was (43.87 ± 11.39) g/L and total blood loss was (1,196.78 ± 344.20) ml; there were no statistically significant differences between two groups.

Conclusion: When placing drainage devices after total hip arthroplasty for the treatment of femoral neck fractures, the level of negative pressure should be chosen according to preoperative level of hemoglobin and HCT in patients. For old patients with femoral neck fracture, low negative pressure is more suitable.