Postoperatively, the use of closed-suction drainage systems in primary total hip arthroplasty (THA) is still common practice. The theoretical advantage of the use of such drains is a reduction in the occurrence of wound hematoma which is associated with increased postoperative pain and impaired wound heeling and infection after surgery. However, a recent meta-analysis of 36 studies involving 5,464 participants found no statistically significant difference in the incidence of wound infection, hematoma, dehiscence or reoperations, but a significantly greater need for allogeneic transfusion in patients managed with a postoperative drain (RR,1.25; 95% CI, 1.04-1.51) (Parker MJ et al, Cochrane Database Syst Rev 2007;CD001825). Despite the lack of sound evidence, the use of drains after surgery has been established and widespread for decades, but only empirically based. Conflicting results have been also published for lower limb arthroplasty surgery regarding the use of low-vacuum or high-vacuum drains. Finally, it can be postulated that if postoperative drains are to be used, low-vacuum salvage/reinfusion drains may be beneficial to the patient in the event of high postoperative blood loss, to maintain higher postoperative haemoglobin levels and to decrease the use of allogeneic blood transfusion.
In this article, the authors report on the results of a randomized controlled blinded single-center trial of 204 primary total hip arthroplasty (THA) patients managed with an intraoperative autologous blood transfusion filter system combined with a postoperative autologous blood transfusion filter unit compared to no drain. On average, 500 mL of autologous blood was retransfused and total blood loss was less in the autotransfusion group (–200 mL; P = 0.01). There were no differences in adverse event or length of hospital stay, but there was a trend towards fewer surgical wound infections in the autotransfusion group. They author conclude that the use of a new intraoperative autologous blood transfusion filter system combined with a postoperative autologous blood transfusion unit resulted in higher postoperative hemoglobin levels and less total blood loss following THA, compared with no drain.
Allogeneic transfusions were needed in 3.9% of patients in the autotransfusion group and 8.8% of patients in the non-drainage group (P = 0.15). Unfortunately, mean preoperative Hb levels were relatively high (≈14 g/dL) and the authors did not perform a subgroup analysis comparing anemic versus non-anemic patients. To ascertain which THA patient populations are more likely to benefit from this conservation strategy, an adequately powered study is warranted. Nevertheless, this study adds to the concept of the importance of hidden blood loss in THA.
– Manuel Muñoz