Application of postoperative autotransfusion in total joint arthroplasty reduces allogeneic blood requirements: a meta-analysis of randomized controlled trials

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are major orthopedic surgeries. Both procedures are associated with significant blood loss, generally from bone osteotomies, severed muscles, periosteal bleeding, and some patient-related factors such as bleeding disorders and comorbidities [1, 2]. It is estimated that perioperative blood loss is between 1000 mL and 1500 mL in TKA and that 18–95% of patients require donor transfusions [3]. Following primary THA, the rate of allogeneic blood transfusion (ABT) can be as high as 30–40% [4, 5]. However, ABT can lead to infection with human immunodeficiency virus and hepatitis C [6], allergic reactions, anaphylaxis, hemolytic reactions, lung injury, or graft-versus-host disease [7]. Not only may these conditions undermine the success of the surgery, but can also result in death. Moreover, allogeneic blood resources are limited and expensive.

To establish stable postoperative hemoglobin (Hb) levels and to reduce the need for ABT, various alternatives to donor transfusion have been proposed. For example, there has been support for preoperative blood donation [8, 9], acute normovolemic hemodilution [10], erythropoietin injections [11], autologous transfusion systems [12, 13, 14, 15, 16, 17, 18], correction of preoperative anemia [19], and pharmacologic agents such as tranexamic acid [20]. The optimal combination of techniques for particular patients and cost-effectiveness remains a matter of debate.

Recently, the concept of reinfusing blood collected from drains following TKA and THA has gained the interest of orthopedists. Drains are used to prevent hematoma accumulation and decrease the possibility of prolonged wound healing and infection [21]. Recent studies have reported that the transfusion of autologous blood has no effect in the majority of cases, but some studies support the method [22, 23, 24]. Furthermore, the usefulness of autotransfusion is uncertain due to methodological difficulties, such as no formal power analysis for study size and significance level, different transfusion triggers, and different autotransfusion devices [23]. In order to clarify the issue, we performed a meta-analysis that evaluated ABT rate, postoperative Hb, and adverse effects after total joint arthroplasty when using autotransfusion drainage, and the use of regular drainage or no drainage.

We conducted a meta-analysis to determine the effectiveness and safety of postoperative autotransfusion for TKA and THA. The findings revealed that postoperative autotransfusion could significantly reduce the number of patients who require postoperative ABT for TKA and THA compared with patients who receive regular drainage. However, the effect was not sustained when comparing autotransfusion with no drainage. The autotransfusion group had higher Hb levels than the regular drainage/no drainage group, and no significant difference in adverse reactions was observed between the two groups.

Although our results were positive for autotransfusion, the heterogeneity of the RRs for ABT rate in TKA was a limitation of the meta-analysis. Thus, the reliability of our meta-analytic estimates concerning TKA is questionable due to significant heterogeneity in methodologies. To reduce this heterogeneity in future trials, factors such as the type of system used, Hb triggers, comparison groups, and anesthesia methods should be taken into account. With this in mind, we performed subgroup and sensitivity analyses of the transfusion rates in TKA and THA. We believe that the variability in autotransfusion systems was an important consideration as at least seven autotransfusion systems were used in the 17 RCTs. Moreover, the skill of the operator performing blood reinfusion varied, which could have caused the differences in the volumes of re-infused blood among the studies. Insufficient data from existing RCTs limited our ability to analyze the effects of the different systems.

A previous meta-analysis drew different and incomplete conclusions regarding the benefits of autotransfusion. Zhao et al. and Markar et al. showed that autotransfusion drainage effectively reduced the demand for ABT after total joint arthroplasty when compared with regular drainage [34, 35]. However, Li et al. found no statistically significant differences in ABT rate between autotransfusion drainage and no/regular drainage in THA [36], which could be explained by the fact that only one study was included in the comparison [33].

Our meta-analysis revealed some distinct differences from the findings of previous studies. First, in this study, strict inclusion and exclusion criteria were observed in order to omit studies that implemented anticoagulants in the autotransfusion system [37, 38] or were performed without a tourniquet. Anticoagulants and tourniquets would affect blood loss during total joint arthroplasty. Second, two new RCTs were published [22, 23], neither of which showed a significant effect of the autotransfusion system compared with no drainage. In addition, few systematic reviews have considered the differences between autotransfusion drainage and no drainage for both TKA and THA. Finally, our research synthetically analyzed all related studies and gathered comprehensive results regarding the effects of autotransfusion in patients who underwent total joint arthroplasty.

The most important finding of this meta-analysis was that there was no significant difference in ABT rate between autotransfusion drainage and no-drainage. Recently, Thomassen et al. examined 575 patients who underwent primary hip and knee replacement with autotransfusion or no drainage [23]. The authors did not identify any significant difference in the need for ABT between the groups, which is in accordance with our results and those of many other studies (e.g., [13, 18, 22, 24, 32, 33]. Although the autotransfusion group had a significant reduction of ABT rate compared with the regular drainage/no drainage group in our meta-analysis, it is clear that autotransfusion drainage and no drainage have similar effects on ABT reduction.

To date, it remains controversial whether autotransfusion is superior to regular drainage. Atay et al. and Moonen et al. reported that the need for ABT was decreased by autotransfusion in both TKA and THA [2, 17]. Heddle et al. and others reported the same results for TKA alone [12, 14]. In contrast, some studies have shown that the use of an autotransfusion system fails to reduce the need for ABT after TKA [30, 31] or THA [18, 33]. This meta-analysis identified a statistically significant reduction in ABT requirements in patients who underwent autotransfusion drainage when compared with those who received regular drainage following TKA or THA. The previous meta-analyses performed by Markar et al. and Zhao et al. reported the same results for TKA alone [34, 35]. Other meta-analyses also compared regular drainage and no drainage for TKA [39] and THA [40], but there was no support for regular drainage in these reports. In conclusion, autotransfusion drainage and no drainage were superior to regular drainage. The mechanisms underlying these results should be explored in the future.

Adverse reactions including wound infection and febrile reactions were similar in the two groups, which mirrors the findings of previous meta-analyses [35, 36]. However, significant differences were noted by Zhao et al. between autotransfusion drainage and suction drainage in TKA with regard to febrile reactions [34]. This echoes Soosman’s report [41], which suggested a higher rate of febrile reactions than previous reports. Considering the low incidence of febrile reactions and wound infections in our results, we can only infer that autotransfusion drainage had a similar degree of safety when compared with regular drainage/no drainage. Notably, the number of included studies was small, limiting the reliability of these results. Further studies with sufficient data are required to evaluate the safety of autotransfusion systems.

We did not pool the data regarding blood loss volume, amount of blood transfusion per patient, length of hospital stay, and adverse reactions such as DVT and swelling because of insufficient data. Most RCTs stated the protocol for transfusion triggers, but whether strict transfusion rules were followed remains unknown. In addition, the transfusion triggers were not identical among the different RCTs. Thus, a subgroup analysis of transfusion triggers was not appropriate.

This meta-analysis has some limitations. First, the reliability of pooled results concerning TKA is limited by significant heterogeneity in methodological approaches. Second, the number of studies including data related to secondary outcomes was small. Thus, further meta-analyses including more studies and more information on safety outcomes are required in the future. Third, the results were based on many unadjusted factors. A more precise analysis should be conducted that allows for the time of randomization, drain insertion time, timing of drain opening and closing, and financial factors. Finally, the protocol for the systematic review was not prospectively registered. Thus, the transparency of our approach cannot be ascertained.

Autotransfusion systems reduce the need for ABT compared with regular drainage, but this reduction is not maintained in comparison to procedures that employ no drainage. The use of autotransfusion is characterized by a reduced need for ABT, higher Hb levels, and similar adverse reactions when compared with control groups (regular drainage and no drainage). However, the reliability of our assessment of secondary outcomes was limited by the inclusion of a small number of studies including these data. Transfusion triggers and the operation procedure should be explored in future study.