Total hip arthroplasty (THA) is a common orthopedic surgery used to treat end-stage hip joint diseases (1, 2). However, THA may result in substantial perioperative blood loss and necessitate transfusion, which could further lead to higher morbidity and mortality, increased length of hospital stay, and delayed functional recovery (3–5). Therefore, perioperative blood-conserving management in THA has always been a major topic in related research efforts (6).

Substantial bleeding in THA is mainly caused by procedures for the dissection of soft tissue, bone resection, and opening of the femoral medullary canal (6). Hemostasis of soft tissue can be controlled using a bipolar coagulator and maintained by mechanical compression (7). However, continuous bleeding from the bone is conspicuous and difficult to manage because the bleeding sites are always deeply seated and difficult to find (7). During surgery, waiting for natural hemostasis to occur is not an option; therefore, additional hemostatic methods are required to effectively and immediately stop bone bleeding (7–9).

Bone wax is a well-known topical hemostatic agent primarily composed of beeswax and softening agents such as petroleum jelly or a mixture of paraffin and isopropyl palmitate (10, 11). Its hemostatic action relies on the mechanical properties of trabecular vascularization of bone to seal the bleeding site and prevent blood flow from broken blood vessels into the bone to promote clot formation (6, 7). Because blood vessels are commonly distributed in the cortical and cancellous bones and osseous hemorrhage from the naked bone section and the femoral canal uncovered by the prostheses is a major source of blood loss in THA, the clinical application of bone wax in THA should be beneficial (11–14).

However, to the best of our knowledge, studies on the effect of bone wax for reducing blood loss in the arthroplasty are very rare (6, 11). Based on the hypothesis that bone wax significantly reduces blood loss in THA and leads to further positive postoperative outcomes, we conducted a prospective, randomized controlled study to determine whether bone wax optimizes perioperative hemostasis protocols in THA.

During the recruitment period from March 2021 to June 2021, 123 patients were scheduled to undergo primary unilateral THA because of end-stage joint diseases at our department. Among 123 patients, 11 patients did not meet the inclusion criteria, and eight patients declined to participate in the study. Therefore, the remaining 104 patients were eligible and formed the study cohort and were then assigned to either the bone wax group or the control group. The flow of patients is plotted in Figure 2. Preoperative demographics and characteristics were not significantly different between the groups (Table 1) (all p > 0.05). All participants included in the study were followed up for 6 months.

Total blood loss, serum Hb level, and change in Hb level on PODs 1 and 3 in patients in the bone wax group were significantly better than those in the control group (Table 2) (p < 0.05). In terms of the risk of transfusion, two patients in the control group required transfusions, whereas none in the bone wax group required transfusion; however, the difference was not significant (Table 2) (p = 0.495). Moreover, patients in the bone wax group had a significantly shorter length of postoperative hospital stay than those in the control group (Table 2) (p = 0.002). No significant differences were observed in lower limb diameters on PODs 1 and 3, ROM at discharge, and Harris hip score 3 weeks and 6 months postoperatively. Regarding adverse events, one case of blood oozing from the wound occurred in the control group. No symptomatic thromboembolic events or other serious complications such as infection occurred in either of the groups.

In this study, we found that the administration of bone wax effectively reduced postoperative total blood loss and changes in Hb levels on PODs 1 and 3. Moreover, patients in the bone wax group had better performance in terms of postoperative serum Hb level, change in Hb level on PODs 1 and 3, and length of postoperative hospital stay (all p < 0.05). The use of bone wax did not increase the incidence of bone wax-related adverse events.

The use of bone wax in orthopedic surgery has been well established in the literature, and many studies have demonstrated its efficacy in reducing blood loss and transfusion rate (7, 10). However, few studies have focused on the efficacy of bone wax in reducing postoperative blood loss after arthroplasty (6, 11). In a prospective randomized controlled study including 100 patients found that the application of bone wax was safe and effective for reducing total blood loss and maintaining higher hemoglobin levels (6). Another retrospective study about 674 consecutive surgeries declared the use of bone wax significantly reduced blood loss, decreased Hb levels, and the risk of transfusion (11). These results were substantiated by our study, however, these studies that have been conducted to determine the efficacy of bone wax in reducing blood loss following total joint replacement have focused on total knee arthroplasty (TKA) and not on THA. Because of the intrinsic difference between THA and TKA, a prospective randomized controlled study with a necessary sample size is appropriate and adequate to validate the effect of bone wax in reducing blood loss in THA. Thus, the effect of bone wax on THA remains unclear. Therefore, to resolve the aforementioned issue, we conducted a randomized controlled study to validate the effect of bone wax in reducing blood loss in THA.

During THA, after cancellous and cortical bones containing vascular tissues are incised, damage to the vasculature can cause osseous hemorrhage which is difficult to control by the natural hemostasis process and could result in severe blood loss, blood transfusions, and even mortality (23). Various surgical techniques have been proposed in different studies to effectively manage bleeding from the cortical and cancellous bone. Among these popular techniques, fibrin sealants require blood from the patient to obtain fibrin-rich cryoprecipitate, and its efficacy in reducing blood loss is heterogeneous in different studies (24). Collagen faces problems with storage stability, cohesiveness, and biocompatibility (10). Bone wax, with advantages such as ease of use during surgery, satisfactory cohesion to bone, malleability, and cost-effectiveness, is widely used for bone hemostasis (6).

Although bone wax has a long history of orthopedic application, as a foreign local agent, many orthopedists have raised concerns, such as failed bone healing, foreign body reaction, granuloma growth, thrombosis, and infection (10, 25–28). However, in the literature, the number of adverse events caused by bone wax is very small (28). Our results also demonstrated that bone wax did not increase the incidence of adverse events after THA.

This study had several limitations. First, this study was a single-center study, so the generalizability of the study may be influenced. However, many factors including individuals, centers, inclusion and exclusion criteria could also affect the generalizability. Second, diagnostic Doppler ultrasound and CT evaluation for symptomatic DVT and PE may miss asymptomatic venous thromboembolism. Finally, the necessary sample size estimation was calculated for our primary outcome, so this study may not be adequate to detect all relevant secondary outcomes.

The administration of bone wax in THA effectively reduced total blood loss, decreased Hb level and length of postoperative stay, without increasing the incidence of adverse events. Therefore, bone wax shows potential and promise as a standard hemostasis agent and can be used for optimizing perioperative blood-conserving management protocols in THA.

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

The studies involving humans were approved by the Ethics Committee on Biomedical Research, West China Hospital of Sichuan University. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

HL: study design and writing. CH: data collections and writing. Z-CD: data collections and data analysis. Z-HL: data collections and data analysis. E-ZZ: writing. Z-KZ: study design. All authors read and approved the final manuscript.

This work was supported by 1.3.5 Project for Disciplines of Excellence, West China Hospital, Sichuan University (No. ZYJC18039), and Regional Innovation and Cooperation Program of Science and Technology Department of Sichuan Province (No. 2021YFQ0028).

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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