David Alfaro, John Callaghan, Ronald Navarro.
Response/Recommendation: At this time, evidence is insufficient to suggest that venous thromboembolism (VTE) prophylaxis should be altered based on race/ethnicity.
Strength of Recommendation: Limited.
Rationale: As VTE is a post-operative complication of utmost importance to orthopaedic surgeons, studies in recent years have examined the relationship between race and post-operative VTE to determine whether a patient’s racial background is correlated to their risk of developing VTE. Multiple studies have found black patient populations to disproportionately suffer from higher rates of VTE following orthopaedic procedures1–11. Multiple studies examining post-operative complications in total knee arthroplasty (TKA) and total hip arthroplasty (THA) found a significant correlation between black race and incidence of VTE1–6. Other studies examining post-operative complications in total shoulder arthroplasty, hip fracture surgery, and spine surgery similarly found an association between black race and VTE7–11. However, this is not a universal finding. A few studies have found no significant correlation between post-operative VTE and race12–16. Blum et al., found no association between VTE and African American race in analysis of a regional database12. However, the patients in the African American group within that study were significantly younger and healthier compared to other racial groups, which may infer an inherent selection bias (as stated by the authors) in patients opting for TKA in that regional study. Another one of these studies demonstrated no significant correlation between race and post-operative VTE and only included elective pediatric orthopaedic procedures, thus the generalizability of these results to older populations is questionable13. One study examining short-term complications following patellofemoral arthroplasty had similar findings, however, the time course chosen excludes any potential VTE events that could have occurred beyond thirty days14. Furthermore, a retrospective study conducted at a Level 1 trauma center found no difference in outcomes with respect to race for operatively treated tibia fractures15. However, the authors note that the study was underpowered to definitively state that there is no difference between the two groups and the analysis of one specific center limits the generalizability of the results. Moreover, a cross-sectional study analyzing data from the Nationwide Inpatient Sample database in the U.S. did find black race to significantly increase patients’ risks of VTE following TKA1. The large statistical power within this study (n=1’460,901) and the use of national data increases the generalizability of this study’s findings compared to the aforementioned studies.
It is currently unclear whether these disparities are associated with environmental differences, such as access to care, implicit bias, and socioeconomic status, or biologic/genetic differences across races. Two recent studies examining post-operative complications in TKA and TKA procedures conducted within an integrated healthcare system found no significant difference in post-operative VTE amongst white, black, and Hispanic populations and a significantly lower rate amongst Asian-Americans17,18. A notable characteristic of these studies is universally insured status of the populations, which may have played a role in mitigation of these disparities. As the model of integrated care and universal insurance within this specific system may not mirror most current systems within the U.S., it is unclear if these results are applicable to other health care delivery systems where access to care is not as robust. Another study seeking to examine whether racial disparities are associated with complications in tibial plateau fracture care, found that while treatment choices were impacted by patient’s racial backgrounds (African Americans and Hispanics were more likely to undergo nonoperative treatment), there was no significant difference in rates of deep venous thrombosis (DVT) or pulmonary embolism (PE) when patients did receive operative treatment16. Additional studies are needed to address the underlying factors contributing to possible differences in VTE due to treatment course amongst races.
There are numerous studies conducted in Asia that have suggested that Asian patients experience lower rates of VTE19–30. An issue with most of these studies is that populations are exclusively Asian and results within these studies are compared to results in Western studies, rather than directly comparing multiple races within a single study. Additionally, several of these studies are retrospective, which is inherently susceptible to bias19–23. One therapeutic study following 184 patients found a low incidence of asymptomatic VTE (5%) and no episodes of fatal or symptomatic VTE in Asian patients undergoing elective hip surgery at a single center24. Additionally, a systematic review examined studies from 1979 to 2009 that included post-operative VTE in Asian patients undergoing hip fracture surgery, THA, and TKA and similarly found lower rates of proximal and symptomatic DVT compared to Western reports with no fatal cases of VTE25. A meta-analysis reviewed studies from 1996-2011 pertaining to Asian patients undergoing TKA and found an overall incidence of symptomatic PE to be 0.01%, overall incidence of DVT to be 40.4%, proximal DVT to be 5.8% and symptomatic DVT to be 1.9%26. Similar results were demonstrated in a meta-analysis conducted by Liew et al., however, there is a discrepancy in the conclusion drawn between these two papers. The former questions the potential benefit of chemical prophylaxis based on lower rates of VTE within these populations. The latter states that though incidence is lower, rates are still significant enough to warrant consideration of prophylaxis for Asian patients27. Complicating the picture further is a prospective study following 724 Taiwanese patients undergoing TKA found a similar incidence of DVT compared to Western studies31. Thus, there remains disagreement as to whether chemoprophylaxis should be routinely utilized within Asian patients who lack significant prothrombotic risk factors. In two studies examining the prevalence of VTE in Asian patients undergoing TKA and THA, respectively, who were treated solely with mechanical prophylaxis, Kim et al., found a low overall incidence of VTE28,29. Yeo et al., found similar results in Asian patients undergoing knee arthroscopy or arthroplasty who were given a regimen of rehabilitation and mechanical prophylaxis30. Loh et al., found that there was no significant difference in VTE between Asian patients given mechanical thromboprophylaxis and those given chemoprophylaxis in addition to mechanical prophylaxis post TKA19. Sugano et al., retrospectively reviewed 3,016 Asian patients undergoing hip surgery at 5 different centers and concluded that mechanical thromboprophylaxis without anticoagulant drugs is safe and effective for this patient population20.
Furthermore, little is known about whether race can sufficiently be utilized as a factor considered when risk stratifying a patient and whether chemoprophylaxis will lead to mitigation of these disparities or create additional disparities (i.e., hemorrhage). Many of the previously mentioned studies within Asian populations demonstrated that mechanical prophylaxis alone may be sufficient for thrombosis prevention, however additional studies conducted with diverse racial/ethnic populations are needed to generalize such results. Piper et al., sought to identify risk factors associated with VTE in patients undergoing spine surgery and found African American race to significantly increase patients’ risk of experiencing VTE32. Researchers in this study also created a risk score based on identified factors, which included African American race, and found that the score was able to predict postoperative VTE rate. Two additional studies incorporated race/ethnicity into a computer learning model that demonstrated proficiency in predicting post-operative VTE in patients undergoing spinal surgeries. These studies suggest the feasibility of indeed utilizing race as a concrete risk factor while risk stratifying patients. However, additional studies are needed to suggest that chemoprophylaxis in conjunction with risk stratification may reduce incidence of VTE in at-risk groups33,34. A study conducted by Heijiboer et al., retrospectively examined data on patients undergoing orthopaedic below-knee surgery and found that nonwhite race was significantly correlated with increased risk of VTE in patients who did not receive chemoprophylaxis. While assessing risk factors for patients who did receive chemoprophylaxis, Heijiboer et al., found no significant correlation between race and VTE35. While it is known that Virchow’s triad (intravascular vessel wall damage, hypercoagulable state, and stasis of flow) contribute to thrombosis, this study may suggest that environmental factors, such as access to care and underuse, impact these factors to a greater extent than inherent biological differences between racial groups. See Table 1 for the rates and odds ratios of VTE for various races reported in the studies. At this time, evidence is insufficient to suggest that VTE prophylaxis should be altered based on race/ethnicity.
Table 1. Rates of VTE and Odds ratios for various races reported in studies.
|Study||Procedure||White rate of|
post-operative VTE (%)
|Latino/Hispanic rate of|
post-operative VTE (%)
|Black rate of|
post-operative VTE (%)
|Asian rate of|
|Odds ratio of VTE|
Black race relative to White race
|Odds ratio of VTE|
Asian race relative to White race
|Odds ratio of VTE|
Hispanic ethnicity relative to White race
|Dai et al.1||TKA||0.83||0.81||1.06||–||1.34||–||0.98|
|Owens et al.2||TKA||1.4||–||2.2||1.1||1.14||0.94||–|
|Cram et al.3*||TKA||0.6||–||1.14||–||–||–||–|
|Cram et al.3*||THA||0.2||–||0.4||–||–||–||–|
|Dua et al.4**||TKA||–||–||–||–||1.3||–||–|
|Dua et al.4**||THA||–||–||–||–||2.2||–||–|
|Zhang et al.5||THA/TKA||–||–||–||–||1.29||–||–|
|SooHoo et al.6*||TKA||–||–||–||–||1.74||–||0.84|
|Lung et al.7||TSA||0.6||0||1||0||3.26||–||–|
|Nayar et al.8*||Hip Fracture Surgery||0.73||–||1.28||0.45||1.8||–||–|
|Best et al.9*||TSA/RTSA||–||–||–||–||1.97||–||–|
|Best et al.9**||TSA/RTSA||–||–||–||–||0.97||–||–|
|Sanford et al.10*||Cervical Spine Surgery||0.1||–||0.5||–||4.343||–||–|
|Sanford et al.10*||Lumbar Fusion||0.8||–||1.3||–||1.55||–||–|
|Sanford et al.10*||Decompression Laminectomy||0.2||–||1.1||–||5.764||–||–|
|Sanford et al.10**||Cervical Spine Surgery||0.1||–||–||–||–||–||–|
|Sanford et al.10**||Lumbar Fusion||1.1||–||3.3||–||3.72||–||–|
|Sanford et al.10**||Decompression Laminectomy||0.8||–||0.6||–||0.773||–||–|
|Fineberg et al.11||Lumbar Decompression/Lumbar Fusion||–||–||–||–||1.8||–||–|
|Blum et al.12||TKA||2.6||–||2.2||–||–||–||–|
|Georgopoulos et al.13||Elective pediatric surgeries||0.06||0.07||0.04||0.15||–||–||–|
|Driesman et al.16||Closed treatment and operative fixation of tibial plateau||0.7||0.6||0.7||–||–||–||–|
|Hinman et al.17||TKA||1.1||0.9||1.1||0.7||1.03||0.59||0.9|
|Okike et al.18||THA||1||0.8||1.1||0.3||1.1||0.29||0.85|
|Piper et al.32||Spine surgery||–||–||–||–||2.11||–||–|
|Kim et al.33||Elective adult spinal deformity procedures||1.9||0.9||1.8||–||–||–||–|
|Kim et al.34||Posterior Lumbar Spine Fusion||1||1||1.1||–||–||–||–|
VTE=Venous thromboembolism; TKA=Total knee arthroplasty; THA=Total hip arthroplasty; TSA=Total shoulder arthroplasty; RTSA=Reverse total shoulder arthroplasty.
*Pulmonary embolism was specifically measured rather than overall VTE.
** Deep venous thrombosis was specifically measured rather than overall VTE.
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35. Heijboer RRO, Lubberts B, Guss D, Johnson AH, DiGiovanni CW. Incidence and Risk Factors Associated with Venous Thromboembolism After Orthopaedic Below-knee Surgery. J Am Acad Orthop Surg. 2019;27(10):e482-e490. doi:10.5435/JAAOS-D-17-00787