The 2007 John Charnley Award. Factors leading to low prevalence of DVT and pulmonary embolism after THA: analysis of genetic and prothrombotic factors

Incidence of Venous Thromboembolism after Primary Total Hip Arthroplasty with Mechanical Prophylaxis in Hong Kong Chinese

Purpose

The incidence of deep vein thrombosis (DVT) following total hip arthroplasty (THA) without chemoprophylaxis could be as high as 50% in Caucasians. However, according to several subsequent studies, the incidence of venous thromboembolic events (VTE) in Asians was much lower. The routine use of chemoprophylaxis, which could potentially cause increased bleeding, infection, and wound complications, has been questioned in low-incidence populations. The objective of this study is to determine the incidence of VTE after primary THA without chemoprophylaxis in an Asian population using a fast-track rehabilitation protocol and to verify the safety profile for use of 'mechanical prophylaxis alone' in patients with standard risk of VTE.

Materials and Methods

This is a retrospective cohort study of 542 Hong Kong Chinese patients who underwent primary THA without chemoprophylaxis. All patients received intermittent pneumatic compression and graduated compression stockings as mechanical prophylaxis. Multimodal pain management was applied in order to facilitate early mobilisation. Routine duplex ultrasonography was performed between the fourth and seventh postoperative day for detection of proximal DVT.

Results

All patients were Chinese (mean age, 63.0±11.9 years). Six patients developed proximal DVT (incidence rate, 1.1%). None of the patients had symptomatic or fatal pulmonary embolism.

Conclusion

The incidence of VTE after primary THA without chemical prophylaxis can be low in Asian populations when following a fast-track rehabilitation protocol. Mechanical prophylaxis alone can be regarded as a reasonably safe practice in terms of a balanced benefit-to-risk ratio for Asian patients with standard risk of VTE.

Incidence of deep vein thrombosis and symptomatic pulmonary embolism in Taiwanese patients with pelvic and/or acetabular fractures: a retrospective study

Venous thromboembolism (VTE) is common in patients with trauma, and thromboprophylaxis has been advocated. However, conflicting results regarding VTE rates in the Asian population following orthopaedic procedures have been presented. We aimed to investigate the VTE incidence in Taiwanese patients with pelvic and/or acetabular fractures and identify the associated risk factors. We included 402 patients who underwent surgery for pelvic and/or acetabular fractures. All patients received mechanical thromboprophylaxis with graduated compression stockings. Duplex scanning was performed postoperatively or during follow-up when signs or symptoms of deep vein thrombosis (DVT) developed. Variables with a significance level of ≤ 0.1 in the univariate analyses were introduced into the multivariate logistic regression analysis to identify DVT risk factors. The overall DVT and symptomatic pulmonary embolism (PE) rate was 3.48% (14/402 patients). Among patients with DVT, 46.1% were asymptomatic. Patients with VTE were significantly older than those without. Multivariate logistic regression analysis revealed that age was a VTE risk factor. The incidence of DVT and symptomatic PE in our cohort was low. Advanced age was a risk factor for VTE. These findings could help clinicians develop appropriate prevention and treatment strategies for VTE in Taiwanese patients with pelvic and/or acetabular fractures.

Associations between Hip Fracture Operation Waiting Time and Complications in Asian Geriatric Patients: A Taiwan Medical Center Study

Early surgical intervention in hip fractures is associated with lower complications. This study aimed to determine the appropriate operation time among Asian geriatric patients. The data of 1118 elderly patients with hip fracture at Mackay Memorial Hospital from 1 January 2011, to 31 July 2019, were retrospectively examined. Association between operation waiting time and the occurrence of complications was calculated using a cubic spline model. Significantly increased incidence of pneumonia, myocardial infarction, and heart failure was observed in 30 and 90 days when the patient’s surgical waiting time exceeded 36 h. The incidence rates of pneumonia across the early and delayed groups within 30 and 90 days were 4.4% vs. 7.9%, and 6.2% vs. 10.7%, those of myocardial infarction were 3.0% vs. 7.2%, and 5.7% vs. 9.3%, and those of heart failure were 15.2% vs. 26.8%, and 16.2% vs. 28.5%. Deep vein thrombosis and pulmonary embolism were not associated with surgical delay. The overall 30-day mortality rate was 5.4%, and no significant difference was observed when the surgical waiting time exceeded 36 h. In summary, operation waiting time exceeding 36-h was associated with increased rates of pneumonia, myocardial infarction, and heart failure in Asian geriatric patients undergoing hip fracture surgery.

The incidence of symptomatic in-hospital VTEs in Asian patients undergoing joint arthroplasty was low: a prospective, multicenter, 17,660-patient-enrolled cohort study

PURPOSE

The aim of this study was to determine the real incidence of symptomatic in-hospital venous thromboembolism (VTE) and identify risk factors for VTEs in Asian patients undergoing total hip (THA) and total knee arthroplasty (TKA).

METHODS

A total of 17,660 patients (20,078 hips and knees) undergoing THA and TKA at 78 hospitals were enrolled. The composite incidence of symptomatic in-hospital DVT and PE was identified as the primary effectiveness outcomes. The primary safety outcomes were the incidences of postoperative complications, especially for major or minor bleeding. Secondary analyses were assessed to identify the risk factors for postoperative VTE.

RESULTS

The overall rates of symptomatic in-hospital DVT in patients undergoing THA and TKA were 0.21% (19/9022) and 0.36% (31/8638), respectively. Symptomatic PE was confirmed in one TKA patient. Safety analysis showed that the incidence of bleeding during hospital stays in patients undergoing THA and TKA was 0.10% (18/17,660). Increased VTE risks were associated with old age, high BMI index, hypertension, cerebrovascular disease, history of venous thromboembolism and no medical prophylaxis usage.

CONCLUSIONS

The incidence of symptomatic VTEs in Asian regions was low compared with that reported in studies targeting Western populations. Approximately 1 in 500 patients undergoing THA and approximately 1 in 300 patients undergoing TKA developed symptomatic VTEs prior to hospital discharge. Old age, high BMI, history of venous thromboembolism, hypertension, cerebrovascular disease, and no medication prophylaxis were risk factors identified in this study.

LEVEL OF EVIDENCE

Prospective cohort study; Level 2.

Deep Vein Thrombosis Prophylaxis after Total Hip Arthroplasty in Asian Patients

In Western patient populations, the reported incidence of imaging-demonstrated deep vein thrombosis (DVT) after total hip arthroplasty (THA) is as high as 70% without prophylaxis. The reported rates of symptomatic pulmonary embolism (PE) after THA in recent studies range from 0.6% to 1.5%, and the risk of fatal PE ranges from 0.11% to 0.19% in the absence of prophylaxis. Predisposing factors to DVT in western patients include advanced age, previous venous insufficiency, osteoarthritis, obesity, hyperlipidemia, dietary and genetic factors. However, Asian patients who have undergone THA have a strikingly low prevalence of DVT and virtually no postoperative PE. Some authors suggest low clinical prothrombotic risk factors and the absence of some DVT-related genetic factors in Asian patient populations decrease the risk of DVT, PE or both. In Korea, the prevalence of DVT after THA without thromboprophylaxis have ranges from 6.8% to 43.8%, and asymptomatic PE have ranges from 0% to 12.9%; there have been only two reported cases of fatal PE. Deep-wound infections resulting from postoperative hematomas or prolonged wound drainage have been reported with routine thromboprophylaxis. The prevalence of DVT differs varies based on patient ethnicity. Guidelines for the use of thromboprophylaxis were altered and focus on the potential value of outcomes compared with possible complications (e.g., bleeding).

High prevalence of factor V Leiden and prothrombin G20101A mutations in Kashmiri patients with venous thromboembolism

AIM

The genetic variants of the factor V (G1691A), prothrombin (G20210A) and MTHFR (C677T) genes have been widely implicated as inherited risk factors for developing venous thrombosis. This study was undertaken to reveal the frequency of these mutations in Kashmiri patients with venous thromboembolism.

METHODOLOGY

A case-control study was designed with 250 VTE patients and 250 healthy controls. The mutations were analysed using ARMS-PCR and PCR-RFLP approach.

RESULT

The factor V Leiden G1691A mutation was found in 17/250 (6.8%) VTE patients and prothrombin G20210A mutation was found in 7/250 (2.8%) VTE patients while no mutation was found in any of the healthy controls. Both the mutations were found to be significantly associated with the increased risk of VTE (p = 0.0001 and 0.0150 respectively) while no association of VTE risk with MTHFR C677T polymorphism was found (p = 0.53).

CONCLUSION

The increased frequency of factor V Leiden G1691A and prothrombin G20210A mutation in VTE patients indicates a significant role of these mutations in the development of VTE in our population. We therefore suggest the routine screening of these two mutations as thrombophilic markers in Kashmiri patients with venous thromboembolism.

The risk factor of preoperative deep vein thrombosis in patients undergoing total knee arthroplasty

OBJECTIVES

The objective of this retrospective study was to investigate the prevalence of asymptomatic deep vein thrombosis (DVT) and the risk of DVT in patients admitted to hospital for total knee arthroplasty (TKA).

METHODS

From September of 2003 to December of 2013, 322 patients admitted for TKA were eligible for this retrospective study. A diagnosis of DVT was confirmed by Doppler ultrasonography. The prevalence of silent DVT in the lower limbs in patients before TKA was assessed. The risk factors for preoperative DVT were investigated, as well as the correlation of DVT in the patient's background and medical history.

RESULTS

Preoperative DVT was diagnosed in 56 patients (17.4%) including 3 patients with proximal DVT. Significantly elevated risks of DVT were found in patients undergoing revision TKA (p < 0.01), patients with rheumatoid arthritis (RA) (p < 0.005), patients with connective tissue diseases (CTDs) (p < 0.05), and female patients (p < 0.05) on univariate analyses. Multiple linear regression analysis showed that RA, CTDs and admission for revision TKA were independent risk factors for preoperative DVT.

CONCLUSIONS

A high prevalence of preoperative DVT was found in patients admitted to hospital for TKA. Admission to the hospital for RA, CTDs and revision TKA were risk factors for preoperative DVT.

Lower Urinary Tract Infection and Periprosthetic Joint Infection after Elective Primary Total Hip Arthroplasty

Purpose

Periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is a grave complication. Urinary tract infection (UTI) as a source for PJI is controversial. Our purposes were, (1) to evaluate the incidence of PJI after elective primary THA and (2) to determine whether UTI was associated with a risk of PJI after elective primary THA.

Materials and Methods

We retrospectively reviewed the medical records of 527 patients who underwent elective primary THA by using universal aseptic technique from May 2003 to October 2007. UTI group (13 patients) was defined as patients who underwent THA in status of having an UTI, and the remaining patients were defined as control group (514 patients). We compared the incidence of PJI in both groups.

Results

During the study period, the incidence of PJI was 0%, regardless of existence (or presence) of UTI.

Conclusion

There was no significant association between UTI and PJI, when cautiously performed THA.

The Efficacy of Low Molecular Weight Heparin for the Prevention of Venous Thromboembolism after Hip Fracture Surgery in Korean Patients

PURPOSE

The aim of this study was to investigate the efficacy of low-molecular-weight heparin (LMWH) for the prevention of venous thromboembolism in Korean patients who underwent hip fracture surgery (HFS).

MATERIALS AND METHODS

Prospectively, a total 181 cases were classified into the LMWH user group (116 cases) and LMWH non-user group (65 cases). Each group was sub-classified according to fracture types as follows: 81 cases of intertrochanteric fracture (group A: 49, group B: 32) and 100 cases of neck fracture (group C: 67, group D: 33). We compared the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) according to LMWH use.

RESULTS

Of the 181 cases, four DVTs were found in the LMWH user groups (1 in group A, and 3 in group C). One case of PE was found in LMWH non-user group D. The incidences of DVT and PE showed no statistically significant differences between the LMWH user and non-user groups (p=0.298 and 0.359, respectively). In subgroup analysis, no statistically significant differences were found between groups A and B and between groups C and D.

CONCLUSION

The administration of LMWH was not effective in the prevention of venous thromboembolism and PE in the Korean patients who underwent HFS.

Effects of Preoperative Glycyrrhizin Infusion for the Prevention of Venous Thrombosis on the Tissue Expression of Antithrombin in a Rat Model

OBJECTIVE

Using a thrombus model prepared by ligation of the inferior vena cava (IVC), the influences of the glycoside, glycyrrhizin, on plasma antithrombin levels and antithrombin mRNA expression levels in the liver and IVC with the inhibition of venous thrombosis were investigated.

MATERIALS AND METHODS

The rat IVC was exposed and ligated for 24 h immediately after the intravenous administration of 300 mg/kg glycyrrhizin. Among antithrombotic drugs, the Xa inhibitor, fondaparinux sodium, was used as a control drug.

RESULTS

The mean thrombus weight was significantly smaller in the glycyrrhizin-treated group (18.3 mg) than in the saline-treated group (34.3 mg). In contrast, the inhibition of thrombosis was not observed in the fondaparinux-treated group. Antithrombin mRNA expression levels in the liver were significantly higher in the ligated groups than in the baseline control group. The mean plasma antithrombin level was significantly lower in the glycyrrhizin group (96.6%) than in the saline group (114.4%), but was not significantly different from that in the baseline control group (102.4%).

CONCLUSION

The pretreatment with glycyrrhizin inhibited venous thrombosis, and antithrombin mRNA expression levels in the liver and IVC as well as plasma antithrombin levels were significantly lower than those in the saline group.

Venous Thromboembolism Following Hip and Knee Replacement Arthroplasty in Korea: A Nationwide Study Based on Claims Registry

The aim of this study was to examine the incidence and trends of clinically relevant venous thromboembolism (VTE) including deep vein thrombosis (DVT) and pulmonary embolism (PE) after hip and knee replacement arthroplasty (HKRA) in Korea. Between January 1 and December 31, 2010, 22,127 hip replacement arthroplasty (HRA) patients and 52,882 knee replacement arthroplasty (KRA) patients were enrolled in the analysis using the administrative claims database of the Health Insurance Review and Assessment Service (HIRA). All available parameters including procedure history and clinically relevant VTE during the 90 days after HKRA were identified based on diagnostic and electronic data interchange (EDI) codes. The overall incidence of VTE, DVT, and PE during the 90 days was 3.9% (n=853), 2.7% (n=597), and 1.5% (n=327) after HRA, while the incidence was 3.8% (n=1,990), 3.2% (n=1,699), and 0.7% (n=355) after KRA. The incidence of VTE after HKRA was significantly higher in patients who had previous VTE history (odds ratio [OR], 10.8 after HRA, OR, 8.5 after KRA), chronic heart failure (2.1, 1.3), arrhythmia (1.8, 1.7), and atrial fibrillation (3.4, 2.1) than in patients who did not. The VTE incidence in patients with chemoprophylaxis was higher than that in patients without chemoprophylaxis. The incidence of VTEs revealed in this retrospective review was not low compared with the results of the studies targeting other Asian or Caucasian populations. It may warrant routine prevention including employment of chemoprophylaxis. However, the limitation of the reviewed data mandates large scale prospective investigation to affirm this observation.

Prevalence of deep vein thrombosis and pulmonary embolism treated with mechanical compression device after total hip arthroplasty

Several reports have suggested that there is a strikingly low prevalence of deep vein thrombosis (DVT) and pulmonary embolism (PE) after total hip arthroplasty (THA) in Asian patients. We determined the prevalence of DVT and PE after the use of a mechanical compression device only without pharmacological thromboprophylaxis in 459 patients (516 hips). The overall prevalence of DVT was 4.8% (27 of 561 hips). Nine of 27 hips had proximal thrombi. Three patients (0.7%) had asymptomatic PE. In our patients, combinations of absent thrombophilic polymorphisms with low clinical prothrombotic risk factors led to a low prevalence of DVT and virtually no symptomatic PE. Therefore, mechanical compression device only suffices to prevent DVT and PE in Asian patients.

Risk factors for venous thromboembolism of total hip arthroplasty and total knee arthroplasty: a systematic review of evidences in ten years

Background

Risk factors for venous thromboembolism (VTE) of total joint arthroplasty (TJA) have been examined by many studies. A comprehensive systematic review of recent findings of high evidence level in this topic is needed.

Methods

We conducted a PubMed search for papers published between 2003 and 2013 that provided level-I and level-II evidences on risk factors for VTE of TJA. For each potential factors examined in at least three papers, we summarize the the number of the papers and confirmed the direction of statistically significant associations, e.g. “risk factor” “protective factor” or “controversial factor”.

Results

Fifty-four papers were included in the systematic review. Risk factors found to be associated with VTE of both total hip arthroplasty and total knee arthroplasty included older age, female sex, higher BMI, bilateral surgery, surgery time > 2 hours. VTE history was found as a VTE risk factor of THA but an controversial factor of TKA. Cemented fixation as compared to cementless fixation was found as a risk factor for VTE only of TKA. TKA surgery itself was confirmed as a VTE risk factor compared with THA surgery.

Conclusions

This systematic review of high level evidences published in recent ten years identified a range of potential factors associated with VTE risk of total joint arthroplasty. These results can provide informations in this topic for doctors, patients and researchers.

The Prevalence of the Prothrombin (F2) 20210G>A Mutation in a Cohort of Sri Lankan Patients with Thromboembolic Disorders

Prothrombin (F2) 20210G>A [rs1799963 G>A] mutation is a genetic variant which predisposes to inherited thrombophilia. Highest prevalence of this rare mutation has been reported among Caucasian and Mediterranean populations with thrombophilic conditions compared to healthy controls. It is absent or occurs in a very low frequency in both thrombophilic patients and healthy controls of most South Asian populations. A previous study has demonstrated that the mutant allele is absent among Sri Lankan healthy controls. This study was conducted to determine the prevalence of the F2 20210G>A mutation among Sri Lankan patients with thrombo-embolic disorders. F2 20210G>A mutation analysis was carried out on 825 patients. These included 374 with arterial thromboembolic disorders, 303 with venous thromboembolic disorders (VTE) and 148 with pregnancy related complications. Genotyping was done using polymerase chain reaction followed by restriction fragment length polymorphism. The overall prevalence of the individuals detected with the mutation was 0.8 % (7/825) with a mutant allele frequency of 0.4 % (7/1,650), and all were heterozygotes. Further classification according to the types of thrombotic events showed a prevalence of 0.5 % (2/374), 1.3 % (4/303), and 0.7 % (1/148) respectively, in the three groups with arterial thrombosis, VTE and pregnancy complications. The respective mutant allele frequencies in the three different groups were 0.3 % (2/748), 0.7 % (4/606) and 0.3 % (1/296). Although these figures are lower than that of Caucasian and Mediterranean populations, they are relatively higher compared to other South Asian populations. Therefore, the F2 20210G>A mutant allele is not entirely absent among Sri Lankan patients with thrombo-embolic disorders.

Comparison of postoperative morbidity between simultaneous bilateral and staged bilateral total knee arthroplasties: serological perspective and clinical consequences

The present study compared simultaneous and two-staged (stages 1 and 2 with 8-month interval on average) bilateral TKAs in terms of postoperative serological status and clinical consequences. The decrease in hemoglobin over 2 weeks postoperatively was similar between groups. C-reactive protein levels and creatine phosphokinase index peaking on day 2 were significantly higher in the simultaneous group than in either staged group (P<0.05). Incidence of DVT on day 7 tended to be higher in the simultaneous group, but the difference was not significant. Considering the approximately 8-month interval and 2-month earlier functional recovery with stage 2 TKAs, 6 months were saved with the simultaneous bilateral TKA group. Collectively, simultaneous bilateral TKA is likely to offer a safe and effective procedure in appropriate clinical settings involving anti-bleeding and anti-venous thromboembolism prophylaxis.

Deep Vein Thrombosis After Total Hip Arthroplasty and Total Knee Arthroplasty in Patients With Previous Ischemic Stroke

The present study evaluated the prevalence and therapy of deep vein thrombosis (DVT) after total hip arthroplasty (THA) and total knee arthroplasty (TKA) in 57 patients with previous ischemic stroke. Postoperative anticoagulants were used for DVT prophylaxis, and batroxobin and prolonged anticoagulants were used for thrombolysis in DVT subjects. The incidence of DVT after THA and TKA in patients with previous ischemic stroke was 16.2% and 20%, respectively. No bleeding complications were observed and no new ischemic stroke occurred during the following 3 months. The prevalence DVT after THA and TKA in patients with previous ischemic stroke was not specific, and the treatment of DVT with batroxobin and anticoagulants was effective and safe.

Who are at risk for thromboembolism after arthroplasty? A systematic review and meta-analysis

BACKGROUND

Thromboembolism, including deep venous thrombosis and pulmonary embolism, is a grave threat to patients undergoing total joint replacement. Using a systematic review and meta-analysis we asked whether gene mutations or polymorphisms could be risk factors for thrombosis after arthroplasty.

METHODS

We performed a comprehensive search of Medline, PubMed, Embase, Cochrane databases, China National Knowledge Infrastructure (CNKI), and Google Scholar, and identified 19 studies detailing genetic investigations of patients with thromboembolism following joint replacement.

RESULTS

Our meta-analyses included 5149 patients who underwent arthroplasty surgery. Significant associations with venous thromboembolism were identified for factor G1691A (odds ratio (OR) 1.41, 95% confidence interval (CI) 1.03 - 1.94, p=0.03), prothrombin G20210A (OR 2.16, 95% CI, 1.27- 3.69, p=0.005), and MTHFR/C677T/TT (OR 2.36, 95% CI 1.03 - 5.42, p=0.04) in Caucasian populations. No significant gene mutation was identified in Asian populations.

CONCLUSION

This study suggests a way to identify patients scheduled for arthroplasty who are at higher risk of thrombosis, enabling individualized treatment.

Does venous thromboembolism affect rehabilitation after hip fracture surgery?

PURPOSE

Venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism, is a serious and life-threatening complication in elderly (older than 65 years) patients undergoing hip fracture surgery (HFS). However, few have reported on the influences of VTE on postoperative rehabilitation in these patients. This study was performed to determine whether VTE affects clinical outcomes in patients who underwent HFS.

MATERIALS AND METHODS

We retrospectively evaluated 330 HFSs in 325 consecutive patients, which were performed from January 2009 to June 2010. From chart review, we identified 15 patients with symptomatic VTE. We compared Geriatric depression scale, Modified Barthel index and Berg balance scale scores as well as 10 meter gait speed at discharge and hospital stay between a symptomatic VTE group and a non-VTE group.

RESULTS

No significant difference in clinical outcomes at discharge between the two groups was found, although hospital stay was longer in patients with symptomatic VTE (p=0.012).

CONCLUSION

East Asian patients have a low incidence of symptomatic VTE after HFS, and the clinical outcomes of patients with symptomatic VTE were similar to patients without VTE, although there was a longer rehabilitation period.

Thromboprophylaxis for deep vein thrombosis and pulmonary embolism after total joint arthroplasty in a low incidence population

Postoperative venous thromboembolism is one of the most serious complications following total joint arthroplasty. Pharmacological and mechanical prophylaxis methods are used to reduce the risk of postoperative symptomatic deep vein thrombosis and pulmonary embolism. Use of pharmacological prophylaxis requires a fine balance between the efficacy of the drug in preventing deep vein thrombosis and the adverse effects associated with the use of these drugs. In regions with a low prevalence of deep vein thrombosis such as Korea, there might be a question whether the benefits of using pharmacological prophylaxis outweigh the risks involved. The current article reviews the need for thromboprophylaxis, guidelines, problems with the guidelines, pharmacological prophylaxis use, and the current scenario of deep vein thrombosis, and discusses whether the use of pharmacological prophylaxis should be mandatory in low incidence populations.

The incidence of pulmonary embolism and deep vein thrombosis after knee arthroplasty in Asians remains low: a meta-analysis

BACKGROUND

While Western literature has mostly reported the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) after TKA with chemoprophylaxis, the Asian literature still has mostly reported the incidence without chemoprophylaxis. This may reflect a low incidence of DVT and PE in Asian patients, although some recent studies suggest the incidence after TKA in Asian patients is increasing. Moreover, it is unclear whether the incidence of DVT and PE after TKA is similarly low among different Asian countries.

QUESTIONS/PURPOSES

We therefore determined the overall incidence of symptomatic PE and DVT without chemoprophylaxis after TKA in the Asian population, determined whether the incidence had a tendency to increase over time in Asia, and compared the incidence of symptomatic PE and DVT among Asian countries through a meta-analysis.

METHODS

We searched the PubMed, Embase, Cochrane Library, Web of Science, and Google Scholar websites for prospective studies published between 1996 and 2011. A total of 1947 patients from 18 studies were reviewed for meta-analysis.

RESULTS

The incidence of symptomatic PE was 0.01%. The incidences of overall DVT, proximal DVT, and symptomatic DVT were 40.4%, 5.8% and 1.9%, respectively. We found no difference in incidence of symptomatic PE among Asian countries and no trends in changes of the incidence over time.

CONCLUSIONS

The incidence of symptomatic PE and DVT after TKA without prophylaxis is low in Asian countries and has not changed over time, despite Westernizing lifestyles and an aging populace. Further investigation with large randomized studies is necessary to confirm our findings and identify risk factors predisposing to DVT.

Orthogenomics: an update

The study of genomics in orthopaedics has considerably lagged behind such study in other medical disciplines. Seminal work from other lines of medical research demonstrates the importance of genomic information in the evolution of personalized medicine. Common techniques for studying genome-phenotype associations include single nucleotide polymorphism, haplotype, and quantitative trait loci analysis. The few genome-based studies in major orthopaedic and related conditions have focused on osteoporosis, osteoarthritis, neuropathy and nerve compression, spinal deformity, trauma and inflammatory response, and pain and analgesia. The nascent field of orthogenomics, newly defined here as the application of genomic study to orthopaedic practice, has produced findings that could affect the practice of orthopaedics. However, more work is required, and the findings must be distilled and harnessed into applicable and achievable steps to improve clinical orthopaedic practice.

Deep venous thrombosis and pulmonary embolism are uncommon in East Asian patients after total hip arthroplasty

BACKGROUND

In Western countries, deep vein thrombosis (DVT) and pulmonary embolism (PE), are relatively common after THA and many surgeons recommend routine pharmacologic thromboprophylaxis. There is some suggestion in the literature that the incidences of DVT and PE may be lower in East Asian patients. Therefore, it would be important to establish the incidences in a large number of East Asian patients who did not receive pharmacologic thromboprophylaxis.

PURPOSE

We therefore determined the incidence of DVT and PE and evaluated the associated risk factors in a series of East Asian patients who underwent primary THA without pharmacologic prophylaxis.

METHODS

We retrospectively evaluated all 861 patients who underwent 992 elective primary THAs from May 2003 to December 2009. We identified patients with symptomatic DVT, symptomatic PE, and fatal PE. For potential risk factors we considered age, gender, body mass index (BMI), administration of aspirin, type of anesthesia, operation time, approach, simultaneous bilateral THAs, and duration of immobilization between symptomatic and asymptomatic patients.

RESULTS

We identified eight patients with symptomatic DVT, one of whom also had a symptomatic PE; there were no cases of fatal PE. The incidences of fatal PE, symptomatic PE, and symptomatic DVT were 0 %, 0.1 %, and 0.8 %, respectively. Longer duration of immobilization predicted symptomatic DVT or PE.

CONCLUSIONS

East Asian patients have a low incidence of symptomatic DVT and PE and virtually no fatal PEs after primary THA. The incidences and risk factors should be taken into consideration when deciding whether to prophylactically treat these patients with pharmacologic agents.

LEVEL OF EVIDENCE

Level IV, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Epidemiology of Prothrombin G20210A Mutation in the Mediterranean Region

There are many genetic and acquired risk factors that are known to cause venous thromboembolic disorders (VTE). One of these is the Prothrombin G20210A mutation, which has been identified in 1996. Prothrombin G20210A mutation causes higher levels of the clotting factor prothrombin in the blood of carriers, which creates a higher tendency towards blood clotting (hypercoagulability), and therefore the carriers become at higher risk of developing VTE. High prevalence of Prothrombin G20210A mutation was reported in Caucasian populations, but the prevalence was almost absent in non-Caucasians. That was most obvious in countries of South Europe and the Mediterranean region. This review article discusses Prothrombin G20210A mutation, how it causes VTE, the origin of the mutation, and its distribution worldwide with special concentration on the Mediterranean area.

Is routine chemical thromboprophylaxis after total hip replacement really necessary in a Japanese population?

Prophylaxis against venous thromboembolism after elective total hip replacement is routinely recommended. Our preference has been to use mechanical prophylaxis without anticoagulant drugs. A randomised controlled trial was performed to evaluate whether the incidence of post-operative venous thromboembolism was reduced by using pharmacological anticoagulation with either fondaparinux or enoxaparin in addition to our prophylactic mechanical regimen. A total of 255 Japanese patients who underwent primary unilateral cementless total hip replacement were randomly assigned to one of three postoperative regimens, namely injection of placebo (saline), fondaparinux or enoxaparin. There were 85 patients in each group. All also received the same mechanical prophylaxis during and after the operation, regardless of their assigned group. The primary measurement of efficacy was the presence of a venous thromboembolic event by day 11, defined as deep-vein thrombosis detected by ultrasonography, documented symptomatic deep-vein thrombosis or documented symptomatic pulmonary embolism. The duration of follow-up was 12 weeks.

The rate of venous thromboembolism was 7.2% with the placebo, 7.1% with fondaparinux and 6.0% with enoxaparin (p = 0.95 for the comparison of all three groups). Our study confirmed the effectiveness and safety of mechanical thromboprophylaxis without the use of anticoagulant drugs after total hip replacement in Japanese patients.

Low risk of thromboembolic complications after fast-track hip and knee arthroplasty

BACKGROUND AND PURPOSE

Pharmacological prophylaxis can reduce the risk of deep venous thrombosis (DVT), pulmonary embolism (PE), and death, and it is recommended 10–35 days after total hip arthroplasty (THA) and at least 10 days after total knee arthroplasty (TKA). However, early mobilization might also reduce the risk of DVT and thereby the need for prolonged prophylaxis, but this has not been considered in the previous literature. Here we report our results with short-duration pharmacological prophylaxis combined with early mobilization and reduced hospitalization.

PATIENTS AND METHODS

1,977 consecutive, unselected patients were operated with primary THA, TKA, or bilateral simultaneous TKA (BSTKA) in a well-described standardized fast-track set-up from 2004–2008. Patients received DVT prophylaxis with low-molecular-weight heparin starting 6–8 h after surgery until discharge. All re-admissions and deaths within 30 and 90 days were analyzed using the national health register, concentrating especially on clinical DVT (confirmed by ultrasound and elevated D-dimer), PE, or sudden death. Numbers were correlated to days of prophylaxis (LOS).

RESULTS

The mean LOS decreased from 7.3 days in 2004 to 3.1 days in 2008. 3 deaths (0.15%) were associated with clotting episodes and overall, 11 clinical DVTs (0.56%) and 6 PEs (0.30%) were found. The vast majority of events took place within 30 days; only 1 death and 2 DVTs occurred between 30 and 90 days. During the last 2 years (854 patients), when patients were mobilized within 4 h postoperatively and the duration of DVT prophylaxis was shortest (1–4 days), the mortality was 0% (95% CI: 0–0.5). Incident cases of DVT in TKA was 0.60% (CI: 0.2–2.2), in THA it was 0.51% (CI: 0.1–1.8), and in BSTKA it was 0% (CI: 0–2.9). Incident cases of PE in TKA was 0.30% (CI: 0.1–1.7), in THA it was 0% (CI: 0–1.0), and in BSTKA it was 0% (CI: 0–2.9).

INTERPRETATION

The risk of clinical DVT, and of fatal and non-fatal PE after THA and TKA following a fast-track set-up with early mobilization, short hospitalization, and short duration of DVT prophylaxis compares favorably with published regimens with extended prophylaxis (up to 36 days) and hospitalization up to 11 days. This calls for a reconsideration of optimal duration of chemical thromboprophylaxis.

Venous thromboembolism in Korean patients undergoing major orthopedic surgery: a prospective observational study using computed tomographic (CT) pulmonary angiography and indirect CT venography

In patients undergoing major orthopedic surgery, data of deep venous thrombosis (DVT) and pulmonary embolism (PE) are lacking as studied by computed tomographic (CT) pulmonary angiography and indirect CT venography (CTPA-CTV). A prospective observational study was performed for 363 Korean patients undergoing major orthopedic surgery to determine the incidence of venous thromboembolism (VTE), especially proximal DVT and PE. The incidence of VTE was 16.3% (n=59). Of them, 8 patients (2.2%) were symptomatic. The rate of VTE was the highest in patients who underwent total knee replacement (40.4%), followed by hip fracture surgery (16.4%), and total hip replacement (8.7%; P<0.001). The incidence of PE was 6.6% (n=24). Of them, 4 patients (1.1%) were symptomatic. Forty-one patients (11.3%) were in the proximal DVT or PE group. Based on multivariate analysis, total knee replacement and age > or =65 yr were significant risk factors for proximal DVT or PE in patients undergoing major orthopedic surgery (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.1-5.1; P=0.025; and OR, 2.1; 95% CI, 1.0-4.4; P=0.046, respectively). Taken together, the overall incidence of PE was 6.6% and rate of symptomatic PE rate was 1.1%. Knee joint replacement and age > or =65 yr were significant risk factors for proximal DVT or PE.

Clinical efficacy of mechanical thromboprophylaxis without anticoagulant drugs for elective hip surgery in an Asian population

To evaluate the clinical efficacy of mechanical thromboprophylaxis after elective hip surgery, we reviewed 3016 patients who underwent hip surgery at 5 centers. Primary total hip arthroplasty (THA), revision THA, and pelvic or femoral osteotomies were performed in 2648, 298, and 70 patients, respectively. Epidural anesthesia, intraoperative calf bandage, early mobilization, and intermittent pneumatic compression postoperatively with additional use of elastic stockings were the basic regimen for thromboprophylaxis. Postoperatively, no cases of fatal pulmonary embolism (PE) were encountered. One symptomatic PE and 4 symptomatic deep vein thrombosis cases were identified, all of which were successfully treated using heparin and warfarin. By 6 months, no deaths had occurred. We conclude that mechanical thromboprophylaxis without anticoagulant drugs is safe and effective for elective hip surgeries in our patient population.

Is one-stage bilateral sequential total hip replacement as safe as unilateral total hip replacement?

We investigated whether simultaneous bilateral sequential total hip replacement (THR) would increase the rate of mortality and complications compared with unilateral THR in both low- and high-risk groups of patients.

We enrolled 978 patients with bilateral and 1666 with unilateral THR in the study. There were no significant pre-operative differences between the groups in regard to age, gender, body mass index, diagnosis, comorbidity as assessed by the grading of the American Society of Anesthesiologists (ASA), the type of prosthesis and the duration of follow-up. The mean follow-up was for 10.5 years (5 to 13) in the bilateral THR group and 9.8 years (5 to 14) in the unilateral group.

The peri-operative mortality rate of patients who had simultaneous bilateral THR (0.31%, three of 978 patients) was similar to that of patients with unilateral THR (0.18%, three of 1666 patients). The peri-operative mortality rate of patients in the bilateral group was similar in high risk and low risk patients (0.70%, two of 285 patients vs 0.14%, one of 693 patients) and this was also true in the unilateral THR group (0.40%, two of 500 patients vs 0.09%, one of 1166 patients). Patients with bilateral THR required more blood transfusions and a longer hospital stay than those in the unilateral THR group. There was no significant difference (p = 0.32) in the overall number of complications between the groups. This was also true for the low-risk (p = 0.81) vs high-risk (p = 0.631) patients.

Our findings confirm that simultaneous sequential bilateral THR is a safe option for patients who are considered to be either high or low risk according to the ASA classification.