Factors leading to decreased rates of deep vein thrombosis and pulmonary embolism after total knee arthroplasty

Deep vein thrombosis after major orthopedic surgery in Taiwan: A prospective cross-sectional study and literature review

BACKGROUND/PURPOSE

Postoperative venous thromboembolism is an important complication in Taiwan. We prospectively investigated the occurrence of deep vein thrombosis (DVT) after major orthopedic surgery without pharmacologic thromboprophylaxis in a cohort of 120 patients (46 males, 74 females, median age 71 years) at our institute.

METHODS

Color duplex compression ultrasonography (CUS) was used to detect DVT before and after the operation, while contrast venography was performed postoperatively for comparison and validation.

RESULTS

Total knee arthroplasty (TKA, 57 cases) and total hip arthroplasty (23 cases) were the most commonly performed operations. The rate of postoperative DVT was 7.5% (9/120), including five with proximal DVT and four with distal DVT. All were detected in the limbs on the operated side. Four of them were symptomatic DVT cases. Venography was performed in 19 patients and confirmed most findings of CUS, indicating the effectiveness of CUS for detecting DVT. The type of surgery (TKA) was significantly correlated with postoperative DVT. No clinically symptomatic pulmonary embolism or sudden death events were noted.

CONCLUSION

Nine out of 120 (7.5%) orthopedic patients without pharmacologic thromboprophylaxis developed postoperative sonographic DVT in our study. The DVT rate is consistent with other reports from various Asian countries and evidence from meta-analyses.

Risk factors for deep vein thrombosis even using low-molecular-weight heparin after total knee arthroplasty

Background

With an increase in deep vein thrombosis (DVT) following total knee arthroplasty (TKA) in the Asian population, most surgeons today use a form of prophylactic anticoagulant agents in patients after TKA. Nevertheless, DVT occasionally develops even in these patients with prophylaxis. The purpose of this study was to identify the risk factors for DVT after TKA in cases of postoperative low-molecular-weight heparin (LMWH) use.

Methods

We designed a retrospective study with 103 patients who underwent primary TKA. From the second postoperative day, 60 mg of LMWH was subcutaneously injected into the patients daily. On the seventh postoperative day, patients had computed tomography angiography to check whether they had DVT. Regarding risk factors, we investigated patients’ gender, age, surgical site (unilateral/bilateral), body mass index, method of anesthesia, preoperative hypertension, diabetes, hypercholesterolemia status, and prothrombin time/international normalized ratio from electronic medical records. We analyzed the statistical significance of these risk factors.

Results

Statistically significant factors in the single-variable analysis were surgical site (unilateral/bilateral), body mass index, preoperative hypertension status, and anesthesia method. Multiple logistic regression analysis with these factors revealed that the surgical site (unilateral/bilateral, p = 0.024) and anesthesia method (p = 0.039) were significant factors for the occurrence of postoperative DVT after TKA.

Conclusions

Patients undergoing simultaneous bilateral TKAs and patients undergoing TKA with general anesthesia need more attention regarding DVT even with chemoprophylaxis using LMWH after TKA.

Incidence of venous thromboembolism in Asian patients undergoing anterior cruciate ligament reconstruction without the use of mechanical or chemical prophylaxis

Background:

Venous thromboembolism (VTE) is a clinically relevant complication of major orthopedic surgeries. The prevalence of VTE and the indications for VTE thromboprophylaxis in Asian patients undergoing arthroscopic anterior cruciate ligament (ACL) reconstruction are not clear. This study aims to evaluate the prevalence of clinically significant venous thromboembolic events (VTE) in Asian patients undergoing arthroscopic ACL reconstruction without mechanical or chemical thromboprophylaxis.

Methods:

All patients who underwent ACL reconstruction by a single surgeon from 2006 to 2018 in a single tertiary institution were reviewed. The inclusion criteria for the study included Asian patients of common ethnic groups in Singapore (Chinese, Malay, Indian) and underwent primary or revision ACL reconstruction, or ACL reconstruction combined with meniscal surgery. The exclusion criteria were patients with incomplete medical records, pre-existing anticoagulant treatment within 1 year prior to the surgery and additional procedures that altered the standard rehabilitation protocol, less than 6 months of follow-up duration. All patients received general anesthesia. The single-bundle ACL technique with autologous hamstring tendon reconstruction was performed. No chemical DVT prophylaxis was given. The patients were screened for clinically for VTE. Symptomatic patients were referred for ultrasonography.

Results:

Of the 581 patients reviewed, 3 patients had a clinical suspicion of deep vein thrombosis, but subsequent ultrasonography showed no thrombosis. Hence, the prevalence of clinically significant VTE was 0%.

Conclusion:

Given the low prevalence of clinically significant VTE, there is no need for routine mechanical or chemical thromboprophylaxis or radiologic screening in Asian patients undergoing arthroscopic ACL reconstruction.

Current state of total knee arthroplasty

Total knee arthroplasty (TKA) is a successful and cost-effective treatment for end-stage degenerative arthritis. The aging of society and an increase in the prevalence of obesity has led to increases in the prevalence of arthritis and the incidence of TKA. Currently, the total number of procedures in Korea per year has reached 90,000. With the rapid growth, we need to know about the current state of TKA. The purpose of this review is to summarize the recent literature regarding TKA. The main indication for TKA is end-stage arthritis with severe pain, reduced function, and no response to conservative management. Metal on the polyethylene-bearing surface and cobalt alloy are used in most TKAs. Despite good clinical outcomes and long-term survival rates after TKA in many papers, 20% of patients are dissatisfied with the outcome of surgery. To improve the patient’s satisfaction, surgeons should understand factors affecting patient’s satisfaction, including patient’s expectations, age, and preoperative mental state. Navigation-assisted surgery and robotic surgery have been introduced in knee arthroplasty to achieve more precise and accurate alignment. There is some evidence to suggest that computer-assisted surgery reduces revision rates. However, clinical efficacy is also controversial, and a long-term follow-up study is required. The common complications of TKA include infection, polyethylene wear, loosening, stiffness, periprosthetic fracture, and thromboembolism. An understanding of the potential complications and pitfalls of TKA is essential for prevention.

Long-Term Outcomes of Ultra-Short Metaphyseal-Fitting Anatomic Cementless Femoral Stem in Total Hip Arthroplasty With Ceramic-on-Ceramic Articulation for Young Patients

BACKGROUND

The aim of this study is to assess the long-term outcomes of this specific stem in patients younger than 50 years old, with regard to clinical and radiographic outcomes, survivorship, and complication rate.

METHODS

Two hundred thirty-nine consecutive series of patients (324 hips) who were younger than 50 years old at the time of surgery were enrolled in the study. Osteonecrosis (50%) and dysplastic hip (34%) were most common diagnoses. Patients were informed to use crutches or walker for 4 weeks to protect the femoral component against rotational stress. The mean follow-up was 15.6 years (range 14-17).

RESULTS

At the latest follow-up, the mean Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index score, and University of California, Los Angeles activity score were 93 points, 13 points, and 7 points, respectively. Three patients (1.3%) had moderate thigh pain. All of the acetabular components and 321 (99%) femoral stems were solidly fixed at the time of the latest follow-up. Three stems (0.9%) were revised for aseptic loosening. Two hips (0.6%) had a dislocation and 2 hips (0.6%) had a periprosthetic fracture. Ceramic fracture or osteolysis was not found in any hip at the time of the final follow-up. Survival rate of the femoral component was 99.1% (95% confidence interval 94-100) and that of the acetabular component was 100% (95% confidence interval 94-100) at 15.6 years.

CONCLUSION

In this series, THA using an ultra-short metaphyseal-fitting anatomic cementless femoral stem provided excellent long-term clinical and radiographic results in patients younger than 50 years old. Furthermore, our initial theoretical concerns about early aseptic loosening due to the absence of distal stem fixation were not justified.

Low relative muscle volume: Correlation with prevalence of venous thromboembolism following total knee arthroplasty

Background

There have been many efforts to find modifiable risk factors for venous thromboembolism (VTE) in the perioperative period of total knee arthroplasty (TKA), while no study has investigated the relationship between the muscle mass and deep vein thrombosis (DVT) or pulmonary embolism frequency following TKA. This study aimed to evaluate the relationship between muscle volume and the prevalence of symptomatic and radiologically confirmed venous thromboembolism (VTE) after total knee arthroplasty (TKA).

Methods

A total of 261 consecutive patients who underwent primary TKA between 2013 and 2015 were enrolled. Computed tomographic venography with pulmonary angiography (CTVPA) was performed between the 5th and 7th postoperative days to assess the presence of VTE. Four parameters of muscle volume at three levels were evaluated on CTVPA: (i) the cross-sectional area of all skeletal muscles (skeletal muscle index) and total psoas area at the level of the third lumbar vertebrae; (ii) the vastus lateralis muscle at the thigh level; and (iii) the posterior crural muscle at the lower leg level. The relationship between the muscle volume at each level and the prevalence of VTE after TKA was evaluated with multivariate adjusted logistic regression models.

Results

The CTVPA scan showed no proximal DVT, and all thrombi were located in muscular, peroneal, and posterior tibial veins. In unilateral TKA, patients with lower muscle volume of the vastus lateralis at the thigh level in the nonoperated limb had significantly higher prevalence of distal DVT in the operated limb (adjusted OR: 2.97 at subclinical DVT revealed by CTVPA and adjusted OR: 2.68 at symptomatic DVT). This finding was also discovered in patients who underwent simultaneous bilateral TKA (adjusted OR: 1.73–2.97 at subclinical DVT and adjusted OR:1.76–1.86 at symptomatic DVT).

Conclusions

The relative muscle volume of the vastus lateralis at the thigh level was negatively associated with the prevalence of symptomatic and radiologically confirmed DVT, suggesting that low thigh muscle mass is an independent risk factor for VTE in the postoperative period of TKA.

Mechanical thromboprophylaxis would suffice after total knee arthroplasties in Asian patients?

PURPOSE

Our prospective study evaluated the incidence and location of deep vein thrombosis (DVT), the risk factors for PE and the natural history of DVT after TKA in patients who have received only mechanical compression device without having any chemical thromboprophylaxis or therapeutic treatment.

METHODS

We studied 408 consecutive patients (691 knees) who underwent primary TKA; 283 patients had one-stage bilateral TKAs and 125 had unilateral TKAs. Coagulation assays, the full blood count and blood typing tests, and serum chemical profiles were undertaken in all patients on three separate occasions. Molecular genetic testing was performed preoperatively to detect the genetic traits involving DVT. Bilateral simultaneous or unilateral venograms were carried out at 6 or 7 days after operation. Perfusion lung scanning was undertaken before and at 7 or 8 days after operation.

RESULTS

In the 691 venograms in 408 patients, only 4 knees (0.6%) were positive for fresh thrombi. In the 4 knees with DVT, thrombi were located in the calf veins. We observed factor V Leiden mutation, antithrombin-III level, and prothrombin promoter G20210A mutation were absent in all patients. We saw no relationship between DVT and coagulation or thrombophilic data. No pulmonary embolism (PE) occurred as shown by negative perfusion lung scan and absence of symptoms.

CONCLUSION

We concluded that the combinations of absent thrombophilic polymorphisms with low clinical prothrombotic risk factors led to low prevalence of DVT and virtually absent PE after TKA in the current series of patients, who had received mechanical compression device only without chemical thromboprophylaxis.

Does tranexamic acid increase the risk of thromboembolism after bilateral simultaneous total knee arthroplasties in Asian Population?

PURPOSE

To ascertain whether tranexamic acid reduces the blood loss and transfusion rate and volumes; increase the prevalence of deep vein thrombosis (DVT); and investigate factors associated with DVT in patients undergoing primary bilateral total knee arthroplasties (TKAs) without use of chemical thromboprophylaxis.

METHODS

There were 874 patients (1748 knees) in the control group who did not receive tranexamic acid and 871 patients (1742 knees) in the study group who received tranexamic acid. Mechanical compression device was applied without any chemical thromboprophylaxis. Transfusion rates and volumes were recorded. DVT was diagnosed using both sonogram and venogram at 7 or 8 day post-operatively.

RESULTS

Intra- and post-operative blood loss and transfusion volumes were significantly lower in the tranexamic acid group. The prevalence of DVT was 14% (245 of 1748 knees) in the control group and 18% (314 of 1742 knees) in the tranexamic acid group. Pre- and post-operative perfusion lung scans revealed no evidence of PE in any patients in either group. Coagulation or thrombophilic data or molecular genetic testing was not significantly different between the two groups.

CONCLUSION

The use of tranexamic acid reduces the volume of blood transfusion and does not increase the prevalence of DVT or PE in the patients who did not receive routine chemical thromboprophylaxis after primary bilateral simultaneous sequential TKAs in Asian patients.

Impact of anesthesia modality and mechanical venous thromboembolism prophylaxis on the incidence of symptomatic deep venous thrombosis after TKA

BACKGROUND

Venous thromboembolic events (VTE) are a common complication of total knee arthroplasty (TKA). Prior studies have discussed the utility of mechanical VTE prophylaxis as a monotherapy for low-risk TKA patients. We assess the incidence of clinically significant deep venous thrombosis (DVT) or pulmonary embolism (PE) in low-risk TKA patients who receive mechanical VTE prophylaxis and undergo spinal, epidural, or general anesthesia for their surgery.

METHODS

A retrospective study was performed on consecutive low-risk patients who received a TKA between July 2002 and June 2015 with spinal anesthesia (n = 65), epidural and general anesthesia (n = 154), or general anesthesia alone (n = 152). Patients with spinal anesthesia had mechanical VTE prophylaxis until 15 h postoperatively, when remobilization was permitted. Patients who received epidural or general anesthesia had mechanical VTE prophylaxis for 2 h postoperatively. Notable outcomes included development of clinically symptomatic DVT or PE, patient demographics, and perioperative lab values. Statistical analysis was performed using SPSS 22, with chi-squared and Fisher's exact tests for categorical variables and the Kruskal-Wallis test with Scheffe's method for continuous variables.

RESULTS

No clinically symptomatic DVT or PE was diagnosed. Patient demographics were equivocal. A statistically significant decrease in prothrombin and activated partial thromboplastin times were noted in the general anesthesia group, but all measurements were within the normal range.

CONCLUSIONS

A short course of mechanical VTE prophylaxis may be appropriate for low-risk patients who can immediately mobilize.

A Systematic Review on the Use of Aspirin in the Prevention of Deep Vein Thrombosis in Major Elective Lower Limb Orthopedic Surgery: An Update from the Past 3 Years

Introduction  Currently there are no consensuses in the national guidance on thromboprophylaxis following major elective lower limb surgery. Emerging clinical evidence suggests that aspirin could be just as effective as anticoagulants with a lower cost. The aim of this study was to provide an update based on literature of the past 3 years for the use of aspirin as thromboprophylaxis after knee and hip arthroplasty.

Materials and Methods  MEDLINE/EMBASE search was performed with appropriate terms for original articles from 2014 to 2017.

Results  Eight articles were found. Five articles concluded that aspirin was an effective prophylactic. The collation of results on the deep vein thrombosis rate involved 43,012 patients who were prescribed aspirin, of which 283 (0.66%) suffered from symptomatic deep vein thromboses. Aspirin was noted for its good side effect profile and cost effectiveness. It was noted that anticoagulants had a higher rate of complications, including bleeding and wound-oozing.

Conclusion  Aspirin is an effective and safe prophylactic against deep vein thrombosis following major elective lower limb arthroplasty surgery.

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.

Prevalence of Venous Thromboembolic Events Is Low in Asians After Total Knee Arthroplasty Without Chemoprophylaxis

BACKGROUND

This retrospective cohort study was designed to establish the prevalence of clinically significant venous thromboembolic events (VTE) in our patients undergoing total knee arthroplasty (TKA) without chemoprophylaxis.

METHODS

A single-surgeon cohort of patients who underwent TKA from 2006 to 2014 were included. All patients had a pneumatic tourniquet applied and a drain inserted postoperatively. Tranexamic acid was not used perioperatively. All patients were under a standardized postoperative protocol with routine mechanical prophylaxis against VTE. None of the patients received prophylactic anticoagulation. All patients ambulated on the second postoperative day. Only symptomatic patients were referred for radiological examination to exclude VTE. We evaluated the patient demographics and calculated the prevalence of VTE in our cohort.

RESULTS

A total of 966 patients were reviewed. Mean age was 66.1 ± 7.8 years. Mean body mass index was 28.2 ± 4.7 kg/m². Mean tourniquet time was 53 ± 23 minutes. Patients stayed in hospital for a mean of 5.4 ± 3.1 days. There was 100% compliance to mechanical prophylaxis. And 11.1% of our patients were on concomitant antiplatelet or anticoagulant use. There were 8 patients with clinically significant VTE. This translates to a prevalence of 0.82%. Seven patients developed deep vein thrombosis and 1 patient died from massive pulmonary embolism.

CONCLUSION

The prevalence of clinically significant VTE in our patients who underwent TKA without routine chemoprophylaxis is 0.82%. With proper patient selection, risk stratification, and stringent perioperative protocols, routine chemoprophylaxis may not be necessary in Asians undergoing TKA.

Obesity and Venous Thromboembolism in Total Knee Arthroplasty Patients in an Asian Population

BACKGROUND

Venous thromboembolism (VTE) is a known complication of total knee arthroplasty (TKA). In addition, obesity has been implicated as a risk factor and justification for chemoprophylaxis for VTE. We wanted to review the prevalence of VTE among our patients and evaluate the incidence rates of VTE among nonobese and obese patients.

METHODS

We reviewed 894 patients who underwent elective unilateral total knee arthroplasty by a single surgeon from March 2003 to November 2014 in our center. Any patients with clinically significant symptoms or signs of VTE such as deep venous thrombosis (DVT) or pulmonary embolism (PE) were diagnosed radiologically. The patient demographics analyzed included age, gender, body mass index, the number of comorbid diseases, and a history of hyperlipidemia.

RESULTS

We found the incidence of VTE of 0.67% in our patients (6 patients of 894). Four of the 6 patients (66.7%) who developed DVT and PE belonged to nonobese group. The frequency of VTE in nonobese patients was 0.65% and 0.73% in the obese patients. There were no significant differences in age, number of comorbidities, and a history of hyperlipidemia between those who developed DVT and PE and those who did not.

CONCLUSION

With the low prevalence of VTE among our study population, including patients with obesity, advanced age, multiple comorbidities, or hyperlipidemia, the practice of routine chemoprophylaxis should be reviewed.

Incidence and Fate of "Symptomatic" Venous Thromboembolism After Knee Arthroplasty Without Pharmacologic Prophylaxis in an Asian Population

BACKGROUND

As the possibility of developing complications after an "asymptomatic" venous thromboembolism (VTE) after total knee arthroplasty (TKA) has been reported very low, "symptomatic" VTEs seem to be the real concern among orthopedic surgeons. Therefore, the purpose of this study was to determine the incidence of "symptomatic" VTEs and the fate of "symptomatic" VTEs after anticoagulation therapy and assess whether routine pharmacologic prophylaxis is necessary in TKA patients.

METHODS

We retrospectively reviewed 2891 consecutive TKAs in 1933 patients. Graduated compression stockings and intermittent pneumatic calf compression devices were used for VTE prophylaxis. The incidence of symptomatic VTE was investigated until 6 months postoperatively. Patients with VTE underwent anticoagulation therapy and followed up to evaluate range of motion, knee society score, Western Ontario and McMaster Universities index scores, and the presence of any complications (mean follow-up period, 3.6 years).

RESULTS

Fifty-three (1.83%) of the 2891 TKAs had suggestive symptoms and/or sign of VTE. Of these 53 cases, 26 (0.90%) were diagnosed as symptomatic VTE, which comprised 10 (0.35%) symptomatic deep venous thromboses, 11 (0.38%) symptomatic pulmonary embolisms (PEs), 5 (0.17%) symptomatic deep venous thromboses combined with PEs, and no fatal PE. There was no significant difference in range of motion, knee society score, and Western Ontario and McMaster Universities index scores between the groups with or without symptomatic VTE. When treated properly after the diagnosis of symptomatic VTE, no specific complications were identified.

CONCLUSION

Symptomatic VTEs are rare in patients who undergo TKAs with mechanical prophylaxis only. Patients with symptomatic VTEs after TKA can be treated without significant sequelae once they are properly treated with anticoagulation after the diagnosis.

Is Routine Thromboprophylaxis Needed in Korean Patients Undergoing Unicompartmental Knee Arthroplasty?

This study was undertaken to determine the prevalence and the natural course of venous thromboembolism (VTE) without thromboprophylaxis to ascertain whether routine thromboprophylaxis is necessary following unicompartmental knee arthroplasty (UKA) in Korean patients. The medical records and multidetector row computed tomography (MDCT) imaging of the consecutive 77 UKAs in 70 patients were reviewed. In all patients, MDCTs were undertaken preoperatively and at 1-week after surgery, and VTE symptoms were evaluated. At postoperative 6-months, follow-up MDCTs were undertaken in all patients in whom VTEs were newly detected after surgery. VTE lesions were newly detected in 18 (26%) of the 70 patients. However, none of the patients complained of VTE-related symptoms and MDCT demonstrated that all VTEs were small and involved limited portion without lower leg edema or pleuroparenchymal complication. At the 6-month follow up MDCT, all types of VTEs were shown to be completely resolved, regardless of their location. All of the VTE lesions maintained an asymptomatic status for 6-month after surgery. VTE following UKA in Korean patients who do not receive thromboprophylaxis seems to occur frequently, but all of the VTEs are clinically insignificant and all VTEs are spontaneously regressed. Routine thromboprophylaxis or thrombolytic treatment in Korean patients undergoing UKA may not be necessary.

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.

Clinical Performance of the 1st American Academy of Orthopaedic Surgeons Clinical Guideline on Prevention of Symptomatic Pulmonary Embolism after Total Knee Arthroplasty in Korean Patients

We sought to document the clinical performance of the 1st American Academy of Orthopaedic Surgeons (AAOS) guideline on the prevention of symptomatic pulmonary embolism (PE) after total knee arthroplasty (TKA) in Korean patients, in terms of the proportions of the each risk-stratified group, efficacy and safety. Consecutive 328 patients underwent TKA were preoperatively assessed for the risks of PE and bleeding and categorized into 4 groups: 1) standard risk, 2) high risk for PE, 3) high risk for bleeding, and 4) high risks both for PE and bleeding. One of three options was administered according to the groups (aspirin in group 1 or 4; enoxaparin and following aspirin in group 2; antithrombotic stocking in group 3). Incidences of symptomatic deep vein thrombosis (DVT) and PE, and major or minor bleeding complications were evaluated. Majority of the patients (86%) were assessed to be with standard risks both for PE and bleeding. No patient experienced symptomatic DVT or PE and major bleeding. Eleven percent of the patients discontinued chemoprophylaxis because of bleeding-related wound complication. In conclusion, the 1st AAOS guideline functions successfully in Korean patients undergoing TKA in terms of prevention of symptomatic DVT and PE while avoiding major bleeding complications.

Prevalence of Deep Vein Thrombosis and Pulmonary Embolism Treated with Mechanical Compression Device After Total Knee Arthroplasty in Asian Patients

The purpose of this study was: (1) to determine the prevalence of deep vein thrombosis (DVT) after the use of a mechanical compression device only, without pharmacological thromboprophylaxis; (2) to investigate the factors associated with DVT; and (3) to investigate the natural course of DVT and PE. We reviewed consecutive series of 874 patients (1434 knees) who received treatment with a mechanical compression device only for prevention of DVT after primary TKA. The prevalence of DVT was 6.6% (94 of 1434 knees). Proximal thrombi were found in 6 of 1434 knees (0.4%). No patient had PE on perfusion lung scans. Further sonograms and venograms for the patients with thrombi at 6 months after the operation revealed that all thrombi were resolved.

Deep venous thrombosis after knee arthroscopy: a systematic review and meta-analysis

PURPOSE

To establish a contemporary literature-based estimate of the incidence of deep venous thrombosis (DVT) after knee arthroscopic surgery.

METHODS

We performed a systematic review and meta-analysis of the English language literature to assess the efficacy of prophylaxis to prevent DVT after knee arthroscopic surgery. Only randomized controlled trials (RCTs) or prospective studies were considered. Studies were excluded if they were not original prospective studies concerning DVT detected by imaging after knee arthroscopic surgery. We calculated pooled proportions of postoperative DVT and proximal DVT.

RESULTS

Nine prospective uncontrolled studies and 4 RCTs were retrieved. Within them, the populations given low-molecular-weight heparin (LMWH) to prevent DVT had a 0.1% to 11.9% incidence of DVT, with an overall 36 DVTs identified (4 proximal), averaging 1.8%. One hundred thirty-six DVTs (29 proximal) were indicated in the populations without prophylaxis, and the DVT incidence varied from 1.8% to 41.2%, averaging 6.8%. Of the RCTs, the pooled risk ratio for DVT to develop was 0.180 (range, 0.065 to 0.499) for those who had LMWH as prophylaxis. An absolute risk reduction of 1.2%--from 1.5% to 0.3%--for the development of proximal DVT was observed.

CONCLUSIONS

Compared with patients who did not receive prophylaxis, the pooled risk ratio for the development of DVT was 0.18 for those who had LMWH prophylaxis. The incidence of proximal DVT is very low after arthroscopic surgery regardless of receiving prophylaxis (4 of 2,184) or not (29 of 1,814). The rate of proximal DVT in total DVT occurrence can be markedly reduced from 21.3% (29 of 136) to 11.1% (4 of 36).

LEVEL OF EVIDENCE

Level IV. This study is a meta-analysis of RCTs and a systematic review of Level IV studies.

The use of pneumatic tourniquets is safe in Asians undergoing total knee arthroplasty without anticoagulation

BACKGROUND

There has always been controversy surrounding the use of pneumatic tourniquets in total knee arthroplasty (TKA) as they have been implicated in venous thromboembolic events (VTE). We aimed to evaluate the incidence of clinically significant VTE in Asians who underwent conventional TKA under tourniquet throughout the duration of surgery, without post-operative chemical VTE prophylaxis, but using post-operative pneumatic compression devices.

METHODS

Five hundred and thirty-one patients of a single surgeon who underwent elective total knee arthroplasty were retrospectively reviewed. All patients had a tourniquet applied to the operated limb. None of the patients received chemoprophylaxis against VTE. Post-operatively, only symptomatic patients were referred for ultrasonography. The patients were then stratified according to the tourniquet time: <60, 61 to 90, 91 to 120, and >120 min. The overall incidence as well as the incidence of venous thromboembolic events for each group was then calculated.

RESULTS

Of the 531 patients reviewed, 3 patients suffered from deep venous thrombosis (DVT) while 1 patient developed a fatal pulmonary embolism (PE). Hence, the overall incidence of clinically significant VTE was 0.75%. The 3 patients with DVT had tourniquet time of 61 to 90 min while the patient with PE had a tourniquet time of more than 120 min.

CONCLUSION

With a low overall incidence of VTE, the use of tourniquet in Asians during conventional total knee arthroplasty appears safe when post-operative pneumatic compression devices are used instead of chemical VTE prophylaxis. However, the risk of VTE seems to increase with a tourniquet time of more than 60 min.

LEVEL OF EVIDENCE

Therapeutic studies, level III.

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.

A Prospective Study of Venous Thromboembolic Prophylaxis using Foot Pumps following Total Knee Replacement in a Chinese Population

Purpose

The purpose of this study was to evaluate foot pumps as mechanical prophylaxis for deep vein thrombosis (DVT) following total knee replacement (TKR) in a Chinese population.

Methods

All consecutive patients following TKR during 2002–2006 received routine duplex ultrasound surveillance for DVT 9 days postoperatively. The demographic data and risk factors were recorded. No medication was given for DVT prophylaxis in all patients.

Results

We evaluated 91 consecutive TKRs in 85 patients. Although 44 knee replacements (Group 1) done before December 2004 were not given foot pumps, 47 knee replacements (Group 2) done afterwards were given foot pumps. All patients were followed up for more than 6 months. DVT was detected in three cases (6.8%) in Group 1 compared with four knees (8.5%) in Group 2. Proximal thrombosis was observed in two knees (4.5%) in Group 1 compared with two knees (4.3%) in Group 2. No patient had pulmonary embolism. Six out of 59 (10.2%) patients who underwent the operations under general anaesthesia suffered from DVT, whereas one in 28 (3.6%) patients operated under spinal anaesthesia had DVT. All had no statistical significance.

Conclusion

The rate of proximal DVT after TKR was low (4.5%) without pharmacological prophylaxis. We advise against the use of pharmacological prophylaxis in Chinese population for TKRs because of the low risk of proximal DVT and its possible bleeding complications. Foot pump did not lower the rate of DVTfurther, and its use for DVT prophylaxis in TKR is not necessary.

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.

Is routine chemoprophylaxis necessary for prevention of venous thromboembolism following knee arthroplasty in a low incidence population?

BACKGROUND

Standard thromboprophylaxis guidelines have not been applied universally in regions with low incidence of deep-vein thrombosis (DVT) considering risks of chemoprophylaxis and low incidence itself. We evaluated the prevalence of DVT, efficacy and safety of chemoprophylaxis, and necessity of pharmacological prevention in a low DVT incidence population.

METHODS

One hundred and forty-eight patients undergoing unilateral total knee arthroplasty (TKA) were prospectively randomized to receive either a placebo or 2.5 mg of fondaparinux once daily for 5 days. Doppler ultrasonography was performed preoperatively and 7 days after surgery. The primary efficacy outcome was prevalence of DVT up to day 7. Secondary efficacy outcome was prevalence of symptomatic venous thromboembolism (VTE) up to day 90. Primary and secondary safety outcomes were incidence of major and minor bleeding, respectively.

RESULTS

The prevalence of total DVT was 25.7 % in placebo group and 6.8 % in fondaparinux group (p = 0.002) and the prevalence of proximal DVT was lower in both groups with no statistical difference. There was no symptomatic VTE in either group up to day 90. Although no major bleeding was developed, fondaparinux group had a significant increase of minor bleeding events (p < 0.001).

CONCLUSIONS

There remains low incidence of VTE following TKA in East Asians even without chemoprophylaxis. Although short-term fondaparinux protocol could reduce the incidence of overall DVT, its routine use seems debatable due to extremely rare proximal DVT and symptomatic PE and drug-related bleeding complication. However, modified and selective use of chemoprophylaxis would be considerable in high risk patients.

Incidence of clinically significant venous thromboembolic events in Asian patients undergoing total knee arthroplasty without anticoagulation

This study aimed to evaluate the incidence of clinically significant venous thromboembolic events (VTE) in Asian patients undergoing total knee arthroplasty (TKA) without anticoagulation. All patients who underwent TKA by a single surgeon from 2006 to 2010 in Singapore General Hospital were reviewed. Only symptomatic patients were referred for ultrasonography. Of the 531 patients reviewed, 3 patients developed symptoms of deep vein thrombosis with subsequent ultrasonographic confirmation, whereas 1 patient developed fatal pulmonary embolism without any clinical or radiologic evidence of deep vein thrombosis. Hence, the incidence of clinically significant VTE was 0.75%. Given the low incidence of clinically significant VTE, there is a need to review the current practice of routine chemoprophylaxis in Asian patients undergoing TKA.

Relationship between deep vein thrombosis and pulmonary embolism following THA and TKA

Patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) are at risk for venous thromboembolisms, including deep vein thrombosis and pulmonary embolism. Most deep vein thromboses are asymptomatic, but they can lead to long-term morbidity to the same extent as symptomatic events. The risk of complications of venous thromboembolisms depends on the location of thrombi; potential long-term complications include recurrent venous thromboembolism, postthrombotic syndrome, and chronic thromboembolic pulmonary hypertension. Risk of recurrence persists for several years after the initial event. Approximately 20% of recurrent events are pulmonary embolisms, and approximately half of those are fatal. The causal relationship between deep vein thrombosis and pulmonary embolism remains controversial. Some consider them distinct clinical entities, while others have found asymptomatic distal deep vein thrombosis to be associated with elevated risk of developing pulmonary embolism. Unique coagulation factors may be associated with orthopedic surgery patients that differentiate them from patients undergoing other types of surgery. Symptomatic and asymptomatic deep vein thrombosis can lead to the development of recurrent venous thromboembolism, pulmonary embolism, postthrombotic syndrome, and chronic thromboembolic pulmonary hypertension, all of which are associated with reduced quality of life and increased health care expenditures. Thromboprophylaxis is therefore important in patients undergoing THA or TKA. However, traditional anticoagulants are not ideal, particularly for long-term use. Orthopedic surgeons should be aware of the causes and potential sequelae of venous thromboembolism and of the new thromboprophylactic agents that can help prevent it.

Is intra-articular multimodal drug injection effective in pain management after total knee arthroplasty? A randomized, double-blinded, prospective study

We performed a prospective, double-blinded, randomized, and controlled study to assess the clinical efficacy and safety of intra-articular multimodal drug injection after total knee arthroplasty. Two hundred eighty-six patients undergoing simultaneous bilateral total knee arthroplasty were randomized to receive the injection of multimodal drugs in one knee and normal saline solution as a placebo in the contralateral knee. All patients received patient-controlled analgesia for 48 hours after surgery, followed by standard analgesia. Visual analog scores for pain during activity and rest and for patient satisfaction were recorded. The range of motion and blood loss were also recorded. Intraoperative intra-articular injection of multimodal drugs into the knee did not improve patient pain and satisfaction, range of motion, or blood loss compared with the placebo control.

Recent Korean perspective of deep vein thrombosis after total knee arthroplasty

This prospective study was performed on 311 consecutive knees in 227 patients for total knee arthroplasty. The aim was to assess the recent incidence of deep vein thrombosis (DVT) after total knee arthroplasty without chemoprophylaxis in Koreans, the efficacy of plasma d-dimer levels as a screening test, and the associated risk factors. Deep vein thrombosis was found in 79 knees (26.60%). There were 9 cases (3.03%) of proximal DVT, 70 cases (23.57%) of distal DVT, and no symptomatic pulmonary embolism. Although this cohort had limited number of patients by a single surgeon, there is still low incidence of proximal DVT in Koreans with rare pulmonary embolism occurrence compared with those of the Western. High postoperative d-dimer levels were correlative, but no appropriate cutoff value was found. Obesity was a significant associated risk factor.

Systematic review and meta-analysis on the rate of postoperative venous thromboembolism in orthopaedic surgery in Asian patients without thromboprophylaxis

BACKGROUND

Postoperative venous thromboembolism (VTE) is a common life-threatening complication after surgery. This review analysed the rate and mortality of VTE after orthopaedic surgery in Asia.

METHODS

Inclusion criteria were: prospective study; deep vein thrombosis (DVT) diagnosed by venography or ultrasonography; hip fracture surgery (HFS), total hip arthroplasty (THA) or total knee arthroplasty (TKA); and no thromboprophylaxis. The pooled proportion was back-calculated by Freeman-Tukey variant transformation, using a random-effects model.

RESULTS

Twenty-two studies (total population 2454) published from 1979 to 2009 were included. Using venography, the pooled rates of all-site, proximal, distal and isolated distal DVT were 31·7, 8·9, 22·5 and 18·8 per cent respectively. With duplex ultrasonography, the respective rates were 9·4, 5·9, 5·9 and 5·8 per cent. After THA or HFS, using venography, the pooled rates of all-site and proximal DVT were 25·8 and 9·6 per cent; with ultrasonography, the respective rates were 10·8 and 7·2 per cent. In TKA groups, using venography, the pooled rates of all-site and proximal DVT were 42·5 and 8·7 per cent; with ultrasonography, the respective rates were 9·5 and 5·2 per cent. The overall pooled rates of symptomatic DVT and symptomatic pulmonary embolism (PE) were 4·5 and 0·6 per cent. No patient died from PE (pooled rate 0·2 per cent).

CONCLUSION

None of these Asian patients undergoing orthopaedic surgery died from VTE. Pooled rates of proximal and symptomatic DVT were lower than in Western reports.

Perioperative complications of simultaneous versus staged unicompartmental knee arthroplasty

BACKGROUND

The complication risk of staged versus simultaneous total knee arthroplasty continues to be debated in the literature. Previous reports suggest unicompartmental knee arthroplasty provides a more rapid functional recovery than total knee arthroplasty. However, little data exist on whether simultaneous unicompartmental knee arthroplasty can be performed without increasing the perioperative risk compared with staged unicompartmental knee arthroplasty.

QUESTIONS/PURPOSES

We therefore asked if there is an increased risk of perioperative complications with bilateral simultaneous unicompartmental knee arthroplasty.

METHODS

We retrospectively compared 141 patients (282 knees) treated with staged unicompartmental knee arthroplasty with 35 patients (70 knees) treated with simultaneous unicompartmental knee arthroplasty to evaluate perioperative complications and short-term results assessed by Knee Society function scores and the Lower Extremity Activity Scale.

RESULTS

Patients who underwent simultaneous unicompartmental knee arthroplasty had a shorter cumulative operative time (109 versus 122 minutes), a shorter cumulative length of hospital stay (1.7 versus 2.5 days), higher Knee Society function scores at most recent followup (88 versus 73), and higher Lower Extremity Activity Scale (12.0 versus 10.2) without a difference in perioperative complications. The simultaneous cohort was younger (59 versus 63 years of age) and less obese (body mass index 31 versus 33 kg/m(2)) than the staged group.

CONCLUSIONS

Although we found a substantial bias for performing simultaneous unicompartmental knee arthroplasty in younger and less obese patients, these data suggest it can be performed without increasing perioperative morbidity or mortality in this patient population.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Risk factors for pulmonary complications, including pulmonary embolism, after total knee arthroplasty (TKA) in elderly Koreans

There has been a steady increase in elective TKA in elderly Koreans. However, there are few reports about the incidence of and risk factors for pulmonary complications, including pulmonary thromboembolism in these patients. We evaluated retrospectively 338 patients aged 60 years and over (290 females, median age 69 years) to assess the incidence and predictive factors for pulmonary complications, including pulmonary thromboembolism after TKA. Of these patients, 264 underwent simultaneous bilateral TKA (78%) by two surgeons and 56 (17%) had general anesthesia. No patient received thromboprophylaxis. There were 49 postoperative pulmonary complications in the 338 patients (14.2%, 49/338). Of the 49 patients, 27 developed atelectasis (27/49), six developed pneumonia (6/49), and four had pleural effusions (4/49) within 7 days of the surgery; 12 patients had a pulmonary thromboembolism (12/49) during their hospitalization. No pulmonary complication was fatal. Multivariate analysis revealed that pulmonary hypertension (right ventricular systolic pressure≥35 mmHg on transthoracic echocardiography; odds ratio (OR)=3.0, p=0.016) was independently associated with pulmonary complications. A resting PaCO(2)≥45 mmHg (OR=22.9, p=0.004) was the only independent predictor of the development of a pulmonary thromboembolism. Pulmonary hypertension may thus predict pulmonary complications and a PaCO(2) greater than 45 mmHg may be a risk factor for pulmonary thromboembolism following TKA. Preoperative blood gas analysis and transthoracic echocardiography can identify those patients at high risk for pulmonary complications, including pulmonary thromboembolism, after TKA in elderly Korean patients.