Changes in circulatory indices of thrombosis and fibrinolysis during total knee arthroplasty performed under tourniquet

Role of Neuromuscular Electrical Stimulation in Increasing Femoral Venous Blood Flow After Total Hip Prosthesis

Objective: This study aimed to investigate the role of neuromuscular electrical stimulation (NMES) in increasing femoral venous blood flow after total hip prosthesis and to evaluate its potential effects on preventing postoperative deep vein thrombosis (DVT).

Materials and methods: A total of 64 patients who underwent total hip prosthesis were randomly separated into two groups. The NMES group (n=32) received low-molecular-weight heparin+NMES. And the non-NMES group (n=32) received a low-molecular-weight heparin+compression bandage.

Results: There was no difference between the groups in terms of the presence of preoperative and postoperative leg edema. The calf diameter was significantly lower in the NMES group than in the non-NMES group in both the preoperative (p=0.003) and postoperative (p=0.008) period. Although the femoral vein peak velocity (VPV) was similar between the groups in the preoperative period, it was significantly higher in the NMES group than in the non-NMES group postoperatively (p=0.001). The femoral VPV after total hip prosthesis increased more in the NMES group (43.2%) compared with the non-NMES group (16.3%). In the non-NMES group, the D-dimer value in the preoperative period was lower than on postoperative days one and five (p<0.05). There was no significant difference between the D-dimer values on postoperative days one and five. In the NMES group, a statistically significant difference was determined between the preoperative and postoperative test results (F(2.93)=20.86, p=0.001). The preoperative D-dimer values were compared to the postoperative values on the first and fifth day, and according to the post hoc test results, the D-dimer values were significantly lower on the fifth postoperative day than on the first postoperative day, and the preoperative value was significantly lower than the fifth postoperative day value (p<0.05). 

Conclusion: Although the two groups were similar in terms of leg edema, there was a significant increase in femoral VPV in the NMES group. This could indicate a potential effect of NMES in preventing postoperative DVT and needs to be confirmed with further studies.

Plasminogen activator inhibitor-1, thrombin-antithrombin, and prothrombin fragment F1+2 have higher diagnostic values than D-dimer for venous thromboembolism after TKA

Objective

To investigate the diagnostic values of D-dimer, plasminogen activator inhibitor-1 (PAI-1), thrombin–antithrombin (TAT), and prothrombin fragment F1 + 2 (F1 + 2) for predicting venous thromboembolism (VTE) after total knee arthroplasty (TKA).

Methods

Ultrasonography and CTPA were performed to diagnose VTE in 252 patients who underwent TKAs. Plasma D-dimer, PAI-1, TAT, and F1 + 2 levels were assessed 1–3 days prior to operation (T1), second hour (T2), first (T3), and third day (T4) after the operation. Receiver–operating characteristic curves (ROC) analysis was conducted and pairwise compared to evaluate the diagnostic value of those biomarkers.

Results

Plasma D-dimer levels differed between patients with and without VTE significantly on T4, PAI-1, TAT, and F1 + 2 levels differed on T3 and T4. The areas under ROC of D-dimer, PAI-1, TAT and F1 + 2 levels were 0.645, 0.773, 0.771 and 0.797, respectively. The most feasible cutoff values of D-dimer, PAI-1, TAT and F1 + 2 in predicting VTE after TKA were 2.24 ug/ml, 35.96 ng/ml, 13.36 ng/mg and 11.1 ng/ml, respectively. Pairwise comparison of ROC curves revealed that D-dimer level had the lowest diagnostic accuracy, whereas PAI-1, TAT and F1 + 2 level had similar diagnostic accuracy. There were significant differences in duration of tourniquet time and duration of anesthesia between patients with and without VTE.

Conclusion

After TKA, using 2.24ug/mL as the threshold value of D-dimer is more accurate than using 0.5ug/mL in the monitoring of VTE, PAI-1, TAT and F1 + 2 are more valuable than D-dimer in predicting VTE. Duration of tourniquet and duration of anesthesia are risk factors for the development of VTE.

[Comparison of hemostatic effect and safety in primary unilateral total hip arthroplasty receiving different anticoagulants after anti-fibrinolysis with tranexamic acid]

Objective

To compare the hemostatic effect and safety in primary unilateral total hip arthroplasty (THA) receiving nadroparin calcium, enoxaparin sodium, rivaroxaban, or apixaban after anti-fibrinolysis with tranexamic acid (TXA) and explore the best anticoagulant.

Methods

A retrospective analysis was conducted on 184 patients who underwent the primary unilateral THA between January 2014 and December 2018, administrated 15 mg/kg TXA before surgery and received nadroparin calcium, enoxaparin sodium, rivaroxaban, or apixaban. The patients were divided into four groups based on the different anticoagulants: 46 patients received nadroparin calcium; 45 patients received enoxaparin sodium; 47 patients received rivaroxaban; the other 46 patients received apixaban. There was no significant difference in age, gender, body mass, body mass index, the types of hip joint diseases, complications, anesthesia mode, operation time, and preoperative laboratory indexes (hemoglobin, hematocrit, platelet, prothrombin time, activated partial prothrombin time, blood volume) ( P>0.05). Perioperative blood data (total blood loss, hidden blood loss, dominant blood loss, postoperative drainage volume, maximum loss of hemoglobin, and blood transfusion rate) and complications (incision, bleeding, and thrombosis) were recorded and compared between groups.

Results

There was no significant difference in total blood loss, hidden blood loss, dominant blood loss, postoperative drainage volume, maximum loss of hemoglobin, and blood transfusion rate between groups ( P>0.05). The comparison of postoperative complications showed that 1 case (2.1%) of redness and swelling of incision occurred in the rivaroxaban group, and 1 case (2.2%) of the other 3 groups each had poor incision healing. No incision infection, fat liquefaction, or other incision complications occurred in the 4 groups. There was no significant difference in incision complication between groups ( P>0.05). There were 2 cases (4.3%) bleeding events (1 case of right inguinal hematoma and 1 case of subcutaneous ecchymosis in front of left leg) in the nadroparin calcium group, while no bleeding event occurred in the other 3 groups, which had no significant difference in bleeding complication between groups ( χ ²=5.612, P=0.132). There was 1 case (2.2%) of intermuscular vein thrombosis of the lower extremity in the nadroparin calcium group and no case in the other 3 groups, which had no significant difference between groups ( χ ²=2.789, P=0.425). Neither deep venous thrombosis nor pulmonary embolism occurred in any group.

Conclusion

No significant difference in the hemostatic effect and incidences of complications for patients underwent primary unilateral THA receiving nadroparin calcium, enoxaparin sodium, rivaroxaban, or apixaban after anti-fibrinolysis with TXA. One of the four anticoagulants can be selected to prevent thrombosis after anti-fibrinolysis with TXA, which has certain safety.

Is the Oral Chemical Prophylaxis Necessary for the Prevention of Venous Thromboembolism after Joint Arthroplasty in a Korean Population?

Purpose

Venous thromboembolism (VTE) is a serious complication that may occur after a major orthopedic surgery. The aim of the present study was to determine the necessity of a chemical thromboprophylactic agent (rivaroxaban [RXB]) by analyzing the prevalence of VTE in Korean arthroplasty patients who received RXB for prophylaxis compared with those who did not receive RXB.

Materials and Methods

A total of 2,603 patients who underwent knee or hip arthroplasty between 1996 and 2017 were prospectively evaluated. Of these, 1,608 patients underwent surgery before January 2010 and were not administered any type of prophylaxis after surgery; the remaining 995 underwent surgery after 2010 and received oral RXB once daily for 5–13 days from the day after hemovac drain removal to postoperative day 14.

Results

The primary study outcome was the prevalence of VTE, pulmonary embolism or death during follow up. The overall incidence of VTE was 1.69% (n=44); of these, 12 occurred in the RXB group and 32 in the non-prophylactic group. The odds ratio of VTE in the RXB group was 0.61. However, the statistical power of the study was 0.313 due to the low incidence of VTE.

Conclusion

Treatment with oral chemical prophylaxis decreased the incidence of VTE after knee or hip arthroplasty in a Korean population. Furthermore, no serious complications occurred after administering oral RXB, which, coupled with its convenience, suggests oral RXB offers an attractive alternative to other agents. However, we recommend that further studies, including a multicenter study, be conducted to achieve adequate statistical power.

Plasma D-dimer is not useful in the prediction of deep vein thrombosis after total knee arthroplasty in patients using rivaroxaban for thromboprophylaxis

Background

Venous thromboembolism (VTE) is a serious complication following total joint replacement. The use of rivaroxaban, a highly selective and direct factor Xa inhibitor, has been used widely as a safe and efficacious way to prevent VTE after total joint replacements. However, little is known about the diagnostic efficacy of plasma D-dimer test on deep vein thrombosis (DVT) in patients using rivaroxaban for thromboprophylaxis. The study is aimed to investigate the trend and the diagnostic efficacy of D-dimer test on DVT in patients with primary total knee arthroplasty (TKA) using rivaroxaban for thromboprophylaxis.

Methods

Two hundred TKA patients using rivaroxaban postoperatively as chemical prophylaxis were reviewed. D-dimer levels were checked at 4 h after the surgery and on postoperative days 1 and 4. Venography was used to document the presence of DVT. The Mann-Whitney U test was used to detect the differences in the D-dimer levels at different time points in patients with and without DVT, followed by Bonferroni corrections for p values. Receiver operating characteristics (ROC) curves were constructed to determine the best cutoff values of the D-dimer test at each time point after the surgery.

Results

Twenty-nine of the 200 patients were found to have deep vein thrombosis by venography, resulting in an incidence of 14.5%. All patients with DVTs occurred in the distal calf veins, and only one patient was symptomatic. We found significant differences in D-dimer concentration between patients with and without DVT at postoperative day 4. The best cutoff value determined by receiver operating characteristics analysis was 3.8 mg/L at postoperative day 4, with an AUC equal to 63.5%, and a sensitivity, specificity, PPV, and NPV of 58.6, 76, 29.3, and 91.5%, respectively.

Conclusions

Rivaroxaban was effective on reducing DVT in patients undergoing TKA. Because all the DVTs occurred in the leg veins, decreased thrombus volume and size might result in poor accuracy of plasma D-dimer test in prediction or diagnosis of postoperative DVT.

Changes in Markers of Thrombin Generation and Interleukin-6 During Unicondylar Knee and Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is associated with a risk of thromboembolism requiring routine thromboprophylaxis, but there is debate about the risk with unicondylar knee arthroplasty (UKA) as it is a more minor procedure. We sought to investigate the relative risk of thromboembolism with UKA compared to TKA and one-staged bilateral TKA (BTKA) by measuring the increase in circulating biochemical markers of thrombin generation during the procedures. Degree of surgical trauma was also assessed by measuring interleukin-6, a marker of metabolic injury.

METHODS

We prospectively studied a total of 75 patients: 25 patients undergoing UKA, unilateral TKA, and BTKA, respectively. All patients had surgery performed with tourniquet and received no tranexamic acid. Blood samples were taken during surgery and assayed for circulating markers of thrombin generation: prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin complexes plus interleukin-6.

RESULTS

Thrombin-antithrombin complexes, increased during all time points (P < .001) but was not significantly different between surgical treatment groups. F1+2 also rose significantly during surgery, with no significant difference between UKA and TKA. There was, however, a significant difference in F1+2 between BTKA and UKA or TKA (P < .02). Interleukin-6 rose minimally with UKA but rose significantly with TKA and BTKA (P < .001).

CONCLUSION

Based on these data of circulating biochemical markers, patients undergoing UKA are at similar risk of thromboembolism with respect to TKA despite a lower index of metabolic injury. We believe that UKA patients should receive thromboprophylaxis comparable to TKA patients.

Stress-induced hyperglycaemia and venous thromboembolism following total hip or total knee arthroplasty

Stress-induced hyperglycaemia is common during orthopaedic surgery. In addition, hyperglycaemia activates coagulation. The aim of the study was to assess whether stress-induced hyperglycaemia is associated with symptomatic or asymptomatic venous thromboembolism (VTE) following orthopaedic surgery. We performed post-hoc analyses in the four RECORD studies (REgulation of Coagulation in major Orthopaedic surgery reducing the Risk of Deep venous thrombosis and pulmonary embolism). Separate analyses were performed for patients undergoing elective total hip or knee replacement. Outcome measures were symptomatic VTE and “total VTE” (defined as the composite of symptomatic VTE, asymptomatic DVT assessed by per protocol venography and all cause mortality). Glucose levels were measured pre-op and 6 hours post-op, categorised into quartiles, based on the distribution in the respective cohorts. The influence of glucose, adjusted for body mass index, age, gender and diabetes mellitus on VTE was assessed by logistic regression analyses. A total of 12,383 patients were eligible for assessment of symptomatic VTE, and 8,512 patients were eligible for assessment of total VTE. Increased glucose levels after total hip replacement were associated with total VTE; adjusted odds ratio (OR) highest versus lowest quartile 1.9 (95% confidence interval [CI] 1.3 to 3.0). Furthermore, increase in glucose levels during total hip replacement was associated with total VTE (OR highest versus lowest quartile 1.8 (95%CI 1.2 to 2.8). This was not observed in patients undergoing total knee replacement, probably due to differences in the applied surgical procedures.

The modification of the thrombin generation test for the clinical assessment of dabigatran etexilate efficiency

A new oral anticoagulant, dabigatran etexilate (DE, a prodrug of direct thrombin inhibitor (DTI) dabigatran), has been used clinically to prevent thrombosis. The assessment of dabigatran efficiency is necessary in some clinical cases, such as renal insufficiency, risk of bleeding, and drug interactions. However, a specific thrombin generation test (TGT) that is one of the most informative and sensitive to anticoagulant therapy (calibrated automated thrombinography (САТ)) shows a paradoxical increase of test parameters, such as endogenous thrombin potential (ETP) and peak thrombin, in patients receiving DE. The paradoxical behaviour of ETP and peak thrombin in these patients in the presence of DTIs is mostly caused by a decrease in the activity of thrombin in the α₂-macroglobulin-thrombin complex that is used as a calibrator in CAT. For a correct estimation of the TGT parameters in patient’s plasma containing DTIs we proposed to use our previously described alternative calibration method that is based on the measurement of the fluorescence signal of a well-known concentration of the reaction product (7-amino-4-methylcoumarin). In this study, the validity of such approach was demonstrated in an ex vivo study in patients with knee replacement and two special patients with multiple myeloma, who received DE for thrombosis prophylaxis.

Less deep vein thrombosis due to transcutaneous fibular nerve stimulation in total knee arthroplasty: a randomized controlled trial

PURPOSE

It has been known for years that deep vein thrombi (DVT) start to develop during total joint arthroplasty. Previously, we reported effective prevention of venous stasis by transcutaneous electrical nerve stimulation (TENS). It is hypothesized that TENS might be a thromboprophylactic tool for the limb undergoing surgery. The purpose of this study is to clarify the clinical efficacy and safety of TENS in patients during total knee arthroplasty (TKA).

METHODS

Ninety patients undergoing primary TKA were involved and randomly allocated to the TENS or control group. In the TENS group, electrical stimulation of the common fibular nerve, which produced a brisk dorsiflexion of the ankle, was performed for the operated leg during surgery. In the control group, no electrical stimulation was applied. Serum D-dimer and soluble fibrin monomer complex (SFMC) levels were measured before surgery, immediately after surgery, and post-operative day (POD) 1. Ultrasonography was performed on POD 1.

RESULTS

Immediately after surgery, D-dimer and SFMC levels of each group were significantly lower in the TENS group compared with control (p < 0.05). The incidence of DVT was 11 % (five cases) in the TENS group while 31 % (14 cases) in control (p = 0.02). There were no adverse effects related to TENS.

CONCLUSIONS

TENS during TKA showed significant effects on preventing DVT. Sustaining muscle pump activation during surgery prevented not only venous stasis, but also hypercoagulability of blood. Intraoperative TENS is a safe and novel strategy against early post-operative thromboembolism, which is difficult to be completed through existing prophylaxis after total joint arthroplasty.

LEVEL OF EVIDENCE

Randomized controlled trial, Level I.

Perioperative Factors and Their Effect on the Fibrinolytic System in Arthroplasty Patients

BACKGROUND

Total joint arthroplasty (TJA) patients are mostly of advanced age and with comorbidities such as increased body mass index (BMI) and impaired glucose tolerance. These factors and type of surgery may affect the fibrinolytic system.

AIM

To investigate the effect of age, sex, BMI, type of surgery, and tranexamic acid (TXA) treatment on the fibrinolytic system in TJA patients.

METHODS

Ninety-nine patients undergoing TJA (32 total hip arthroplasty [THA] and 67 total knee arthroplasty [TKA]) were included in this study. Blood samples were drawn at preoperative clinic appointments and on postoperative day 1. Antigenic levels of d-dimer, plasminogen activator inhibitor 1 (PAI-1), and tissue plasminogen activator (tPA) were measured using a commercially available enzyme-linked immunosorbent assay kit. Antiplasmin activity was measured using functional method. Age, gender, hemoglobin (Hb) levels, and BMI were collected from the records.

RESULTS

Preoperative d-dimer and tPA levels were positively correlated with age, whereas preoperative antiplasmin was negatively correlated with age. Body mass index was only associated with preoperative tPA levels. There was no significant difference in postoperative levels of d-dimer, PAI-1, tPA, or antiplasmin between patients treated with TXA or without TXA. Percentage change in d-dimer and tPA showed significantly lower values in patients treated with TXA compared to the nontreated group. Type of surgery did not affect the fibrinolytic markers.

CONCLUSION

These results confirm that advanced age and elevated BMI positively contribute to fibrinolytic dysregulation in TJA patients, whereas TXA seems to decrease the fibrinolytic activity.

Fibrinolytic Dysregulation in Total Joint Arthroplasty Patients

Background:

The alterations of the fibrinolytic components in osteoarthritic joint disease and their postsurgical modulation are not clearly understood. Preexisting hemostatic dysfunction may lead to both thrombotic and bleeding events in these patients.

Aim:

To profile fibrinolytic parameters in patients undergoing total joint arthroplasty prior to and on postoperative day 1.

Methods:

A total of 98 total joint arthroplasty patients were included in this study. Blood samples were drawn preoperatively and on postoperative day 1 status posttotal knee or total hip arthroplasty surgery. d-Dimer, plasminogen activator inhibitor 1 (PAI-1), and tissue plasminogen activator (tPA) were measured using commercially available enzyme-linked immunosorbent assay kits. Antiplasmin activity was measured by using a functional method.

Results:

Preoperative PAI-1, d-dimer, and tPA levels were significantly higher in arthroplasty patients compared to healthy controls. Preoperative antiplasmin level was lower than controls. Postoperative levels of PAI-1 and d-dimer were increased compared to preoperative values. Postoperative antiplasmin values were lower than preoperative levels. Changes in tPA was not significant. There was no correlation between preoperative PAI-1 and d-dimer levels. Pre- and postoperative percentage changes in each individual were calculated for PAI-1, d-dimer, tPA, and antiplasmin. There was a positive correlation between d-dimer and PAI-1. Negative correlations between antiplasmin and d-dimer and between antiplasmin and PAI-1 were noted.

Conclusion:

These results confirm the perturbation in the fibrinolytic system of patients undergoing total joint arthroplasty surgery. Surgical intervention may also enhance the observed changes. The alterations in the fibrinolytic system may lead to the observed hemostatic complications such as bleeding, hematoma formation, or potential need for blood transfusion.

Does tranexamic acid alter the risk of thromboembolism following primary total knee arthroplasty with sequential earlier anticoagulation? A large, single center, prospective cohort study of consecutive cases

INTRODUCTION

In order to decrease the blood loss and transfusion requirement, tranexamic acid (TXA) has attracted the public's attention in total knee arthroplasty (TKA). However, the safety profile of TXA hindered its wide adoption. And the balance of anti-coagulation sequential anti-fibrinolysis has not yet been explored. This large, single center, prospective cohort study of consecutive cases aimed to investigate the epidemiology of vascular occlusive events associated with TXA and introduce our preliminary results of novel thromboprophylaxis.

MATERIALS AND METHODS

We prospectively collected patients' data of our institution through National Health Database. The primary outcome was the incidence of venous thromboembolism and mortality within 30days following primary TKA. Subgroup analysis was performed on the basis of TXA administration methods.

RESULTS

During 2012 to 2014, a total of 2532 unilateral TKA procedures were conducted in our institution, 2222 with TXA, 310 without TXA. The total occurrence of vascular occlusive events was statistically significantly higher (17.55% Vs 9.35%, p<0.001) in the TXA group but this finding was confined to the calf veins, with the main difference being the incidence in the calf muscular veins (13.68% Vs 6.77%, p=0.001). Statistical difference was not detected neither in the incidence of symptomatic DVT nor asymptomatic DVT. No episode of symptomatic PE and all-cause mortality within 30days occurred postoperatively. Subgroup analysis revealed no significant difference with regard to the incidence of DVT (p>0.05).

CONCLUSION

This study confirmed that the incidence of postoperative VTE was unchanged when TXA was administered in primary unilateral TKA. And our study further indicated that earlier anticoagulation should be adopted to keep the balance between anti-fibrinolysis and anti-coagulation after administering TXA.

The Patient's Age and American Society of Anesthesiologists Status Are Reasonable Criteria for Deciding Whether to Perform Same-Day Bilateral TKA

We investigated whether basing a decision to perform same-day bilateral TKA (SD BTKA) on the patient's age and American Society of Anesthesiologists (ASA) status was reasonable. We retrospectively reviewed the records of 1386 patients who underwent 2086 TKAs (686 unilateral TKAs [UTKAs], 1038 SD BTKAs, and 362 one-week staged BTKAs). For the entire cohort, patients undergoing SD BTKA had a higher risk of major complications compared to those undergoing UTKA. However, there was no difference in the incidence of complications for patients aged<75 years with an ASA status of 1 or 2 who underwent UTKA or SD BTKA. If patients are selected based on age and ASA status, SD BTKA may have a risk of postoperative complication similar to UTKA.

Topical hemostatic procedures control blood loss in bilateral cemented single-stage total knee arthroplasty

BACKGROUND

Blood management is critical in total knee arthroplasty (TKA). In bilateral, single stage TKA, blood loss seems more prominent. We believe it is important to control all potential bleeding within the wound tissue.

PURPOSE

The purpose of the study was to evaluate a series of topical procedures used to reduce blood loss and transfusion in single-stage bilateral cemented total knee arthroplasty: antifibrinolysis with tranexamic acid, vasoconstriction with epinephrine, sealing of the bone section intraoperatively, and closure of the drainage tube within the first 4 h postoperatively.

MATERIALS AND METHODS

Patients with osteoarthritis of the knees were randomly divided into two groups. In group A, 5 ml (25 mg/ml) tranexamic acid (TXA) and 5 ml analgesic containing epinephrine (3 μg/ml) solution were injected at several points into the posterior capsule before installation of the prosthesis. The femoral medullar canal was closed with autograft bone and then sealed compressively with cement. Before the tourniquet was released, 10 ml TXA solution and 10 ml analgesic containing epinephrine were injected at several points into the periosteum, synovium, joint capsule, tendons, and deep fascia tissue (injection of analgesic containing epinephrine into subcutaneous fat and dermis was avoided). The residual nail holes in the bone and the uncovered bone section were covered with bone wax. The tourniquet was then removed, and active bleeding points were stanched. TXA solution (20 ml) was injected into the articular cavity after wound closure. The drainage tube was clamped for 4 h, then opened. In group B, injection of analgesic containing epinephrine into soft tissue, control of active bleeding, and clamping of the drainage tube for 4-h, only, were performed.

RESULTS

Ninety patients were enrolled in the study. Compared with those in group B, intraoperative blood loss, drainage volume, total postoperative blood loss, and number of patients requiring allogenic blood transfusion were significantly reduced in group A. There was no significant difference between the incidence of complications in the groups.

CONCLUSIONS

Our topical procedures enable effective and safe reduction of blood loss and the number of patients requiring transfusion in single-stage bilateral osteoarthritic TKA.

The management of patients on dual antiplatelet therapy undergoing orthopedic surgery

Cardiovascular disease is prevalent in patients undergoing orthopedic surgery. Many patients who have undergone previous percutaneous coronary intervention (PCI) with stenting are on dual antiplatelet therapy in order to minimize the risk of stent thrombosis. The optimal management of these patients in the perioperative setting remains unclear. We aim to provide information about the management of patients who have undergone a PCI with stents who are subsequently indicated for an orthopedic procedure. We will review the concerns from a cardiologist's and orthopedic surgeon's perspective in regards to the management of these patients in the perioperative setting. In addition, the current American Heart Association, American College of Cardiology, Society for Cardiovascular Angiography and Interventions, and American College of Surgeons guidelines are reviewed. The decision to discontinue dual antiplatelet therapy in a patient who has undergone a PCI with stent should be made only after careful review of the risks for thrombosis and bleeding. Best practice suggests that these risks should be jointly assessed by the orthopedic surgeon and cardiologist. Those patients with stents at high risk of thrombosis should have surgery delayed if possible. There is little data supporting a significantly increased bleeding risk associated with mortality in orthopedic patients when antiplatelet therapy is continued perioperatively.

Prévention de la maladie thromboembolique en orthopédie et traumatologie

Orthopaedic and trauma surgery are classified according 3 groups of venous thromboembolic risk. Elective total hip replacement (THR) or total knee replacement (TKR), hip fracture surgery or trauma patients are at high risk. Isolated lower extremity injury with fracture is at moderate risk whereas this risk is low without fracture as well as with knee arthroscopy. In THR and TKR, low molecular weight heparin (LMWH), fondaparinux or melagatran-ximelagatran are strongly recommended. The routine use of other anticoagulants, in particular vitamin K antagonist are not recommended. In patients at high risk of venous thromboembolism as for example trauma patients, optimal use of intermittent pneumatic compression is an alternative option in case of contra-indication to anticoagulant prophylaxis. Graduated compression stockings enhance the efficacy of pharmacological methods. In schedule surgery, initiation of prophylaxis with LMWH may be started postoperatively. To reduce the haemorrhagic risk of anticoagulants, timing of first postoperative dose is essential and is proper to each drug. Duration of prophylaxis depends on the surgical and the individual patients' risk. Extended prophylaxis in THR for up to 42 days with LMWH and up to 35 days with fondaparinux in hip fracture surgery is recommended. However extended prophylaxis after 14 days in TKR has not demonstrated a higher efficacy and should only be considered for patients with additional risk factors. In patients with isolated lower extremity injury or undergoing knee arthroscopy, LMWH should not be routinely used according to a low or a moderate risk and/or the duration of prophylaxis required. But LMWH has to be considered for patients with additional risk factors. Prophylaxis in other orthopedic procedures has not been assessed and will be extrapolated from the above recommendations.

Perioperative morbidity in bilateral one-stage total knee replacements

A retrospective review was done on 501 patients who had bilateral sequential one-stage total knee replacements from September 1995 to April 2000 to evaluate perioperative (inhospital) morbidity. One thousand two knee replacements were done with the patients receiving regional anesthesia, on 286 women and 215 men with an average age of 66 years. The average transfusion requirement was 2.8 units of blood per patient. There were no deaths, myocardial infarctions, or cerebrovascular accidents. The mean length of hospital stay was 7.2 days. One hundred forty-four perioperative complications were observed in 109 patients (21.8%). These complications included 27 arrhythmias (5%), one congestive heart failure (0.2%), 65 lower extremity deep venous thromboses (13%), 14 fat emboli (3%), and two pulmonary emboli (0.4%). Other major complications were pneumonia (1%), acute renal failure (0.4%), ileus (2%), and mental status changes (2%). Wound complications included two deep infections (0.4%), three hematomas (0.6%), and five delayed wound healings (0.9%). According to the current study the perioperative morbidity and mortality is acceptable if the procedure is used for selected patients. Patients with significant comorbidities should have a staged bilateral total knee replacement.

Activation of blood coagulation in patients undergoing postoperative blood salvage and re-infusion of unwashed whole blood after total knee arthroplasty

BACKGROUND

Perioperative blood salvage is commonly used in cardiovascular surgery and has been more recently introduced in major orthopedic surgery. Limited information is available on the influence of re-infused whole blood on the hemostatic system in orthopedic patients.

MATERIALS AND METHODS

The aim of this study was to assess whether perioperative salvage and re-infusion of unwashed whole blood is associated with an activation of blood coagulation in patients undergoing total knee replacement. Consecutive patients receiving re-infusion were included in the study (n=13). Patients undergoing total knee replacement without perioperative blood salvage and re-infusion served as controls (n=6). In patients receiving re-infusion thrombin-antithrombin complexes (TAT), plasmin-antiplasmin complexes (PAP) and fibrinogen were assayed at the following times: before surgery (baseline), immediately before re-infusion (T0), immediately (T1), 2 h (T2) and 24 h (T3) after the end of re-infusion. In control patients blood samples were drawn at the average times corresponding to each of the sampling time in the patients receiving re-infusion. The first post-surgery LMWH dose was given within 12 h after surgery.

RESULTS

TAT and PAP increased after surgery both in patients receiving re-infusion and controls. An increase of TAT and PAP was observed immediately after re-infusion with respect to baseline (TAT 513.1 +/- 259.1 microg/l vs. 5.3 +/- 4.9, p<0.0001; PAP 7408.0 +/- 1892.1 microg/l vs. 461.4 +/- 217.1, p<0.0001) and to controls (TAT 60.4 +/- 26.9 microg/l, p=0.002; PAP 2208.3 +/- 1446.4 microg/l, p<0.001). The levels of TAT and PAP in patients receiving re-infusion remained high at 2 h after re-infusion compared to those of the controls (TAT 124.1 +/- 38.3 microg/l vs. 38.08 +/- 18.9, p=0.016; PAP 5690.7 +/- 1435.5 microg/l vs. 1613.9 +/- 706.0, p<0.001) and decreased 24 h thereafter. Fibrinogen level was lower in patients receiving re-infusion compared to controls.

CONCLUSIONS

Whole blood re-infusion is associated with an activation of blood coagulation in patients undergoing total knee replacement. The clinical relevance of this activation has to be tested in prospective studies with adequate sample size.

A multimodality regimen for deep venous thrombosis prophylaxis in total knee arthroplasty

Data indicate that deep venous thrombosis (DVT) occurs at the time of knee arthroplasty. Nevertheless, literature concerning DVT prophylaxis has only recently addressed this contention. This prospective study evaluated the efficacy of a perioperative prophylactic regimen. Between January 1996 and June 2001, 1,308 knees (964 surgeries) underwent total knee arthroplasty. Patients were treated routinely with intraoperative heparin (1000 units intravenous push before inflation of the tourniquet and 500 units at deflation), hypotensive epidural anesthesia (MAP 70-90), external pneumatic compression boots, and aspirin (325 mg, PO, BID for 6 weeks). Duplex venous ultrasonography was performed before discharge. DVT was detected in 4% of cases (1% proximal and 3% distal). Bleeding complications occurred in 1%, and perioperative medical complications occurred in 12%.

Nonpharmacologic thromboembolic prophylaxis in total knee arthroplasty

Deep venous thrombosis is the most common complication in patients having elective total knee replacement. Pneumatic compression devices play an important role in the prophylaxis of deep venous thrombosis and effectively decrease the risk of distal deep venous thrombosis. The combination therapy with pharmacologic agents has the benefit of decreasing the rate of proximal deep venous thrombosis and therefore is recommended. In the absence of clinical data, recent in vivo flow studies suggest that calf or combined foot and calf compression are superior to foot compression alone. Epidural anesthesia in comparison with general anesthesia decreases the incidence of thromboembolic disease after total knee arthroplasty. Although hypotensive anesthesia and intraoperative heparin have been proven to substantially lower the incidence of deep venous thrombosis after total hip arthroplasty, the current literature does not support its application during the implantation of a total knee replacement. Pneumatic compression devices are an important part of deep venous thrombosis prophylaxis especially in the early postoperative period considering that pharmacologic anticoagulation is contraindicated in the first 12 hours after spinal anesthesia and in the presence of an epidural line.

Extended-duration prophylaxis against venous thromboembolism after total hip or knee replacement: a meta-analysis of the randomised trials

BACKGROUND

The optimum duration of prophylaxis against venous thromboembolism after total hip or knee replacement is uncertain. Our primary objective was to establish the efficacy of extended-duration prophylaxis on symptomatic venous thromboembolic events.

METHODS

We identified randomised trials comparing extended-duration prophylaxis using heparin or warfarin with placebo or untreated control in patients undergoing elective total hip or knee replacement by searching electronic databases (MEDLINE, EMBASE), references from retrieved articles, and abstracts from conference proceedings, and by contact with pharmaceutical companies and investigators. Two reviewers independently extracted data on study design, symptomatic and symptomless venographic venous thromboembolism, death, and bleeding outcomes. Results from individual trials were combined with the Mantel-Haenszel method.

FINDINGS

Nine studies met our inclusion criteria (3999 patients), eight with low molecular weight heparin, and one with unfractionated heparin. Extended-duration prophylaxis for 30-42 days significantly reduced the frequency of symptomatic venous thromboembolism (1.3% vs 3.3%, OR 0.38; 95% CI 0.24-0.61, numbers needed to treat [NNT]=50), with no statistical evidence of heterogeneity (x(2) test, p=0.69). There was a greater risk reduction in patients undergoing hip replacement (1.4% vs 4.3%, 0.33; 0.19-0.56, 34) compared with knee replacement (1.0% vs 1.4%, 0.74; 0.26-2.15, 250). A significant reduction in symptomless venographic deep vein thrombosis was also observed (9.6% vs 19.6%, 0.48; 0.36-0.63, 10). There was no increase in major bleeding but extended-duration prophylaxis was associated with excess minor bleeding (3.7% vs 2.5%, 1.56; 1.08-2.26, numbers needed to harm [NNH]=83).

INTERPRETATION

Among patients undergoing total hip or knee replacement, extended-duration prophylaxis significantly reduces the frequency of symptomatic venous thromboembolism. The reduction in risk is equivalent to about 20 symptomatic events per 1000 patients treated.

Hypotensive epidural anesthesia in total knee replacement without tourniquet: reduced blood loss and transfusion

BACKGROUND AND OBJECTIVES

[corrected] For decades, hypotensive anesthesia has been used in an attempt to reduce intraoperative blood loss. Hypotensive epidural anesthesia (HEA) is a relatively new technique in hypotensive anesthesia. Use of a tourniquet has been shown to be associated with a higher risk of cardiovascular and thromboembolic complications. The effect of HEA on blood loss and need for transfusion in total knee replacement (TKR) is not known.

METHODS

Thirty consecutive patients scheduled for TKR were randomized to HEA without tourniquet or spinal anesthesia with the use of a tourniquet (SPI). HEA was performed as an epidurally induced sympathetic block and there was an infusion of low-dose epinephrine to stabilize the circulation.

RESULTS

Intraoperative mean arterial blood pressure was 48 mm Hg (HEA) versus 83 mm Hg (SPI) (P <.001). Intraoperative blood loss was 146 mL (HEA) versus 13 mL (SPI) (P <.001). Postoperative blood loss at any time was significantly reduced in the HEA group, and total loss of blood was 1,056 mL (HEA) versus 1,826 mL (SPI) (P <.001). Half of the bleeding took place during the first 3 postoperative hours and 80% during the first 24 hours. In the HEA group, 57% of the patients went through surgery and the hospital stay without receiving blood transfusion versus 19% in the SPI group (P <.05). There was a significantly reduced amount of blood transfusion in the HEA group (193 mL) versus 775 mL in the SPI group (P <.005). No cardiopulmonary, cerebral, or renal complications were registered.

CONCLUSIONS

We conclude that HEA is a safe technique that allows TKR without a tourniquet. Compared with spinal anesthesia, the use of HEA for TKR significantly reduces blood loss and the need for blood transfusion.

Microvascular surgery in a bloodless field

Although tourniquets play an integral role in extremity surgery, no clear guidelines exist for the use of tourniquets in microsurgery. We undertook a study in 12 healthy volunteers to better understand the coagulation properties of blood distal to an inflated tourniquet. At a 15-min inflation time, blood distal to an inflated tourniquet clots faster than blood taken from the opposite arm after addition of exogenous thrombin (12.5 s vs 17.5 s, P < 0.0001). Neither fibrinopeptide A (FPA) levels nor tissue plasminogen activator (tPA) levels were different from those of controls. Tissue factor pathway inhibitor (TFPI), an endogenous local anticoagulant, was slightly but significantly elevated in tourniquet blood. Although much remains to be understood, we believe that microvascular surgery in a bloodless field is safe and efficacious. Nine patients are presented who successfully underwent microvascular surgery in a bloodless field, using various types of extremity tourniquets.

The knee joint in rheumatoid arthritis

Rheumatoid arthritis may present in the knee within a wide spectrum of manifestations. Disease progression, treatment protocols, surgical treatments and the possible complications of these treatments differ distinctly from those of osteoarthritis.

Effect of tourniquet use on activation of coagulation in total knee replacement

Total knee replacement often is performed with tourniquet application. The advantages of a dry field, including fixation, are well known, but it still is debatable if tourniquet application increases deep vein thrombosis. Measurement of coagulation markers is a well accepted method of studying thrombogenesis activation intraoperatively and postoperatively. Twenty patients undergoing total knee replacement with subarachnoid anesthesia were assigned randomly to two groups: either with tourniquet application (Group I) or without tourniquet application (Group II). There were no differences between patients in the two groups in terms of age, gender, diagnosis (all had osteoarthritis), operative time, and total (intraoperative and postoperative) blood loss. Markers for thrombin generation and fibrinolysis were measured. Blood samples were drawn at four times: baseline before the operation; after bone cuts; after cement fixation (Group II) or 2 minutes after tourniquet deflation (Group I); and 1 hour after surgery. Markers of thrombin generation and fibrinolysis showed a significant increase from baseline in all the patients. In Group II these markers started to increase during surgery, whereas in Group I the increase occurred at the end of the procedure when the tourniquet was deflated. The total amount of thrombin generation was significantly higher in Group II (without tourniquet), whereas fibrinolysis was significantly greater in Group I. Total knee replacement is accompanied by a hypercoagulative state with or without the use of a tourniquet, but it seems to be higher when the tourniquet is not used. In addition, tourniquet application may increase fibrinolysis.

Thromboembolic disease prophylaxis in total knee arthroplasty using intraoperative heparin and postoperative pneumatic foot compression

A prospective study was performed to assess the clinical efficacy of intraoperative heparin combined with postoperative pneumatic foot compression and aspirin for thromboembolic disease prophylaxis after primary total knee arthroplasty (TKA). This group of 48 patients all had a primary TKA performed under epidural anesthesia. The cohort of patients was compared with a similar cohort of patients matched for age and comorbidity. The control group consisted of 61 patients (41 unilateral patients, 20 bilateral patients) with 81 TKAs who received epidural anesthesia and postoperative pneumatic foot compression and aspirin. The same surgeon and anesthesiologist performed all cases. All patients had the pneumatic foot compression device applied in the recovery room and received 325 mg of enteric-coated aspirin twice a day beginning the night of surgery. Venography was performed on the fifth postoperative day for both groups to determine the incidence of deep vein thrombosis (DVT). In the control group with postoperative pneumatic foot compression (group 1), the overall incidence of DVT was 27% (22 of 81), with 10% (8 of 81) major calf DVT and no proximal (popliteal or femoral) DVT. In the study group with intraoperative heparin and postoperative pneumatic foot compression (group 2), the overall incidence of DVT was 25% (12 of 48), with 8% (4 of 48) major calf DVT and no proximal DVT. There was no statistically significant difference between groups 1 and 2 for the incidence of overall DVT (P > .05) or major calf DVT (P > .05). No complications were associated with the use of intraoperative heparin or the pneumatic compression device, and no patient developed a symptomatic pulmonary embolism up to 3 months postoperatively. Although this study confirms that pneumatic foot compression combined with aspirin is an effective form of DVT prophylaxis after TKA, the added benefit of intraoperative heparin was not statistically proven. Although greater statistical power is needed to determine whether intraoperative heparin provides an added benefit, this study reveals a low incidence of DVT in TKA with this protocol.

The effect of tranexamic acid on local and plasma fibrinolysis during total knee arthroplasty

The aim of the present study was to investigate aspects of coagulation and fibrinolysis during knee arthroplasties in order to find out. 1. whether an increased fibrinolysis is correlated to an increased blood loss 2. whether there is a difference in markers for coagulation and fibrinolysis in peripheral venous blood compared to those in blood from the wounds 3. whether the administration of tranexamic acid modifies the fibrinolytic response. Twenty-four patients were included. Twelve patients were given tranexamic acid intravenously at the end of the operation. The dose was repeated three hours later. The other 12 patients were given an equivalent amount of placebo. The administration was randomised and double-blind. Levels of prothrombin fragments 1 + 2, D-dimers, plasminogen, alpha 2-antiplasmin, tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAI-1) in venous blood were investigated just before the operation, at the end of the operation and three hours later. At the end of the operation blood for analysis was also drawn from the wound. Coagulation and fibrinolysis was activated during and after surgery. The activation was significantly higher in blood from the wounds than in peripheral venous blood. We found no direct correlation between the degree of fibrinolysis and blood loss. The administration of tranexamic acid reduced fibrinolysis in the wounds but not in peripheral venous blood. The postoperative blood loss was reduced by half.

Knee closure in total knee replacement: a randomized prospective trial

A randomized prospective study of 75 total knee replacements in 64 patients who were randomized to capsular closure with the knee in full extension or in flexion was done. Thirty-one knees received a posterior cruciate ligament retaining prosthesis and 44 knees received a posterior stabilized prosthesis. Preoperatively, there was no significant difference between the groups, and patients were stratified by surgeon and type of prosthesis. Postoperatively, all patients were evaluated by a physical therapist who did not know the type of prosthesis the patient received. In addition to the range of motion obtained at discharge; the number of days required to achieve unassisted transfer; the number of days required to achieve assisted and unassisted use of a walker, cane, and stairs; and the number of days to discharge from the hospital were recorded. All patients were also evaluated at 2 to 3 months postoperatively, and the Knee Society clinical rating system scores were compared. There was no statistically significant difference in any of the early rehabilitation parameters or in the 2- to 3-month followup data. Moreover, there was no statistically significant difference in the rate of complications. With stratification according to the type of prosthesis used or the surgeon performing the operation, there was still no statistically significant difference in any of the studied parameters. It was therefore concluded that the degree of knee flexion at the time of capsular closure in total knee replacement has no effect on early rehabilitation after total knee replacement.