The incidence of venous thromboembolism after total hip arthroplasty: a specific hypotensive epidural anesthesia protocol

Controlled hypotension during neuraxial anesthesia is not associated with increased odds of in-hospital common severe medical complications in patients undergoing elective primary total hip arthroplasty - A retrospective case control study

Introduction

The use of controlled hypotension during neuraxial anesthesia for joint arthroplasty is controversial. We conducted a large institutional database analysis to assess common in-hospital complications and mortality of patients undergoing primary total hip arthroplasty (THA) under controlled hypotension and neuraxial anesthesia.

Methods

We conducted a large retrospective case control study of 11,292 patients who underwent primary THA using neuraxial anesthesia between March 2016 and May 2019 in a single institution devoted to musculoskeletal care. The degree and duration of various mean arterial pressure (MAP) thresholds were analyzed for adjusted odds ratios with composite common severe complications (in-hospital myocardial infarction, stroke, and/or acute kidney injury) as the primary outcome.

Results

Sixty-eight patients developed common severe complications (0.60%). Patients with complications were older (median age 75.6 vs 64.0 years) and had a higher American Society of Anesthesiologists (ASA) classification (45.6% vs 17.6% ASA III). The duration of hypotension at various MAP thresholds (45 to 70 mm Hg) was not associated with increasing odds of common severe medical complications.

Conclusions

Controlled hypotension (ranging from 45 to 70 mmHg) for a moderate duration during neuraxial anesthesia was not associated with increased odds of common severe complications (myocardial infarction, stroke, and/or acute kidney injury) among patients receiving neuraxial anesthesia for elective THA.

Multimodal thromboprophylaxis in low-risk patients undergoing lower limb arthroplasty: A retrospective observational cohort analysis of 1400 patients with ultrasound screening

PURPOSE

This study reports the results of a multimodal thromboprophylaxis protocol for lower limb arthroplasty involving risk stratification, intraoperative calf compression, aspirin prophylaxis and early (within 4 h) post-operative mobilisation facilitated by the use of local infiltration analgesia. The study also aimed to identify risk factors for venous thromboembolism (VTE) within a 3-month period following surgery for patients deemed not at elevated risk.

METHODS

Patients undergoing knee/hip arthroplasty or hip resurfacing were preoperatively screened for VTE risk factors, and those at standard risk were placed on a thromboprophylaxis protocol consisting of intraoperative intermittent calf compression during surgery, 300 mg/day aspirin for 6 weeks from surgery and early mobilisation. Patients were screened bilaterally for deep vein thrombosis (DVT) on post-operative days 10-14. If proximal DVT was detected, patients were anticoagulated and outcomes were recorded. Symptomatic VTE within 3 months of surgery were recorded separately. Patient notes were retrospectively collated and cross-validated against ultrasound reports.

RESULTS

At initial screening, the rate of proximal DVT was 0.54% (1.1% for knee and 0.27% for hip), and distal DVT was 6.63% (20.11% for knee and 2.31% for hip). One small, nonfatal pulmonary embolism (PE) was detected within 3 months of surgery (0.28% of total knee arthroplasty patients or 0.07% of total). All proximal DVTs were treated successfully with anticoagulants; however, one patient suffered a minor PE approximately 10 months post-operatively. Regression analysis identified knee implant and advanced age as independent risk factors for VTE in this cohort.

CONCLUSION

Although knee arthroplasty patients remained at higher risk than hip replacement/resurfacing patients, the incidence and outcomes of VTE remained positive compared with protocols involving extended immobilisation, and episodes of PE were extremely rare. Thus, we conclude that patients at standard preoperative risk of VTE may safely be taken through the post-operative recovery process with a combination of intraoperative mechanical prophylaxis, early mobilisation and post-operative aspirin, with closer attention required for older patients and those undergoing knee surgery.

Low-Dose Aspirin Is Adequate for Venous Thromboembolism Prevention Following Total Joint Arthroplasty: A Systematic Review

BACKGROUND

Patients undergoing total joint arthroplasty (TJA) are at risk of developing venous thromboembolism (VTE) without adequate prophylaxis. Since the American Academy of Orthopedic Surgeons issued guidelines in 2007 recommending aspirin 325 mg bis in die for 6 weeks, aspirin has been favored as the main VTE prophylaxis. However, the appropriate dose and duration of aspirin are not well-studied. This systematic review aims to identify any differences between high and low dose as well as duration for aspirin thromboprophylaxis after TJA as outlined by previous studies.

METHODS

A search was performed using Ovid MEDLINE, EMBASE, and PubMed, including articles up to July 2016. Studies were included if they contained at least 1 cohort that underwent TJA with aspirin as the sole chemoprophylaxis and reported either (1) symptomatic VTE or (2) secondary outcomes such as major bleeding or 90-day mortality.

RESULTS

Forty-five papers were included. There were no significant differences in symptomatic pulmonary embolism, symptomatic deep vein thrombosis, 90-day mortality, or major bleeding between patients receiving low-dose or high-dose aspirin. Patients treated with aspirin for <4 weeks had a higher risk of major bleeding (1.59%) vs patients treated for 4 weeks (0.15%), which may be attributed to premature cessation or differential reporting. Patients treated with aspirin for <4 weeks had a statistically higher 90-day mortality (1.95%) vs patients treated for 4 weeks (0.07%). There was no significant difference between incidence of pulmonary embolism or deep vein thrombosis and the durations of aspirin treatment.

CONCLUSION

This review suggests that low-dose aspirin is not inferior to high-dose aspirin for VTE thromboprophylaxis in TJA patients. Additionally, patients treated with aspirin for less than 4 weeks may have a higher risk of major bleeding and 90-day mortality compared to patients treated for a longer duration.

Real-world effectiveness and safety of pharmacological thromboprophylaxis in patients undergoing primary total hip and knee arthroplasty: A narrative review

In this narrative review of the real-world effectiveness and safety of pharmacological thromboprophylaxis following primary total hip and knee arthroplasty, a total of 12 non-interventional observational studies were included. Pharmacological thromboprophylaxis included warfarin, heparins, dabigatran, rivaroxaban, apixaban, acetylsalicylic acid, and fondaparinux. The absolute risks varied across the included studies. These variations can be explained by differences in patient populations, drug exposure, follow-up time, and definition of outcomes, which makes it a challenge to compare the risk estimates. These findings emphasize the need for a large population-based real-world study to provide comparable risk estimates associated with different pharmacological thromboprophylaxis.

The Role of Intraoperative Intermittent Pneumatic Compression Devices in Venous Thromboembolism Prophylaxis in Total Hip and Total Knee Arthroplasty

Venous thromboembolism (VTE) is a common complication after total hip arthroplasty (THA) and total knee arthroplasty (TKA), occurring in up to 85% of patients who are not treated with prophylaxis. The initiation of VTE development may occur intraoperatively. This study investigated whether this gap in VTE prophylaxis can be addressed by the use of intraoperative intermittent pneumatic compression devices (IPCDs) and if intraoperative IPCDs have a meaningful benefit in preventing symptomatic VTE. The authors defined symptomatic VTE as deep venous thrombosis in either lower extremity or a pulmonary embolism. The authors evaluated the medical records of 3379 patients who underwent THA or TKA at their institution in 2014 and 2015. Effects of various factors, including age, sex, body mass index, and smoking status, were compared between these 2 cohorts. Patients who experienced a symptomatic VTE were also matched by age, sex, and procedure type with randomly selected controls. In the patient sample, 47 patients (1.4%) developed VTE. Forty (1.2%) of these patients underwent TKA, whereas 7 (0.2%) underwent THA. Venous thromboembolism occurred less frequently in patients who received intraoperative IPCDs (0.8%) than in patients who did not receive them (1.5%); however, this difference did not reach statistical significance. Total knee arthroplasty was associated with increased odds of VTE compared with THA, as was female sex. These results did not show a statistically significant benefit to the intraoperative use of IPCDs. Pneumatic compression remains a fast, easy, low-cost, low-risk, intuitive intervention that can supplement the postoperative multimodal approach and is worthy of further study. Intraoperative IPCD use should be considered for patients with a higher risk of VTE. [Orthopedics. 2018; 41(1):e98-e103.].

Bilateral Total Hip Arthroplasty: 1-Stage or 2-Stage? A Meta-Analysis

BACKGROUND

Total hip arthroplasty (THA) is one of the most successful orthopedic surgeries performed in the last 50 years. However, controversies still exist between conducting 1- or 2-stage bilateral THA.

METHODS

Using PubMed, Ovid, Embase, and Cochrane library databases, we searched for papers written between January 1995 and October 2015 that contained the following search terms: "one-stage or two-stage" or "simultaneous or staged," and "hip" and "arthroplasty or replacement." A meta-analysis was conducted with the collected pooled data about major and minor systemic complications, surgical complications, and other perioperative data associated with 1- and 2-stage bilateral THA. Statistical analysis was performed by the Mantel-Haenszel method, and the fixed effect model was used to analyze data.

RESULTS

There were 13 studies with 17,762 patients who underwent 1-stage bilateral THA and 46,147 patients who underwent 2-stage bilateral THA. One-stage bilateral THA had a lower risk of major systemic complications, less deep venous thrombosis, and shorter operative time compared with 2-stage bilateral THA. There were no significant differences in death, pulmonary embolism, cardiovascular complication, infections, minor complications, and other surgical complications between procedures.

CONCLUSION

One-stage bilateral THA was superior to 2-stage bilateral THA in terms of major systemic complication, deep venous thrombosis, and surgical time compared with 2-stage bilateral THA. However, this study does not encourage performing 1-stage over 2-stage bilateral THA. Higher evidence level studies are necessary for further analysis.

A protocol avoiding allogeneic transfusion in joint arthroplasties

INTRODUCTION

Arthroplasties of hip and knee are associated with blood loss, which may lead to adverse patient outcome. Performing arthroplasties in Jehovah's Witness patients who do not accept transfusion has been a matter of concern. We developed a protocol, which avoids transfusion in arthroplasties of Jehovah's Witness patients, and evaluated the feasibility and safety of the protocol.

MATERIALS AND METHODS

The target of preoperative hemoglobin was more than 10 g/dL. When preoperative hemoglobin was lower than 10 g/dL, 4000 U erythropoietin (3 times a week) and 100 mg iron supplement (every day) were administered until the hemoglobin reached 10 g/dL. When the preoperative hemoglobin was higher than 10 g/dL, 4000 U erythropoietin and 100 mg iron supplement were administered once, before operation. During the operation, cell saver was used. Postoperatively, erythropoietin and iron supplements were administered until the hemoglobin reached 10 g/dL, similar to the preoperative protocol. We evaluated the feasibility of our protocol, perioperative complications and hematologic changes.

RESULTS

From 2002 to 2014, 186 Witness patients visited our department. In 179 patients (96.2 %), 77 total knee arthroplasties, 69 bipolar hemiarthroplasties and 33 total hip arthroplasties were performed. The mean hemoglobin level was 12.3 g/dL preoperatively, 9.4 g/dL on postoperative day 3 and 10.3 g/dL on postoperative day 7. One patient died immediately after the arthroplasty and the remaining 178 patients survived.

CONCLUSIONS

Total joint arthroplasty could be done without transfusion using this protocol in most of our patients. The rates of infection and mortality were similar with known infection and mortality rates of arthroplasties. In patients who do not want allogeneic transfusions, our protocol is a safe alternative to perform joint arthroplasties.

Proximal deep venous thrombosis and pulmonary embolus following total joint arthroplasty

It has been proposed that prevention of deep venous thrombosis (DVT) will lead to a reduction in pulmonary embolism (PE). This retrospective comparative study examines the association between symptomatic proximal DVT (occurring at or proximal to the popliteal fossa) and PE in total joint arthroplasty (TJA) patients. We evaluated 1031 patients with DVT symptoms and 428 with PE symptoms. A total of 227 patients were evaluated for both. No statistically significant association found between developing PE and DVT within 90 days after TJA (P=0.94). Our findings raise into question the mechanical propagation theory. Formation of DVT and PE may be independent events in patients undergoing TJA. Evaluating the efficacy of thromboprophylaxis using DVT as end point may not reflect its efficacy for prevention of PE.

Review article: Anti-embolism stockings

The National Institute for Health and Clinical Excellence (NICE) guidelines recommend combined mechanical and pharmacological prophylaxis to reduce the risk of venous thromboembolism (VTE) in patients undergoing orthopaedic surgery. There is increasing evidence that anti-embolic stockings (AES) have little effect on reducing such risk. Articles in the MEDLINE, EMBASE, and Cochrane Library were reviewed. Studies on the use of pharmacological prophylaxis recommended in the 2010 NICE guidelines including low-molecular-weight heparin, unfractionated heparin, rivaroxaban, and dabigatran with and without AES in patients undergoing orthopaedic surgery were included. A total of 1171 trauma and elective orthopaedic patients in 4 studies were included; 587 received pharmacological prophylaxis alone, and 584 received a combination of pharmacological prophylaxis and above- or belowknee AES. Of the respective patients, 44 (7.5%) and 31 (5.3%) developed deep vein thrombosis (p=0.1587) and 7 (1.2%) and 9 (1.5%) developed pulmonary embolism (p=0.8493). The overall VTE rates did not differ significantly (p=0.2864). No death from VTE was reported. Addition of AES did not confer significant benefit in terms of reducing the risk of VTE in orthopaedic patients.

Safety of thromboembolic chemoprophylaxis in spinal trauma patients requiring surgical stabilization

STUDY DESIGN

Retrospective review.

OBJECTIVE

To determine the incidence of thromboembolic events, bleeding complications such as epidural hematomas, and wound complications in patients with spinal trauma requiring surgical stabilization.

SUMMARY OF BACKGROUND DATA

Literature addressing the safety and efficacy of chemoprophylactic agents in postoperative patients with spinal trauma is sparse. As a result, significant variability exists regarding administration of thromboembolic chemoprophylaxis in this population. The risk of bleeding complications is particularly concerning.

METHODS

Patients with spinal trauma who underwent surgical stabilization in 2009 and 2010 at a single level 1 trauma center were retrospectively reviewed. Exclusion criteria included patients who underwent solely decompressive procedures, noninstrumented fusions, kyphoplasty, or had incomplete medical records. Patients who received chemoprophylaxis were compared with patients who did not. Demographical information and injury data were collected. Primary outcome measures were prevalence of thromboembolic events, epidural hematomas, and persistent wound drainage requiring irrigation and debridement.

RESULTS

Two hundred twenty-seven of 373 patients were included (56 in the untreated group, 171 in the treated group). Eight patients in the untreated group (14.3%) and 12 patients in the treated group (7%) developed postoperative thromboembolism (P = 0.096). There was 1 pulmonary embolism in the untreated group (1.8%), and 4 pulmonary embolisms in the treated group (2.3%). Surgical irrigation and debridement for wound drainage was required for 1.8% of patients in the untreated group and for 5.3% of patients in the treated group. No epidural hematomas were noted in either group. The treated group had more spinal levels fused (P = 0.46), higher injury severity scores (0.001), and longer hospitalizations (0.018). Patients who developed postoperative thromboembolism had significantly higher body mass indexes (P = 0.01), injury severity scores (0.001), number of spinal levels fused (P = 0.004), incidence of neurological deficits (0.001), and longer hospitalizations (0.16) compared with those who did not.

CONCLUSION

The use of chemoprophylaxis appears to be safe in at-risk patients in the immediate postoperative period after spinal trauma surgery. No epidural hematomas occurred, and the risk of wound drainage is small. Body mass index, injury severity score, presence of neurological deficits, and number of spinal levels fused should be considered when determining which patients should receive chemoprophylaxis after surgical stabilization.

Is venous foot pump effective in prevention of thromboembolic disease after joint arthroplasty: a meta-analysis

The goal of this meta-analysis was to evaluate the efficacy of venous foot pumps in prevention of venous thromboembolism following joint arthroplasty. Using different databases, we found 13 prospective clinical trials published meeting our inclusion criteria. In total, 1514 patients were included in the final analysis. Venous foot pump devices are effective in prevention of venous thromboembolic disease after total hip and knee arthroplasty compared to chemoprophylaxis. This was especially significant in prevention of major deep vein thrombosis and pulmonary emboli rate. The use of mechanical devices like venous calf or foot pump, either alone or in combination with less potent chemical prophylaxis, on the other hand can reduce the rate of venous thromboembolism and complications of potent chemoprophylaxis like wound hematoma.

Aspirin for elective hip and knee arthroplasty: a multimodal thromboprophylaxis protocol

PURPOSE

Multimodal thromboprophylaxis includes preoperative thromboembolic risk stratification and autologous blood donation, surgery performed under regional anaesthesia, postoperative rapid mobilisation, use of pneumatic compression devices and chemoprophylaxis tailored to the patient's individual risk. We determined the 90-day rate of venous thromboembolism (VTE), other complications and mortality in patients who underwent primary elective hip and knee replacement surgery with multimodal thromboprophylaxis.

METHODS

A total of 1,568 consecutive patients undergoing hip and knee replacement surgery received multimodal thromboprophylaxis: 1,115 received aspirin, 426 received warfarin and 27 patients received low molecular weight heparin and warfarin with or without a vena cava filter.

RESULTS

The rate of VTE, pulmonary embolism, proximal deep vein thrombosis (DVT) and distal DVT was 1.2, 0.36, 0.45 and 0.36 %, respectively, in patients who received aspirin. The rates in those who received warfarin were 1.4, 0.9, 0.47 and 0.47 %, respectively. The overall 90-day mortality rate was 0.2 %.

CONCLUSIONS

Multimodal thromboprophylaxis in which aspirin is administered to low-risk patients is safe and effective following primary total joint replacement.

Meta-analysis of cause of death following total joint replacement using different thromboprophylaxis regimens

We performed a meta-analysis of modern total joint replacement (TJR) to determine the post-operative mortality and the cause of death using different thromboprophylactic regimens as follows: 1) no routine chemothromboprophylaxis (NRC); 2) Potent anticoagulation (PA) (unfractionated or low-molecular-weight heparin, ximelagatran, fondaparinux or rivaroxaban); 3) Potent anticoagulation combined (PAC) with regional anaesthesia and/or pneumatic compression devices (PCDs); 4) Warfarin (W); 5) Warfarin combined (WAC) with regional anaesthesia and/or PCD; and 6) Multimodal (MM) prophylaxis, including regional anaesthesia, PCDs and aspirin in low-risk patients. Cause of death was classified as autopsy proven, clinically certain or unknown. Deaths were grouped into cardiopulmonary excluding pulmonary embolism (PE), PE, bleeding-related, gastrointestinal, central nervous system, and others (miscellaneous). Meta-analysis based on fixed effects or random effects models was used for pooling incidence data. In all, 70 studies were included (99 441 patients; 373 deaths). The mortality was lowest in the MM (0.2%) and WC (0.2%) groups. The most frequent cause of death was cardiopulmonary (47.9%), followed by PE (25.4%) and bleeding (8.9%). The proportion of deaths due to PE was not significantly affected by the thromboprophylaxis regimen (PA, 35.5%; PAC, 28%; MM, 23.2%; and NRC, 16.3%). Fatal bleeding was higher in groups relying on the use of anticoagulation (W, 33.8%; PA, 9.4%; PAC, 10.8%) but the differences were not statistically significant. Our study demonstrated that the routine use of PA does not reduce the overall mortality or the proportion of deaths due to PE.

Thromboembolic events are uncommon after open treatment of proximal humerus fractures using aspirin and compression devices

BACKGROUND

Thromboembolic phenomena have long been recognized as a major cause of morbidity and mortality in hospitalized patients, especially those undergoing reconstructive surgery. We have been empirically treating patients with aspirin, early ambulation, and mechanoprophylaxis after operative management of proximal humerus fractures. However, we have not established the incidence of postoperative deep vein thrombosis and pulmonary embolism in this population.

QUESTIONS/PURPOSES

We determined the incidence of deep vein thrombosis and pulmonary embolism in patients having surgery for displaced proximal humerus fractures treated with our thromboprophylactic regimen.

PATIENTS AND METHODS

We prospectively followed 50 patients with proximal humerus fractures who underwent fixation with plate osteosynthesis (n = 40) or hemiarthroplasty (n = 10) between August 2005 and December 2008. Deep vein thrombosis prophylaxis consisted of oral enteric-coated aspirin, pneumatic calf compression pumps, and early ambulation in all patients unless medically contraindicated. Color-flow Doppler ultrasound of the affected arm and both lower extremities was performed at a mean of 14 days (range, 7-21 days) postoperatively to evaluate for deep vein thrombosis. All patients clinically suspected to have suffered a pulmonary embolism underwent a CT angiogram.

RESULTS

We identified no patients with deep vein thrombosis or pulmonary embolism in this population.

CONCLUSIONS

Deep vein thrombosis and pulmonary embolism are not uncommon after major reconstructive surgery about the shoulder in untreated patients. Our data suggest these events can be low after surgery for proximal humerus fractures followed by a thromboprophylactic regimen including aspirin, mechanical devices, and early mobilization.

LEVEL OF EVIDENCE

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

Cardiac and thromboembolic complications and mortality in patients undergoing total hip and total knee arthroplasty

OBJECTIVE

To study 90-day complications following total hip arthroplasty (THA) or total knee arthroplasty (TKA).

METHOD

In a population-based cohort of all Olmsted County residents who underwent a THA or TKA (1994-2008), we assessed 90-day occurrence and predictors of cardiac complications (myocardial infarction, cardiac arrhythmia or congestive heart failure), thromboembolic complications (deep venous thrombosis or pulmonary embolism) and mortality.

RESULTS

90-day complication rates after THA and TKA were: cardiac, 6.9% and 6.7%; thromboembolic, 4.0% and 4.9%; and mortality, 0.7% and 0.4%, respectively. In multivariable-adjusted logistic regression analyses, ASA class III-IV (OR 6.1, 95% CI:1.6-22.8) and higher Deyo-Charlson comorbidity score (OR 1.2, 95% CI:1.0-1.4) were significantly associated with odds of 90-day cardiac event post-THA in patients with no known previous cardiac event. In those with known previous cardiac disease, ASA class III-IV (OR 4.4, 95% CI:2.0-9.9), male gender (OR 0.5, 95% CI:0.3-0.9) and history of thromboembolic disease (OR 3.2; 95% CI:1.4-7.0) were significantly associated with odds of cardiac complication 90 days post-THA. No significant predictors of thromboembolism were found in THA patients. In TKA patients with no previous cardiac history, age >65 years (OR 4.1, 95% CI:1.2-14.0) and in TKA patients with known cardiac disease, ASA class III-IV (OR 3.2, 95% CI:1.8-5.7) was significantly associated with odds of 90-day cardiac events. In TKA patients with no previous thromboembolic disease, male gender (OR 0.5, 95% CI:0.2-0.9) and higher Charlson index (OR 1.2, 95% CI:1.1-1.3) and in patients with known thromboembolic disease, higher Charlson index score (OR 1.2, 95% CI:1.1-1.4) was associated with odds of 90-day thromboembolic events.

CONCLUSION

Older age, higher comorbidity, higher ASA class and previous history of cardiac/thromboembolic disease were associated with an increased risk.

Incidence of symptomatic venous thromboembolism in oncologic patients undergoing lower-extremity endoprosthetic arthroplasty

BACKGROUND

As both cancer and major orthopaedic surgery are risk factors for venous thromboembolism, patients undergoing lower-extremity oncologic endoprosthetic arthroplasty for neoplastic processes are at substantial risk of the development of symptomatic venous thromboembolism. Therefore, the primary purpose of this study was to determine the incidence of symptomatic venous thromboembolism in patients undergoing lower-extremity oncologic endoprosthetic arthroplasty. Secondary purposes were to assess whether chemoprophylaxis influenced the incidence of venous thromboembolism, surgical complications, or the incidence of local sarcoma recurrence. We also sought to determine whether any known risk factors for venous thromboembolism could be identified in this patient population.

METHODS

We performed a retrospective comparative review of 423 patients who had undergone mega-endoprosthetic reconstruction following cancer resection. Univariate analysis was used to assess the association between chemoprophylaxis and the incidence of venous thromboembolism, to postulate the surgical complications associated with chemoprophylaxis, and to assess the rate of recurrence of local sarcoma as well the association between risk factors and venous thromboembolism.

RESULTS

Seventeen patients (4.0%) (95% confidence interval: 2.5% to 6.3%) had a venous thromboembolic event, ten with deep venous thrombosis and seven with nonfatal pulmonary embolism. Risk factors and chemoprophylactic regimens were not statistically associated with the occurrence of venous thromboembolism.

CONCLUSIONS

The incidence of symptomatic venous thromboembolism in our group of cancer patients who underwent lower-extremity endoprosthetic arthroplasty was lower than anticipated. A significant difference was not identified between the use of any or no chemoprophylactic agent and the incidence of venous thromboembolism or complication rates. No risk factors were associated with the incidence of symptomatic venous thromboembolism.

Is deep vein thrombosis a good proxy for pulmonary embolus?

It is assumed that prevention of deep venous thrombosis (DVT) is likely to lead to a reduction in the incidence of pulmonary embolus (PE). This study examines the association between symptomatic DVT and PE in patients undergoing orthopedic procedures. We reviewed medical records of 1495 patients who underwent evaluation for DVT or PE within 90 days of an index orthopedic procedure at our institution between 2004 and 2008. Only 27 cases were positive for both DVT and PE (1.7% of the total cohort, 10.8% of cases scanned for both DVT and PE). Tests of association, performed across the entire cohort and within specific subsets of patients, did not demonstrate that patients were more likely to have both DVT and PE than to have either DVT or PE. The high association between DVT and PE that is assumed to exist does not seem to hold true for orthopedic surgery patients.

Comparison of ACCP and AAOS guidelines for VTE prophylaxis after total hip and total knee arthroplasty

Orthopedists have expressed concerns regarding the utility for and applicability to their practices of guidelines from the American College of Chest Physicians (ACCP) for thromboprophylaxis in the settings of total hip and total knee arthroplasty (THA and TKA, respectively). These concerns include the acceptance by the ACCP of venographically assessed asymptomatic deep venous thrombosis as a meaningful clinical trial endpoint and a potential underestimation by the ACCP of the true risk of major bleeding and wound complication in unselected patient populations outside carefully controlled clinical trials. Because symptomatic pulmonary embolism is rare after THA and TKA, the American Academy of Orthopaedic Surgeons has developed a clinical practice guideline focused on preventing this complication while minimizing the risk of bleeding due to pharmacologic prophylaxis. These guidelines are reviewed here.

Multimodal pain management after total hip and knee arthroplasty at the Ranawat Orthopaedic Center

Improvements in pain management techniques in the last decade have had a major impact on the practice of total hip and knee arthroplasty (THA and TKA). Although there are a number of treatment options for postoperative pain, a gold standard has not been established. However, there appears to be a shift towards multimodal approaches using regional anesthesia to minimize narcotic consumption and to avoid narcotic-related side effects. Over the last 10 years, we have used intravenous patient-controlled analgesia (PCA), femoral nerve block (FNB), and continuous epidural infusions for 24 and 48 hours with and without FNB. Unfortunately, all of these techniques had shortcomings, not the least of which was suboptimal pain control and unwanted side effects. Our practice has currently evolved to using a multimodal protocol that emphasizes local periarticular injections while minimizing the use of parenteral narcotics. Multimodal protocols after THA and TKA have been a substantial advance; they provide better pain control and patient satisfaction, lower overall narcotic consumption, reduce hospital stay, and improve function while minimizing complications. Although no pain protocol is ideal, it is clear that patients should have optimum pain control after TKA and THA for enhanced satisfaction and function.

LEVEL OF EVIDENCE

Level V, expert opinion. See the Guidelines for Authors for a complete description of levels of evidence.

Deep vein thrombosis after reconstructive shoulder arthroplasty: a prospective observational study

This clinical study was performed to document the prevalence of deep vein thrombosis (DVT) after prosthetic shoulder replacement surgery. We prospectively followed 100 consecutive shoulder arthroplasty procedures (total shoulder replacement in 73 and hemiarthroplasty in 27) in 44 male and 56 female patients for 12 weeks (mean age, 67 years; range, 17-88 years). Risk factors for venous thromboembolic disease were assessed preoperatively and postoperatively. A 4-limb surveillance color flow Doppler ultrasound was performed at 2 days (100 patients) and 12 weeks (50 patients randomly selected) after surgery, and the presence and location of DVT were recorded. Postoperative symptomatic or fatal pulmonary emboli (PE) were also recorded. The overall prevalence of DVT was 13.0%, consisting of 13 DVTs in 12 patients. These included 6 ipsilateral and no contralateral upper extremity DVTs and 5 ipsilateral and 2 contralateral lower extremity DVTs. The prevalence of DVT was 10.0% (10/100) at day 2 after surgery and 6.0% (3/50) at week 12 after surgery. The incidence of symptomatic nonfatal PE was 2.0% (2/100), and that of fatal PE was 1.0% (1/100). Risk factors associated with venous thromboembolic disease did not reach statistical significance because of the small study population sample size. At our institution, the prevalence of DVT after reconstructive shoulder arthroplasty was 13.0%, a rate comparable to that after hip arthroplasty (10.3%) but lower than that after knee arthroplasty (27.2%). Shoulder arthroplasty surgeons should be aware of the potential risk of perioperative thromboembolic complications in both the acute and subacute postoperative periods.

Intraoperative embolism and hip arthroplasty: intraoperative transesophageal echocardiographic study

OBJECTIVES

Cardiopulmonary complications are well known in orthopaedic surgery. The aim of the present study was to evaluate the relevance and the origin of embolization, to correlate the event with the procedure and to establish the clinical relevance of this phenomenon.

METHODS

We performed transesophageal echocardiography (TEE) on 40 patients during total hip arthroplasty, 19 males and 21 females, average age 66 years, with a negative medical history for heart and lung diseases, who underwent an operation for hip prosthesis (22 patients) or surgery for medial fracture (18 patients). Of these, 22 patients received a cemented prosthesis and 18 patients received an uncemented one.

RESULTS

During the placement of the acetabular and femoral components, and during the relocation of the hip joint, a snow flurry appearing in the right heart was followed by several highly echogenic and mobile emboli of various sizes.

CONCLUSIONS

Our data suggest that the presence of emboli detected by TEE in the right heart and pulmonary artery appears to derive principally from the reaming of the femoral canal and the placement of the femoral stem, particularly during the placement of cemented prostheses. However, the passage of embolic material had no adverse sequelae. For these reasons routine, intraoperative TEE cannot be recommended in orthopaedic surgery.

Multimodal thromboprophylaxis following primary hip arthroplasty

We report a retrospective review of the incidence of venous thromboembolism in 463 consecutive patients who underwent primary total hip arthroplasty (487 procedures). Treatment included both total hip replacement and hip resurfacing, and the patients were managed without anticoagulants. The thromboprophylaxis regimen included an antiplatelet agent, generally aspirin, hypotensive epidural anaesthesia, elastic compression stockings and early mobilisation. In 258 of these procedures (244 patients) performed in 2005 (cohort A) mechanical compression devices were not used, whereas in 229 (219 patients) performed during 2006 (cohort B) bilateral intermittent pneumatic calf compression was used.

All operations were performed through a posterior mini-incision approach. Patients who required anticoagulation for pre-existing medical problems and those undergoing revision arthroplasty were excluded. Doppler ultrasonographic screening for deep-vein thrombosis was performed in all patients between the fourth and sixth post-operative days. All patients were reviewed at a follow-up clinic six to ten weeks after the operation. In addition, reponse to a questionnaire was obtained at the end of 12 weeks post-operatively.

No symptomatic calf or above-knee deep-vein thrombosis or pulmonary embolism occurred. In 25 patients in cohort A (10.2%) and in ten patients in cohort B (4.6%) asymptomatic calf deep-vein thromboses were detected ultrasonographically. This difference was statistically significant (p = 0.03). The regimen followed by cohort B offers the prospect of a low incidence of venous thromboembolism without subjecting patients to the higher risk of bleeding associated with anticoagulant use.

Multimodal thromboprophylaxis for total hip and knee arthroplasty based on risk assessment

BACKGROUND

Orthopaedic surgeons are increasingly challenged to find a prophylaxis regimen that protects patients from thromboembolism while minimizing adverse clinical outcomes such as bleeding. We used a multimodal approach in which the treatment regimen is selected according to patient risk factors.

METHODS

We retrospectively reviewed the records on 1179 consecutive total joint arthroplasties in 970 patients who had undergone primary and revision total hip and total knee replacement. Preoperatively, patients were assigned to one of two deep venous thrombosis prophylactic regimens on the basis of an assessment of their risk factors. Eight hundred and fifty-six patients (1046 operations) were considered to be low risk and were managed with aspirin, dipyridamole, or clopidogrel bisulfate as well as intermittent pneumatic calf compression devices. One hundred and fourteen patients (133 operations) were considered to be high risk and were managed with low-molecular-weight heparin or warfarin and intermittent calf compression. All patients were mobilized from bed within twenty-four hours after surgery, and all underwent Doppler ultrasonography within the twenty-four hours before hospital discharge. All of the patients were followed for six months postoperatively. The prevalence of asymptomatic and symptomatic distal and proximal deep venous thrombosis, symptomatic and fatal pulmonary emboli, overall mortality, and bleeding complications was determined. Thrombotic events were expressed as a percentage of 1179 operations because some patients had two or more operations.

RESULTS

Overall, there were no fatal pulmonary emboli, three symptomatic pulmonary emboli (prevalence, 0.25%), and five clinically symptomatic deep venous thrombi (0.4%). Sixty-one asymptomatic deep venous thrombi (5.2%) were found with use of routine postoperative Doppler ultrasound scans. There were three deaths (prevalence, 0.25%) that were unrelated to thromboembolism, and there were two nonfatal gastrointestinal bleeding events (prevalence, 0.17%). Wound hematomas occurred in association with five (0.4%) of the 1179 operations. Three nonfatal pulmonary emboli (prevalence, 0.3%) were detected in association with the 1046 procedures in the low-risk group, and none were detected in association with the 133 operations in the high-risk group (p = 0.767). Clinically symptomatic deep venous thrombosis was detected in association with four (0.38%) of the 1046 operations in the low-risk group and one (0.75%) of the 133 operations in the high-risk group (p = 0.93). Asymptomatic distal deep venous thrombosis was detected in association with thirty-seven (3.5%) of the 1046 procedures in the low-risk group and four (3.0%) of the 133 operations in the high-risk group. Asymptomatic proximal thrombosis was detected in association with fourteen (1.3%) of the 1046 procedures in the low-risk group and six (4.5%) of the 133 procedures in the high-risk group (p = 0.03). Wound hematomas occurred only in patients being managed with warfarin or low-modular-weight heparin (p = 0.0001).

CONCLUSIONS

A multimodal thromboembolic prophylactic regimen is consistent with protecting patients while limiting adverse clinical outcomes secondary to thromboembolic, vascular, and bleeding complications.

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

We evaluated 136 hips (104 patients) to determine the prevalence of and contributing factors in deep vein thrombosis (DVT) and pulmonary embolism (PE) in those who were not given thromboprophylaxis when undergoing primary cementless total hip arthroplasty (THA). We performed coagulation assays, a full blood count, blood typing, and serum chemical profile tests for all patients on three separate occasions. Molecular genetic testing was performed preoperatively to detect the genetic traits involving DVT. DVT was diagnosed by roentgenographic venography, and PE was diagnosed by perfusion lung scanning. Our patients had a low prevalence of DVT and no patient had PE. Patients with bilateral THA had similar rates (p = 0.158; CI, -0.134-0.125) of venographic DVT as patients with unilateral THA (16 of 65 or 25% versus 12 of 72 or 17% respectively). We observed a relationship between DVT and factor V Leiden mutation, antithrombin-III level, and prothrombin promoter G20210A mutation. We saw no relationship between DVT and coagulation or thrombophilic data. We conclude combinations of absent thrombophilic polymorphisms with low clinical prothrombotic risk factors led to low prevalence of DVT and virtually absent PE after THA in the current series of patients, who had not received any form of prophylactic or therapeutic treatment for DVT.

[Self-active physical thrombosis prophylaxis in the patients' bed with the Phlebostep: acceptance and measurement of venous blood flow in immobilized patients]

BACKGROUND

Despite the broad use of low molecular weight heparin, deep vein thrombosis is still a relevant risk for immobilized patients in orthopedic surgery. Patients can reduce this risk by active training exercises with a muscle pump. The aim of this study was to test the acceptance and effect of a self-developed training device to accelerate venous return as well as a technical optimization. The device was installed for in-patients in orthopedic and traumatology departments.

PATIENTS AND METHODS

A simple pillow-like device was developed, which can be positioned against the foot end of the patient's bed (Phlebostep). The device gives a sound-based feedback to the patient while pushing actively against it with complete ankle flexion. A digital integrated counter device allows direct feedback to the physician and nursing staff at any time. Initial testing including duplex sonography for venous flow measurements were done on 10 orthopedic in-patients. Prior testing on 7 healthy volunteers was carried out to define the effect of various amounts of pressure on the Phlebostep on the venous blood flow. Additionally, a questionnaire on the general acceptance and user-friendliness was filled out by 84 patients who had used the Phlebostep.

RESULTS

The optimal pressure force was defined as 35 mmHg for further measurements. The venous flow measurements in the 10 postoperative patients revealed an increased venous blood flow in the affected leg by an average of 99.9%. Analysis of the questionnaire from the 84 patients showed a high degree of acceptance.

CONCLUSION

In addition to the technical feasibility, this study showed that use of the Phlebostep resulted on average in a doubling of venous return. The increase of venous flow offers an additional effective device for thrombosis prophylaxis through patient's own active movements and is clearly superior to the use of devices such as antithrombosis stockings alone. The Phlebostep found a high degree of acceptance with the patients.

Thromboembolism in patients undergoing total knee arthroplasty with epidural analgesia

We retrospectively reviewed the charts of 381 consecutive patients who underwent primary unilateral or bilateral total knee arthroplasty with regional anesthesia between 1995 and 2002. All operations in this study were performed at the Cleveland Clinic Foundation by the senior author. Calf-high intermittent pneumatic compression stockings were used in all patients, and routine ultrasound examinations were performed at an average of 3 days after surgery. We compared the early postoperative rates of venous thromboembolism between patients with indwelling epidural catheters and no chemoprophylaxis and those with spinal anesthesia combined with low-molecular-weight heparin. We found no significant difference between the 2 groups.

Low-dose warfarin coupled with lower leg compression is effective prophylaxis against thromboembolic disease after hip arthroplasty

Consecutive patients having elective total hip arthroplasty were prescribed 1 mg of warfarin for 7 days preceding surgery, variable doses while in hospital (target international normalized ratio, 1.5-2.0), and discharged to rehabilitation center or home taking 1 mg daily until 4-week to 6-week follow-up visit. Lower leg pneumatic compression was used postoperatively and elastic compression stockings after discharge. Hospital and clinic charts plus auxiliary sources were reviewed for evidence of thromboembolic diseases (TED). Of 1003 consecutive patients studied, 3 (0.3%, 95% CI 0.0-0.6%) had symptomatic TED, including 2 with deep venous thrombosis and 1 with nonfatal pulmonary embolus. Follow-up rate was 99.1%. Complications from warfarin were minimal. Very-low-dose warfarin coupled with lower leg compression is effective prophylaxis against TED after elective hip arthroplasty when prescribed as described.

The 2007 ABJS Nicolas Andry Award: three decades of clinical, basic, and applied research on thromboembolic disease after THA: rationale and clinical results of a multimodal prophylaxis protocol

Total hip arthroplasty is an operation with a high risk for venous thromboembolism. Three decades of research conducted at the Hospital for Special Surgery identified the exact timing of the thrombogenic stimulus during surgery, defined the role of magnetic resonance venography, and established the role of certain genetic and acquired predispositions. Based on these studies, we implemented a multimodal prophylaxis consisting of a series of safe preventive measures applied before, during, and immediately after surgery to reduce the risk of venous thromboembolism. If these safe preventive measures are strictly observed, postoperative pharmacologic prophylaxis does not need to be aggressive in the patient without predisposing factors who mobilizes promptly, thus diminishing the risk of bleeding associated with the use of anticoagulants and the overall cost of care. Our clinical experience with more than 5000 total hip arthroplasties performed during the last decade and closely followed prospectively for a minimum of 3 months clearly shows this multimodal prophylaxis is safe and effective resulting in a very low prevalence of thromboembolism.

Thromboembolic disease after total hip arthroplasty: who is at risk?

The strong activation of the clotting cascade that occurs during total hip arthroplasty places patients at increased risk for venous thromboembolism. The risk is higher in those patients with the following predisposing factors, listed in approximate order of importance: hip fracture; malignancy, particularly if associated with chemotherapy; antiphospholipid syndrome; immobility; history of venous thromboemholism; administration of tamoxifen; raloxifene; oral contraceptives or estrogen; morbid obesity; stroke; atherosclerosis; and an American Society of Anesthesiologists physical status classification of 3 or greater. The following risk factors are weak or controversial: advanced age; diabetes mellitus; congestive heart disease; atrial fibrillation; varicose veins; and smoking. However, 50% of patients who develop thromboembolism after total hip arthroplasty have no clinical predisposing factors. In a matched, controlled study, we defined the major genetic predispositions that increase the risk of venous thromboembolism after total hip arthroplasty: deficiency of antithrombin III (< 75%) and protein C (< 70%), and prothrombin gene mutation. Preoperative genetic screening in conjunction with the recognized clinical risk factors can help categorize postoperative venous thromboembolism risk and differentiate patients who can be protected with milder and safer prophylaxis (eg, aspirin, intermittent pneumatic compression) compared with those at higher risk who need to be anticoagulated.

The benefit of aspirin chemoprophylaxis for thromboembolism after total knee arthroplasty

The threat of thromboembolic events after total knee arthroplasty has been substantially reduced during the past decade. Currently, the risk of fatal pulmonary embolism is approximately 0.1%. This is due to a confluence of changes in our medical practices, including early mobilization, less traumatic surgery, increased use of regional anesthesia, pneumatic compression devices, and chemoprophylactic agents. Because many chemoprophylactic agents are associated with an increased risk of bleeding, we have chosen aspirin as our preferred method of chemoprophylaxis. This study seeks to determine if aspirin is as effective as newer chemoprophylactic agents as judged by the prevalence of fatal or nonfatal pulmonary embolus, readmission for deep venous thrombosis, and risk of bleeding. Aspirin was the principle chemoprophylactic agent for 3473 consecutive patients having total knee arthroplasty. All patients were followed for a minimum of 6 weeks. There were nine deaths: two from pulmonary embolism, five cardiac events, one stroke, and one fat embolism. Three cardiac-related deaths occurred in patients for whom pulmonary embolism could not definitively be ruled out. Therefore, the best case and worst case scenarios for fatal pulmonary embolism were 0.06% and 0.14%, respectively. Thirteen patients underwent reoperation for hematoma (0.4%). Therefore, we have demonstrated aspirin combined with early mobilization, regional anesthesia, foot pumps, and improved surgical techniques is safer than and equally efficacious as other chemoprophylaxis agents.

Perioperative morbidity after single-stage bilateral total hip arthroplasty: a matched control study

We asked whether the perioperative morbidity and mortality of patients having bilateral single-stage total hip arthroplasties would be increased. We retrospectively compared 400 patients who had bilateral total hip replacements with a matched group of 400 patients who had unilateral total hip replacements. Patients were matched according to age (+/- 1 year), gender, American Society of Anesthesiologists (ASA) classification, body mass index (+/- 4 kg/m), and diagnosis (osteoarthritis, 81.2%). There were no deaths in either group. The group of patients who had bilateral total hip arthroplasties had a greater number of minor complications per hip (0.34 +/- 0.6 versus 0.25 +/- 0.6) but only a trend toward an increased number of major complications per hip (0.037 +/- 0.2 versus 0.015 +/- 0.1). Patients who had bilateral total hip arthroplasties had a trend toward increased risk of dislocation (1.6%/hip versus 0.5%/hip). The patients in this group also had increased number of fat emboli syndrome per surgically treated hip (0.015 versus 0.0025). Based on a calculation per surgically treated hip, patients who had bilateral total hip arthroplasties had a similar percentage of blood transfusions (1.2 versus 0.9/hip), but more patients received allogeneic blood (23% versus 3.8%). The ASA classification was the only independent predictor for minor complications, major complications, and fat emboli syndrome. We think bilateral single-stage total hip arthroplasties have an acceptable perioperative risk for patients with ASA Class 1 or 2 physical status.

Venous thromboembolism is rare with a multimodal prophylaxis protocol after total hip arthroplasty

We evaluated the safety and efficacy of a multimodal approach for prophylaxis of thromboembolism after total hip arthroplasty, which includes preoperative discontinuation of procoagulant medication; autologous blood donation; hypotensive epidural anesthesia; intravenous administration of heparin during surgery and before femoral preparation; aspiration of intramedullary contents; pneumatic compression; knee-high elastic stockings; and early mobilization and chemoprophylaxis for 4 to 6 weeks (aspirin 83%; warfarin 17%). One thousand nine hundred forty-seven consecutive, nonselected patients (2032 total hip arthroplasties) who received this multimodal prophylaxis were observed prospectively for 3 months. The incidence of asymptomatic deep vein thrombosis assessed by ultrasound in the first 171 patients was 6.4%. The incidence of clinical deep vein thrombosis in the subsequent 1776 patients was 2.5%. Symptomatic pulmonary embolism occurred in 0.6% (12 of 1947; nine in patients receiving aspirin and three in patients receiving Coumadin), none of them fatal. One patient died of a myocardial infarct. This multimodal approach is safe and efficacious and compares favorably with those reported in the literature and with our historic controls. If these preventive measures are strictly observed during the perioperative period, postoperative chemoprophylaxis does not need to be aggressive in the patient without predisposing factors. Our low rate of deep vein thrombosis and pulmonary embolism do not support routine anticoagulation prophylaxis with drugs that increase risk of bleeding.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

The John Charnley Award: heritable thrombophilia and development of thromboembolic disease after total hip arthroplasty

We retrospectively assessed whether heritable thrombophilia-hypofibrinolysis was more common in patients developing venous thromboembolism after total hip replacement than among control patients who did not develop venous thromboembolism, as an approach to better identify causes of venous thromboembolism after total hip arthroplasty. Twenty patients with proximal deep venous thrombosis after THA and 23 patients with symptomatic pulmonary embolism were compared with 43 control patients who did not have postoperative venous thromboembolism. Five of 42 patients with venous thromboembolism (12%) and 0 of 43 control patients (0%) had antithrombin III deficiency (< 75%). Nine of 42 patients with venous thromboembolism (21%) and 2 of 43 control patients (4.7%) had protein C deficiency (< 70%). Ten of 43 patients with venous thromboembolism (9 heterozygous, 1 homozygous; 23%) and 1 of 43 control patients (heterozygous; 2%) had the prothrombin gene mutation. Patients who had venous thromboembolism after total hip arthroplasty were more likely than matched control patients to have heritable thrombophilia with antithrombin III or protein C deficiency, or homo-heterozygosity for the prothrombin gene mutation. Screening for these three tests of heritable thrombophilia before total hip arthroplasty should improve the identification of patients with a reduced risk of venous thromboembolism who may need only mild thromboprophylaxis, and of those patients with heritable thrombophilia in whom prophylaxis should be more aggressive.

LEVEL OF EVIDENCE

Prognostic study, Level II-1 (lesser-quality RCT). See the Guidelines for Authors for a complete description of levels of evidence.

Identifying Orthopedic Patients at High Risk for Venous Thromboembolism Despite Thromboprophylaxis

OBJECTIVE

To evaluate risk factors for venous thromboembolism (VTE) despite thromboprophylaxis in major orthopedic surgery patients at a tertiary care hospital.

METHODS

Charts from consecutive patients who underwent total hip replacement (THR), total knee replacement (TKR), or hip fracture surgery (HFS) [hip pinning or hemiarthroplasty] from August 1, 1999, to April 30, 2000, at a large Canadian teaching hospital were abstracted using standardized case report forms. Data were collected on patient characteristics, surgical characteristics, and thromboprophylaxis regimen. Results of tests performed for suspected VTE were documented. Associations between characteristics of interest and objectively confirmed VTE were examined in multivariate analysis.

RESULTS

Over the study period, 310 patients underwent major orthopedic surgery and received standard thromboprophylaxis with either dalteparin or enoxaparin (mean duration of prophylaxis, 7 days). Of these, 34% underwent THR, 30% underwent TKR, and 36% underwent HFS. Of 83 suspected cases of VTE, 44 cases (7 proximal and 37 distal deep venous thrombosis [DVT]); 14% of study population) were confirmed with objective testing. Multivariate analyses revealed that knee surgery (odds ratio [OR], 4.8; 95% confidence interval [CI], 2.3 to 10.1) and type of low molecular weight heparin (LMWH) [enoxaparin (more protective): OR, 0.39; 95% CI, 0.20 to 0.80] independently predicted VTE. No patient characteristics (including previous VTE, malignancy, hormonal therapy, postoperative complications) were associated with VTE.

CONCLUSION

Despite standard thromboprophylaxis, symptomatic breakthrough VTE, primarily distal DVT, developed in 14% of patients undergoing major orthopedic surgery. Factors that independently predicted VTE in our population were TKR surgery and type of LMWH. TKR patients may warrant more aggressive postoperative physiotherapy and ambulation and adjunctive prophylactic measures such as pneumatic compression. Due to the heterogeneity of different LMWH compounds, direct comparison of the effectiveness of enoxaparin with dalteparin for orthopedic prophylaxis in prospective, randomized trials seems warranted.

Thromboembolic disease prophylaxis in total hip arthroplasty

We sought to determine if using aspirin and exercise as prophylaxis against thromboembolic disease in patients having total hip arthroplasties would provide results as effective as or better than those reported in the literature using other chemical agents. One thousand eight hundred thirty-five total hip arthroplasties were done in 1585 patients using a posterior approach. Surgery was done with the patient under general anesthesia in 459 instances and regional anesthesia in 1376 instances. Graduated elastic stockings were used in 1117 instances and intermittent compression stockings were used in 718 instances. Passive exercises of the major joints of the operated extremity were done intraoperatively, and active exercises were done postoperatively. Patients received a suppository containing 10 grains of aspirin immediately after surgery and 325 mg twice a day for the length of their hospitalization. Fatal pulmonary embolism developed after two (0.10%) surgical procedures. Nonfatal pulmonary embolisms were diagnosed in 17 (0.9%) patients, and deep venous thrombosis was diagnosed in 17 (0.9%) patients. The low incidence of thromboembolic complications recorded in this series suggests that our postoperative protocol, including 325 mg of aspirin twice a day during hospitalization and exercise, is an effective and inexpensive method of prophylaxis after total hip arthroplasty.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

Deep venous thrombosis prophylaxis: better living through chemistry--in opposition

The best prophylactic regimens for thromboembolic disease continue to be debated despite years of investigation. The surgeon must balance the clinical risks and benefits. A decision depends on accurate data and our ability to balance the risks of fatal pulmonary embolism (PE) to the risk of bleeding. The current risk for fatal PE is 0.1% with most current prophylactic regimes. The risk of perioperative bleeding increases 1.8% to 5.2% with low molecular weight heparins or warfarin and generally is dose dependent. Most of the current prophylactic recommendations are based on the presence or absence of deep venous thrombosis (DVT). However, the correlation between the presence of a DVT and the risk of PE is low and inconsistent. Therefore, DVT may not be an accurate surrogate marker for the patient at risk after total joint surgery. Our experience with 2800 consecutive total knee arthroplasty patients, using aspirin as our principle agent, shows a fatal PE risk of 0.1% and a low risk of bleeding. Therefore, our current recommendation is aspirin.

The effect of intraoperative heparin administered during total hip arthroplasty on the incidence of proximal deep vein thrombosis assessed by magnetic resonance venography

Intraoperative, unfractionated heparin, administered intravenously before the femoral work, has demonstrated to be effective in reducing the strong thrombotic stimulus that occurs during total hip arthroplasty (THA) surgery. This randomized, double-blind, prospective study included only THA patients with significant comorbidities predisposing them to deep vein thrombosis (DVT). The 2 groups consisted of study patients who received a single dose of intravenous, intraoperative, unfractionated heparin and control patients who received a single dose of intravenous, intraoperative saline. Magnetic resonance venography was used as the DVT diagnostic tool. The overall prevalence of proximal femoral vein clots was 2.2% (3 of 134), whereas pelvic thrombosis was detected in 10.4% (14 of 134). This study demonstrated that pelvic thrombi may form following THA and that a single dose of intraoperative heparin does not prevent their formation, but may be effective at preventing ipsilateral femoral thrombi. This study strongly supports a multimodal approach to DVT prophylaxis following THA.

Risk factors for pulmonary emboli after total hip or knee arthroplasty

Because it is difficult to predict which patients may sustain a pulmonary embolism after total hip or knee arthroplasty, we assessed multiple thrombophilic and hypofibrinolytic parameters to identify risk factors. Twenty-nine patients who survived a known pulmonary embolism after total knee or total hip arthroplasty were matched by age, gender, race, arthritic diagnosis, procedure, and surgery date with 29 patient-controls who had a total hip or knee arthroplasty but who did not have a symptomatic known pulmonary embolism or deep vein thrombosis. Twenty-one serologic measures and five genes associated with thrombophilia, hypofibrinolysis, or both were assessed without knowledge of group assignment. All patients with pulmonary embolism had at least one abnormality of plasminogen activator inhibitor activity, dilute Russell's viper venom time, prothrombin time, or total cholesterol versus 13 of 27 (48%) control patients. Forty-seven percent of patients who experienced pulmonary embolism had at least two abnormalities of plasminogen activator inhibitor activity, dilute Russell's viper venom time, prothrombin time, or total cholesterol, versus 7% of control patients. Preoperatively, to identify patients at high risk of pulmonary embolism, plasminogen activator inhibitor activity, dilute Russell's viper venom time, prothrombin time, and cholesterol levels were most predictive. Using at least one abnormality of these four measures as a screening test to detect risk of pulmonary embolism, the test is sensitive (100%), and the predictive value of a negative test is high (100%). After additional prospective study, this may allow identification of patients at low risk (the majority of patients) in whom anticoagulation may not be required and a small group of patients at high risk for pulmonary embolism in whom prophylactic anticoagulation should be provided.

Advancements in minimally invasive total hip arthroplasty

Orthopedic surgeons have successfully performed total hip arthroplasty (THA) for more than 40 years. During this time it has continued to evolve into a more predictable and refined procedure. Minimally invasive surgery represents one of the most recent techniques to have emerged within THA. In conventional THA, the incision typically measures 20-30 cm depending on the patient. Although conventional THA affords wide exposure of the hip joint, it also leads to a predictably large blood loss and significant rehabilitation time. Minimally invasive approaches, defined as less invasive to the skin, muscles, or bone, may reduce complications and potentially improve recovery time. Minimizing the recovery process is becoming increasingly desirable in a society that demands an individual to return to normal activities after a short recovery. There are a number of potential approaches and methods that may improve the results of THA. Complications of minimally invasive surgery may include sciatic or femoral nerve palsy, component malpositioning, intraoperative fracture, leg length discrepancy, and damage to muscles or skin by excessive retraction.

Incidence rates of dislocation, pulmonary embolism, and deep infection during the first six months after elective total hip replacement

BACKGROUND

The lengths of acute hospital stays following total hip replacement have diminished substantially in recent years. As a result, a greater proportion of complications occurs following discharge. Data on the incidence trends of major complications of total hip replacement would facilitate recognition and management of these adverse events.

METHODS

We used Medicare claims data on beneficiaries sixty-five years and older who had had elective, primary total hip replacement for a reason other than a fracture (58,521 patients) or had had revision total hip replacement (12,956 patients) between July 1, 1995, and June 30, 1996. We calculated incidence rates of dislocation, pulmonary embolism, and deep hip infection per 10,000 person-weeks for four time-periods following the admission for the surgery (during the index hospitalization, from discharge to four weeks postoperatively, from five to thirteen weeks postoperatively, and from fourteen to twenty-six weeks postoperatively). We then used life-table methods to estimate the cumulative incidence of each complication over the first six postoperative months.

RESULTS

Of the patients who had had a primary total hip replacement, 3.9% had a dislocation, 0.9% had a pulmonary embolism, and 0.2% had a deep infection in the first twenty-six postoperative weeks. In the revision total hip replacement cohort, the proportions with dislocation, pulmonary embolism, and deep infection were 14.4%, 0.8%, and 1.1%, respectively. The rates of these adverse outcomes were highest during the index hospitalization, diminished considerably in the period from discharge to four weeks postoperatively, and continued to drop in the periods from five to thirteen and fourteen to twenty-six weeks postoperatively.

CONCLUSIONS

The incidence rates of dislocation, pulmonary embolism, and deep infection are highest immediately after total hip replacement, but they continue to be elevated throughout the first three postoperative months. With the lengths of hospital stays continuing to diminish, an increasing proportion of complications will occur in outpatients. These findings provide a basis for developing strategies to prevent these complications in the postdischarge management of patients who have had elective total hip replacement.

LEVEL OF EVIDENCE

Prognostic study, Level II-1 (retrospective study). See p. 2 for complete description of levels of evidence.

Correlation of thrombophilia and hypofibrinolysis with pulmonary embolism following total hip arthroplasty: an analysis of genetic factors

BACKGROUND

The increased thromboembolic risk associated with total hip arthroplasty is multifactorial. We assessed whether the prevalence of abnormalities shown by newer genetic screening tests for thrombophilia and hypofibrinolysis was higher in patients in whom pulmonary embolism had developed after total hip arthroplasty than it was in matched control patients.

METHODS

Fourteen patients with documented pulmonary embolism after total hip arthroplasty and fourteen matched control patients who had undergone total hip arthroplasty without any clinical indication of thromboembolism were evaluated for risks of thrombophilia and hypofibrinolysis. Functional tests of hemostasis included evaluations of prothrombin time; activated partial thromboplastin time; levels of fibrinogen, serum homocysteine, protein C and S, and antithrombin III; activated protein-C resistance; and dilute Russell viper venom time. Molecular genetic testing was performed for factor-V Leiden, prothrombin promoter G20210A, methylenetetrahydrofolate reductase C677T, plasminogen activator inhibitor-1 4G/4G, and platelet glycoprotein IIb/IIIa A1/A2 or A2/A2 mutations.

RESULTS

The total number of genetic thrombophilic abnormalities identified was higher in the pulmonary embolism group (twenty-four abnormalities) than in the control group (fifteen abnormalities). Only patients with pulmonary embolism were found to have heterozygosity or homozygosity for the prothrombin G20210A mutation (four of fourteen patients; p = 0.05 compared with the control group) and a decreased antithrombin-III level (three of thirteen patients; p = 0.10 compared with the control group). Patients with pulmonary embolism were much more likely than control patients to have at least one thrombophilic abnormality: seven of fourteen patients with pulmonary embolism had a low antithrombin-III level or the prothrombin G20210A gene mutation compared with none of the fourteen in the control group (Fisher exact test, p < 0.01). The presence of the prothrombin G20210A gene mutation was significantly correlated with pulmonary embolism (r = 0.41, p = 0.03), as was the presence of least one abnormality (a low antithrombin-III level or the presence of the prothrombin G20210A gene mutation) (r = 0.58, p = 0.001).

CONCLUSIONS

Genetic thrombophilia and hypofibrinolysis were more frequent in patients who had had pulmonary embolism after total hip arthroplasty than in those who had not. The presence of multiple genetic thrombophilic polymorphisms, particularly prothrombin G20210A and antithrombin III, rather than any single genetic prothrombotic abnormality, appears to signal an increased thromboembolic risk in patients undergoing total hip arthroplasty. Future refinements and availability of these tests will likely allow preoperative identification of patients with an increased genetic predisposition for thromboembolism.