Magnetic resonance venography to evaluate the deep venous system of the pelvis in patients who have an acetabular fracture

A prophylactic TXA administration effectively reduces the risk of intraoperative bleeding during open management of pelvic and acetabular fractures

This study aimed to evaluate the efficacy of perioperative intravenous TXA in reducing blood loss in pelvic and acetabular fracture patients managed surgically. The study included 306 consecutive patients, divided as: group I, 157 patients who did not receive perioperative infusion of TXA and group II, 149 patients who received perioperative TXA. The perioperative blood test results and complication rates were compared between the two groups. The average perioperative hematocrit was higher during the preoperative period than during the first, second and third postoperative day in both groups. In the estimated blood loss between the two groups, there was a significant difference of 1391 (± 167.49) ml in group I and 725 (± 403.31) ml in group II respectively (p = 0.02). No significant difference was seen in the total of intraoperative transfusion units as well as in the total units of blood transfused. There was a reduced level of postoperative hemoglobin (9.28 ± 17.88 g/dl in group I and 10.06 ± 27.57 g/dl in group II compared to the values obtained in preoperative investigations (10.4 ± 2.37 g/dl in group I and 11.4 ± 2.08 g/dl in group II); with a significant difference in postoperative transfusion rates (p = 0.03). Therefore, the use of TXA effectively reduces the risk of intraoperative bleeding during open management of pelvic and acetabular fractures.

Corona Mortise- anatomical variants and implications in pelvic-acetabular surgery: An evidence based review

Background

Corona Mortise is the name given to the anastomotic vessels forming a communication between external and internal iliac vascular systems. These channels have a high tendency to cause uncontrollable bleeding if injured and are particularly at risk during the anterior approach to acetabulum. While previous studies have described them as arterial or venous connections or both, there is still a lack of consensus regarding exact nature and location of these vessels, which make their timely identification all the more challenging.

Objective

The present review is aimed at performing a comprehensive review of existing literature and discuss the anatomy and implications of correct identification of Corona Mortise in pelvic-acetabular surgery.

Conclusion

Corona Mortise is more commonly venous than arterial. This not only makes haemorrhage control more challenging but also precludes the use of pre-operative angiography. However, most authors do not recommend a change in surgical approach for fear of damaging these vessels.

Thromboembolic events in pelvic and acetabulum fractures: a systematic review of the current literature on incidence, screening, and thromboprophylaxis

PURPOSE

Rates of venous thromboembolic events (VTEs) as high as 41% deep vein thrombosis (DVT) were reported in association with pelvic and acetabular fractures (PAFs). There is no clear consensus on VTE prophylaxis for PAFs. Extracting evidence-based guidelines is key to overcome this challenging complication. The aims of this review are (A) to highlight the incidence of VTEs in PAFs, (B) to examine the screening and prophylaxis methods available in the current literature, and (C) direct future creation of a best practice protocol to reduce the risk of VTE in PAFs.

METHODS

We performed a systematic search of Medline, EMBASE databases, and the Cochrane library. MESH terms were used to identify studies pertinent to VTE in PAFs, including incidence, prophylaxis, and screening.

RESULTS

In total, 28 studies were identified and grouped into four categories including incidence, screening, prophylaxis, and the use of inferior vena cava filters (IVCFs). Incidence of VTE ranged from 0.21 to 41% for DVT and 0 to 21.7% for PE. Nine studies screened 1360 patients using different imaging modalities. Ten articles, 2836 patients, examined different thromboprophylaxis protocols. Two out of three studies investigating the use of IVCF showed significant reduction of the rates of PE.

CONCLUSION

Incidence of VTE in PAF varies significantly with different protocols. The current literature shows that screening is still controversial. The combination of chemical and mechanical prophylaxis starting at 24 hours from the injury would provide the best protection. Guidelines were extracted; however, higher level multicenter studies are still required to guide future protocols.

Incidence and risk factors of preoperative deep venous thrombosis following pelvic and acetabular fractures: a retrospective case–control study

The objective of this study was to investigate the prevalence of preoperative deep venous thrombosis (DVT) in the pelvic cavity and lower extremities following pelvic and acetabular fractures and to identify the risk factors of the occurrence of DVT. Duplex ultrasound (DUS) screening and blood tests were conducted in patients admitted from June 2012 to December 2020 for surgical treatment of pelvic and acetabular fractures. Univariate analyses were performed on data of demographics, comorbidities, time from injury to surgery, injury mechanism, accompanied injury, and laboratory results. The optimal cutoff values of continuous variables with statistical significance were obtained by using the receiver operating characteristic (ROC) curve. A multivariate logistic regression analysis was then employed to examine the independent values in terms of predicting preoperative DVT. A total of 607 patients with pelvic and acetabular fractures were included, among whom 82 (13.5%) patients sustained preoperative DVTs. Specifically, 31.7% (26/82) were diagnosed with proximal DVTs. Fifty-two (63.4%) patients had DVT within 7 days after injury, and 67 (81.7%) patients within 10 days. The multivariate logistic regression analysis identified 6 factors independently associated with the presence of preoperative DVT, including age > 46 years (odds ratio [OR] = 2.94), BMI > 26.73 kg/m2 (OR = 3.91), time from injury to surgery > 9 days (OR = 5.39), associated injury (OR = 7.85), ALB < 32.8 g/L (OR = 2.71) and FIB > 3.095 g/L (OR = 3.34). Despite the modern prophylactic regimen, the preoperative DVT in patients with pelvic and acetabular fractures still draws the attention of orthopaedic surgeons. Better understanding these risk factors can help surgeons refine the risk stratification profile and perform early interdisciplinary management for patients at high risk of DVT.

Assessment of deep vein thrombosis using routine pre- and postoperative duplex Doppler ultrasound in patients with pelvic trauma : a prospective study

AIMS

The aims of this study were to assess the pre- and postoperative incidence of deep vein thrombosis (DVT) using routine duplex Doppler ultrasound (DUS), to assess the incidence of pulmonary embolism (PE) using CT angiography, and to identify the factors that predict postoperative DVT in patients with a pelvic and/or acetabular fracture.

METHODS

All patients treated surgically for a pelvic and/or acetabular fracture between October 2016 and January 2020 were enrolled into this prospective single-centre study. The demographic, medical, and surgical details of the patients were recorded. DVT screening of the lower limbs was routinely performed using DUS before and at six to ten days after surgery. CT angiography was used in patients who were suspected of having PE. Age-adjusted univariate and stepwise multiple logistic regression analysis were used to determine the association between explanatory variables and postoperative DVT.

RESULTS

A total of 191 patients were included. A DVT was found preoperatively in 12 patients (6.3%), of which six were proximal. A postoperative DVT was found in 42 patients (22%), of which 27 were proximal. Eight patients (4.2%) had a PE, which was secondary to a DVT in three. None of the 12 patients in whom a vena cava filter was implanted prophylactically had a PE. Multivariate logistic regression analysis indicated that the association with the need for spinal surgery (odds ratio (OR) 19.78 (95% confidence interval (CI) 1.12 to 348.08); p = 0.041), intramedullary nailing of a long bone fracture (OR 4.44 (95% CI 1.05 to 18.86); p = 0.043), an operating time > two hours (OR 3.28 (95% CI 1.09 to 9.88); p = 0.035), and additional trauma surgery (OR 3.1 (95% CI 1.03 to 9.45); p = 0.045) were statistically the most relevant independent predictors of a postoperative DVT.

CONCLUSION

The acknowledgement of the risk factors for the development of a DVT and their weight is crucial to set a threshold for the index of suspicion for this diagnosis by medical staff. We suggest the routine use of the DUS screening for DVT in patients with a pelvic and/or acetabular fracture before and six to ten days after surgery. Cite this article: Bone Joint J 2022;104-B(2):283-289.

The efficiency and safety of intravenous tranexamic acid administration in open reduction and internal fixation of pelvic and acetabular fractures

PURPOSE

This study aimed to investigate the efficiency and safety of tranexamic acid use in open reduction and internal fixation of pelvis and acetabulum fractures.

MATERIALS AND METHODS

73 consecutive patients were included. 1000 mg TXA was administered intravenously to all patients before surgery. The patients were evaluated on the basis of preoperative, postoperative first and third day hemoglobin-hematocrit values, amount of drainage collected, total blood loss, transfusion rates and complications.

RESULTS

Mean operative time was 120.1 min. Average decrease in hematocrit levels between preoperative and postoperative first day was 2.1 g/dL. Average collected blood from the drain was 177 mL. Mean total blood loss was 1137 mL. Transfusion rate of the patients was 21%. Mean transfused units was 0.9 units. Three patients died within 3 weeks after the operation due to myocardial infarction, acute kidney failure and pneumonia. There were no cases of symptomatic venous or pulmonary thromboembolism during the 90 days of follow-up.

CONCLUSION

Use of TXA in pelvic and acetabular fractures was found to be effective in reducing total blood loss, hemoglobin drop and transfusion rates without increasing venous and pulmonary thromboembolism in our series.

Incidence of DVT and PE after surgical reconstruction for pelvic and acetabular fractures: Does routine duplex scanning affect management?

BACKGROUND

Prevention and detection of thromboembolism with pelvic and acetabular fractures remains controversial. The aim of this study was to evaluate a protocol using LMWH prophylaxis and duplex screening both pre-operatively (if there is a delay > 72 h to surgery) and post-operatively at day 5-7. We assessed the incidence of thromboembolism and associated risk factors.

METHODS

A total of 255 consecutive patients who underwent pelvic and/or acetabular reconstruction in a major trauma and tertiary referral centre between January 2013 and December 2015 were studied. Forty-three patients were excluded due to non-adherence to protocol leaving 212 patients included in the study.

RESULTS

Patients were of mean age 49 years (15-94) and mean ISS 24.5 (4-66). Pre-operative screening detected two patients with asymptomatic above-knee DVT who then underwent pre-operative IVC filter insertion. Post-operative screening detected seven patients (3%) with lower limb DVTs (3 proximal and 4 below knee). The three patients with proximal DVTs were fully anticoagulated and did not develop symptomatic PE. Six patients (2.8%) developed post-operative PE, four of which were symptomatic and confirmed by CT angiography. Seven patients (3%) died in the post-operative period due to non-VTE-related causes. The overall rate of VTE was 6%, including DVT 4% and PE 2.8%. PE was associated with administration of tranexamic acid in ED (p > 0.03) and total amount of blood transfused during admission (p > 0.001). VTE was not associated with age, injury type, ISS, delay to surgery or associated injuries.

CONCLUSION

A protocol-based approach to VTE prophylaxis and screening in trauma patients with pelvic and/or acetabular reconstruction resulted in no VTE-related mortality. Pre- and post-operative screening for DVT changed the management in five patients, with none developing PE. Patients requiring more aggressive resuscitation had a higher rate of PE. The VTE rate was lower than previously reported.

Significant Reduction of Pulmonary Embolism in Orthopaedic Trauma Patients

OBJECTIVES

To report results of a protocol to lessen incidence of pulmonary embolism (PE) among orthopaedic trauma patients.

DESIGN

Retrospective review.

SETTING

Level 1 trauma center.

PATIENT/PARTICIPANTS

Orthopaedic trauma inpatients were included in the study.

INTERVENTION

On arrival, an orthopaedic trauma patient's PE risk is calculated using a previously developed tool. If possible, patients at high risk are given their first dose of enoxaparin before leaving the emergency room. If other injuries preclude enoxaparin, then chemoprophylaxis is held for 24 hours. Twenty-four hours after arrival, the patient's ability to receive enoxaparin is reassessed. If possible, enoxaparin is started, with dosing twice a day. If enoxaparin is still contraindicated, a removable inferior vena cava filter is placed. Adequacy of enoxaparin dosing is tested using anti-factor Xa assay, drawn 4 hours after the third dose of enoxaparin. If the anti-factor Xa result is less than 0.2 IU/mL, a removable inferior vena cava filter is placed. If the result is 0.2-0.5 IU/mL, enoxaparin dosing is continued. If greater than 0.5 IU/mL, the dose of enoxaparin is reduced.

OUTCOME MEASURE

The main outcome measure was rate of PE.

RESULTS

From September 1, 2015 to December 31, 2015, our hospital admitted 420 orthopaedic trauma patients. Fifty-one patients were classed as high risk for PE. In September through December 2015, 9 sustained PE, 1 of which was fatal. From September 1, 2016 to December 31, 2016, our hospital admitted 368 orthopaedic trauma patients with comparable age and Injury Severity Score to 2015. Forty patients were at high risk for PE, 1 sustained a nonfatal PE. PE incidence from September to December 2016 was significantly lower than in 2015 (P = 0.02). Overall, 26 patients managed under the new protocol had IVCFs placed, 21 had their filters removed, and 3 died with filters in place. There were no complications during filter placement or removal. One patient had hemorrhage felt to be attributable to enoxaparin.

CONCLUSIONS

Our protocol emphasizes more robust enoxaparin dosing, and more frequent use of IVCF, but only among those at high risk. We lessened the incidence of PE, with a low complication rate.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Is there a role for antifibrinolytics in pelvic and acetabular fracture surgery?

BACKGROUND

Pelvic and acetabular fractures are rare, complex injuries associated with significant morbidity. Fixation of these injuries requires major orthopaedic surgery which in itself is associated with substantial blood loss owing to the extensile operative approach and prolonged operating time required to address the complex fracture anatomy. In order to reduce morbidity, a multifactor approach to blood conservation must be adopted.

CURRENT ROLE OF ANTIFIBRINOLYTICS IN ORTHOPAEDIC SURGERY

The use of antifibrinolytics to reduce operative blood loss is well documented in many surgical specialties, including orthopaedic surgery. Elective spinal surgery and joint arthroplasty have benefited from the introduction of antifibrinolytics; however, their role in trauma and fracture surgery is not fully defined. Pelvic and acetabular fracture surgery would benefit from further investigation on the benefit and safety of these agents.

CONCLUSION

Routine use cannot be recommended at this time but agents may be considered on a case-specific basis.

Venous Thromboembolism Prophylaxis in Orthopaedic Trauma Patients: A Survey of OTA Member Practice Patterns and OTA Expert Panel Recommendations

OBJECTIVES

First, to provide the readership with a summation of the current practice patterns of North American orthopaedic surgeons for venous thromboembolism prophylaxis after musculoskeletal trauma. Second, to establish a set of guidelines and recommendations based on the most current and best available evidence for venous thromboembolism (VTE) prophylaxis after musculoskeletal trauma.

METHODS

A 24 item questionnaire titled "OTA VTE Prophylaxis Survey" was sent to active members of the Orthopaedic Trauma Association. PubMed and OVID/MEDLINE were used to search the current published literature regarding VTE prophylaxis in trauma patients using the following search terms: deep venous thrombosis, DVT, pulmonary embolism, PE, venous thromboembolism, VTE, prophylaxis, trauma, fracture, pneumatic compression device, PCD, sequential compression device, SCD, screening, ultrasound, duplex, ultrasonography, DUS, venography, magnetic resonance venography, MRV, inferior vena cava, IVC, filter, and IVCF. Each recommendation was graded using articles that were considered by the subcommittee as "the best available evidence" using the grading system adopted and endorsed by the American Academy of Orthopedic Surgeons' Evidenced Based Quality and Value committee.

RESULTS

Overall, 185 of 1545 members completed the online survey. The range and variety of prophylaxis and screening methods used among orthopaedic trauma surgeons in North America is large, with a number of agents or methods for which no literature exists to support their use in musculoskeletal trauma. A set of recommendations and guidelines were constructed based on the results of the literature analysis and graded according to guidelines mentioned above.

CONCLUSIONS

Due to the wide variability in practice patterns, poor scientific support for various therapeutic regimens and important medical-legal implications highlighted by the survey, a standardized set of guidelines and recommendations for VTE prophylaxis after musculoskeletal trauma will be critical in helping to improve patient care and minimize surgeons' exposure to potentially litigious activity.

LEVEL OF EVIDENCE

Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

Surgical treatment for pelvic ring fractures in pediatric and adolescence age

BACKGROUND

Fractures of the pelvis in pediatric population are extremely rare. Children with complex pelvic fractures are most often pedestrians who have been struck by a motor vehicle. Head injuries are the main cause of death, unlike the adult, where severe hemorrhages are common and contribute to mortality. Long-term follow-up studies have reported significant residual morbidity in children's pelvic fractures treated non-operatively. The aim of this study is to analyze our cases in order to evaluate the final outcome and to suggest the surgical indications for the management of this kind of injuries.

MATERIALS AND METHODS

From January 2000 to July 2011, eight pediatric patients were surgically treated for pelvic ring fractures in our department. The functional result at follow-up was evaluated using the functional independence measure (FIM).

RESULTS

In most cases the clinical outcome was good with functional recovery of the hip and complete resumption of physical activity. The mean FIM score was 125.3. One patient underwent permanent colostomy for perineal lacerations, one case showed a slight scoliosis at follow-up, and one patient showed the early fusion of the triradiate cartilage. One patient presented a deep thrombosis of the common femoral vein.

CONCLUSIONS

Fractures of the pelvic ring should be carefully assessed by radiographs and CT scan. The centralization of these young patients is important to get the experience and ensure the proper treatment. A correct indication for surgery may prevent or limit the consequences of these complex fractures.

Incidence of venous thromboembolism in fractures around and below the knee with physical prophylaxis

Fractures occurring at the distal part of the lower extremities are recognized to have a relatively lower risk of venous thromboembolism (VTE); however, few detailed reports exist on the subject. The purpose of this study was to investigate the incidence of VTE in fractures around and below the knee. Overall, 109 consecutive patients with fractures around and below the knee who were surgically treated at the authors' hospital were analyzed retrospectively. Physical prophylaxis was performed in all patients. Until April 2009, VTE screening was performed by contrast-enhanced computed tomography or ultrasonography when the D-dimer value did not decline predictably, exceeded 20 μg/mL 5 days after trauma and surgery, or increased above 20 μg/mL after a period of decline. After April 2009, ultrasonography was routinely performed pre- and postoperatively irrespective of the D-dimer value. The patients were divided into 2 groups based on the absence or presence of accompanying injuries, including head, chest, abdominal, or spinal injury and other fractures of the pelvis and lower extremities. Overall, VTE and pulmonary thromboembolism were detected in 28 (25.7%) patients and 5 (4.6%) patients, respectively. All cases were asymptomatic. The VTE incidence rates were 8.6% (former screening) and 40% (newer screening) in patients with isolated fractures and 25% (former screening) and 41.7% (newer screening) in patients with accompanying injuries. The pulmonary thromboembolism incidence rates were 2.9% (former screening) and 0% (newer screening) in patients with isolated fractures and 3.2% (former screening) and 25.0% (newer screening) in patients with accompanying injuries. Surgeons should be vigilant for symptoms of VTE in patients with fractures occurring at the distal part of the lower extremities.

Venous thromboembolism in Japanese patients with fractures of the pelvis and/or lower extremities using physical prophylaxis alone

PURPOSE

To investigate the rate of venous thromboembolism (VTE) in Japanese patients with fractures of the pelvis and/or lower extremities using physical prophylaxis alone.

METHODS

Records of 66 men and 60 women aged 15 to 95 (mean, 57) years with fractures of the pelvis and/ or lower extremities were retrospectively reviewed. They were screened for VTE based on D-dimer values. Contrast-enhanced computed tomography and/or ultrasonography were performed when the D-dimer value did not decline predictably or exceeded 20 μg/ml even 5 days after injury or surgery. Physical prophylaxis for VTE in terms of graduated compression stockings and intermittent pneumatic compression were applied for all patients.

RESULTS

Of the 126 patients, 24 were detected to have VTE (10 of 29 with multiple fractures and 14 of 97 with single fractures). Six patients were detected to have asymptomatic pulmonary thromboembolism (PTE), whereas 20 patients were detected to have deep vein thrombosis (bilaterally in 7). The rates of VTE were high in patients with multiple fractures (35%), pelvic fractures (18%), and femoral shaft fractures (50%). The rate of PTE was high in patients with pelvic fractures (12%).

CONCLUSION

The rate of VTE in the Japanese patients was similar to that in western populations. Our screening method was useful for preventing fatal PTEs. Surgeons should be vigilant for VTE during the first 2 weeks after injury, especially in patients with multiple and pelvic fractures.

Sequential duplex ultrasound screening for proximal deep venous thrombosis in asymptomatic patients with acetabular and pelvic fractures treated operatively

BACKGROUND

Recent evidence-based practice guidelines recommend against routine ultrasound screening for proximal deep vein thrombosis (DVT) in asymptomatic pelvic fracture patients. However, the majority of trauma surgeons favor this practice. Furthermore, the timing of screening has been inconsistently described. The purpose of this study was to examine the utility of sequential scans in asymptomatic acetabular and pelvic fracture patients treated operatively.

METHODS

In 2003, a screening protocol for DVT was begun for asymptomatic patients with these fractures treated operatively. Duplex ultrasound screening was used to evaluate the lower extremities for proximal DVT. Scans were to be obtained preoperatively and then postoperatively on the day before planned discharge from the hospital. A DVT prophylaxis protocol was also instituted. Between 2003 and 2007, 343 patients were identified for study. Patients were followed for thromboembolic complications for a minimum of 3 months.

RESULTS

Two hundred twenty-nine patients received both preoperative and postoperative scans. Of these, 35 patients (15%) had an asymptomatic DVT: 16 (7%) preoperatively and 19 (8%) postoperatively. Two patients (1%) with negative scans had a postoperative symptomatic pulmonary embolism (PE) diagnosed the day after surgery, but fatal PE did not occur. In the remaining 114 patients, 27 received a prophylactic inferior vena cava filter, 6 had a preoperative symptomatic DVT or PE before scanning, 25 received only the postoperative scan (3 being positive), and 56 were not scanned postoperatively. Of the 56 not scanned postoperatively, 2 (4%) were readmitted with a symptomatic proximal DVT but none for PE, and a fatal PE did not occur.

CONCLUSIONS

Despite the possible diagnostic utility of sequential duplex ultrasound screening, it does not decrease the risk of PE in acetabular and pelvic fracture patients.

LEVEL OF EVIDENCE

IV.

The natural history of pelvic vein thrombosis on magnetic resonance venography after vaginal delivery

OBJECTIVE

Venous thromboembolism constitutes the leading cause of direct maternal mortality in the developed world. To date, there are no studies using magnetic resonance venography (MRV) to delineate the incidence and natural history of intraluminal filling defects in the postpartum period in patients with low thrombosis risk.

STUDY DESIGN

This was a prospective cohort study of women at low thrombosis risk postvaginal delivery undergoing MRV in the early postpartum period.

RESULTS

In 30 eligible and consenting participants, independently adjudicated MRV, conducted on a median of postpartum day 1, identified definite thrombosis in 30% (95% confidence interval [CI], 13.6-46.4%) of study participants. All episodes of definite thrombosis were identified in the iliac and ovarian veins. Probable thrombosis was identified in an additional 27% of study participants (95% CI, 10.3-41.7%), and possible thrombosis in an additional 10% (95% CI, 0-20.7%).

CONCLUSION

In this group of low-risk postpartum patients, we identified a high prevalence of definite pelvic vein intraluminal filling defects of uncertain clinical significance. This study suggests that some degree of pelvic vein intraluminal filling defect may be a normal finding after uncomplicated vaginal delivery.

Thrombo-prophylaxis in pelvic and acetabular trauma patients: a UK consensus?

AIMS

The incidence of deep vein thrombosis, non-fatal pulmonary embolism and fatal pulmonary embolism may be as high as 61%, 10% and 2%, respectively, in patients with pelvic and acetabular injuries. A survey of the pelvic and acetabular units across the United Kingdom was performed to ascertain the thrombo-prophylaxis policy for these patients. In particular, questions were asked about different regimes on post-operative patients, conservatively managed patients and those simply discussed over the telephone. We enquired about their known rates of DVT and PE and their methods of data collection.

METHODS

Postal questionnaires were sent to 22 pelvic and acetabular trauma centres around the United Kingdom.

RESULTS

Replies from 18 units were received in which a total of 837 operations are performed per year. Forty-five percent of pelvic and acetabular units do not routinely prescribe chemical prophylaxis for post-operative patients and 56% do not prescribe prophylaxis for conservatively managed patients. The policy of the remaining units showed no consistency in duration or agent. Fifty-three percent of units use a database to collect information related to the numbers of patients operated up on. Forty-seven percent have no defined method for collecting DVT and PE numbers. For this reason, reported rates of proximal DVT, non-fatal PE and fatal PE were below that expected at 2.5%, 0.8% and 0.1%, respectively.

CONCLUSIONS

Despite high rates of thrombo-embolic complications in patients with pelvic and acetabular injuries there is no UK consensus on prescribing prophylaxis.

Is routine thromboprophylaxis justified among Indian patients sustaining major orthopedic trauma? A systematic review

Venous thromboembolism (VTE) is one of the most common preventable cause of morbidity and mortality after trauma. Though most of the western countries have their guidelines for thromboprophylaxis in these patients, India still does not have these. The increasing detection of VTE among Indian population, lack of awareness, underestimation of the risk, and fear of bleeding complications after chemical prophylaxis have made deep vein thrombosis (DVT) a serious problem, hence a standard guideline for thromboprophylaxis after trauma is essential. The present review article discusses the incidence of DVT and role of thromboprophylaxis in Indian patients who have sustained major orthopedic trauma. A thorough search of 'PubMed' and 'Google Scholar' revealed 10 studies regarding venous thromboembolism in Indian patients after major orthopedic trauma surgery (hip or proximal femur fracture and spine injury). Most of these studies have evaluated venous thromboembolism in patients of arthroplasty and trauma. The incidence, risk factors, diagnosis and management of VTE in the subgroup of trauma patients (1049 patients) were separately evaluated after segregating them from the arthroplasty patients. Except two studies, which were based on spinal injury, all other studies recommended screening/ thromboprophylaxis in posttraumatic conditions in the Indian population. Color Doppler was used as common diagnostic or screening tool in most of the studies (eight studies, 722 patients). The incidence of VTE among thromboprophylaxis-receiving group was found to be 8% (10/125), whereas it was much higher (14.49%, 40/276) in patients not receiving any form of prophylaxis. Indian patients have definite risk of venous thromboembolism after major orthopedic trauma (except spinal injury), and thromboprophylaxis either by chemical or mechanical methods seems to be justified in them.

Thromboprophylaxis following major skeletal trauma: a systematic review

PURPOSE

Venous thromboembolic disease following skeletal polytrauma is a major issue for trauma surgeons, but there is no consensus of opinion regarding the optimal form of prophylaxis. The purpose of this paper was to compare the incidence of venous thromboembolic events (VTE) after major skeletal trauma managed with different prophylactic methods and their combinations.

METHODS

A search of AMED, CINAHL, Cochrane Library, EMBASE and MEDLINE databases was performed from their inception to July 2010. A search of unpublished literature databases was undertaken. All randomised controlled trials assessing the incidence of VTE events between two or more forms of thromboprophylaxis for patient following major skeletal trauma were included. Two reviewers independently identified all eligible articles, extracted the data, and critically appraised all included publications using the Critical Appraisal Skills Programme tool.

RESULTS

A total of 11 papers were identified. The findings of this study suggest that low molecular weight heparin (LMWH) may be superior to low dose heparin (LDH), and that LMWH should be used in addition to mechanical prophylaxis measures in patients following major skeletal trauma. There is limited evidence for the use of electrostimulation. There appeared to be no significant difference between the use of LDH compared to calf compression devices. However, the evidence-base was insufficient in both size and methodological quality.

CONCLUSIONS

There is currently insufficient research to be able to inform trauma surgeons as to the optimal method of thromboprophylaxis for patients following major skeletal trauma.

A systematic review of thromboprophylaxis for pelvic and acetabular fractures

OBJECTIVES

Pelvic and acetabular fractures have been identified as risk factors for deep venous thrombosis (DVT) and thromboembolic complications. A systematic review was performed to evaluate the effectiveness of thromboprophylactic strategies to prevent DVT or pulmonary embolism (PE) after pelvic or acetabular fractures.

DATA SOURCES

Relevant articles were identified by searching MEDLINE, MEDLINE In Process & Other Non-indexed Citations, EMBASE, CENTRAL, and the Cochrane Database of Systematic Reviews. All languages and years indexed were searched.

STUDY SELECTION

Manuscripts were included if (1) the study included an intervention or strategy aimed at preventing thromboembolic disease, (2) the subjects in the study had suffered a pelvic or acetabular fracture, and (3) the primary outcome of the study was DVT or PE.

DATA EXTRACTION

The intervention, sample size, DVT, and/or PE incidence, and method of diagnosis were recorded for each study.

DATA SYNTHESIS

Eleven studies with 1760 subjects were included. Included studies were grouped into 5 types of interventions: mechanical compression devices, inferior vena cava filters, low-molecular weight heparins, ultrasound screening, and magnetic resonance venography screening. Most studies were observational designs with minimal control data for comparison. Quantitative pooling was not possible based on significant study heterogeneity.

CONCLUSIONS

Although several strategies have been used to prevent thromboembolism in pelvic and acetabular fracture patients, our results suggest that clinicians have limited data to guide their prophylactic decisions. Well-designed clinical trials to prevent and detect venous thromboembolism in pelvic and acetabular trauma are still needed.

Operative fixation of acetabular fractures in the pregnant patient

OBJECTIVE

To describe in utero radiation exposures in pregnant patients undergoing acetabular fracture repair.

DESIGN

Retrospective case series.

SETTING

University-affiliated regional trauma center.

PATIENT/PARTICIPANTS

Eight pregnant patients with acetabular fractures treated over a 6-year period. There were an additional 518 acetabular fractures in nonpregnant patients treated during the same time period.

INTERVENTION

Open reduction and internal fixation of the acetabulum fracture.

OUTCOME MEASUREMENTS

None. This is a descriptive series reporting fetal radiation doses, fetal fluoroscopy exposure times, and fetal viability after treatment.

RESULTS

The gestational age of the fetuses at presentation ranged from 5 to 26 weeks. Infant delivery averaged 27 weeks from the time of surgery and all pregnancies reached 36 weeks. Apgar scores were normal each child including 1 twin delivery. There were 4 posterior wall fractures, 3 transverse or posterior wall fractures, and 1 posterior column fracture. Intraoperative pelvic fluoroscopy averaged 39 seconds. There were no operative complications and fracture reductions were anatomic in 7 patients. Computed tomography scan of the pelvis conferred the greatest exposure risk to the fetus and fluoroscopy conferred the least. In each case that required a computed tomography scan of the pelvis, the calculated radiation exposure dose to the fetus was greater than 5 cGy.

CONCLUSIONS

The results of this study demonstrate that with a team approach and the judicious use of radiographic imaging during the surgical care of a displaced acetabular fracture in the pregnant patient, minimal risk to the baby can be achieved in pursuit of acceptable articular reductions.

Long-term consequences of pelvic trauma patients with thromboembolic disease treated with inferior vena caval filters

BACKGROUND

The use of inferior vena cava (IVC) filters for prevention of pulmonary embolism (PE) in high-risk trauma patients is well accepted. High rates of recurrent venous thrombosis, however, and postthrombotic syndrome (PTS) have been reported in nonsurgical patients with medical comorbidities. Patients with pelvic trauma and thromboembolic disease have a unique thrombogenic pathophysiology, and the long-term consequences of filter placement in these patients are unknown. We sought to evaluate the outcomes of patients who sustained pelvic trauma, and who developed venous thrombosis and were treated with a vena caval filter.

METHODS

A cohort of 102 consecutive patients was treated for a pelvic or acetabular fracture who developed deep vein thrombosis (DVT) preoperatively and had a caval filter placed. Thromboembolic events and complications were evaluated by both retrospective chart review and a prospective questionnaire. Eighty-eight patients (86%) returned the questionnaire at an average follow-up of 4 years.

RESULTS

No patients were readmitted to the hospital for recurrent venous thrombosis or PE. Six patients (7%) described new swelling in the lower extremities, and one (1%) demonstrated evidence of PTS. No deaths occurred related to PE.

CONCLUSIONS

The use of IVC filters appears to be safe and effective in preventing PE in patients with pelvic trauma and established venous thrombosis. The risk of recurrent DVT is low and PTS is negligible in these patients. Filter placement use is not associated with the same long-term complications as in patients with thrombosis because of chronic medical comorbidities.

Acetabular fractures in the 21st century

Acetabular fractures are uncommon other than in the polytrauma setting, and most orthopaedic surgeons will never develop a wide exposure to them. The early management of these injuries can have profound effects on the long term outcomes from what is often a significant injury in a young patient. We present a current review of the anatomy, classification and management guidelines for acetabular fractures, including a comprehensive review of the major decision making processes, as well as describing the most common complications and the expected outcomes.

Thromboembolic disease after combined anterior/posterior reconstruction for adult spinal deformity: a prospective cohort study using magnetic resonance venography

STUDY DESIGN

Thromboembolic disease (TED) after anterior/posterior spinal reconstructions was prospectively evaluated in 66 consecutive patients.

OBJECTIVE

Determine the incidence of TED after anterior/posterior spinal reconstruction.

SUMMARY OF BACKGROUND DATA

Few studies have examined the rate of TED after potentially high-risk combined anterior/posterior reconstructions. Magnetic resonance venography (MRV) is more effective at detecting pelvic deep venous thrombosis (DVT) than conventional screening, but has not been used in these patients.

METHODS

We undertook a prospective cohort study of 66 consecutive adult patients (mean, 52.7 +/- 9.6 years) undergoing combined anterior/posterior spinal reconstructions for spinal deformity. All patients received only mechanical DVT prophylaxis. After surgery, MRV and bilateral lower extremity Doppler ultrasounds were obtained to screen for DVT, and contrast-enhanced spiral computed tomography scans were obtained for clinical suspicion of pulmonary embolism (PE).

RESULTS

The total incidence of postoperative TED was 13.6% (9 patients). The overall rate of DVT was 9.1% (6 patients), one-third occurring in the pelvis. PE developed in 7.6% (5 patients). In 2 patients, PE developed less than 48 hours after positive dopplers. In 3 patients, PE developed despite negative screening studies. Right-sided thoracoabdominal approaches were associated with an increased risk of developing DVT (P = 0.03, Odds Ratio 9.8), PE (P = 0.01, Odds Ratio 20), and TED (P = 0.004, Odds Ratio 12).

CONCLUSION

We report a high rate of TED after extensive anterior/posterior spinal reconstructions, for which a right-sided thoracoabdominal approach is an independent risk factor and screening ineffective at preventing PE. These patients should be considered at high risk for postoperative TED.

Imaging of deep vein thrombosis

Background

Deep vein thrombosis of the leg affects 1–2 per cent of the population with an annual incidence of 0·5–1 per 1000. It presents with non-specific symptoms and signs making clinical diagnosis difficult. Techniques to image and diagnose this condition are advancing rapidly.

Methods and results

A literature review from 1980 to 2007 was undertaken using PubMed, The Cochrane Library, Medline and Embase. The most frequently used diagnostic test is duplex ultrasonography which is accurate above the knee and has a low cost, but is limited by inaccuracy when assessing the pelvic and distal veins and in diagnosing a new thrombosis in the post-thrombotic limb. Magnetic resonance imaging (MRI) and sonographic elasticity imaging are more recent techniques that have shown promise in overcoming these limitations. However, their availability is currently restricted because they are expensive. Computed tomography (CT) is sensitive, specific and provides good imaging of the pelvis. It has the advantage that it can be performed at the same time as CT pulmonary angiography.

Conclusion

MRI has some specific advantages over duplex ultrasonography, but requires refinement before it can be used clinically. Venography or CT venography should be considered when duplex scanning is inadequate.

MR venography with true fast imaging with steady-state precession for suspected lower-limb deep vein thrombosis

PURPOSE

To compare true fast imaging with steady-state precession (FISP) magnetic resonance (MR) venography for suspected deep vein thrombosis (DVT) with contrast agent-enhanced venography.

MATERIALS AND METHODS

This was a prospective study of randomly selected patients with a clinical suspicion of DVT of the lower limb. Standard contrast venography was performed and compared with MR venography from the inferior vena cava to the feet in 24 patients with use of true FISP sequences (repetition time, 3.74 msec; echo time, 1.8 msec). Two radiologists independently read the MR venography and contrast venography studies. Segment visibility, secondary signs of DVT, and additional diagnoses were noted.

RESULTS

MR venography demonstrated all venous segments in the pelvis and thigh. When results were analyzed on a per-patient basis, there was good agreement between contrast venography and MR venography (kappa = 0.64; 95% CI, 0.33-0.94; P = .0001). When the venous system was analyzed on a segmental basis, there was very good agreement between contrast venography and MR venography (kappa = 0.81; 95% CI, 0.68-0.94; P = .0001). The sensitivity and specificity for DVT detection were 100% for the iliac and popliteal segments and 100% and 98%, 68% and 94%, and 87% and 98%, respectively, for the femoral, below-knee, and all veins. Eleven of 14 patients without DVT had an alternative diagnosis suggested by MR venography.

CONCLUSIONS

MR venography with axial true FISP allows noninvasive rapid diagnosis of acute DVT in the iliac, femoral, popliteal, and calf muscle veins. MR venography is much less reliable in the tibial or peroneal veins. It may demonstrate a nonvenous cause of a patient's symptoms.

Acetabular fractures in the elderly: treatment recommendations

Acetabular fractures in the elderly population are marked by a high degree of variability in terms of patient and fracture characteristics. Successful outcomes depend on application of highly individualized management principles by experienced teams. Reviewed are indications and outcomes associated with various management options, including closed treatment, open reduction internal fixation, and acute or staged total hip arthroplasty. Proper initial management choices are critical, as early failures and subsequent salvage surgery can be accompanied by significant morbidity. Clinical results after ORIF closely follow the quality of articular reduction and the ability to maintain a congruent reduction of the hip joint. Fracture characteristics predictive of anatomic articular reduction should be treated with ORIF. Fracture characteristics predictive of early post-traumatic arthritis should be treated with simultaneous ORIF and THA. Presented is one referral institution's treatment algorithm and management approach.

The accuracy of MRI in diagnosis of suspected deep vein thrombosis: systematic review and meta-analysis

Magnetic resonance imaging (MRI) may be used to diagnose deep vein thrombosis (DVT) in patients for whom ultrasound examination is inappropriate or unfeasible. We undertook a systematic review of the literature and meta-analysis to estimate the diagnostic accuracy of MRI for DVT. We searched databases of medical literature and citation lists of retrieved articles. We selected studies that compared MRI with a reference standard in patients with suspected DVT or suspected pulmonary embolus, or high-risk asymptomatic patients. Data were analysed by random effects meta-analysis. We included 14 articles in the meta-analysis. Most compared MRI with venography in patients with clinically suspected DVT. The pooled estimate of sensitivity was 91.5% (95% CI: 87.5-94.5%) and the pooled estimate of specificity was 94.8% (95% CI: 92.6-96.5%). Sensitivity for proximal DVT was higher than sensitivity for distal DVT (93.9% versus 62.1%). However, pooled estimates should be interpreted with caution as estimates of both sensitivity and specificity were subject to significant heterogeneity (P<0.001). Individual studies reported sensitivity ranging from zero to 100%, while specificity ranged from 43 to 100%. MRI has equivalent sensitivity and specificity to ultrasound for diagnosis of DVT, but has been evaluated in many fewer studies, using a variety of different techniques.

Prophylaxis against deep-vein thrombosis following trauma: a prospective, randomized comparison of mechanical and pharmacologic prophylaxis

BACKGROUND

Deep-vein thrombosis following skeletal trauma is an important yet poorly studied issue. The purpose of the present study was to evaluate the efficacy of two different strategies for prophylaxis against deep-vein thrombosis and pulmonary embolus following blunt skeletal trauma.

METHODS

Two hundred and twenty-four inpatients were enrolled in a prospective, randomized study investigating venous thromboembolic disease following trauma. Two hundred patients completed the study, which compared two different regimens of prophylaxis. The patients in Group A received enoxaparin (30 mg, administered subcutaneously twice a day) starting twenty-four to forty-eight hours after blunt trauma. The patients in Group B were managed with pulsatile foot pumps at the time of admission combined with enoxaparin on a delayed basis. All patients were screened with magnetic resonance venography and ultrasonography before discharge.

RESULTS

There were ninety-seven patients in Group A and 103 patients in Group B. Twenty-two patients (including thirteen in Group A and nine in Group B) had development of deep-vein thrombosis, with two (both in Group A) also having development of pulmonary embolism. The prevalence of deep-vein thrombosis was 11% for the whole series, 13.4% for Group A, and 8.7% for Group B; the difference between Groups A and B was not significant. There were eleven large or occlusive clots (prevalence, 11.3%) in Group A, compared with only three (prevalence, 2.9%) in Group B (p = 0.025). The prevalence of pulmonary embolism was 2.1% in Group A and 0% in Group B. Wound complications occurred in twenty-one patients in Group A, compared with twenty patients in Group B. Patients who had development of deep-vein thrombosis during the inpatient portion of the study required a mean of 7.4 units of blood during hospitalization, compared with 3.9 units of blood for those who did not (p < 0.05).

CONCLUSIONS

Our results indicate that early mechanical prophylaxis with foot pumps and the addition of enoxaparin on a delayed basis is a very successful strategy for prophylaxis against venous thromboembolic disease following serious musculoskeletal injury. The prevalence of large or occlusive deep-vein thromboses among patients who had been managed with this protocol was significantly less than that among patients who had been managed with enoxaparin alone.

Thromboprophylaxis in pelvic and acetabular trauma surgery

We prospectively studied the outcome of a protocol of prophylaxis for deep vein thrombosis (DVT) in 103 consecutive patients undergoing surgical stabilisation of pelvic and acetabular fractures. Low-molecular-weight heparin (LMWH) was administered within 24 hours of injury or on achieving haemodynamic stability. Patients were screened for proximal DVT by duplex ultrasonography performed ten to 14 days after surgery.

The incidence of proximal DVT was 10% and of pulmonary embolus 5%. Proximal DVT developed in two of 64 patients (3%) who had received LMWH within 24 hours of injury, but in eight of 36 patients (22%) who received LMWH more than 24 hours after the injury (p < 0.01). We conclude that LMWH, when begun without delay, is a safe and effective method of thromboprophylaxis in high-risk patients with major pelvic or acetabular fractures.

The effect of screening for deep vein thrombosis on the prevalence of pulmonary embolism in patients with fractures of the pelvis or acetabulum: a review of 973 patients

OBJECTIVES

In patients with pelvic or acetabular fractures, to compare the prevalence of pulmonary embolism in a time period without screening for deep vein thrombosis to that seen when a screening protocol was in place.

DESIGN

Retrospective.

SETTING

County hospital.

PATIENTS

All patients with closed fractures of the pelvis or acetabulum treated during the study periods.

INTERVENTION

Prophylaxis for deep vein thrombosis was the same for both groups. From November 1, 1997 though November 31, 1999, a screening protocol for deep vein thrombosis was employed using ultrasound and magnetic resonance venography. From January 1, 2000 through December 1, 2001, no screening was used.

MAIN OUTCOME MEASUREMENT

Pulmonary emboli were recorded.

RESULTS

The 1997 to 1999 time period included 486 patients with fractures of the pelvis or acetabulum; the 2000 to 2001 time period included 487. In the period when a screening protocol was in place, 10 patients (2%) were diagnosed with pulmonary embolism by pulmonary arteriogram, autopsy, or ventilation perfusion scan. All but 2 who were diagnosed with pulmonary embolism had undergone screening for deep vein thrombosis, and none of the screening tests were positive. In the 2000 to 2001 time period, when no screening for deep vein thrombosis was done, 7 patients (1.4%) were diagnosed with pulmonary embolism, by pulmonary arteriogram, autopsy, spiral computed tomography scan, or high clinical suspicion. There was no significant difference between the prevalence of pulmonary embolism seen in 1997 to 1999 and that seen in 2000 to 2001 (P = 0.48).

CONCLUSION

Discontinuation of screening for the diagnosis of deep vein thrombosis did not change the rate of pulmonary embolism.

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.

Iliac compression syndrome and recanalization of femoropopliteal and iliac venous thrombosis: a prospective study with magnetic resonance venography

OBJECTIVES

Poor iliac vein recanalization has been associated with compression of the left common iliac vein by the right common iliac artery (RCIA/LCIV compression); however, this finding has been difficult to confirm. In a baseline study, RCIA/LCIV compression was detected with magnetic resonance imaging in patients with deep venous thrombosis. We compared recanalization of left femoropopliteal and iliac thrombosis with and without RCIA/LCIV compression.

METHODS

This was a prospective blinded study carried out in a 1355-bed university hospital. Thirty-one patients were recruited from consecutive cohorts of patients with iliofemoral and femoropopliteal DVT who underwent direct thrombus magnetic resonance imaging, venous enhanced peak arterial magnetic resonance venography, and magnetic resonance arteriography as part of the baseline study relating RCIA/LCIV compression to extent of thrombosis. Magnetic resonance venography was performed 6 weeks, 6 months, and 1 year after diagnosis of deep venous thrombosis. Femoropopliteal and iliac venous segments that were occluded at diagnosis were classified as occluded, partially occluded, or patent on follow-up scans.

RESULTS

At 6-week follow-up, recanalization of all segments was incomplete. At both 6-month and 1-year follow-up, recanalization of left iliac segments associated with RCIA/LCIV compression was poorer compared with recanalization of left iliac segments not associated with compression (6 of 6 occluded vs 1 of 6 occluded and 1 of 6 partially occluded at 6 months, P =.015; 6 of 6 occluded vs 5 of 5 patent at 1 year, P = .002). This was due to complete failure of recanalization of left common iliac veins associated with RCIA/LCIV compression in 6 of 6 cases. All other iliac and femoropopliteal segments including left external iliac veins associated with RCIA/LCIV compression had high rates of recanalization at both 6 months and 1 year.

CONCLUSION

RCIA/LCIV compression is associated with persistent occlusion of the left common iliac vein. The recanalization rate for all other femoropopliteal and iliac segments was high.

CT for thromboembolic disease

Pulmonary embolism (PE) and deep venous thrombosis (DVT) constitute the two clinical manifestations of venous thromboembolic disease (VTE). The recent innovation of computed tomography venography (CTV) in conjunction with CT pulmonary arteriography (CTPA) provides a single noninvasive diagnostic test that can evaluate both components of VTE. PE is often an underestimated, underdiagnosed, and, consequently, undertreated disease entity. Herein, we review the epidemiology of thromboembolic disease, the diagnostic algorithm used in evaluation of patients with suspected VTE, and protocols for performing CTPA and CTV. Interpretation of these examinations is discussed in detail, because CTPA may pose new challenges to the practicing radiologist.

Deep venous thrombosis: diagnosis by using venous enhanced subtracted peak arterial MR venography versus conventional venography

PURPOSE

To assess diagnostic accuracy and interobserver variability at venous enhanced subtracted peak arterial (VESPA) magnetic resonance (MR) venography compared with those at conventional venography for the diagnosis of femoral and iliac deep venous thrombosis (DVT).

MATERIALS AND METHODS

A single anteroposterior maximum intensity projection (MIP) venogram of the femoral and iliac veins was constructed by using VESPA MR venography in 55 symptomatic patients suspected of having lower limb DVT. All patients also underwent conventional venography, results of which were used as the standard of reference. VESPA MR venograms were interpreted by two independent reviewers (reviewers A and B) who were unaware of other results. Sensitivity and specificity of VESPA MR venography for the diagnosis of thrombus in the femoral and iliac veins were calculated. Interobserver variability was calculated for these observations by using weighted kappa with equally spaced weights for positive, nondiagnostic, and negative studies. Nondiagnostic studies were reinterpreted separately by reviewer A on the basis of source data.

RESULTS

Sensitivity of VESPA MR venography for the femoral veins (20 of 20) and iliac veins (seven of seven) was 100% for both reviewers. Specificity was 100% (39 of 39 for reviewer A, 40 of 40 for reviewer B) for the iliac veins and 97% (31 of 32) for the femoral veins for both reviewers. Segments in which the VESPA MR venograms were nondiagnostic were excluded from this analysis. Interobserver variability as calculated by using weighted kappa for positive, negative, and nondiagnostic studies was 0.85 for femoral veins and 0.97 for iliac veins. Interpretation of the source data led to correct diagnosis in six of six cases in which the VESPA MR venograms were nondiagnostic.

CONCLUSION

VESPA MR venography yielded MIP venograms that were highly accurate for the diagnosis of DVT in femoral and iliac veins. Interpretation of the studies was also highly reproducible.

Effect of mechanical compression on the prevalence of proximal deep venous thrombosis as assessed by magnetic resonance venography

BACKGROUND

Patients have been shown to be at greater risk for deep venous thrombosis, particularly proximal thrombosis, after total hip arthroplasty. Proximal thrombi are more likely to develop into pulmonary emboli than are distal thrombi. The purpose of this randomized, prospective study was to compare the prevalence of pelvic and proximal lower-extremity deep venous thrombosis after primary total hip arthroplasty between patients treated with an impulse mechanical compression device for prophylaxis and those treated with prophylactic stockings.

METHODS

One hundred patients were evaluated, with use of magnetic resonance venography, for proximal deep venous thrombosis after total hip arthroplasty. Fifty patients were treated with a mechanical compression device on both lower extremities, and the other fifty patients received only prophylactic stockings. Both groups of patients received hypotensive epidural anesthesia and 325 mg of aspirin twice a day.

RESULTS

Overall, proximal deep venous thrombi were found in 15% of the 100 patients. Of the fifty patients treated with mechanical compression, 8% (four) had a positive venogram. Of the fifty control patients, 22% (eleven) had a positive venogram (p < 0.05). However, overall the rate of occlusive thrombi was 6% (six) compared with an overall rate of nonocclusive thrombi of 9% (nine). The rate of occlusive thrombi was 2% (one of fifty) in the study group and 10% (five of fifty) in the control group (p = 0.04).

CONCLUSIONS

On the basis of this study, we concluded that patients managed with total hip arthroplasty benefit from a reduction in the rates of femoral and pelvic deep vein thrombosis when they are treated with hypotensive epidural anesthesia, mechanical compression, and aspirin and are subsequently assessed with magnetic resonance venography.

Prospective comparison of contrast-enhanced computed tomography versus magnetic resonance venography in the detection of occult deep pelvic vein thrombosis in patients with pelvic and acetabular fractures

OBJECTIVE

To determine the rate of pelvic vein thrombosis following acetabular or pelvic fracture identified by enhanced computed tomography venography or magnetic resonance venography.

DESIGN

Prospective evaluation of computed tomography venography and magnetic resonance venography in patients with pelvic and acetabular trauma as a screening tool for deep vein thrombosis.

SETTING

Level I trauma center.

RESULTS

Thirty patients with pelvic or acetabular fractures and who met the study criteria were prospectively screened with magnetic resonance venography and computed tomography venography to determine preoperative presence of pelvic venous thrombosis. Pelvic deep vein thrombosis was detected by computed tomography venography in two patients (7%) and by magnetic resonance venography in four patients (13%). Invasive selective pelvic venographies were performed on the five subjects who tested positive on either one or both screening tests. Only one computed tomography venography case was validated by invasive pelvic venography. The false-positive rate for computed tomography venography was 50%, and the false-positive rate for magnetic resonance venography was 100%.

CONCLUSIONS

We cannot recommend the sole use of either computed tomography venography or magnetic resonance venography to screen and direct the treatment of asymptomatic thrombi in patients with fracture of the pelvic ring because of the high false positive rates. If these studies are used as screening tools, confirmation of the presence of thrombosis with selective venography should be performed prior to initiating invasive treatment with a vena cava filter. Clinical decisions based solely on one of these imaging techniques may result in inappropriate aggressive treatment due to the high false-positive rate.

Mechanical prophylaxis against deep-vein thrombosis after pelvic and acetabular fractures

BACKGROUND

Deep-vein thrombosis is a common complication following pelvic and acetabular fractures. The hypothesis of this study was that pulsatile mechanical compression is superior to standard sequential mechanical compression for decreasing the prevalence of deep-vein thrombosis in patients with pelvic or acetabular fracture.

METHODS

A prospective, randomized, blinded study of two methods of mechanical prophylaxis against deep-vein thrombosis was conducted. One hundred and seven patients were randomized into either Group A (fifty-four patients), in which a thigh-calf low-pressure sequential-compression device was used, or Group B (fifty-three patients), in which a calf-foot high-pressure pulsatile-compression pump was used. All patients underwent duplex ultrasonography and magnetic resonance venography. The two groups were comparable with regard to demographics, fracture type, fracture treatment, time from the injury to the prophylaxis, and patient compliance.

RESULTS

Deep-vein thrombosis developed in ten patients (19%) in Group A, with seven (13%) having a large or occlusive clot and one (2%) having a documented pulmonary embolism. Deep-vein thrombosis developed in five patients (9%) in Group B, with two (4%) having a large or occlusive clot and none having a documented pulmonary embolism. Nine of the nineteen detected thromboses were in the deep pelvic veins. The difference in the prevalence of large or occlusive clots between the two groups demonstrated a trend but, with the numbers available, was not significant (p = 0.16). Increased patient age and the time elapsed from the injury to the surgery were found to be associated with higher rates of thrombosis.

CONCLUSIONS

Pulsatile compression was associated with fewer deep-vein thromboses than was standard compression, with the difference representing a trend but not reaching significance with the number of patients studied.

Isolated pelvic deep venous thrombosis: relative frequency as detected with MR imaging

PURPOSE

To determine the relative frequency of deep venous thrombosis (DVT) isolated to the pelvic veins, as demonstrated with magnetic resonance (MR) imaging.

MATERIALS AND METHODS

The reports of 769 MR examinations performed from June 1993 through December 1999 in patients with suspected DVT were reviewed retrospectively. MR venography was performed by using a two-dimensional gradient-recalled-echo sequence (typically repetition time, 34 msec; echo time, 13 msec; flip angle, 60 degrees ). The presence of DVT was categorized by location in the pelvis, thigh, or calf.

RESULTS

DVT was identified in 167 (21.7%) of the 769 MR examinations. Thirty-four (20.4%) of the 167 studies demonstrated DVT isolated to the pelvic veins.

CONCLUSION

The relative frequency of isolated pelvic DVT detected with MR venography was higher than that reported in prior studies with ultrasonography (US) or ascending venography. MR venography should be performed in patients with suspected pelvic DVT or when clinical suspicion persists despite a negative US study.

Accuracy of magnetic resonance imaging in the diagnosis of deep vein thrombosis in asymptomatic patients with injuries of the lower extremity. A pilot study

This is a prospective comparative study of magnetic resonance imaging (MRI) of the deep veins versus contrast venography in consecutive patients treated for various injuries to their lower extremities, showing no clinical symptoms of deep vein thrombosis. The majority of examinations referred to in this study were performed according to the following methodology: First, the patient was subjected to MRI. Subsequently, within a 24-h interval, he/she was subjected to contrast venography. The acquired results were compared in a blinded manner. The diagnostic indices for MRI were calculated on the assumption that the results of contrast venography were sure to give an accurate indication of either presence or absence of thrombosis. Thirty-six patients were included in the study, of which 27 (15 males) completed it. The overall incidence of distal deep venous thrombosis (DVT) was 22% (6/27). One patient showed extension of a crural thrombus into the popliteal vein. MRI did not detect any of the thrombi. This lack of result was ascribed to failure to fully demonstrate all segments of the crural veins. However, MRI did show three proximal thrombi in the superficial femoral vein, which were not shown by the venograms. Thus, both the sensitivity and specificity of MRI were 0%, so MRI proved to be of no value in the diagnosis of asymptomatic deep venous thrombosis in this study.

Venous thromboembolism after acute stroke

BACKGROUND

Treatment for venous thromboembolism (VTE) is highly effective in preventing morbidity and mortality, yet pulmonary embolism (PE) accounts for up to 25% of early deaths after stroke. This is because the current diagnostic paradigm is reactive rather than proactive: the clinician responds to VTE when it becomes symptomatic, in the expectation that initiation of treatment will prevent progression to more serious manifestations. This approach is flawed, because sudden death from PE is frequently unheralded and nonfatal symptomatic pulmonary emboli are often unrecognized or misdiagnosed.

SUMMARY OF COMMENT

Morbidity and mortality from PE could be reduced either by more effective thromboprophylaxis or earlier diagnosis and treatment of established VTE. The fact that early use of short-term, low-dose, unfractionated heparin (UFH) is not associated with sustained, clinically meaningful benefit suggests that a fundamental change in the diagnostic approach to VTE is needed, one which requires a greater appreciation that clinically apparent events are merely the tip of the thromboembolism iceberg.

CONCLUSIONS

Research into a strategy of screening for subclinical VTE in these patients is needed, with a view to identifying a subgroup at risk of progression to symptomatic and life-threatening events, in whom outcome might be improved by anticoagulation.