Introduction. Venous Thromboembolism is a well documented complication of Total hip and total knee replacement, and NICE guidelines recommend use of pharmacological prophylaxis routinely after these procedures. Current practice in our department is use of mechanical prophylaxis routinely, and chemical prophylaxis in high risk cases only. Previous departmental audit has shown VTE rates to be lower than the national average, however medical and haematology audit has contradicted this, and suggested that practices should be revised to include chemical prophylaxis routinely. This study seeks to determine whether we are seeing the full extent of the problem and whether our practices should be revised accordingly. Methods. Retrospective study of all patients presenting to our hospital with suspected DVT/PE from February 2009 – August 2009. Patients were identified through radiology records; every patient undergoing venous Doppler studies or CT pulmonary angiography were included. The casenotes of patients with positive scans were reviewed; and relevant information extracted from the notes. Results. 475 patients presenting with suspected DVT/PE between February 2009 and August 2009. 39 confirmed DVT; 37 confirmed PE. 87% admitted under acute medical intake. 2 confirmed DVT's in post operative THR/TKR patients, accounting for 5.1% of DVT's in this timeframe. No PE's following THR/TKR in this timeframe. Overall postoperative THR/TKR accounts for 2.6% of confirmed VTE in this hospital. Rates of DVT 1.19% of total hip replacements; 0.93% of total knee replacements. Discussion. Actual rates of VTE low amongst our post operative patients, suggesting current methods of thromboprohylaxis are effective. Changes in thromboprophylaxis practices probably not cost-effective; however it is difficult to justify not changing practices due to recent publication of NICE guidance. Rates comparable to previous audit, suggesting that patients are not being ‘missed by orthopaedic audit’

Thromboembolism following total hip arthroplasty is a common complication that may result in significant morbidity and mortality. Despite this, optimal prophylactic regimen is controversial. According to the literature, the prevalence of deep venous thrombosis during the early post-operative period ranges from 13% in patients utilizing low molecular weight heparin to 18% in patients treated with sequential compression devices alone. We investigated the efficacy of a comprehensive approach encompassing the use of aspirin, intermittent compression devices (‘foot pumps’), and early mobilization in a cohort of 290 consecutive patients after non-cemented total hip replacements. The surgical procedures were carried out under epidural anesthesia in most cases (91%). All patients were allowed full weight bearing and received ambulation training starting on the first post-operative day. Ankle-high pneumatic boots (‘foot pumps’) were used early immediately surgery. Aspirin (325 mg po/qd) was used as a pharmacological measure to prevent thromboembolism. The presence of deep vein thrombosis was determined with the routine use of venous duplex scans on post-operative day number 5 to 10 (mean 6.8). The duration of the follow-up was 3 months. No patients were lost to follow-up. Four distal DVT and two proximal DVT were detected in five patients (3%). None of the patients developed symptomatic pulmonary embolism during the follow-up period. There were no major wound complications. Venous thromboembolic disease after hip replacement surgery is largely associated with postoperative immobilization and venous stasis. It is the authors’ opinion that a prevention strategy should include mechanical as well as pharmacological measures. The concomitant use of epidural anesthesia, “foot pumps”, aspirin and early full weight bearing ambulation may be effective in further reducing the incidence of DVT after surgery

Background

Venous Thrombo-Embolism is a recognized complication of lower limb immobilization. In the neuropathic patient total contact casting (TCC) is used in the management of acute charcot neuroathropathy and/or to off-load neuropathic ulcers, frequently for long time periods. To our knowledge there is no literature stating the prevalence of VTE in patients undergoing TCC. We perceive that neuropathic patients with active charcot have other risk factors for VTE which would predispose them to this condition and would mandate the use of prophylaxis. We report a retrospective case series assessing the prevalence of VTE in the patients being treated with TCCs.

Abstract

The aim of this study was to identify factors independently associated with symptomatic venous thromboembolism (VTE) following acute Achilles tendon rupture (ATR), and to suggest a clinical VTE risk assessment tool for patients with ATR.

From 2010–2018, 984 consecutive adults (median age 47yrs, 73% male) sustaining an ATR were retrospectively identified. There were 95% managed non-operatively (below-knee cast 52%, n=507/984; walking boot 44%, n=432/984), with 5% (n=45/984) undergoing primary operative repair (<6wks). VTE was diagnosed using medical records and national imaging archives, reviewed at a mean of 5yrs (1–10) post-injury. Regression was performed to identify factors independently associated with VTE.

Incidence of VTE within 90 days of ATR was 3.6% (n=35/984; deep vein thrombosis 2.1% [n=21/984], pulmonary embolism 1.9% [n=19/984]). Age ≥50yrs (adjusted OR [aOR] 2.3, p=0.027), personal history of VTE/thrombophilia (aOR 6.1, p=0.009) and family history of VTE (aOR 20.9, p<0.001) were independently associated with VTE. These non-modifiable risk factors were incorporated into a VTE risk assessment tool. 23% of patients developing VTE (n=8/35) had a relevant personal or family history, but incorporating age into the tool identified 69% of patients with VTE (n=24/35). Non weight-bearing ≥2wks after ATR was also independently associated with VTE (aOR 3.2, p=0.026).

Age ≥50 years, personal history of VTE/thrombophilia and a positive family history were independently associated with VTE following ATR. Incorporating age into our suggested VTE risk assessment tool enhanced sensitivity in identifying at-risk patients. Early weight-bearing in an appropriate orthosis may be beneficial in VTE risk reduction.

We report preliminary results from the first, multicenter prospective study designed to define the incidence of symptomatic (Venous Thromboembolism) VTE in patients with isolated leg fractures distal to the knee. Eight hundred and twenty-six enrolled patients have completed three months of follow up. By three months, only seven patients had sustained a symptomatic VTE with no fatal PE. Symptomatic and fatal VTE were infrequent complications after isolated leg fractures distal to the knee without thromboprophylaxis. Routine thromboprophylaxis may not be warranted in isolated leg fractures distal to the knee. To report results from the first, multicenter prospective study designed to define the incidence of symptomatic Venous Thromboembolism (VTE) in patients with isolated leg fractures distal to the knee. Symptomatic and fatal VTE are infrequent complications after isolated leg fractures distal to the knee without thromboprophylaxis. Routine thromboprophylaxis may not be warranted in isolated leg fractures distal to the knee. From August 2002 to April 2004, one thousand eight hundred and eight consecutive patients with isolated leg fractures distal to the knee were screened for entry at five hospitals in Ontario. Patients with major trauma, active cancer and previous VTE were excluded. Thromboprophylaxis was not allowed. Patients were followed prospectively for three months, with telephone calls at fourteen days, six weeks and three months. Suspected DVT and PE were investigated in a standardized manner. Eight hundred and twenty-six enrolled patients have completed three months of follow up. The mean age was forty-five years (range sixteen to ninety-three) and 59.5% of this cohort was female. 99% of these fractures were unilateral and 97% were closed. Fractures included: fibula (38%), metatarsal (29%), phalanges (13%), calcaneus, talus or tarsal (10%), tibia (10%) and patella (7%). Only 11% of fractures were surgically treated. 88% of fractures received a cast or splint for a mean duration of 41+/− 20 days. Complete follow-up was available for 97.5% of this cohort. By three months only seven patients had sustained a symptomatic VTE (2 proximal DVT, 3 calf DVT, 2 PE) with no fatal PE-an incidence of 0.9% (95% CI 0.3 to 1.8%). Funding: This study was funded by a research grant from Pharmacia

Abstract

Prolonged bedrest in hospitalized patients is a major risk factor for venous thromboembolism (VTE), especially in high risk patients with hip fracture. Thrombelastography (TEG) is a whole blood viscoelastic hemostatic assay with evidence that an elevated maximal amplitude (MA), a measure of clot strength, is predictive of VTE in orthopaedic trauma patients. The objective of this study was to compare the TEG MA parameter between patients with hip fracture who were more mobile post-operatively and discharged from hospital early to patients with hip fracture with reduced mobility and prolonged hospitalizations post-operatively.

In this prospective cohort study, TEG analysis was performed in patients with hip fracture every 24-hours from admission until post-operative day (POD) 5, then at 2- and 6-weeks post-operatively. Hypercoagulability was defined by MA > 65. Patients were divided into an early (within 5-day) and late (after 5-day) discharge group, inpatient at 2-weeks group, and discharge to MSK rehabilitation (MSK rehab), and long term care (LTC) groups. Two-sample t-test was used to analyze differences in MA between the early discharge and less mobile groups. All statistical tests were two-sided, and p-values < 0.05 were considered statistically significant.

In total, 121 patients with a median age of 81.0 were included. Patients in the early discharge group (n=15) were younger (median age 64.0) and more likely to ambulate without gait aids pre-injury (86.7%) compared to patients in the late discharge group (n=105), inpatients at 2-weeks (n=48), discharged to MSK rehab (n=30), and LTC (n=20). At two weeks post-operative, the early discharge group was significantly less hypercoagulable (MA=68.9, SD 3.0) compared to patients in the other four groups. At 6-weeks post-operative, the early discharge group was the only group to demonstrate a trend towards mean MA below the MA > 65 hypercoagulable threshold (MA=64.4, p=0.45). Symptomatic VTE events were detected in three patients (2.5%) post-operatively. All three patients had hospitalizations longer than five days after surgery.

In conclusion, our analysis of hypercoagulability secondary to reduced post-operative mobility demonstrates that patients with hip fracture who were able to mobilize independently sooner after hip fracture surgery, have a reduced peak hypercoagulable state. In addition, there is a trend towards earlier return to normal coagulation status as determined by the TEG MA parameter. Post-operative mobility status may play a role in determining individualized duration of thromboprophylaxis following hip fracture surgery. Future studies comparing TEG to clinically validated mobility tools may more closely evaluate the contribution of venous stasis due to reduced mobility on hypercoagulation following hip fracture surgery.

Prolonged bedrest in hospitalized patients is a major risk factor for venous thromboembolism (VTE), especially in high risk patients with hip fracture. Thrombelastography (TEG) is a whole blood viscoelastic hemostatic assay with evidence that an elevated maximal amplitude (MA), a measure of clot strength, is predictive of VTE in orthopaedic trauma patients. The objective of this study was to compare the TEG MA parameter between patients with hip fracture who were more mobile post-operatively and discharged from hospital early to patients with hip fracture with reduced mobility and prolonged hospitalizations post-operatively.

In this prospective cohort study, TEG analysis was performed in patients with hip fracture every 24-hours from admission until post-operative day (POD) 5, then at 2- and 6-weeks post-operatively. Hypercoagulability was defined by MA > 65. Patients were divided into an early (within 5-day) and late (after 5-day) discharge group, inpatient at 2-weeks group, and discharge to MSK rehabilitation (MSK rehab), and long term care (LTC) groups. Two-sample t-test was used to analyze differences in MA between the early discharge and less mobile groups. All statistical tests were two-sided, and p-values < 0.05 were considered statistically significant.

In total, 121 patients with a median age of 81.0 were included. Patients in the early discharge group (n=15) were younger (median age 64.0) and more likely to ambulate without gait aids pre-injury (86.7%) compared to patients in the late discharge group (n=105), inpatients at 2-weeks (n=48), discharged to MSK rehab (n=30), and LTC (n=20). At two weeks post-operative, the early discharge group was significantly less hypercoagulable (MA=68.9, SD 3.0) compared to patients in the other four groups. At 6-weeks post-operative, the early discharge group was the only group to demonstrate a trend towards mean MA below the MA > 65 hypercoagulable threshold (MA=64.4, p=0.45). Symptomatic VTE events were detected in three patients (2.5%) post-operatively. All three patients had hospitalizations longer than five days after surgery.

In conclusion, our analysis of hypercoagulability secondary to reduced post-operative mobility demonstrates that patients with hip fracture who were able to mobilize independently sooner after hip fracture surgery, have a reduced peak hypercoagulable state. In addition, there is a trend towards earlier return to normal coagulation status as determined by the TEG MA parameter. Post-operative mobility status may play a role in determining individualized duration of thromboprophylaxis following hip fracture surgery. Future studies comparing TEG to clinically validated mobility tools may more closely evaluate the contribution of venous stasis due to reduced mobility on hypercoagulation following hip fracture surgery.

Current orthopedic practice requires consideration of apparently contradictory recommendations regarding VTE prevention among THR/TKR patients. American College of Chest Physicians (ACCP) 8th Clinical Practice Guidelines for the Prevention of Venous Thromboembolism recommend against aspirin for VTE prophylaxis in any patient. 1. The American Academy of Orthopedic Surgeons (AAOS) Guideline recommends pulmonary embolism risk stratification, then implementation of one of many possible courses including the use of aspirin. 2. . We conducted a prospective observational study among consecutive patients presenting for total hip or knee arthroplasty. Pre-operative PE risk stratification was performed at the discretion of the surgeon. Patients identified as usual risk for PE received aspirin. Patients considered being at elevated risk for PE received warfarin. This observational study protocol called for one year of data collection. At approximately 8 months 656 patients were enrolled, and the surgeon principally implementing PE risk stratification and administration of aspirin chose to stop enrolling patients due to a high incidence of pulmonary emboli. One hundred fifty five patients received thromboprophylaxis with aspirin 600 mg PR in the PACU, then 325 mg BID for one month (reduced to 81 mg daily if GI symptoms were present). The remaining 501 patients received an ACCP-based warfarin protocol managed by a pharmacist anticoagulation management service. Our hypothesis is the null hypothesis; that an AAOS-based approach to hromboembolism prevention is not inferior to an ACCP-based approach. The a priori primary endpoints of the AVP Study are clinically overt VTE, DVT, PE, major bleeding, and death. All patients will receive a 90 day follow-up questionnaire in person or by telephone. Additionally, the electronic medical record of Intermountain Healthcare will be interrogated for ICD-9 codes germane to the outcomes of interest. Ninety day follow-up has been completed for approximately 140 patients. The dataset will be locked upon completion of the 90 day follow-up among those patients who last received PE risk stratification and aspirin therapy (data lock early June, 2009). We anticipate preliminary data available for report by July, 2009

Venous thromboembolism (VTE) is a preventable cause of morbidity and mortality in patients undergoing elective hip arthroplasty surgery. The balance of post-operative VTE prophylaxis and risk of post-operative haemorrhage remains at the forefront of surgeon's mind. The National Institute for Clinical Excellence (NICE) has altered their prophylaxis guidance in the setting of total hip arthroplasty (THA). The aim of this study was to present the VTE incidence in 8,890 patients who underwent total hip arthroplasty between January 1997 and March 2018 with Aspirin as the primary agent for pharmacological thromboprophylaxis.

Analysis of prospective data collection from consecutive patients undergoing THA was performed with the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) occurring within 6 months of the index operation as the primary outcome measure. 90-day all-cause mortality of this cohort of patients was also analysed.

8890 patients were reviewed. This included 7235 primary, 224 complex primary and 1431 revision cases. The incidence of DVT was 0.64% after elective THA and the incidence of PE was 0.54%. There was no difference in the incidence between primary and revision cases. The 90-day all-cause mortality was 0.88%. Cardiovascular and respiratory disease were the main causes of death following surgery. Only 0.03% of deaths (n= 3) within 90 days of index surgery were due to VTE.

Our results support the use of aspirin as an effective form of prophylaxis against VTE following THA. It is not associated with an increased incidence in symptomatic DVT, PE or death compared to other published studies. The fact that it is inexpensive, readily available, requires no monitoring and does not pose an increased risk of bleeding are other attractive advantages of using aspirin for VTE prophylaxis.

Introduction

Total contact casting (TCC) is one of the most commonly utilized modalities in the management of diabetic feet. We undertook a retrospective review to determine the prevalence of symptomatic VTE events in patients treated in a weight bearing TCC in our diabetic foot unit, and to formulate guidelines for VTE prophylaxis.

Considerable debate exists regarding which agent(s) should be preferred for venous thromboembolism (VTE) chemical prophylaxis following joint replacement. We assessed the practice of surgeons regarding VTE chemical prophylaxis for primary THR and TKR, pre and post issuing of updated NICE guidance in 2018.

A survey, circulated through the British Hip Society and regional trainee networks/collaboratives, was completed by 306 UK surgeons at 187 units. VTE chemical prophylaxis prescribing patterns for surgeons carrying out primary THR (n=258) and TKR (n=253) in low-risk patients were assessed post publication of 2018 NICE recommendations. Prescribing patterns before and after the NICE publication were subsequently explored. Questions were also asked about surgeon equipoise for participation in future RCTs.

Following the new guidance, 34% (n=87) used low-molecular weight heparin (LMWH) alone, 33% (n=85) aspirin (commonly preceded by LMWH), and 31% (n=81) direct oral anticoagulants (DOACs: with/without preceding LMWH) for THR. For TKR, 42% (n=105) used aspirin (usually monotherapy), 31% (n=78) LMWH alone, and 27% (n=68) DOAC (with/without preceding LMWH). NICE guidance changed the practice of 34% of hip and 41% of knee surgeons, with significantly increased use of aspirin preceded by LMWH for THR (before=25% vs. after=73%;p<0.001), and aspirin for TKR (before=18% vs. after=84%;p<0.001). Significantly more regimens were NICE guidance compliant after the 2018 update for THR (before=85.7% vs. after=92.6%;p=0.011) and TKR (before=87.0% vs. after=98.8%;p<0.001). Support from surgeons for future RCTs was dependent on the clinical question, ranging from 48% participation in trials (effectiveness of aspirin vs. a DOAC) to 79% (effectiveness of 14 days LMWH vs. 28 days LMWH).

Over one-third of surveyed surgeons changed their VTE chemical prophylaxis in response to 2018 NICE recommendations, with more THR and TKR surgeons now compliant with latest NICE guidance. The major change in practice was an increased use of aspirin for VTE chemical prophylaxis. Furthermore, there is an appetite amongst UK surgeons for participating in future RCTs, with a trial comparing standard versus extended duration LMWH likely feasible in current practice.

Introduction

We studied the safety and efficacy of multimodal thromboprophylaxis (MMP) in patients with a history of venous thromboembolism (VTE) undergoing total hip arthroplasty (THA). MMP includes discontinuation of procoagulant medications, VTE risk stratification, regional anesthesia, an intravenous bolus of unfractionated heparin before femoral work, rapid mobilization, the use of pneumatic compression devices, and chemoprophylaxis tailored to the patient's risk.

Introduction

Venous thromboembolism (VTE), defined as either pulmonary embolism (PE) or deep venous thrombosis (DVT), is a rare, but serious complication following total hip arthroplasty (THA). Current VTE guidelines recommend pharmacologic agents with or without intermittent pneumatic compression devices (IPCDs). At our institution, both 81mg aspirin (ASA) twice a day (BID) and portable IPCDs were prescribed to THA patients at standard risk for VTE. The aim of this study is to determine if discontinuing the use of portable outpatient IPCDs is safe and does not increase the rate of VTE in patients undergoing THA.

The selection of venous thromboembolism (VTE) prophylaxis after total joint arthroplasty (TJA) has been controversial. Although the aspirin controversy is presumably resolved, there is no medical evidence for the “optimal” VTE prophylaxis regime for individual patients.

A risk-stratified multi-modal VTE prophylaxis protocol was developed and adopted by consensus. VTE risk factors and bleeding risk factors were categorised into six VTE/bleeding risk levels: (1) pre-operative vitamin K antagonists (VKA) use, (2) bleeding risk factors, (3) hypercoagulable state, (4) pre-operative anti-platelet therapy [clopidogrel use], (5) VTE risk factors, (6) no VTE or bleeding risk factors. The pharmacologic agents used for each risk level were: (1) resume VKA with low molecular weight heparin (LMWH) bridge, (2) pharmacologic agents contra-indicated and mechanical prophylaxis only, (3) VKA for 90 days with LMWH bridge, (4) resume anti-platelet therapy, (5) LMWH in hospital and discharge on aspirin for 90 days, (6) aspirin for 90 days (starting in hospital). In addition to pharmacologic treatment, all patients received multi-modal prophylaxis including early mobilisation, mechanical foot pumps, and neuraxial anesthesia when not contra-indicated. Prior to surgery, a VTE/bleeding risk factor checklist was completed determining the risk level. The intervention cohort included all TJA patients from January 1, 2010 to December 31, 2012. The comparison cohort included all TJA patients from the year prior to implementation of the protocol at the same community hospital. Thirty day all-cause non-elective re-admissions, 30 day same-site re-operations, 90 day VTE events, and protocol compliance were abstracted from the electronic medical record.

The intervention group consisted of 2679 patients (1075 hip arthroplasty patients and 1604 knee arthroplasty patients). The comparison group consisted of 1118 patients (323 hip arthroplasty patients and 795 knee arthroplasty patients). The 30 day all cause non-elective re-admission rate was 2.72% (73/2679) in the intervention group and 4.29% (48/1118) in the comparison group (p=0.0148). The 30 day same-site re-operation rate was 1.38% (37/2679) in the intervention group and 1.25% (14/1118) in the comparison group (p=0.8773). The 90 day VTE event rate was 1.57% (42/2679) in the intervention group and 3.40% (38/1118) in the comparison group (p=0.0007). The VTE rate was higher for knee arthroplasty patients 2.00% (32/1604) than for hip arthroplasty patients 0.93% (10/1075) (p=0.0379). The rate of VTE events was higher for patients that deviated from the VTE protocol 5.03% (10/199) than for all risk groups treated per the protocol 1.29% (32/2481) (p=0.0007).

The risk-stratified multi-modal VTE prophylaxis protocol simultaneously reduced 30 day all-cause non-elective re-admissions and 90 day VTE events. The possible causes for reducing 30 day re-admissions and reducing 90 day VTE events are: (1) reducing bleeding events by using aspirin for VTE prophylaxis in more than 80% of patients, (2) extending VTE prophylaxis to 90 days, and (3) using multi-modal prophylaxis. The risk-stratified multi-modal VTE prophylaxis protocol for total joint arthroplasty is consistent with 9 of the 10 recommendations in the AAOS Clinical Practice Guideline. The risk-stratification checklist provides a standardised tool to assess risks, discuss risks, and make shared decision with patients. Patient treatment that deviated from the protocol had a significantly higher VTE rate (5.03%). Protocol compliance increased each year from 91.1% in 2010 to 94.2% in 2012.

Patients with a history of venous thromboembolism (VTE) are considered at very high risk for recurrence after lower limb arthroplasty (LLA). However, the chance of a new VTE episode after LLA has not been yet quantified. The aim of this study was to define the incidence of VTE recurrence following knee and hip arthroplasty.

The case notes for all LLA patients treated at our hospital from 2009 to 2011 were reviewed. There were 5946 primary and revision LLA operations in total; 118 of these interventions were performed in 106 patients with a history of VTE. This group included 69 females and 37 males with a mean age of 69.9. Routine thromboprophylaxis for LLA patients included mechanical (footpumps & TED stockings) plus chemical prophylaxis using Aspirin 150 mg for 6 weeks. Patients with a VTE history had the same mechanical prophylaxis but received warfarin for 3 months.

There were no fatal VTEs within 90 days of surgery. There were 5 episodes (4.2%) of VTE recurrence and specifically 4 PE and one DVT (femoral vein) at 4 months after the operation. Two of the PEs were asymptomatic, diagnosed on CTPA scans being requested for low O2 saturations on routine monitoring. In the group of patients without a VTE history there were 35 VTE episodes (0.6%), indicating a significantly lower rate of VTE (p=0.001) in comparison with the study group.

Patients with a history of VTE had a 4.2% chance of having a further VTE. This is seven times greater than the rate among all other patients despite using more aggressive chemoprophylaxis.

Introduction A prospective cohort study was conducted to assess the incidence of venous thromboembolism (VTE) in 300 patients undergoing elective spinal surgery. Although this subject has been extensively studied in patients undergoing joint replacement surgery, the true incidence of VTE related to spinal surgery remains unknown. We also sought to assess the efficacy of various forms of VTE prophylaxis, another area which has not been adequately studied.

Methods Bilateral lower extremity venous duplex scans were performed pre-operatively, within one week postoperatively and at 4 to 6 weeks post-operatively. Information was collected regarding age, gender, body mass index, type and duration of surgical procedure, intra-operative blood loss and blood transfusion, pre- and post-operative mobility and other risk factors for VTE. All patients received vigorous mechanical prophylaxis with 56% of patients receiving pharmacological prophylaxis (unfractionated or low molecular weight heparin) according to surgeon preference.

Results The overall incidence of post-operative deep vein thrombosis (DVT) was 3.4%. The incidence in those receiving pharmacological prophylaxis was 1.2% versus 6.3% in those who received mechanical prophylaxis alone (p< 0.05). Just under half of the post-operative DVTs (1.4%) occurred after hospital discharge with none of these patients receiving heparin. There were two cases of pulmonary embolism (0.7%), both occurring during hospitalization, and there were no deaths. There was no difference in blood loss or transfusion rates between patients receiving or not receiving pharmacological prophylaxis and there were no serious complications related to blood loss. There was a surprisingly high incidence of abnormalities detected on pre-operative scanning, with DVT occurring in 3.0% and superficial thrombophlebitis in 24.8%.

Discussion The incidence of DVT in patients after spinal surgery was 3.4% and was significantly lower (1.2 %) in patients who received pharmacological prophylaxis. Given that the rates of bleeding-related complications were not different between the two groups, we conclude that it is both efficacious and safe to use pharmacological prophylaxis in combination with mechanical prophylaxis routinely in patients undergoing spinal surgery. A 27.8% incidence of pre-operative venous abnormalities may reflect pre-operative immobility due to pain in this group of patients, and justifies the use of ultrasound scanning as an important pre-operative screening tool. In addition, the high incidence of late-onset DVT justifies the need for follow-up scanning several weeks after discharge. This study is the amongst the largest of its type to date, however a larger, randomized and controlled trial is now necessary to confirm these results and allow the formulation of unambiguous guidelines for spinal surgery and VTE prophylaxis.

Surgeons want to counsel their patients accurately about the risks of rare complications. This is difficult for venous thromboembolism (VTE), as most studies report rates of asymptomatic disease. We calculated the rate of confirmed, symptomatic deep vein thrombosis (DVT) and pulmonary embolism (PE) after elective lower limb surgery in our hospital.

We scrutinised referrals for venous Doppler ultrasound and computed tomography pulmonary angiography, identifying all cases of DVT or PE over an 18 month period. These patients were cross-referenced with our elective orthopaedic database and Healthcare Resource Group coding data.

Out of 1071 total hip replacements, there were three DVTs and two PEs, giving an incidence of 0.28% for DVT and 0.19% for PE. Out of 1351 total knee replacements, there were four DVTs and three PEs (incidence 0.29% and 0.22% respectively). Out of 1988 non-arthroplasty hip and knee procedures, there were no DVTs and two PEs (incidence 0.1%). For 1763 elective surgical foot procedures, there were five DVTs (incidence 0.28%), and no PEs.

Currently, Rivaroxaban is offered to patients undergoing hip and knee replacement surgery, but other patients do not receive anticoagulants routinely. Our low incidence of VTE supports this policy and is reassuring for surgeons.

In response to the recent publication in April 2007 of NICE guidelines on venous thromboembolism, we report our practice and experience of VTE in adult hip and knee arthroplasty.

It is generally agreed that the 2 major complications of VTE are sudden death as a result of pulmonary embolism and post thrombotic syndrome. NICE guidelines make 2 assumptions:

That chemical and mechanical prophylaxis can reduce these complications

We have studied a large cohort of patients who had Aspirin only as chemical prophylaxis to determine the incidence of clinical thromboembolism before and after discharge and the mortality from PE at 90 days. We performed a prospective analysis of consecutive patients undergoing primary total knee and hip replacement from November 2002 to November 2007. In total 2050 patients had total knee replacement and 2203 patients had total hip replacement. All patients were treated at one specialist centre under the care of one surgeon. Data was complete and accurate for all patients at 90 days post-operatively.

Standard practice was the use of 150mg Aspirin from Day 1 post-operatively for a total of six weeks combined with spinal anaesthesia and early mobilisation.

The overall rate for Fatal Pulmonary embolism 0.07% (3/4253), overall death rate 0.3%(13/4253), for treated non-fatal PE 0.66% (28/4253) and for treated above knee DVT was 0.33%(14/4253).

Our data suggests that fatal pulmonary embolism is not common and does not account for most deaths following total hip and knee arthroplasty. We suggest there is no evidence that chemical/mechanical prophylaxis reduces the risk of sudden death from PE following elective primary joint replacement and with modern surgical practice elective hip and knee replacement should no longer be considered high risk procedures.