Abstract

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.

Venous Thromboembolism (VTE) prophylaxis is an essential part of orthopaedic surgeries in preventing life-threatening thromboembolic events such as Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE). Orthopaedic surgery has the highest incidence rate of thromboembolic events as compared to any other surgical specialities, making it an essential component in managing any orthopaedic case. At Queen's Medical Centre (QMC), a major trauma centre in the United Kingdom (UK), sees up to 750 NOF fracture cases annually, making it one of the busiest trauma and orthopaedic centres in the UK. Our study aims to evaluate how VTE Prophylaxis is conducted in a UK Major Trauma Centre for NOF and pelvic fragility fractures and how human factors can improve its efficacy. The Nottingham University Hospitals (NUH) Trust has implemented new guidelines from August 2019 that patients with fragility fractures such as NOF and pelvic fractures are prescribed with 28 days VTE prophylaxis with Enoxaparin, or their own anti-coagulants if risk of thrombosis exceed the risk of bleeding. This is an adaptation from the trust to align their guidelines closer to the NICE 2018 guidelines. We will be evaluating the initial compliance of VTE Prophylaxis, identify and utilise human factors, then re-analyse the department after implementing interventions on the same batch of junior doctors working in the department. Data of 100 patients with fragility fractures were collected, 50 consecutive patients in the pre-intervention window during August 2019 and 50 in the post-intervention window during November 2019. The pre-intervention data had 43 NOF and 7 Pelvic fractures. Our study showed that 93% of NOF fracture and 100% of pelvic fracture received the correct course of VTE prophylaxis. The data was presented at the local department junior doctor academic session. Three simple human factor interventions were implemented over the course of September and October: Education to the trauma and orthopaedic department on the new guideline, extended VTE labels on drug charts for patients with fragility fractures, VTE reminder labels at doctors' stations. Another 50 consecutive patients' data were collected during November 2019. Data shows that 97.8% of NOF (p>0.05) and 60% of pelvic fracture (p>0.05) received the correct course of VTE prophylaxis. Our data has shown an increase in correct VTE prescription for NOF fracture patients, which is the main bulk of our fragility fracture patients whilst we see a drop in pelvic fracture patients. Due to the limited time frame of four months where junior doctors in the UK rotate between specialities, we are only able to collect data during the first month, implement interventions between datasets and collect data on the final month of the four-month rotation. A future bigger study might provide a more significant result on the department. We believe that the key to achieving 100% VTE prophylaxis in the T&O department is optimising human factors, educating junior doctors, who are not orthopaedic trained, with sufficient information of the guidelines, and evidence of the risk and benefits of providing prolonged VTE prophylaxis for orthopaedic patients. In conclusion, we found that QMC, a major trauma centre with high patient volume and turnover, has a high level of compliance with VTE prophylaxis for fragility fractures and it is imperative that utilising human factors will inch the department closer to its goal of 100% VTE compliance

The Hospital (Trust) guidelines generally recommend 40mg of Low molecular weight heparin (LMWH) twice daily (BD) for all patients over 100kg for those undergoing total hip (THR) and knee replacements (TKR) respectively. British National Formulary (BNF) recommends 40mg of LMWH once daily (OD) for all patients regardless of their overall weight or body mass index (BMI).

We evaluated the outcome of prophylactic LMWH dosage for patients undergoing THR and TKR by monitoring surgery related venous-thromboembolic events up to a minimum of three months after surgery.

A retrospective audit was carried out after obtaining institutional approval and all consecutive elective patients weighing over 100kg and undergoing THR and TKR were included. All patients were followed up for a minimum of 3 months after their operation to investigate the dose of prophylactic LMWH received, and whether they had developed any venous thromboembolic events (VTE) post operatively. This was done using a combination of electronic notes, drug charts and deep venous thrombosis (DVT) or computed tomography pulmonary angiogram (CTPA) reports on the hospital/trust database.

A total of 53 patients underwent elective THR (18) and TKR (35) between the period of March 2017 and September 2017. Forty-four patients received 40 mg OD and 9 patients had 40 mg BD. None of the patients developed a confirmed DVT or pulmonary embolism in the 3 months following surgery regardless of the dose received.

We demonstrate that there is no clinical benefit in having patients over 100kg on twice daily LMWH with the aim of preventing post-op thromboembolic complications. This conclusion is in line with the BNF recommendations for VTE prophylaxis.

Background

Few studies have compared aspirin with DOACs (direct oral anticoagulants = direct thrombin inhibitors and factor Xa inhibitors) for venous thromboembolism (VTE) prophylaxis following total hip and knee replacement (THR and TKR). We assessed the efficacy and safety of aspirin compared with DOACs for VTE prophylaxis following THR and TKR using the world's largest joint replacement registry.

Introduction

Pulmonary emboli (PE) after total hip and knee arthroplasties is an uncommon event. However, once it happens, it may results in sudden death. Thus, the prophylaxis of venous thromboembolism (VTE), including symptomatic deep vein thrombosis (DVT) and PE, is one of the challenging trials for Orthopaedic surgeons. Many procedures have been developed, e.g. early mobilization, compression stocking, intermittent pneumatic compression (IPC) devices, and anticoagulation agents. However, the most effective treatment for prophylaxis against VTE after the arthroplasties remains undecided.

Recently, many low molecular weight heparin (LMWH) agents are developing, and these are strongly effective for anticoagulation. However, these agents sometimes lead to bleeding complications, and result in uncontrolled critical bleeding. We are introducing our protocol with conventional aspirin as VTE prophylaxis after the arithroplasties.

Background

Venous thromboembolisms are serious complications of arthroplasty of the lower extremities. Although early ambulation and active leg exercise is recommended, postoperative patients with surgical pain have difficulty in moving their legs. Therefore, we developed a novel leg exercise apparatus (LEX) to facilitate active leg movement even during the early postoperative period (Fig 1). LEX is a portable apparatus that allows patients to actively move their legs while in the supine position. LEX enables dorsiflexion, plantar flexion, combined eversion and inversion of the ankle, and multi-joint movement of the leg.

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.

Aim:

Enhanced recovery pathway is compromised by increased wound oozing due to chemical thromboprophylaxis increasing length of stay (LoS) and complications. We aimed to analyse the difference between LoS, VTE episodes, deep infection and return to theatre between matched cohort of patients either receiving combination therapy of Clexane followed by Rivaroxaban or Rivaroxaban only.

Purpose:

Starting February 2012, our institution changed from enoxaparin (Lovenox) to the Factor Xa inhibitor, rivaroxaban (Xarelto) for venous thromboembolism prophylaxis after primary total hip (THA) and total knee arthroplasty (TKA). The purpose of our study was to compare rates of venous thromboembolism and rates of major bleeding between these two medications when used for venous thromboembolism prophylaxis after primary THA and TKA.

Rivaroxaban has been recommended for routine use as a thromboprophylactic agent in patients undergoing lower-limb arthroplasty. Starting January 2011, our unit has converted from aspirin to Rivaroxaban use routinely following lower-limb arthroplasty for venous thromboembolism (VTE) prophylaxis. The aim of this audit was to retrospectively review its efficacy and the morbidity associated with its use.

All patients undergoing primary and revision lower-limb arthroplasty between February 2011 and July 2011 were reviewed. All patients undergoing total knee replacement surgery and total hip replacement surgery received oral rivaroxaban 10 mg daily post-operatively for 14 days and 35 days respectively. Outcome measures recorded were; investigation for DVT/PE, rate of DVT/PE, wound complications (infection, dehiscence, leaking, bleeding), blood transfusion rate and readmission rate within 6 weeks of surgery.

Of the 162 patients identified, 19 were excluded due to insufficient information or because they did not receive rivaroxaban as VTE prophylaxis. 141 patients (mean age 71.7 years) were included. 69 primary and 5 revision total knee replacements were performed. 60 primary and 7 revision total hip replacements were performed. 9 patients (6.4%) underwent Doppler USS for a painful swollen leg with 1 (0.7%) DVT diagnosed. None were investigated for a pulmonary embolus. 25 (17.7%) patients developed wound complications: 10 superficial infections requiring oral antibiotics, 2 deep infections requiring theatre washout, 1 wound dehiscence, 5 continuously leaking wounds, 5 bleeding wounds/haematomas. 26 (18.4%) patients required post-operative blood transfusion (average 2.2 units). 12 (8.5%) patients were re-admitted within 6 weeks with post-op complications (6 wound complications, 5 painful/swollen limbs, 1 large per-vaginal bleed).

In keeping with previous literature, the rate of VTE following lower-limb arthroplasty using rivaroxaban as prophylaxis is low. However, the rate of morbidity was higher when compared with the use of aspirin in our centre between April and September 2010.

Introduction

Ankle fractures are one of the commonest orthopaedic injuries. A substantial proportion of these are treated non-operatively at outpatient clinics with cast immobilization. Recent literature and NICE guidelines suggest risk assessment and provision of appropriate thromboembolism in patients with lower limb casts. We conducted this survey to assess the current practice in UK regarding thromboembolism prophylaxis in these patients.

The National Institute of Clinical Excellence (NICE) published guidance for reducing the risk of venous thromboembolism (VTE) in January 2010. This guidance has had a significant impact on the management of all inpatients. It is now mandatory to risk assess every inpatient and commence appropriate treatment if indicated. The guidelines specifically exclude outpatients although NICE recognises' that lower limb cast immobilisation is a risk factor for VTE. The purpose of our study was to establish the current practice for the management of outpatients treated with lower limb casts in England.

The NHS Choices website lists 166 acute hospitals in England. A telephone audit was conducted in February 2011. A member of the on call orthopaedic team was asked: 1. Are you aware of the NICE guidelines for VTE prophylaxis? 2. In your department, outpatients treated with a lower limb cast, are they risk assessed for VTE? 3. If a patient undergoes Open Reduction Internal Fixation (ORIF) for an ankle fracture and is discharged wearing a cast, are they given VTE prophylaxis? 4. If yes - for how long are they treated?

Responses were obtained from 150 eligible hospitals (1 FY1, 28 FY2, 44 ST1-ST2, 76 ST3+, 1 Consultant). 62% of responders stated that they were aware of the NICE guidance. 40% of responders stated that outpatients were routinely risk assessed for VTE. 32% of responders stated that ankle fractures treated with an ORIF and discharged wearing a cast would receive VTE prophylaxis. The duration of treatment varied from 5 days, to 6 weeks, to removal of cast.

The management of patients treated with a lower limb cast is variable and inconsistent throughout England. Although there are no national guidelines for this patient group, the routine risk assessment of outpatients was higher than anticipated by the authors. We recommend that if VTE prophylaxis is commenced as an inpatient, then it should be continued until the cast is removed.

Purpose of the study. To determine the effectiveness, complications and side effects of Rivaroxaban when used for extended thromboprophylaxis in patients undergoing primary and revision knee arthroplasty. Methods. Venous Thromboembolism (VTE) prophylaxis following knee arthroplasty remains controversial. As an Orthopaedic Unit, in July 2009 we developed guidelines to help ensure that our patient management was fully compliant with National Institute for Health and Clinical Excellence (NICE) guidelines regarding risk assessment and extended oral prophylaxis following primary and revision knee arthroplasty. We opted to trial the oral anticoagulant drug Rivaroxaban for an initial period of 12 months. All patients undergoing primary or revision knee arthroplasty between 1. st. July 2009 and 30. th. June 2010 and who had no contraindications to the prescription of Rivaroxaban were included in a prospective audit aimed at determining compliance with the newly developed unit guidelines as well as the effectiveness and possible side effects/complications associated with the drug therapy. All patients were monitored for a period of 90 days post operatively. Results. A total of 415 patients were included in the audit (336 primary knee arthroplasty, 27 revision knee arthroplasty, 6 patello-femoral resurfacing, 46 medial unicompartmental knee arthroplasty). Of this group eight had a confirmed VTE (six deep vein thrombosis, two pulmonary embolism). A further 29 patients had post-operative complications which may be attributed in part to the action of Rivaroxaban. The drug was discontinued prematurely for 22 patients. Conclusions. Our results indicate that Rivaroxaban is effective in providing extended VTE prophylaxis to patients undergoing knee arthroplasty surgery. However, as anticipated, anticoagulation therapy does cause associated wound problems

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 patient1. 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 aspirin2.

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.