Thromboprophylaxis for acetabular injuries in the UK

Injury, Int. J. Care Injured (2006) 37, 806—812

www.elsevier.com/locate/injury

Thromboprophylaxis for acetabular injuries in the UK What prophylaxis is used? J.M. Geoghegan *, K. Hassan, D. Calthorpe Department of Trauma and Orthopaedics, Derbyshire Royal Infirmary, Derby DE1 2QY, United Kingdom Received 5 August 2005; received in revised form 26 April 2006; accepted 2 May 2006

KEYWORDS Acetabular fracture; Thromboprophylaxis; Venous thrombosis surveillance screening; Literature review

Summary Due to chronic underfunding and the absence of a comprehensive and coordinated national approach to the management of acetabular trauma throughout the UK, patients can incur prolonged recumbancy. We have performed a postal questionnaire to establish the current clinical practice in the specialist pelvic and acetabular units throughout the UK, with respect to time to surgery from injury, thromboprophylaxis, and surveillance. We have identified 21 units, and 37 surgeons in the NHS who deal with acetabular trauma. The mean time to surgery from injury in the UK is 8.5 days (range 2—19 days). Mechanical thromboprophylaxis was used in 67% (14) of the units. No unit routinely uses prophylactic IVC filters. Chemical thromboprophylaxis is routinely used in 100% (21) of the units. Ninety-five percent (20) used prophylactic doses of LDH or LMWH. Clinical surveillance alone for thromboembolism is employed in 90% (19) of the units. Only 2 (10%) units routinely perform radiological surveillance with ultrasound Doppler, pre-operatively. Currently there is no published directory of dedicated pelvic and acetabular surgeons in the UK. There is no general consensus on the approach to thromboprophylaxis and surveillance in acetabular trauma in the UK. There is no consensus approach to thromboprophylaxis and surveillance in the literature. # 2006 Elsevier Ltd. All rights reserved.

Introduction

* Corresponding author at: 8 Cumbria Grange, Gamston, Nottingham, NG2 6LZ, United Kingdom. Tel.: +44 1159145495. E-mail address: [email protected] (J.M. Geoghegan).

Although it is widely recognised that pelvic disruption in association with high-energy trauma is a life threatening injury, the potential morbidity and mortality associated with acetabular injuries is perhaps less well understood. This may explain why there is no comprehensive or coordinated national approach

0020–1383/$ — see front matter # 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2006.05.001

Thromboprophylaxis for acetabular injuries in the UK to the management of acetabular injuries throughout the UK at this time, despite previous local and regional reports4,39 that highlighted the necessity for prompt specialist management of these complex injuries. Following a recent devastating experience, which illustrated the main addressable issues including thromboprophylaxis, surveillance, and prompt and appropriate referral for specialist management, we have identified 21 units throughout the UK who deal with pelvic and acetabular injuries. As the chronic underfunding of trauma continues to manifest in sometimes prolonged periods of recumbency while awaiting transfer for appropriate specialist care, we have attempted to establish whether there is a comprehensive and coordinated approach to thromboprophylaxis and surveillance in the management of these injuries in the UK. We present the current clinical practice with regard to thromboprophylaxis and surveillance in the management of acetabular injuries in the UK. Current practice is balanced by evidence based literature review in an attempt to identify best practice.

Methods We have identified twenty-one units throughout the UK, where the specialist treatment for pelvic and acetabular injuries is available. We formulated a questionnaire aimed at identifying the number of cases treated in each unit per year, the number of surgeons involved in each unit, and the mean time to surgery from injury. We requested details on thromboprophylaxis and surveillance protocols employed in these units in order to ascertain actual clinical practice. Non-responders were followed up until 100% response was achieved. The data was recorded on a Microsoft Excel spreadsheet.

Results A postal questionnaire was sent to 21 UK NHS Trauma & Orthopaedic Units identified as offering a service in the specialist management of acetabular injuries. All 21 units (100%) replied. Although the questionnaire was specifically related to acetabular injuries, only one unit specified an exact number of cases for acetabular surgery for that year. In 20 units, it was not possible to identify accurately whether their cases involved pelvic, acetabular or combined pelvic and acetabular surgery. Notwithstanding the above, the best information available to our knowledge at this time is that 37 specialist surgeons carried out 872 pelvic and acetabular operations in 2003 in the UK. The mean time from injury to

807 Table 1

Summary of clinical practice

Number of units Total number of surgeons Total cases per year (2003) Number of cases per unit Mean days from injury to surgery

21 37 872 Range = 10—150 8.5 days (range 2—19)

Mechanical thromboprophylaxis Chemical thromboprophylaxis DVT surveillance — radiological

67% 100% 10%

Table 2 Mechanical thromboprophylaxis modalities used in practice Mechanical device

Percentage

AV boots Calf compression device TEDS Routine prophylactic IVC filters Therapeutic IVC filters

24 19 52 0 52

surgery was 8.5 days (range = 2—19 days). The number of cases per unit (range = 10—150) and the number of surgeons per unit (range 1—3) varied greatly (Table 1). Current clinical practice for thromboprophylaxis in acetabular fracture cases was subdivided into mechanical and chemical methods. Surveillance techniques used were also reviewed (Tables 2 & 3). Mechanical thromboprophylaxis was used in 14 of the units (Table 4). Five use arterio-venous (AV) boots, 4 use calf pumps, and 11 use TED stockings. Nine of the units use only one form of mechanical device, 4 employed two methods (AV boot or calf pump + TED), and one unit uses all three methods. No unit surveyed routinely use prophylactic inferior vena cava (IVC) filters in acetabular fracture cases for thromboprophylaxis. One centre uses prophylactic IVC filters in cases greater than 10 days from injury who await surgery and one centre consider a

Table 3

Chemical thromboprophylaxis in practice

Chemical agent

Percentage

Heparin/LMWH Aspirin

95 5

Table 4 Routine venous thromboembolic surveillance in practice Routine DVT surveillance screening

Percentage

Clinical surveillance 90 USS doppler radiological surveillance 10 Other radiological surveillance modalities 0

808 history of previous venous thromboembolism (VTE) an indication for a prophylactic IVC filter. Eleven use therapeutic IVC filters when a deep vein thrombosis has been diagnosed radiologically (Table 2). Chemical thromboprophylaxis is routinely used in all of the units surveyed. Twenty units used prophylactic doses of unfractionated heparin (LDH) or low molecular weight heparin (LMWH) (Table 3). The remaining centre uses aspirin alone in ‘‘more minor injuries’’ and warfarin in ‘‘more major injuries’’. Two units use heparin and then aspirin, and six use warfarin for up to 3 months post-operatively. Clinical surveillance for thromboembolism alone is employed in 19 of the units (Table 4). Only 2 units routinely perform radiological surveillance with ultrasound Doppler on its acetabular fracture cases pre-operatively. One of these units routinely screens patients pre-operatively, 7 days post-op and again 7—10 days later if the patient remains immobile. The other unit screens 1—3 days pre-operatively. Two further units will screen patients following late transfers from other centres. Nineteen units will screen patients for venous thrombosis if clinically suspected (two units failed to complete this question). The modality chosen for this was ultrasound Doppler (8), ultrasound Doppler and venography (4), venography alone (1), and no response (8). Only one unit routinely screens patients after discharge, but this unit does not routinely screen pre-operatively or post-operatively.

Discussion Our study has identified 21 NHS Trauma & Orthopaedic Units with a total of 37 surgeons in the UK, with a regionally recognised expertise in treating pelvic and acetabular trauma. Currently there is no published directory of dedicated pelvic and acetabular surgeons in the UK. The Department of Health, The Trauma Audit and Research Network, AO UK, The British Trauma Society, The British Orthopaedic Association or The Royal College of Surgeons (England, Edinburgh, Glasgow and Ireland), have no record of the NHS Trauma and Orthopaedic Units in the UK that offer such a service in this specialist area or the surgeons whom have a specialist interest in pelvic and acetabular injuries and surgery. Referral it would seem is based on repute and follows traditional lines. We are aware that there is progress towards developing a European Society of Pelvic and Acetabular Surgeons. We have found that the mean time to surgery from injury in the UK is 8.5 days with a large range from unit to unit (2—19 days) in the UK. We could be criticised for the accuracy of our figures relating to

J.M. Geoghegan et al. the total number of acetabular fracture cases (Table 1), but the figures offered in this paper are offered in good faith as the only and best figures currently available. Indeed lack of certainty as to the exact number of acetabular cases carried out in the UK per year underpins the fact that we are unaware as to the actual extent of the problem, is noteworthy itself. This highlights the difficulty in providing and maintaining adequate resources in the treatment of these injuries across the UK. We acknowledge the limitations of a postal questionnaire, and accept that conclusions from this can only provide a broad scope of current clinical practice. We are addressing the issue of the total numbers of pelvic and acetabular surgeons and the total number of surgical cases performed in the UK in a separate study. In general, the surgical management of an acetabular fracture is not an emergency, with treatment whether operative or non-operative aiming to reduce morbidity rather than mortality. A poorly managed acetabular fracture rarely results in death, but the patient will suffer the consequences of early post-traumatic arthritis.18 Long term clinical outcome has been correlated to the complexity of the fracture,21 the quality of reduction,9,19,21,23 associated femoral head injuries,9,21,23 time to surgery,5,9,15,21,30 age of the patient,21,23 and operative complications. There is little guidance in the literature with respect to the optimal time for surgery. Outcomes have been reported to be improved in those operated on within 14 days,5,9 whilst other investigators have reported their results of surgery in those operated upon less than 21 days from injury.21,23,24 Marvin Tile41 believes that the optimal time for surgery is 5—10 days following injury, as beyond 12 days there are increasingly poor results; surgery should only be considered after 21 days in exceptional circumstances. The Better Care for the Severely Injured3 has recommended standards of care for pelvic and acetabular fractures should include referral within 24 h to a tertiary centre, early transfer and reconstruction surgery within 10 days of injury. Four of the units surveyed were not able to meet this target; this includes the two busiest units in the country. Whilst we are unaware of any evidence from the literature to suggest that delay to surgery from injury is associated with increased mortality, reconstruction allows the patient to become progressively more mobile, therefore reducing one of the risk factors for venous thrombosis and thromboembolism. The risk of pulmonary embolism in patients with pelvic and acetabular fractures is 2—10%. Fatal pulmonary embolism remains the third most common cause of death in patients sustaining major trauma who live beyond the first day from injury,10,36,38 and it occurs

Thromboprophylaxis for acetabular injuries in the UK in 0.5—2% of patients with pelvic trauma.25 Thromboprophylaxis is commonly employed to reduce the risk of venous thrombosis. Prophylaxis can be either chemical or mechanical. Currently there are no studies in trauma patients to suggest that there is additive protection using combinations of mechanical and pharmacological prophylaxis. The National Institute for Health and Clinical Excellence (NICE) is expected to publish its guidance in April 2007 entitled ‘‘Venous Thromboembolism: The prevention of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in patients undergoing orthopaedic surgery and other high risk surgical procedures’’. It is not clear whether this will also address the issues of the trauma patient.

Chemical thromboprophylaxis . . .: the evidence The inherent heterogeneity of the trauma population means that research is limited in this field. There are concerns about bleeding risk associated with the use of anticoagulants11,17 and the reliance on an insensitive screening test, duplex scanning, as the efficacy end point.12 Due to the high risk of venous thromboembolism in trauma, recommendations have been made using information from the limited studies in this field combined with extrapolation from other high risk groups.6,26,29 THRIFT II35 concluded that there insufficient data to support specific recommendations for thromboprophylaxis in trauma and that patients should be individually assessed.35 Data now exists that infers that LMWH is superior to LDH for prophylaxis in moderate to high risk trauma patients12,13,33 however Velmanhos et al.44 have shown no difference in the PE rates when comparing LMWH with LDH. LMWH should be strongly considered for use in all high risk patients (except those with head injuries) when their bleeding risk is acceptable.12,13,33 There is no evidence from the literature to show that the use of pharmacological agents, in particular heparin, significantly reduces the incidence of PE and in particular fatal PE.44

Mechanical thromboprophlaxis Elastic graduated compression stockings increase lower limb venous return. There use may be prevented by localised soft tissue injury and swelling. They have never been evaluated in trauma patients. AV Boots mimic the effect of weight bearing by compressing the venous plexus of the foot, increasing femoral blood flow without muscular assistance. Compliance with foot pumps is poor and may limit its use. There is no evidence that their use reduces proximal DVT. There is little evidence of the effect

809 of AV boots in trauma patients; most studies have been in the orthopaedic literature, with small numbers of cases.33 Stannard et al.40 studied mechanical prophylaxis against DVT after pelvic and acetabular fractures and found that pulsatile sequential compression was associated with fewer DVT than standard compression, but this difference was not significant. PE and occasionally fatal PE still occur despite the presence of an IVC filter.14,22,31,32,34 The risks of IVC filters are recurrent non fatal PE (3%) and symptomatic occlusion of the IVC (4.5%).34 Recently there has been an increase in the use of retrievable filters, which may be more appropriate in the trauma patient whose risk of PE may be high for a relatively short period.20,28,33 Currently there is insufficient evidence to recommend the prophylactic insertion of IVC filters in trauma patients, even in those at high risk for VTE.12,13,33 IVC filter insertion is primarily indicated for patients with proven proximal DVT with absolute contraindications to full anticoagulation or requires major surgery in the near future.12,13,33

Routine DVT surveillance . . .: the evidence Surveillance both clinical and radiological in the asymptomatic patient is performed to detect VTE to allow prompt and early treatment in an attempt to decrease the associated complications of postthrombotic limb, PE, chronic lung dysfunction and fatal PE. The majority of patients, who die from a pulmonary embolism, have no prior symptoms of VTE. The sensitivity of detecting a suspected DVT in a patient using clinical examination is extremely unreliable, with a sensitivity of 60—96% and a specificity of 20—72%.2 Doppler ultrasound is widely available; it is of low cost, and permits relatively easy serial examinations, however it is highly operator dependant and is frequently unable to visualise pelvic veins. Sensitivity of non-invasive USS testing for asymptomatic proximal DVT is considerably lower than for symptomatic thrombi.1,42,43 Agnelli et al.1 and Wells et al.42 compared venography and ultrasonography in elective asymptomatic patients, and found USS to have a sensitivity of 62% in detecting proximal asymptomatic DVT. Duplex scanning will fail to detect proximal DVT in a significant proportion of trauma patients and may not result in fewer PE.8 Contrast venography is the gold standard for the diagnosis of DVT in the leg. Pelvic thrombi however are not routinely detected with conventional venography and lower limb injuries can preclude its use. Most screening studies evaluate only the injured extremity; however DVT frequently involves the uninjured extremity as

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Table 5 Summary of literature review Chemical thromboprophylaxis

Mechanical thromboprophylaxis

Surveillance screening

Low molecular weight heparin — when bleeding risk is acceptable (except in those with concurrent head injuries/or other contraindications) There is no evidence from the literature to show that the use of pharmacological agents, in particular heparin, significantly reduces the incidence of PE and in particular fatal PE 44 TEDS stockings — use may be prevented by localised soft tissue injury and swelling. Have not been evaluated in trauma patients AV boots — little evidence of the effect of AV boots in trauma patient; most studies have been in the orthopaedic literature, with small numbers of cases 33 Prophylactic IVC filters — insufficient evidence to recommend the prophylactic insertion of IVC filters in trauma patients12,13,33 Therapeutic IVC filters — IVC filter insertion is primarily indicated for patients with proven proximal DVT with absolute contraindications to full anticoagulation or requires major surgery in the near future12,13,33 Currently there is no evidence from the literature to support the use of routine surveillance. There is no evidence to show that routine screening reduces the risk of fatal PE12,13,33

well.7,27,36 Montgomery et al.27 used MR venography to show that in patients with acutely displaced acetabular fractures, 34% had asymptomatic thrombi; 76% of these where in the injured extremity, 12% were bilateral and 12% had thrombi seen in the uninjured extremity. It has a high sensitivity and specificity for the detection of DVT within the thigh and pelvis. It was further suggested that it will eliminate the complications from contrast venography, prevent the placement of filters in high risk patients who do not have thrombi, and decrease the prevalence of pulmonary embolism arising from occult pelvic vein thrombosis.27 However, MRI is expensive and relatively inaccessible and may not be possible in all patients. There is no scientific evidence from the literature as to when surveillance screening should be performed and whether it should be serial, irrespective of the modality chosen. In studies where routine radiological screening is performed, the risk of PE remains 2—4%, often developing in patients with negative screening results.8,16,37 Routine screening cannot be justified in trauma patients, but may well

be beneficial in patients who are transferred from another centre where effective prophylaxis was not utilized, or in high risk patients in whom early prophylaxis has not been possible prior to major surgical intervention. Currently there is no evidence from the literature to support the use of routine surveillance. There is no evidence to show that routine screening reduces the risk of fatal PE.12,13,33

Conclusion We have identified 21 tertiary referral units in the UK that offer reconstructive surgery for acetabular fractures. This study shows that there is great variation in the time to surgery from injury with acetabular fracture cases throughout the UK, with the larger units that accept and treat patients from outside their region experiencing the greatest delay to surgery. We would seem to be unaware of the exact number of acetabular injuries and surgical cases that are performed in the UK each year. Currently there is no published directory to identify

Table 6 Proposed protocol for thromboprophylaxis in acetabular trauma cases in a ‘‘referring unit’’ Chemical thromboprophylaxis Mechanical thromboprophylaxis

Surveillance screening

LMWH: when bleeding risk is acceptable (except in those with concurrent head injuries/or other contraindications) TEDS: limited evidence to support in trauma patients. However, universally available and little associated comorbidity AV boots: limited evidence to support use in trauma patients. Poor compliance. Little associated comorbidity Therapeutic IVC filters: for patients with proven proximal DVT with absolute contraindications to full anticoagulation or requires major surgery in the near future. Not routinely

Note: Know your referral centre/s and their preferences — discuss unusual cases.

Thromboprophylaxis for acetabular injuries in the UK surgeons/units that offer specialist facilities for pelvic and acetabular trauma in the UK. This highlights the difficulty in providing, maintaining and improving adequate resources in the treatment of these injuries across the UK. Due to chronic underfunding and the absence of a comprehensive and coordinated national approach to the management of acetabular trauma throughout the UK, patients may incur prolonged recumbancy. There is no general consensus on the approach to thromboprophylaxis and surveillance in acetabular trauma in the UK. There is no consensus approach to thromboprophylaxis and surveillance in the literature (Table 5). Balancing the collective wisdom of the UK pelvic and acetabular surgeons with evidence based medicine; we propose to adopted the following protocol for these injuries in our large District General Hospital (Table 6).

Acknowledgements Mr David Hann and Mr Philip Radford Consultant Orthopaedic and Trauma Surgeons, Queens Medical Centre Nottingham for their support and advice. Anne Cannon for her secretarial assistance. Mr Greg Hattan and Mr Khosrow Sehat for their professional advice.

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