Injury, Int. J. Care Injured 46 (2015) 1108–1111
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Symptomatic venous thromboembolism following circular frame treatment for tibial fractures S. Vollans a,*, A. Chaturvedi a, K. Sivasankaran a, T. Madhu a, Y. Hadland b, V. Allgar c, H.K. Sharma d a
Orthopaedics, Hull Royal Infirmary, Hull, United Kingdom Ilizarov Nursing, Hull Royal Infirmary, Hull, United Kingdom Statistics, University of York, Health Sciences, York, United Kingdom d Consultancy in Orthopaedic Surgery, Hull Royal Infirmary, Hull, United Kingdom b c
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 7 April 2015
Introduction: Venous thromboembolism (VTE) is a significant cause of morbidity and mortality following tibial fractures. The risk is as high as 77% without prophylaxis and around 10% with prophylaxis. Within the current literature there are no figures reported specifically for those individuals treated with circular frames. Our aim was to evaluate the VTE incidence within a single surgeon series and to evaluate potential risk factors. Methods: We retrospectively reviewed our consecutive single surgeon series of 177 patients admitted to a major trauma unit with tibial fractures. All patients received standardised care, including chemical thromboprophylaxis within 24 h of injury until independent mobility was achieved. We comprehensively reviewed our prospective database and medical records looking at demographics and potential risk factors. Results: Seven patients (4.0% 2.87%) developed symptomatic VTE during the course of frame treatment; three deep vein thrombosis (DVTs) and four pulmonary embolisms (PEs). Those with a VTE event had significantly increased body mass index (BMI) (p = 0.01) when compared to those without symptomatic VTE. No differences (p > 0.05) were observed between the groups in age, gender, smoking status, fracture type (anatomical allocation or open/closed), delay to frame treatment, weight bearing status post-frame, inpatient stay or total duration of frame treatment. Conclusion: This study suggests that increased BMI is a statistically significant risk factor for VTE, as reported in current literature. In addition, we calculated the true risk of VTE following circular frame treatment for tibial fracture in our series is from 1.13% to 6.87%, which is at least comparable to other forms of treatment. ß 2015 Elsevier Ltd. All rights reserved.
Keywords: Tibial fracture External fixation Ilizarov Taylor spatial frame TSF Deep vein thrombosis DVT Venous thromboembolism VTE Pulmonary embolism PE Incidence
Introduction Venous thromboembolism (VTE) is a frequent and potentially life-threatening complication after trauma [1,2]. Without prophylaxis the incidence of deep vein thrombosis (DVT) following trauma is over 50% [3–5]. The risk of pulmonary embolism (PE) can range from 2.3% to 20% depending on associated injuries [3]. The risk of fatal PE is fortunately limited to less than 0.5% [6]. Overall, the risk of VTE is five times higher in patients with fractures of the tibia, as compared to trauma patients without these injuries [3].
* Corresponding author. Tel.: +07816549712. E-mail address: [email protected] (S. Vollans). http://dx.doi.org/10.1016/j.injury.2015.04.003 0020–1383/ß 2015 Elsevier Ltd. All rights reserved.
Pathogenesis is multifactorial but relates to venous stasis, direct and indirect damage to the vascular intimal layer, and generalised activation of the coagulation cascade; Virchow’s triad [7,8]. Hypercoagulability is found in 85% of trauma patients [9] and persists for more than one month in 80% of cases. Most DVTs that occur in trauma patients begin in the deep veins of the calf and often do not extend proximally. For that reason they often remain asymptomatic [3,11]. In fact, less than 2% of trauma patients suffer symptomatic DVT. This can be mostly attributed to the fact that in lower limb trauma patients, the presence of pre-existing leg pain and swelling complicate the clinical diagnosis of DVT [12,13]. Various mechanical and chemical methods are available for prophylaxis. None of these methods have been shown to provide complete prevention from VTE. The risk of venographic proven DVT can be
S. Vollans et al. / Injury, Int. J. Care Injured 46 (2015) 1108–1111
1109
whether they were closed or open. Patients received either Ilizarov or Taylor Spatial Frame (TSF) based on fracture configuration. We retrospectively reviewed all patients’ notes in addition to our database to confirm there were no other admissions under other specialities with VTE events. We made note of the following parameters: age, gender, body mass index (BMI), smoking status, fracture type (anatomy and open/closed), delay to frame treatment, weight bearing status post-frame, inpatient stay, total duration of frame treatment and injury severity score (ISS). Descriptive statistics were calculated; means with standard deviation (s.d.) for parametric, and medians with interquartile ranges for non-parametric data. The Student T-test (TT) was used to compare age and BMI (unpaired parametric data). Fishers exact test (FE) for gender, smoking, fracture type and postop weight bearing status (categorical data). Mann–Whitney U test (MW) was used to analyse delay to frame, inpatient stay and duration of frame treatment (unpaired nonparametric data).
reduced to less than 10% with prophylaxis regardless of the type of treatment for fracture or the VTE prophylaxis used [14]. Circular frames are now widely used in the treatment of tibial fractures and these results are not currently represented in the literature. There are few reports available regarding the risk of VTE in this subset of patients during their course of treatment. Sems et al. [15] reported a risk of 2.1% following their protocol of early spanning external fixation followed by definitive internal fixation, while Ramos et al. [16] reported no cases of DVT when they treated 39 distal tibial fractures with circular frames. The aim of this paper was to review data from a large single surgeon series of consecutive circular frames treating tibial fractures of all types. We planned to calculate the incidence of VTE events in our series. In addition, to further identify contributory risk factors leading to VTE events.
Patients and methods
Results A retrospective review of prospectively collected data within our unit was performed. Hull Royal Infirmary is a major trauma centre, treating patients directly from its own Emergency Department and surrounding hospitals. Consecutive patients treated between 2004 and 2011 with circular frames for acute tibial fracture were included. Patients were treated initially with an above knee plaster backslab including the foot. If soft tissue resuscitation or provisional reduction/alignment was required, a temporary external fixator was applied, which remained until definitive surgery. All patients had a standardised VTE risk assessment on admission and if no contraindications, received a single subcutaneous prophylactic dose of Dalteparin 5000 units once daily starting immediately. Chemical thromboprophylaxis was continued until patients were mobilising weight bearing as tolerated. Patients with tibial shaft fractures were allowed to fully weight bear postoperatively, but those with periarticular fractures were advised to non-weight bear, progressing to weight bearing as tolerated at 6 weeks. Where either the ankle or knee joint was spanned, prophylaxis was continued until the joint spanning fixation was removed—this was irrespective of weight bearing status. Potentially symptomatic patients were deemed to be so if they subjectively complained of increasing pain and swelling in the lower limb. Wells score (two-level DVT score) as recommended by the National Institute of Clinical Excellence [17] was not felt appropriate, as all patients would score above the threshold value of 2, leading to further investigation. Suspected patients underwent ultrasound Doppler scan to diagnose DVT and Computed Tomography Pulmonary Angiogram (CTPA) to diagnose PE. Once VTE was diagnosed, patients received treatment dose of Dalteparin initially and warfarin thereafter for 3–6 months. All patients were operated on by the senior author, who was directly involved in peri-operative care until discharge. Fractures were classified according to anatomy (plateau, shaft or pilon) and
During the study period 177 patients were treated with circular frames for tibial fractures. The average ISS score was 9 (mode), 4 individuals had previous history of VTE and 3 females were on the oral contraceptive pill on admission. Sixty-two individuals required spanning external fixation prior to definitive surgery and the remaining individuals had an above knee back-slab until surgery. Ilizarov frames were used in 115 patients, and TSFs in 62. There was 100% compliance of VTE prophylaxis, with all patients receiving low molecular weight heparin (LMWH) within 24 h of injury. The median delay to surgery was 9 days in the nonVTE group and 4 days in the VTE group. The median inpatient stay was 11 days in the non-VTE group and 15 days in the VTE group. The frame duration was 23 weeks in the non-VTE group and 29 weeks in the VTE group. The interquartile ranges of these median averages were such that these three results were not statistically significant. Symptomatic VTE occurred in 7 patients (Table 1), which represents a proportion of 4.0% 2.87% (95%CI); DVT in 3 patients (1.7%) and PE in 4 (2.3%). None of the seven patients had either a past medical history of VTE or were taking the oral contraceptive pill. Diagnosis of VTE events was made between 2 weeks and 38 weeks post injury. PE tended to be diagnosed earlier than DVT, but the numbers were too small to analyse further. The demographics (age, gender, BMI and smoking status) of the complete case series, in addition to subgroups of patients with and without VTE events are shown in Table 2. The BMI of the VTE group was found to be significantly higher than the non-VTE group (p = 0.01). The other patient related factors were found to be nonsignificant (p > 0.05). The non-demographic related variables with statistical analysis are illustrated in Table 3. In all these results the VTE group was comparable to the non-VTE group, with no statistical difference seen, though trends in the VTE group were observed towards earlier surgery, longer inpatient stay and longer frame durations.
Table 1 VTE group demographics, including whether DVT or PE and time from injury to diagnosis.
1 2 3 4 5 6 7
Age
Gender
BMI
Smoking
Fracture type
Open or closed
Delay to frame/days
Weight bearing
Inpatient stay/days
Frame duration/weeks
VTE Occurrence/weeks after injury
46 31 57 33 53 60 60
M F M F F M M
32 29 32 33 39 29 28
N N N N Y Y N
Plateau Shaft Pilon Shaft Shaft Plateau Pilon
C O C C O C C
4 1 8 4 9 3 31
NWB FWB NWB FWB FWB NWB NWB
37 7 25 12 11 44 15
54 21 18 29 30 33 26
PE 15/52 DVT 2/52 PE 4/52 PE 10/52 DVT 38/52 DVT 38/52 PE 13/52
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Table 2 Patient factors within the series by VTE occurrence, with statistical analyses (TT = Student T-test, FE = Fisher’s exact,
Age—mean yrs (s.d.) Gender (female) BMI—mean (s.d.) Smoker
Non-VTE group n = 170
VTE group n = 7
Statistics
45 (15.9) 50 (28%) 27.4 (4.8) 39 (22%)
45 (16.0) 47 (28%) 27.2* (4.8) 37 (22%)
49 (12.3) 3 (43%) 31.9* (3.6) 2 (29%)
p = 0.510 p = 0.405 p = 0.010 p = 0.650
Major trauma often precipitates one or all the factors in Virchow’s triad; hypercoagulability, endothelial injury and venous stasis [18]. Consumption of clotting factors, acidosis, hypothermia, packed cell administration and dilution from intravenous crystalloid alter the patients’ coagulation state [19,20]. Meissner et al. [10] suggested this hypercoagulation state persists for at least one month after injury in 80% of patients. In another study by Selby et al. [21], significant hypercoagulability was noted within the first 24 h following trauma. This state was significantly higher in women than men, and remained elevated between 5 and 14 days, when it began to return towards normal. Direct injury to blood vessels at the time of trauma causes intimal damage leading to local thrombosis. In addition, prolonged bed rest, immobilisation, hypoperfusion and paralysis all promote venous stasis [3]. Geerts et al. [3] and Knudson et al. [22] identified through logistic regression analysis, factors to be independently predictors for DVT: age above 40 years, lower extremity fracture, ventilator days of >3 and operative time of more than 2 h [23]. Presence of spinal, pelvic or lower extremity fractures significantly increases the risk of VTE as opposed to other injuries [3,23]. VTE was seen five-times more commonly with tibial or femoral fractures [3]. This is mainly due to reduced mobility and longer hospital stays in these patients. Gender, mechanism of injury, and injury severity score were not significantly associated with increase risk of VTE [3]. Surprisingly, there is minimal literature on VTE rates in patients with tibial fractures. Lapidus et al. [24] studied 36,388 orthopaedic patients over a 10 year period looking at symptomatic VTE which were clinically suspected and subsequently proven with ultrasound or post-mortem. Within their cohort of 1072 patients with tibial fractures they reported rates for proximal, diaphyseal and distal tibial fractures of 3.8% (95%CI 2.3–6.3), 2.2% (95%CI 1.2–4.0) and 1.7% (95%CI 0.6–5.3), respectively. Abelseth et al. [25] performed venographic surveillance looking for silent DVTs in 90 patients with operatively treated tibial fractures without chemical thromboprophylaxis. The incidence for plateau, shaft and
Table 3 Results and statistical analysis of the non-patient factors (MW = Mann Whitney Utest, 2 3 FE = 2 3 contingency table Fisher’s exact).
Timings Delay to surgery/days Inpatient stay/days Frame duration/weeks Fracture type Plateau (14%) Shaft (46%) Pilon (40%) Closed/open Closed (73%) Open (27%) Weight bearing FWB NWB
indicates significance).
All patients n = 177
Discussion
Non-VTE group n = 170
*
VTE group n=7
Statistics
9 11 23
4 15 29
p = 0.30 (MW) p = 0.10 (MW) p = 0.10 (MW)
2 2 3
23 80 67
p = 0.36 (2 3 FE)
5 2
125 45
p = 1.0 (FE)
88 82
4 3
p = 1.0 (FE)
(TT) (FE) (TT) (FE)
plafond fractures was 43%, 22% and 12.5%, respectively. Geerts et al. [3] also exposed this contrast between silent and symptomatic DVT rates from their venographic surveillance study of 716 major trauma patients. Without chemical prophylaxis an incidence of DVT of 58% was observed, of which only 3 (0.4%) patients had any clinical features prior to venography. Without prophylaxis the incidence of venogram proven DVT is reported to be as high as 77% [23] reducing to less than 10% with prophylaxis irrespective of the type of chemical thrombo-prophylaxis or the definitive fixation technique [14]. Proximal extension of DVT above the knee is uncommon, with a risk of PE ranging from 2.3% to 22% and fatal PE < 0.5% [6]. In terms of clinical presentation and assessment, less than 2% of patients with positive venogram for DVT are symptomatic [3,26,27]. Agudelo et al. [28] suggested the clinical diagnosis of DVT is often unreliable in trauma patients, due to associated swelling and pain from the extremity fracture. The commonly used Homan’s sign even in high-risk patient has a sensitivity and specificity of less than 50%. Wells et al. [29] introduced a risk stratifying assessment model which improved inter-observer reliability and in 85% of cases successfully predicted the presence of a DVT upon subsequent ultrasound scanning. Whilst the Wells score is used in our hospital, its use leads to over investigation of tibial fractures, secondary to the presence of perioperative pain, erythema and swelling. The clinical judgement and experience of the senior author looking for symptoms and signs of increasing pain in the leg or thigh, redness and swelling was vital to ensure accurate and timely referral for diagnostic tests. The true incidence of VTE following lower extremity fracture without the use of venograms is difficult to determine and will be higher than we report. In addition though, there continues to be a lack of understanding with regard to the clinical significance of asymptomatic or silent DVT, in relation to subsequent morbidity and mortality. It is widely accepted that silent DVTs do not progress clinically and, as such are not treated in the same way as symptomatic DVT [25]. More recent studies looking at DVT surveillance in major trauma and intensive care have shown a reduction in the incidence of PE as a result of early diagnosis and subsequent treatment of silent DVTs [30]. In the presence of a confirmed DVT, the incidence of a so-called silent PE is 66%, but diagnosis is not necessary as there are no associated short or longterm clinical consequences [31]. There is a lack of literature both regarding the incidence of VTE in circular frame management, and the appropriate protocol for thromboprophylaxis. Sems et al. [15] noted an incidence of 2.1% in patients treated with external fixation followed by definitive internal fixation for tibial fractures. Ramos et al. [16] reported no symptomatic DVTs in their series of 39 distal tibial fractures treated using Ilizarov frames with low-molecular weight heparin prophylaxis starting from the day of admission until 10 days after leaving the hospital. The risk of VTE in our study following circular frame treatment for tibial fracture was 4.0% (true value between 1.13% and 6.87%). Calculating the true incidence would be difficult due to the number of patients required to power the study. The current study has shown that the use of LMWH from the day of admission until the patient is weight bearing as tolerated results in a risk of VTE, which is at least no higher than other forms of
S. Vollans et al. / Injury, Int. J. Care Injured 46 (2015) 1108–1111
treatment. As 71% of patients in our series developed VTE 10 weeks or more following surgery including 2 patients after frame removal, more questions are raised. Since the incidence of VTE is small and appears to be unrelated to weight bearing or mobility, is prophylaxis justified at all in circular frames for trauma and if so, for what duration? Further studies are certainly required to increase the bulk of literature regarding the subject and since randomised control trials are not feasible, further case series followed by a systematic review may eventually offer some answers. Conflict of interest statement On behalf of my co-authors, I can confirm that there are no conflicts of interest to declare, in relation to financial or personal relationships with other people or organisations that could inappropriately influence (bias) our work. References [1] Ashrani AA, Heit JA. Incidence and cost burden of post-thrombotic syndrome. J Thromb Thrombolysis 2009;28:465–76. [2] Ruppert A, Lees M, Steinle T. Clinical burden of venous thromboembolism. Curr Med Res Opin 2010;26:2465–73. [3] Geerts WH, Code KI, Jay RM, Chen E, Szalai JP. A prospective study of venous thromboembolism after major trauma. N Engl J Med 1994;331:1601–6. [4] Kudsk KA, Fabian TC, Baum S, Gold RE, Mangiante E, Voeller G. Silent deep vein thrombosis in immobilized multiple trauma patients. Am J Surg 1989;158:515–9. [5] Geerts WH, Heit JA, Clagett GP, Pineo GF, Colwell CW, Anderson Jr FA, et al. Prevention of venous thromboembolism. Chest 2001;119(1):132S–75S. [6] Giannoudis PV, Soucacos PN. An update on venous thromboembolism in trauma, orthopaedic and reconstructive surgery. Curr Vasc Pharmacol 2011;9:1–2. [7] Virchow RLK. Collected essays on scientific medicine. Meidinger: Frankfurt Am Main; 1856 [in German]. [8] Nillius AS, Nylander G. Deep vein thrombosis after total hip replacement: a clinical and phlebographic study. Br J Surg 1979;66:324–6. [9] Engelman DT, Gabram SG, Allen L, Ens GE, Jacobs LM. Hypercoagulability following multiple trauma. World J Surg 1996;20:5–10. [10] Meissner MH, Chandler WL, Elliot JS. Venous thromboembolism in trauma: a local manifestation of systemic hypercoagulability. J Trauma 2003;54:224–31. [11] Sevitt S, Gallagher N. Venous thrombosis and pulmonary embolism: a clinicopathological study in injured and burned patients. Br J Surg 1961;48:475–89. [12] Paiement GD, Mendelsohn C. The risk of venous thromboembolism in the orthopedic patient: epidemiological and physiological data. Orthopedics 1997;20(Suppl.):7–9. [13] Cipolle M, Wojcik R, Seislove E, Wasser TE, Pasquale MD. The role of surveillance duplex scanning in preventing venous thromboembolism in trauma patients. J Trauma 2002;52:453–62.
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[14] Goel DP, Buckley R, deVries G, Abelseth G, Ni A, Gray R. Prophylaxis of deepvein thrombosis in fractures below the knee: a prospective randomised controlled trial. J Bone Joint Surg Br 2009;91:388–94. [15] Sems SA, Levy BA, Dajani K, Herrera DA, Templeman DC. Incidence of deep venous thrombosis after temporary joint spanning external fixation for complex lower extremity injuries. J Trauma 2009;66:1164–6. [16] Ramos T, Karlsson J, Eriksson BI, Nistor L. Treatment of distal tibial fractures with the Ilizarov external fixator—a prospective observational study in 39 consecutive patients. BMC Musculoskelet Disord 2013;14:30. [17] National Institute for Health and Care Excellence (NICE). Venous Thromboembolic diseases: the management of venous thromboembolic diseases and the role of the thrombophilia testing. In: National Institute for Health and Care Excellence (NICE) guideline CG144. Manchester, UK: National Institute for Health and Care Excellence (NICE); 2012 June. [18] The PIOPED Investigators. Value of the ventilation/perfusion scan in acute pulmonary embolism: results of the prospective investigation of pulmonary embolism diagnosis (PIOPED). JAMA 1990;263:2753–9. [19] Kakkar VV, Howe CT, Nicolaides AN, Renney JT, Clarke MB. Deep vein thrombosis of the leg: is there a high risk group. Am J Surg 1970;120:527–30. [20] Gillum RF. Pulmonary embolism and thrombophlebitis in the United States, 1970–1985. Am Heart J 1987;114:1262–4. [21] Selby R, Geerts W, Ofosu FA, Craven S, Dewar L, Phillips A, et al. Hypercoagulability after trauma: hemostatic changes and relationship to venous thromboembolism. Thromb Res 2009;124:281–7. [22] Knudson MM, Ikossi DG, Khaw L, Morabito D, Speetzen LS. Thromboembolism after trauma: an analysis of 1602 episodes from the American College of Surgeons National Trauma Data Bank. Ann Surg 2004;240:490–8. [23] Thorson CM, Ryan ML, Van Haren RM, Curia E, Barrera JM, Guarch GA, et al. Venous thromboembolism after trauma: a never event. Crit Care Med 2012;40:2967–73. [24] Lapidus LJ, Ponzer S, Pettersson H, de Bri E. Symptomatic venous thromboembolism and mortality in orthopaedic surgery—an observational study of 45,968 consecutive procedures. BMC Musculoskelet Disord 2013;14:177. [25] Abelseth G, Buckley RE, Pineo GE, Hull R, Rose MS. Incidence of deep vein thrombosis in patients with fractures of the lower extremity distal to the hip. J Orthop Trauma 1996;10:230–5. [26] Norwood SH, McAuley CE, Berne JD, Vallina VL, Kerns DB, Grahm TW, et al. A potentially expanded role for enoxaparin in preventing venous thromboembolism in high risk blunt trauma patients. J Am Coll Surg 2001;192: 161–7. [27] Wenzl ME, Hasse W, Seide K, Wolter D. Prevention of thromboembolism with low-molecular-weight heparin in orthopedic surgery: a 5-year experience. Clin Appl Thromb Hemost 2004;10:1–4. [28] Agudelo JF, Morgan SJ, Smith WR. Venous thromboembolism in orthopedic trauma patients. Orthopedics 2005;28:1164–71. [29] Wells PS, Hirsh J, Anderson DR, et al. Accuracy of clinical assessment of deep vein thrombosis. Lancet 1995;345:1326–30. [30] Piotrowski JJ, Alexander JJ, Brandt CP, McHenry CR, Yuhas JP, et al. Is deep vein thrombosis surveillance warranted in high-risk trauma patients. Am J Surg 1996;172:210–3. [31] Garcı´a-Fuster MJ, Fabia MJ, Furio´ E, Pichler G, Redon J, Forner MJ, et al. Should we look for silent pulmonary embolism in patients with deep venous thrombosis? BMC Cardiovasc Disord 2014;14:178.
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Symptomatic venous thromboembolism following circular frame treatment for tibial fractures S. Vollans a,*, A. Chaturvedi a, K. Sivasankaran a, T. Madhu a, Y. Hadland b, V. Allgar c, H.K. Sharma d a
Orthopaedics, Hull Royal Infirmary, Hull, United Kingdom Ilizarov Nursing, Hull Royal Infirmary, Hull, United Kingdom Statistics, University of York, Health Sciences, York, United Kingdom d Consultancy in Orthopaedic Surgery, Hull Royal Infirmary, Hull, United Kingdom b c
A R T I C L E I N F O
A B S T R A C T
Article history: Accepted 7 April 2015
Introduction: Venous thromboembolism (VTE) is a significant cause of morbidity and mortality following tibial fractures. The risk is as high as 77% without prophylaxis and around 10% with prophylaxis. Within the current literature there are no figures reported specifically for those individuals treated with circular frames. Our aim was to evaluate the VTE incidence within a single surgeon series and to evaluate potential risk factors. Methods: We retrospectively reviewed our consecutive single surgeon series of 177 patients admitted to a major trauma unit with tibial fractures. All patients received standardised care, including chemical thromboprophylaxis within 24 h of injury until independent mobility was achieved. We comprehensively reviewed our prospective database and medical records looking at demographics and potential risk factors. Results: Seven patients (4.0% 2.87%) developed symptomatic VTE during the course of frame treatment; three deep vein thrombosis (DVTs) and four pulmonary embolisms (PEs). Those with a VTE event had significantly increased body mass index (BMI) (p = 0.01) when compared to those without symptomatic VTE. No differences (p > 0.05) were observed between the groups in age, gender, smoking status, fracture type (anatomical allocation or open/closed), delay to frame treatment, weight bearing status post-frame, inpatient stay or total duration of frame treatment. Conclusion: This study suggests that increased BMI is a statistically significant risk factor for VTE, as reported in current literature. In addition, we calculated the true risk of VTE following circular frame treatment for tibial fracture in our series is from 1.13% to 6.87%, which is at least comparable to other forms of treatment. ß 2015 Elsevier Ltd. All rights reserved.
Keywords: Tibial fracture External fixation Ilizarov Taylor spatial frame TSF Deep vein thrombosis DVT Venous thromboembolism VTE Pulmonary embolism PE Incidence
Introduction Venous thromboembolism (VTE) is a frequent and potentially life-threatening complication after trauma [1,2]. Without prophylaxis the incidence of deep vein thrombosis (DVT) following trauma is over 50% [3–5]. The risk of pulmonary embolism (PE) can range from 2.3% to 20% depending on associated injuries [3]. The risk of fatal PE is fortunately limited to less than 0.5% [6]. Overall, the risk of VTE is five times higher in patients with fractures of the tibia, as compared to trauma patients without these injuries [3].
* Corresponding author. Tel.: +07816549712. E-mail address: [email protected] (S. Vollans). http://dx.doi.org/10.1016/j.injury.2015.04.003 0020–1383/ß 2015 Elsevier Ltd. All rights reserved.
Pathogenesis is multifactorial but relates to venous stasis, direct and indirect damage to the vascular intimal layer, and generalised activation of the coagulation cascade; Virchow’s triad [7,8]. Hypercoagulability is found in 85% of trauma patients [9] and persists for more than one month in 80% of cases. Most DVTs that occur in trauma patients begin in the deep veins of the calf and often do not extend proximally. For that reason they often remain asymptomatic [3,11]. In fact, less than 2% of trauma patients suffer symptomatic DVT. This can be mostly attributed to the fact that in lower limb trauma patients, the presence of pre-existing leg pain and swelling complicate the clinical diagnosis of DVT [12,13]. Various mechanical and chemical methods are available for prophylaxis. None of these methods have been shown to provide complete prevention from VTE. The risk of venographic proven DVT can be
S. Vollans et al. / Injury, Int. J. Care Injured 46 (2015) 1108–1111
1109
whether they were closed or open. Patients received either Ilizarov or Taylor Spatial Frame (TSF) based on fracture configuration. We retrospectively reviewed all patients’ notes in addition to our database to confirm there were no other admissions under other specialities with VTE events. We made note of the following parameters: age, gender, body mass index (BMI), smoking status, fracture type (anatomy and open/closed), delay to frame treatment, weight bearing status post-frame, inpatient stay, total duration of frame treatment and injury severity score (ISS). Descriptive statistics were calculated; means with standard deviation (s.d.) for parametric, and medians with interquartile ranges for non-parametric data. The Student T-test (TT) was used to compare age and BMI (unpaired parametric data). Fishers exact test (FE) for gender, smoking, fracture type and postop weight bearing status (categorical data). Mann–Whitney U test (MW) was used to analyse delay to frame, inpatient stay and duration of frame treatment (unpaired nonparametric data).
reduced to less than 10% with prophylaxis regardless of the type of treatment for fracture or the VTE prophylaxis used [14]. Circular frames are now widely used in the treatment of tibial fractures and these results are not currently represented in the literature. There are few reports available regarding the risk of VTE in this subset of patients during their course of treatment. Sems et al. [15] reported a risk of 2.1% following their protocol of early spanning external fixation followed by definitive internal fixation, while Ramos et al. [16] reported no cases of DVT when they treated 39 distal tibial fractures with circular frames. The aim of this paper was to review data from a large single surgeon series of consecutive circular frames treating tibial fractures of all types. We planned to calculate the incidence of VTE events in our series. In addition, to further identify contributory risk factors leading to VTE events.
Patients and methods
Results A retrospective review of prospectively collected data within our unit was performed. Hull Royal Infirmary is a major trauma centre, treating patients directly from its own Emergency Department and surrounding hospitals. Consecutive patients treated between 2004 and 2011 with circular frames for acute tibial fracture were included. Patients were treated initially with an above knee plaster backslab including the foot. If soft tissue resuscitation or provisional reduction/alignment was required, a temporary external fixator was applied, which remained until definitive surgery. All patients had a standardised VTE risk assessment on admission and if no contraindications, received a single subcutaneous prophylactic dose of Dalteparin 5000 units once daily starting immediately. Chemical thromboprophylaxis was continued until patients were mobilising weight bearing as tolerated. Patients with tibial shaft fractures were allowed to fully weight bear postoperatively, but those with periarticular fractures were advised to non-weight bear, progressing to weight bearing as tolerated at 6 weeks. Where either the ankle or knee joint was spanned, prophylaxis was continued until the joint spanning fixation was removed—this was irrespective of weight bearing status. Potentially symptomatic patients were deemed to be so if they subjectively complained of increasing pain and swelling in the lower limb. Wells score (two-level DVT score) as recommended by the National Institute of Clinical Excellence [17] was not felt appropriate, as all patients would score above the threshold value of 2, leading to further investigation. Suspected patients underwent ultrasound Doppler scan to diagnose DVT and Computed Tomography Pulmonary Angiogram (CTPA) to diagnose PE. Once VTE was diagnosed, patients received treatment dose of Dalteparin initially and warfarin thereafter for 3–6 months. All patients were operated on by the senior author, who was directly involved in peri-operative care until discharge. Fractures were classified according to anatomy (plateau, shaft or pilon) and
During the study period 177 patients were treated with circular frames for tibial fractures. The average ISS score was 9 (mode), 4 individuals had previous history of VTE and 3 females were on the oral contraceptive pill on admission. Sixty-two individuals required spanning external fixation prior to definitive surgery and the remaining individuals had an above knee back-slab until surgery. Ilizarov frames were used in 115 patients, and TSFs in 62. There was 100% compliance of VTE prophylaxis, with all patients receiving low molecular weight heparin (LMWH) within 24 h of injury. The median delay to surgery was 9 days in the nonVTE group and 4 days in the VTE group. The median inpatient stay was 11 days in the non-VTE group and 15 days in the VTE group. The frame duration was 23 weeks in the non-VTE group and 29 weeks in the VTE group. The interquartile ranges of these median averages were such that these three results were not statistically significant. Symptomatic VTE occurred in 7 patients (Table 1), which represents a proportion of 4.0% 2.87% (95%CI); DVT in 3 patients (1.7%) and PE in 4 (2.3%). None of the seven patients had either a past medical history of VTE or were taking the oral contraceptive pill. Diagnosis of VTE events was made between 2 weeks and 38 weeks post injury. PE tended to be diagnosed earlier than DVT, but the numbers were too small to analyse further. The demographics (age, gender, BMI and smoking status) of the complete case series, in addition to subgroups of patients with and without VTE events are shown in Table 2. The BMI of the VTE group was found to be significantly higher than the non-VTE group (p = 0.01). The other patient related factors were found to be nonsignificant (p > 0.05). The non-demographic related variables with statistical analysis are illustrated in Table 3. In all these results the VTE group was comparable to the non-VTE group, with no statistical difference seen, though trends in the VTE group were observed towards earlier surgery, longer inpatient stay and longer frame durations.
Table 1 VTE group demographics, including whether DVT or PE and time from injury to diagnosis.
1 2 3 4 5 6 7
Age
Gender
BMI
Smoking
Fracture type
Open or closed
Delay to frame/days
Weight bearing
Inpatient stay/days
Frame duration/weeks
VTE Occurrence/weeks after injury
46 31 57 33 53 60 60
M F M F F M M
32 29 32 33 39 29 28
N N N N Y Y N
Plateau Shaft Pilon Shaft Shaft Plateau Pilon
C O C C O C C
4 1 8 4 9 3 31
NWB FWB NWB FWB FWB NWB NWB
37 7 25 12 11 44 15
54 21 18 29 30 33 26
PE 15/52 DVT 2/52 PE 4/52 PE 10/52 DVT 38/52 DVT 38/52 PE 13/52
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Table 2 Patient factors within the series by VTE occurrence, with statistical analyses (TT = Student T-test, FE = Fisher’s exact,
Age—mean yrs (s.d.) Gender (female) BMI—mean (s.d.) Smoker
Non-VTE group n = 170
VTE group n = 7
Statistics
45 (15.9) 50 (28%) 27.4 (4.8) 39 (22%)
45 (16.0) 47 (28%) 27.2* (4.8) 37 (22%)
49 (12.3) 3 (43%) 31.9* (3.6) 2 (29%)
p = 0.510 p = 0.405 p = 0.010 p = 0.650
Major trauma often precipitates one or all the factors in Virchow’s triad; hypercoagulability, endothelial injury and venous stasis [18]. Consumption of clotting factors, acidosis, hypothermia, packed cell administration and dilution from intravenous crystalloid alter the patients’ coagulation state [19,20]. Meissner et al. [10] suggested this hypercoagulation state persists for at least one month after injury in 80% of patients. In another study by Selby et al. [21], significant hypercoagulability was noted within the first 24 h following trauma. This state was significantly higher in women than men, and remained elevated between 5 and 14 days, when it began to return towards normal. Direct injury to blood vessels at the time of trauma causes intimal damage leading to local thrombosis. In addition, prolonged bed rest, immobilisation, hypoperfusion and paralysis all promote venous stasis [3]. Geerts et al. [3] and Knudson et al. [22] identified through logistic regression analysis, factors to be independently predictors for DVT: age above 40 years, lower extremity fracture, ventilator days of >3 and operative time of more than 2 h [23]. Presence of spinal, pelvic or lower extremity fractures significantly increases the risk of VTE as opposed to other injuries [3,23]. VTE was seen five-times more commonly with tibial or femoral fractures [3]. This is mainly due to reduced mobility and longer hospital stays in these patients. Gender, mechanism of injury, and injury severity score were not significantly associated with increase risk of VTE [3]. Surprisingly, there is minimal literature on VTE rates in patients with tibial fractures. Lapidus et al. [24] studied 36,388 orthopaedic patients over a 10 year period looking at symptomatic VTE which were clinically suspected and subsequently proven with ultrasound or post-mortem. Within their cohort of 1072 patients with tibial fractures they reported rates for proximal, diaphyseal and distal tibial fractures of 3.8% (95%CI 2.3–6.3), 2.2% (95%CI 1.2–4.0) and 1.7% (95%CI 0.6–5.3), respectively. Abelseth et al. [25] performed venographic surveillance looking for silent DVTs in 90 patients with operatively treated tibial fractures without chemical thromboprophylaxis. The incidence for plateau, shaft and
Table 3 Results and statistical analysis of the non-patient factors (MW = Mann Whitney Utest, 2 3 FE = 2 3 contingency table Fisher’s exact).
Timings Delay to surgery/days Inpatient stay/days Frame duration/weeks Fracture type Plateau (14%) Shaft (46%) Pilon (40%) Closed/open Closed (73%) Open (27%) Weight bearing FWB NWB
indicates significance).
All patients n = 177
Discussion
Non-VTE group n = 170
*
VTE group n=7
Statistics
9 11 23
4 15 29
p = 0.30 (MW) p = 0.10 (MW) p = 0.10 (MW)
2 2 3
23 80 67
p = 0.36 (2 3 FE)
5 2
125 45
p = 1.0 (FE)
88 82
4 3
p = 1.0 (FE)
(TT) (FE) (TT) (FE)
plafond fractures was 43%, 22% and 12.5%, respectively. Geerts et al. [3] also exposed this contrast between silent and symptomatic DVT rates from their venographic surveillance study of 716 major trauma patients. Without chemical prophylaxis an incidence of DVT of 58% was observed, of which only 3 (0.4%) patients had any clinical features prior to venography. Without prophylaxis the incidence of venogram proven DVT is reported to be as high as 77% [23] reducing to less than 10% with prophylaxis irrespective of the type of chemical thrombo-prophylaxis or the definitive fixation technique [14]. Proximal extension of DVT above the knee is uncommon, with a risk of PE ranging from 2.3% to 22% and fatal PE < 0.5% [6]. In terms of clinical presentation and assessment, less than 2% of patients with positive venogram for DVT are symptomatic [3,26,27]. Agudelo et al. [28] suggested the clinical diagnosis of DVT is often unreliable in trauma patients, due to associated swelling and pain from the extremity fracture. The commonly used Homan’s sign even in high-risk patient has a sensitivity and specificity of less than 50%. Wells et al. [29] introduced a risk stratifying assessment model which improved inter-observer reliability and in 85% of cases successfully predicted the presence of a DVT upon subsequent ultrasound scanning. Whilst the Wells score is used in our hospital, its use leads to over investigation of tibial fractures, secondary to the presence of perioperative pain, erythema and swelling. The clinical judgement and experience of the senior author looking for symptoms and signs of increasing pain in the leg or thigh, redness and swelling was vital to ensure accurate and timely referral for diagnostic tests. The true incidence of VTE following lower extremity fracture without the use of venograms is difficult to determine and will be higher than we report. In addition though, there continues to be a lack of understanding with regard to the clinical significance of asymptomatic or silent DVT, in relation to subsequent morbidity and mortality. It is widely accepted that silent DVTs do not progress clinically and, as such are not treated in the same way as symptomatic DVT [25]. More recent studies looking at DVT surveillance in major trauma and intensive care have shown a reduction in the incidence of PE as a result of early diagnosis and subsequent treatment of silent DVTs [30]. In the presence of a confirmed DVT, the incidence of a so-called silent PE is 66%, but diagnosis is not necessary as there are no associated short or longterm clinical consequences [31]. There is a lack of literature both regarding the incidence of VTE in circular frame management, and the appropriate protocol for thromboprophylaxis. Sems et al. [15] noted an incidence of 2.1% in patients treated with external fixation followed by definitive internal fixation for tibial fractures. Ramos et al. [16] reported no symptomatic DVTs in their series of 39 distal tibial fractures treated using Ilizarov frames with low-molecular weight heparin prophylaxis starting from the day of admission until 10 days after leaving the hospital. The risk of VTE in our study following circular frame treatment for tibial fracture was 4.0% (true value between 1.13% and 6.87%). Calculating the true incidence would be difficult due to the number of patients required to power the study. The current study has shown that the use of LMWH from the day of admission until the patient is weight bearing as tolerated results in a risk of VTE, which is at least no higher than other forms of
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