T
he incidence of thromboembolic disease in foot and ankle surgery is not well characterized. A prospective study by Mizel et allsurveyed15 orthopedic surgeons and found a 0.22% incidence of deep vein thromboses (DVT) and 0.15% incidence of nonfatal pulmonary emboli in 2253 patients over 1 year. Routine screening was not per-formed, and clinical suspicion was the impetus for obtaining studies. No fatal pulmonary embolisms were reported. This study specifically addressed postop-erative events in primarily elective, non-traumatic foot and ankle reconstructive cases, without controlling for the use of thromboembolic prophylaxis. No study in the literature has specifically addressed prophylaxis against thrombotic events in patients with foot and ankle trauma.
Trauma patients are at higher risk for thrombotic events due to increased
hypercoagulability and decreased func-tion of the fibrinolytic system.2Increased
hypercoagulability results from stasis from required immobilization, direct endothelial damage to the vessels, and specific alterations in the clotting mecha-nism including increased tissue factor release. Clinical studies of trauma patients have corroborated this physio-logical data, showing increased incidence of DVT and pulmonary embolism in patients with single extremity and multi-ple extremity trauma.3-5 Furthermore,
these patients are frequently immobilized for prolonged periods before surgery, which also places them at higher risk than the general population of elective surgical patients.
This study focused on a specific sub-population of foot and ankle patients who we believed to be at an increased risk: those who sustained an acute traumatic
injury and are evaluated, immobilized, and released for delayed definitive man-agement. The soft tissues of the foot and ankle are often severely affected by trau-ma, and many surgeons currently delay surgery until swelling decreases to avoid skin slough and infection. Due to health-care economics, convenience, or planned transfer of care to a different surgeon, many patients, who in the past would have been admitted for elevation and observation, are instead provisionally treated and released with surgery sched-uled at a later time. Although patients admitted to the hospital are frequently given prophylaxis against DVT, those who are discharged for later follow-up are usually not treated. This study exam-ined the attitudes of surgeons treating foot and ankle injuries with regard to thromboembolic prophylaxis.
M
ATERIALS ANDM
ETHODSA one page survey consisting of 9 This study hypothesized that thromboembolism in patients with foot and
ankle trauma is higher than currently recognized, and that prophylaxis varies among surgeons. A questionnaire sent to members of two orthopedic spe-cialty societies surveyed the use of thromboembolic prophylaxis over 1 year. Most did not use preoperative prophylaxis. Postoperatively, 44% of surgeons used prophylaxis, most commonly sequential compression devices and low molecular weight heparin. This survey suggests that thromboembolic pro-phylaxis is used by ⬍50% of surgeons treating foot and ankle trauma. The reported cases of thromboembolism in this study underline the need for a prospective investigation.
abstract
A Survey of Orthopedic Surgeons
Regarding DVT Prophylaxis in Foot
and Ankle Trauma Surgery
J
ENNIFERM
ORIATISW
OLF, MD*; C
HRISTOPHERW. D
IG
IOVANNI, MD†
From the *Department of Orthopedics, Mayo Clinic, Rochester, Minn; and the †Department of Orthopedics, Brown University School of Medicine, Rhode Island Hospital, Providence, RI. The authors thank Douglas S. Wolf for assist-ing with the database design, and Steven Reinert for statistical assistance.
Reprint requests: Christopher W. DiGiovanni, MD, Dept of Orthopedics, Brown University School of Medicine, Rhode Island Hospital, 593 Eddy St, Providence, RI 02903.
questions was mailed to 1400 surgeons— 947 active and candidate members of the American Orthopaedic Foot and Ankle Society and 453 active and candidate mem-bers of the Orthopaedic Trauma Association (Figure). The questionnaire was reviewed and sanctioned by each society prior to mailing. Members with emeritus, interna-tional, honorary, or resident status were
excluded. A stamped return envelope was provided for ease of response, and partici-pation was voluntary and anonymous.
Responses were tabulated at 6 weeks, after which no further returned question-naires were accepted for this study. A cus-tom-designed Microsoft Access database (Microsoft, Redmond, Wash) was used to organize the data. Using Stata statistical
software (Stata Corp, College Station, Tex), the data were tabulated and analyzed.
R
ESULTSAt 6 weeks, 508 responses from 1400 questionnaires mailed were received, a response rate of 36%. Five hundred sur-geons reported their location; 489 were from the United States. Eight were from
DVT Prophylaxis in Elective Foot and Ankle Surgery
1. How many ELECTIVE FOOT AND/OR ANKLE TRAUMA cases did you perform between January 1, 2000 and December 31, 2000 (ex: Achilles rupture, Lisfranc injury, calcaneal or ankle fracture, etc...evaluated as an acute trauma, then sent home and brought back at a later date for operation)?__⬍5 ___5-10 ___11-20 ___21-30 ___31-40 ___41-50 ___51-75 ___76-100
a. Do you routinely splint all these patients before surgery? ___YES ___NO
If not, who do you splint? ___I splint no one ___I only splint if (explain):___________________________________ b. How many of the patients in Question #1 developed a: Syptomatic DVT? ____ Symptomatic PE? ____
2. Do you use PRE-operative DVT prophylaxis in the outpatient setting during the interim before elective surgery for these foot/ankle trauma patients? ___Always ___Sometimes ___Never
a. If always, what do you use? (check all that apply, AND circle the one MOST commonly) ___Aspirin ___SC heparin ___LMW heparin ___Warfarin ___External Foot and Leg Pumps ___Compressive Stockings
b. If sometimes, is this only in patients with risk factors? ___YES ___NO
WHICH risk factors? ___Immobility ___Previous DVT ___Venous stasis disease ___Malignancy ___Hematologic clotting risks ___Oral contraceptives ___Obesity ___Diabetes ___Multiply injured patient ___Pregnancy
___Other: _______________________________________________
3. Do you routinely use INTRA-operative DVT prophylaxis in these same patients? ___YES ___NO
If YES, what type? ___Foot pumps ___Leg pumps ___Compressive stockings ___Intra-operative heparin ___Immediate preoperative warfarin or heparin ___Other:____________________________________
4. Do you routinely use POST-operative DVT prophylaxis in these patients? ___YES ___NO (if yes, check all used. AND circle the ONE agent used most commonly)
___Compressive stockings ___Sequential compression devices (Leg pumps) ___Warfarin ___Subcutaneous heparin ___Subcutaneous low molecular weight heparin (eg, Lovenox, Fragmin) ___Foot intrinsics exercises
___High dose aspirin (eg, 325 mg bid) ___Low dose aspirin (ex, 80 mg qd) ___Foot pumps ___Early mobilization (when?______________________)
a. If YES, for how long do you treat patients with DVT prophylaxis?
___⭐1 week ___2 weeks ___3 weeks ___4 weeks ___5 weeks ___6 weeks ___⬎6 weeks b. If NO, are there certain circumstances in which you do? ___YES ___NO
What risk factors would lead you to place a patient on post-operative DVT prophylaxis? __________________________________ What agent would you use? ____________________________________________
5. Do you routinely treat foot/ankle trauma patients who are immediately admitted and kept in the hospital for upcoming surgery (as opposed to those patients in Question #1) with DVT prophylaxis? ___YES ___NO
a. If YES, do you treat them ___always ___only if they have risk factors (please list: ________________________________) b. What agent would you use? __________________________________________________________________
6. Do you screen for DVT in any of the elective foot/ankle trauma patients in Question #1 after surgery? ___YES ___NO a. If YES, which ones? ___All ___Only those with risk factors
b. How do you screen them? ___Ultrasound ___Venography Other: ___________________________________
c. When do you screen them? ___Postoperative day 2 ___Postoperative day 3 ___1 week ___⬎1 week ___Before discharge 7. Prophylaxis against DVT in elective foot and ankle trauma patients is: ___Mandatory ___Sometimes needed ___Waste of time 8. How many foot and ankle surgical cases TOTALdid you perform last year? ___
How many of THESE patients developed a: ___asymptomatic DVT (ie, pre-screened) ___symptomatic DVT (post-confirmed by studies) ___Symptomatic nonfatal PE ___fatal PE
9. Your Practice Location (State/Province, and Country): _____________________________________________________
Figure: Survey sent to 1400 orthopedic surgeons regarding DVT prophylaxis for foot and ankle trauma. Abbreviations: DVT=deep vein thrombosis, LMW=low molecular weight, PE=pulmonary embolism, and SC=subcutaneous.
Canada, and 1 each from England and Switzerland. One orthopedic surgeon working in a locum tenons position also responded.
Questionnaires were accepted if part of each of the nine questions was answered; thus, the total denominator of responses for each question varied. A wide range of case numbers was reported for foot and ankle trauma patients who were evaluated acutely (eg, in an emer-gency department) and sent home for sub-sequent scheduled surgery (Table 1). The majority of surgeons (90%) stated they splinted these patients before surgery, with exceptions reported for calcaneal fractures and Achilles tendon ruptures.
The questionnaire surveyed surgeons about the use of pre-, intra-, and postopera-tive thromboembolic prophylaxis in this patient population. Sixty-seven percent of surgeons never used preoperative prophy-laxis, with 29% reporting occasional use (Table 2). For those surgeons who occasion-ally used thrombosis prophylaxis, the most common risk factor influencing this deci-sion was a history of DVT or pulmonary embolism. Only 4% always used preopera-tive protecpreopera-tive measures against DVT. The most commonly reported agents used were external foot pumps, aspirin, and low mole-cular weight heparin. Other modalities were compression stockings, warfarin, and sub-cutaneous heparin.
Most surgeons did not use any form of intraoperative prophylaxis (Table 2). For
the 15% minority who used prophylaxis, most used compression stockings (52%) followed by foot pumps and leg pumps. A few surgeons reported using warfarin or heparin intraoperatively or immediately prior to surgery.
Forty-four percent of surgeons stated that they used some form of postoperative DVT prophylaxis, and most indicated mul-tiple interventions. The most common modalities for postoperative prophylaxis included sequential compression devices (41%), low molecular weight heparin, and early mobilization (Table 3). The length of prophylaxis use varied; one third of sur-geons reported use for ⭐1 week (Table 4).
Routine postoperative prophylaxis was not used by ⬎50% of respondents. However, certain risk factors led a majority of this group to use thrombosis protection. The most common risk factors included his-tory of DVT or pulmonary embolism, mul-titrauma, and obesity. Surgeons reported
the use of warfarin, low molecular weight heparin, and aspirin as prophylaxis most commonly.
Most surgeons surveyed (88%) did not screen for DVT in the foot and ankle trau-ma population. Of those who reported using screening, it was most commonly done for patients with risk factors. Ultrasound was the preferred imaging modality, with some surgeons using physi-cal examination for screening. No surgeon listed venography or any other diagnostic study.
When asked about a different subset of patients with foot and ankle trauma, those immediately admitted to the hospital pend-ing surgical treatment, surgeons were more likely to use thromboembolic prophylaxis.
TABLE 3
Postoperative Thromboembolic Prophylaxis Modalities Prophylaxis No. Surgeons Reporting Use (%)
Compressive stockings 16 (7)
Sequential compression devices (leg pumps) 91 (41)
Warfarin sodium 33 (15)
Subcutaneous heparin 17 (7)
Subcutaneous low molecular weight heparin 85 (38)
Foot intrinsics exercises 33 (15)
High dose aspirin 40 (18)
Low dose aspirin 40 (18)
Foot pumps 51 (29)
Early mobilization 86 (38)
TABLE 4
Length of DVT Prophylaxis Use Interval of Use No. Surgeons (%)
⬍1 week 69 (33) 1-2 weeks 37 (18) 2-3 weeks 22 (11) 4-5 weeks 32 (16) 6 weeks 30 (15) ⬎6 weeks 14 (6)
Abbreviation: DVT= deep vein thrombosis
TABLE 1
Summary of Reported Foot and Ankle Trauma Cases No. Cases
Performed No. Surgeons (%)
⬍5 23 (5) 5-10 41 (8) 11-20 83 (17) 21-30 90 (18) 31-40 56 (11) 41-50 67 (13) 51-75 68 (14) 76-100 72 (14) TABLE 2
Use of Pre-, Intra-, and Postoperative DVT Prophylaxis No. Surgeons Use (Used/Total) (%) Preoperative Never 333/499 (67) Sometimes 146/499 (29) Always 20/499 (4) Intraoperative Used 430/508 (85)
Did not use 78/499 (15) Postoperative
Used 223/508 (44)
Did not use 285/508 (56)
In this population, 59% of surgeons use prophylaxis, with an even split between treating only patients with risk factors and treating all patients. Risk factors quoted were similar to the outpatient surgery population, with the most common being a history of a thrombotic event and multi-trauma. Again, low molecular weight heparin, aspirin, and warfarin were the most commonly used agents.
Surgeons were then queried for their general opinion of DVT prophylaxis and its necessity in elective scheduled foot and ankle trauma patients. Seventy per-cent believed that prophylaxis was some-times needed. Few surgeons believed that some form of prophylaxis was mandatory, with 25% stating that prophylaxis was unnecessary.
Finally, surgeons were asked to list the total number of foot and ankle surgeries they had performed during the year surveyed. The median number was 100, with a mean of 170 (range: 0-1300 surgeries). The total for all surgeons was 86,175 cases. Respondents were then asked to report how many DVT and pulmonary embolism episodes occurred in their patients. Surgeons reported 43 asymptomatic and 376 sympto-matic DVT episodes over 1 year. Sixty-four nonfatal pulmonary embolism events and 18 fatal pulmonary embolism events were noted in a 1-year period in this respondent group. These were not stratified by use or nonuse of thromboembolic prophylaxis.
D
ISCUSSIONThromboembolic phenomena in foot and ankle surgery have not been studied extensively, particularly in comparison to the extensive literature on this subject in hip and knee surgery.6-15Although it is a
common belief that foot and ankle surgery does not generally require throm-botic prophylaxis, this has never been evaluated in the sub-population of trauma patients who undergo delayed treatment.
Several studies have shown a strong correlation between lower extremity trau-ma and a higher risk of thromboembolic disease. A study by Kudsk et al4showed
that 60% of trauma patients immobilized for at least 10 days had stenographically proven DVT, with proximal thrombi extension occurring in 50%. Geerts et al3
performed a prospective study of venous thromboembolism in a trauma unit. Without the use of any prophylaxis,
mul-titrauma patients (Injury Severity Score
⭓9) studied with venography had a 58% incidence of DVT, most of which were clinically silent. Lower extremity frac-tures were shown to correlate significant-ly with DVT.
Lassen et al16 published a prospective
randomized study of low molecular weight heparin given to patients immobilized for long periods following a fracture or Achilles tendon rupture. In the placebo group, 35 (19%) of 188 patients developed DVT as shown by stenography, and 2
patients went on to a pulmonary embolus. This study provides further evidence of the thromboembolic risk posed by lower extremity fractures and prolonged immobi-lization.
The foot and ankle literature on the occurrence of DVT or pulmonary embolism comprises mostly case reports 17-19or notes of DVT as a complication.20-23
Mizel et al1 surveyed 15 surgeons who
reported the 1-year incidence of throm-boembolic disease by filling out a question-naire on each surgical patient, with a 0.22% rate of DVT and a 0.15% rate of pulmonary embolism. In that study, patients with mul-tiple trauma were specifically excluded, screening for venous thromboses or pul-monary emboli was based on clinical fac-tors, and the use or nonuse of prophylaxis was not controlled or recorded.
Solis and Saxby24 studied 201 patients
undergoing foot and ankle surgery with routine screening ultrasound at the first postoperative follow-up. Trauma patients were not specifically evaluated in this study. Ultrasound was performed for screening at the popliteal vein and distally; thus, no proximal thromboses were detectable or reported, which may have underestimated results. No patients were treated with thromboembolic prophylaxis. This study showed a 3.5% (7/201) inci-dence of DVT. Hindfoot surgery,
immobi-What is already known on this topic
■The need for prophylaxis perioperatively in foot and ankle trauma patients, who as a subset may be at increased risk for DVT and pulmonary embolism by virtue of their immobilization and injury, has never been evaluated.
■This article suggests complications occur in these patients and reinforces that cur-rent treatment choice, duration of therapy, and need for screening continue to be based on anecdotal experience or habit rather than on reliable outcomes data. The data infer that we as a specialty may be under (or over) treating these patients.
■Although the need for thromboembolic prophylaxis and identification of appropri-ate risk factors in foot and ankle trauma patients remains unknown, the data in this study suggest that a prospective, multicenter investigation would be of benefit in answering this question more definitively. Such a study would allow a safer and more cost-effective approach to the management of this problem.
What this article adds
Approximately 44% of
surgeons used some form
of prophylaxis against
DVT postoperatively,
whereas few surgeons used
pre- or intraoperative
prophylaxis.
lization combined with hindfoot surgery, increased tourniquet time, and increased age were significantly correlated with an increased incidence of DVT.
A recent study detailed three cases of pulmonary embolism following operative fixation of ankle fractures in which no anti-coagulation was used.25 Retrospectively,
the possible risk factors analyzed included obesity, age ⬎40 years, and immobiliza-tion in these patients. The authors conclud-ed that thromboembolic prophylaxis should be considered in lower extremity surgery in patients presenting with risk fac-tors for thrombosis.
In the current study, we focused on electively operated foot and ankle trau-ma patients, a subpopulation that has not previously been studied regarding thromboembolic disease risk. This anonymous and voluntary cross-section-al survey was performed to gather infor-mation on the practices of surgeons who care for this subgroup of patients. In this survey, surgeons were asked about their practice in the year 2000. Approximately 44% of surgeons used some form of pro-phylaxis against DVT postoperatively, whereas few surgeons used pre- or intra-operative prophylaxis. Of those surgeons using postoperative prophylaxis, 33% used it for ⭐1 week. The most common types of prophylaxis reported were sequential compression devices, low molecular weight heparin, and early mobilization. Ninety percent of surgeons did not screen routinely for DVT, and those who did screen used ultrasound almost exclusively.
The weaknesses of this questionnaire-based survey include limited demographic and risk information on the thromboembol-ic events reported, its voluntary nature (which is open to selection bias and incom-plete questionnaire results), and a lack of discrete numbers of cases against which to compare reported events. It is also subject to the recollection bias of a retrospective evaluation. The study was designed, how-ever, to assess surgeons’ attitudes about
DVT prophylaxis to determine whether a more in-depth analysis would be useful.
This study is valuable because of its cross-sectional nature with input from a large number of surgeons. Additionally, this survey shows a wide variability in throm-boembolic prophylaxis, particularly post-operatively. Science does not dictate what surgeons are doing regarding thromboem-bolic prophylaxis in the foot and ankle trau-ma population. The reported thromboem-bolic events in this surgeon survey indicate that DVT and pulmonary embolism occur in foot and ankle surgery cases and under-line the need for a prospective analysis of this issue.
R
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