Prophylactic and Early Therapeutic Use of the Greenfield Filter in Hip and Knee Joint Arthroplasty
Roger H. Emerson, Jr., MD, Richard Cross, MD, and William C. Head, MD
Abstract: The orthopaedic literature does not provide clear guidelines for the protection of the extremely high-risk thromboembolic patient undergoing hip and knee total joint or related reconstructive surgery. Nor is there agreement of how to protect the immediate postoperative patient with thromboembolic complications. The authors. believing that routine anticoagulation measures are ill-advised in these two circumstances. elected instead to place a Greenfield vena cava filter for prevention of life-threatening thromboembolism. Using prospective selection criteria, 47 patients could be followed over a 24-76-month period. There were no clinical embolic episodes in either group and no late complications of the filter placement. The few complications in this series were related to insertion, only one of which lead to minor long-term disability. The caval patency rate was 96%. The authors have concluded that such prophylactic use of the Greenfield vena cava filter is justified since it contributes to safer and more reliable total hip and total knee surgery with only minor morbidity. Key words: deep vein thrombosis, pulmonary embolism, vena cava interruption, hip/knee arthroplasty.
Perioperative prophylaxis of venous thromboembolic disease has become widely accepted for major reconstructive joint surgery (4, 5, 8, 9, 17, 18, 21, 26). However, the methods shown to be efficacious for patients without significant risk factors for deep vein thrombosis (DVT) or pulmonary embolism (PE) have not been studied widely in the exceptionally high-risk situation, and probably are not sufficient in this latter setting (13, 17, 20). While lower extremity deep vein thrombosis can lead to permanent venous insufficiency (4, 5), pulmonary emboli can be fatal (8, 17, 19, 20, 24, 28). The reported incidence of fatal pulmonary emboli in
the setting of lower extremity joint replacement surgery is 1-5% (8,17,28). Most ofthese are not heralded by clinical DVT (1, 3, 19,24, 26). Donaldson et al. have shown that two-thirds of those sustaining a fatal PE die within 30 minutes of the event (6), and Patterson et al. found that five of six patients dying from pulmonary embolism after total joint surgery did so before anticoagulation could be instituted (24). What to do, therefore. for the total hip or total knee patient with a significant history of major thromboembolic disease, or what to do for the fresh postoperative patient with a major thromboembolic event? Full intravenous anticoagulation might be protective, but has an excessive complication rate, as reported recently by Patterson et al. (24). Mechanical
From the Department of Orthopaedic Surgery. Southwest Medical School. Dallas, Texas. Reprint requests: Roger H. Emerson. Jr .. MD. 8230 Walnut Hill Lane, Suite 106. Dallas, TX 75231.
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devices such as cyclic compression boots are appealing, but have not been shown to be effective in this exceptionally high-risk setting (16), are unable by design to be protective from emboli, and, in fact, compression devices on the leg may be contraindicated where there is semiactive thrombotic disease . Careful surveillance might be an option, but, again , is not protective from emboli and does not address the issue of profound cardiovascular collapse from an embolism where even full anticoagulation will not suffice. Using a prospective protocol. the authors have identified two groups of exceptionally high-risk hip and knee reconstructive patients. One group received an elective Greenfield vena caval filter prior to their orthopaedic surgery, to provide prophylactic embolic protection. The other group received a filter after operation, following development of an extensive deep vein thrombosis where full intravenous anticoagulation was felt to be contraindicated, as documented by Patterson et al. (24) , for prevention of embolic complications. The purpose of this study is to establish the safety and efficacy of prophylactic or early postoperative vena cava interruption with the Greenfield filter in this special cohort of patients.
Materials and Methods Since 1983, all patients with (1) chronic deep vein thrombosis; (2) prior deep vein thrombosis or pul monary embolism with a major complication of an ticoagulation; (3) a major prior pulmonary embolism; or (4) deep vein thrombosis or pulmonary embolism within the first 7 postoperative days, were considered candidates for a Greenfield Filter. Groups 1- 3 received filters before operation, and group 4 received the filter after operation. Patients with a remote history of thromboembolic disease underwent routine thromboembolic prophylaxis with low -dose warfarin followed by careful sur veillance with either venogram or ultrasound. A preoperative venogram was done on all of the study patients until 1986, at which time venous doppiers and B-mode ultrasound were done on some of the patients, although most continued to have rou tine venography. If these studies were entirely normal, no filter was placed , unless the patient was in the group that could not receive any prophylactic oral anticoagulation. After surgery, a venous doppler was done three times a week while in the hospital. followed by a venogram if abnormal. No systematic venous imaging was done after hospital discharge.
The filters were placed by three different vascular surgeons who were consulted concerning the overall anticoagulation management of the patient. In this series, all but one of the filters was placed 1 or more days prior to the orthopaedic procedure. Between January 1983 and October 1987, in the course of a busy adult reconstructive orthopaedic practice, 50 patients met this criteria for Greenfield filter insertion. One patient refused the filter, and in one patient it could not be placed from either the neck or inguinal approach. This leaves a final series of 48 patients, with 48 filters placed. The average age was 69 years (range, 33-86 year s), with 27 women and 21 men. Thirty-three were placed prophylactically and 15 for treatment. Four of the treatment group were part of a staged reconstruction, so the filter was placed for both treatment of an acute thromboembolic event and prophylaxis, anticipating subsequent surgery. The final series was made up of 37 prophylactic filters (70%) and 11 purely treatment filters (30%). Twenty-one patients underwent primary THA, 4 primary TKA, 13 revision THA, 5 revision TKA, and 5 other procedures (tendon allograft to knee, hip disarticulation, 3 Girdlestone procedures). All of the orthopaedic procedures on these patients were performed by the senior authors. Follow-up period of this series has been 24-76 months, average 44 months. Thirty -nine filters were placed under general anesthesia and 9 under local. The practice is now to place most under local anesthesia, with anesthesia standby. All were placed via the right internal jugular vein, except two, which were placed via the cornmon femoral when the jugular approach could not be used (Fig. I) . One patient had a failed attempt at insertion in the neck and the other patient had had a previous vascular bypass performed in the neck. Ideal position of the filter was below the renal veins, usually opposite the L 2-3 interspace (Fig. 2,3). The technique of insertion is published elsewhere, but the general principle is to position the filter introducer at the level desired, as determined by fluoroscopy with a venacavagrarn. to determine the location of the renal veins, and then withdraw the introducer leaving the filter in place. A guide wire through the filter maintains a vertical orientation of the filter in the vena cava uo. 22) (Fig. 2). No routine antithrombotic treatment was used in conjunction with the filter when it was placed prophylactically prior to surgery. In the group receiving the filter in the first postoperative week, all patients were taking prophylactic warfarin; the warfarin dose
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which were prophylactic filters. Five of these patients are on chronic anticoagulation, three following postfilter thigh thrombosis. Two use vascular stockings routinely. All but one of these seven pat ients had some preoperative vascular symptoms. All of these seven had good relief of their joint symptoms, however, and would have the surgery again. There were two documented vena cava occlusions, by venography during hospitalization, for a patency rate of 96 %, only one of which is cau sing ongoing symptoms. The latter has typical post phlebitic cornplaints of swelling and leg discomfort with standing, but continues to work. He has no venous dermatitis. The other den ies an y vascular symptoms at th is time , but required a long course of anticoagulation, and experienced 6 months of leg swelling. In this group of 48 patients, there were no woundhealing complications of the hip or knee surgery. There was no mortality from thromboembolic disease and no clinical incidence of postfilter pulmonary emboli. In addition, there was no significant loss of ambulatory function in those few patients who had ongoing vascular symptoms. There are, however. insufficient numbers of pat ients in this series, assuming even a 5% mortality, to make the statistical claim that the use of the filter has prevented a death.
Fig. 1. The usual insertion route for the Greenfield filter is via the right jugular vein, placing the filter below the renal veins.
was gradually increased to full anticoagulation levels, with careful observation of the wound.
Results This group of patients is actively being followed in the author's office as part of an ongoing total joint follow-up protocol. One ofthe patients had deceased of unrelated causes over a year after the implanting of his filter. He had a history of a PE and had no postoperative vascular symptoms. Of the remaining 47 patients, many complained of mild foot and ankle swelling, usually no more than they had before operation. Only seven found their symptoms subjectively worse than before surgery, four of which were treatment and three of
Fig. 2. The preferred location of the Greenfield filter is below the renal veins. During placementof the device, the filter is maintained at the desired level and the introducer pulled back. Theguide wire remains to maintain the filter's vertical position.
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A Fig. 3. (A) AP and (B) lateral radiographs showing typical position in the Greenfield filter opposite the L2-13 interspace.
Complications The complications associated with insertion of the filter reponed here are worthy of note. One patient developed a post-general anesthesia bronchitis requiring antibiotic treatment, and postponement of orthopaedic reconstruction. There was one placement error, slightly above L2ratherthan below, and therefore, possibly above the renal vein, but producing no symptoms or problems. There was one hemothorax requiring a chest tube, resolving with no sequela. Surprisingly, there were two instances of vagus nerve injury from the internal jugular ap-
preach, by the same consulting vascular surgeon, one transient for 3 weeks, and one with permanent hoarseness requiring injection treatments to the chords to regain a more audible voice. The vagus nerve is in the same sheath as the internal jugular vein, and needs to be carefully separated from the other structures and protected during insertion. This should be avoidable and occurred early in the series. There was no clinical evidence in this series suggestive of migration of the filter. Only patients with bothersome vascular symptoms have been further studied clinically, by means of plain abdominal x-ra y and venous doppler and B-mode ultrasound.
Greenfield Filter in Hip and Knee Arthroplasty
Discussion In the recent literature, the scope of venous thromboembolic disease has become well-defined (4-6,8, 9,17,18,21,23,27). In essence, the research to date has been divided into the following areas: defining the risk factors, assessing different prophylactic regimens, assessing different detection methods, and finally, looking at cost-effectiveness. The area least investigated is determining groups at special risk, and how best to treat each of them. Hip and knee reconstructive patients, even without a history of thromboembolic problems, are considered high-risk categories (7, 14, IS, 26). In fact, the incidence of thromboembolic complications is the highest in this type of surgery compared to others (17).
That prophylactic treatment can reduce the incidence of thromboembolic disease and make surgery safer, especially in the orthopaedic surgical groups, is now well-documented (18, 26). The purpose in this setting is "primary prevention" or preventing the occurrence of the disease, as discussed by Paiement (23). At the same time, controversy still abounds since there is no ideal prophylactic method (9) but, rather, it would appear that the method used should be tailored to fit the category of risk for the patients being treated (9, 17). The studies establishing the efficacy of the various prophylactic methods have been done for the most part on patients with no history of thromboembolic disease, since it is universally accepted that this latter group is at extreme risk of recurrent thrombosis, thereby skewing the results. The efficacy of most prophylactic methods in this patient category has not been established (17, 20, 23). These patients are already suffering from thromboembolic disease, and conceptually the goal of "prophylaxis" is to limit the extent of the disease rather than prevent its occurrence. Gold advocates full warfarin anticoagulation for these patients (9). Acceptance of this mode of treatment in the past has been hampered by frequent postoperative wound or gastrointestinal hemorrhage (23, 24, 29).
Little has been written in the orthopaedic literature about vena cava interruption. Brooks et al. (1) recently reported on a hip fracture patient with documented preoperative extensive deep venous thrombosis who underwent insertion of a Greenfield filter prior to uneventful hemiarthroplasty surgery. Woolson and Harris (29) have reported a series of
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5 patients in whom a Greenfield filter was used after operation after full intravenous anticoagulation produced wound bleeding. This bleeding occurred within the first 10 days after surgery. One of these patients, who was bleeding into the hip on full intravenous anticoagulation, requiring angiographic embolization, died of complications of a recurrent pulmonary embolism that occurred before the filter was placed. Woolson and Harris come short of recommending prophylactic filter placement, but acknowledged that earlier filter insertion in this case would have prevented a death. Golueke et al. (10) have made cogent arguments for expanding the use of Greenfield filters, citing an overall 4.6% morbidity rate and 0% mortality rate. Only 23% of their filters were placed prophylactically, for both orthopaedic and nonorthopaedic cases. Current indications from the literature for Greenfield filter placement are clinical circumstances where anticoagulation is either contraindicated, failed, or inadequate (11, 20). Recent experience with the Greenfield filter reported elsewhere has been positive. In particular, ease of insertion, excellent patency rate, and minimal morbidity has made the Greenfield filter the method of choice for vena caval interruption (20). The conical design enhances caval patency, reported as 97%, by Greenfield et aI. (20). Our own data is in general agreement, with a patency rate of 96% in our series. Recurrent emboli have been reported, up to 4% (11), although none occurred in this series, using only clinical criteria for detection. Distal migration of Greenfield filters has been reported (25), although it is a rare occurrence. Frank dislodgement of the filter is rare, although embolization to the right ventricle has been reported (2). In our series, no systematic radiographic study of the filters was undertaken in the total absence of abdominal or other catastrophic clinical events, making any such investigation necessary. That the retrieval of Greenfield filters can be accomplished when indicated is of note (12), although we have made no recommendation or attempt to do so in any of our patients. A word of caution must be raised about insertion complications, however, which caused most of the morbidity in this series. While all of our complications were minor and few in number, they nonetheless caused increased patient inconvenience and some disability. Insertion of these filters should only be undertaken by experienced personnel. These complications should be avoidable. Deep vein thrombosis continues to be a problem after filter placement, with serious persisting venous
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symptoms in 15% (7/47) of this series. Obviously, vena cava filters have no antithrombotic role, and if it is safe to do so, the literature supports the continued use of anticoagulation measures, for 3-4 months (20). This might have diminished the number of postfilter thromboses (3) that we saw in our series. It is our practice at this time to follow this recommendation.
3.
4.
5. 6.
Conclusion We believe that the data reported here support the expanded use of Greenfield filters in these two patient populations. Since we were able to safely perform complex hip and knee reconstructions without any pulmonary emboli and with minimal morbidity and no mortality, in a group at the highest risk of these complications, we conclude that our protocol using the Greenfield filter should be advocated to others involved in this type of surgery. The literature does not provide a comparable series of patients for comparison with other methods, so other protective measures may prove equally effective. We believe that it is likely that we have prevented a major embolic event, and possibly a death, in our series of patients. In the circumstance of a patient requiring full intravenous anticoagulation within the first week after surgery, especially a revision case with a large wound surface, we recommend that a filter be placed to protect the patient from embolism, and then treatment of the thrombotic event with a slowly increasing anticoagulation regimen, not reaching full therapeutic levels until the wound is mature, at least 10 days from surgery. This is a technically demanding procedure and should be performed only by those skilled in its use. Most of our complications were related to insertion. These should be avoidable. Follow-up study in this series, up to 76 months, has shown no late deterioration in the clinical status.
7.
8.
9. 10.
II. 12. 13.
14.
15.
16.
17.
18.
19.
References 20. I. Brooks RL, Winslow MC, Kenmore PI: The week-old hip fracture: indication for prophylactic use of a vena cava filter? Orthopedics 10:1287, 1988 2. Castaneda F, Herrera M, Cragg AH et al: Migration
21.
of a Kimray-Greenfield filter to the right ventricle. Radiology 149:690, 1983 Culver 0, Crawford JS, Gardiner JH, Wiley AM: Venous thrombosis after fractures of the upper end of the femur. J Bone Joint Surg 52B:61, 1970 Dalen JE, Paraskos JA, 'Ockene IS et al: Venous thromboembolism: scope of the problem. Chest 89:370S, 1986 Dalen JE, Alpert JS: Natural history of pulmonary embolism. Prog Cardiovasc Dis 16:259, 1975 Donaldson GA, Williams C. Scannell JG: A reappraisal of the Trendelenberg operation for massive fatal embolism. N Engl J Med 268: 171, 1963 Dorr LD, Sakimura L Mohler JG: Pulmonary emboli following total hip arthroplasty: incidence study. J Bone Joint Surg 61A:I083, 1979 Eskland G, Solheim K. Skjorten F: Anticoagulant prophylaxis, thromboembolism and mortality in elderly patients with hip fractures. Acta Chir Scand 131: 16, 1966 Gold EW: Prophylaxis of deep venous thromboembolism. Orthopedics 1I: 1197, 1988 Golueke PJ, Garrett WV, Thompson JE et al: Interruption of the vena cava by means of the Greenfield filter: expanding the indication. Surgery 103: 111, 1988 Greenfield LT, Peyton R, Crute S, Barnes R: Greenfield vena cava filter experience. Arch Surg 116: 1451, 1981 Greenfield U, Crute SL: Retrieval of the Greenfield vena cava filter. Surgery 88:719, 1980 Harris WH, Salzman EW, Athanasoulis C: Comparison of warfarin, low-molecular-weight dextran, aspirin, and subcutaneous heparin in prevention of venous thromboembolism following total hip replacement. J Bone Joint Surg 56A: 1552, 1974 Harris WH, Salzman EW, Desanctic RW: The prevention of thromboembolic disease by prophylactic anticoagulation. J Bone Joint Surg 49A:81, 1967 Hartman JT, Altner PC, Freeark RJ: The effect of limb elevation preventing venous thrombosis. J Bone Joint Surg 52A:1618, 1970 Hartman JT, Pugh JL, Smith RD et al: Cyclis sequential compression of the lower limb in prevention of deep venous thrombosis. J Bone Joint Surg 64A: 1059, 1982 Hull RD, Raskob GE, Hirsh J: Prophylaxis of venous thromboembolism: an overview. Chest 89:374S, 1986 Hull RD, Raskob GE: prophylaxis of venous thromboembolic disease following hip and knee surgery. J Bone Joint Surg 68A: 146, 1986 Johnson R, Green JR. Charnley J: Pulmonary embolism and its prophylaxis following the Charnley total hip replacement. Clin Orthop 127:123, 1977 Jones TJ, Barnes RW, Greenfield U: Greenfield vena caval filter: rationale and current indications. Ann Thorac Surg 42:S48, 1986 Lowe LW: Venous thrombosis and embolism. J Bone Joint Surg 63B:155, 1981
Greenfield Filter in Hip and Knee Arthroplasty
22. Menzoian JO . LoGerfc FW. Doyle JE et al: Technical modifications in the placement of inferior vena caval filter devices. Am J Surg 142:216. 1981 23. Paiement GD. Bell D. Wessinger SJ. Harris WH: New advances in the prevention. diagnosis. and cost effectiveness of venous thromboembolic disease in patients with total hip replacement. Proceedings of the Hip Society. Chapter 8. p. 94. 1986 24. Patterson BM. Marchand R. Ranawat C: Complications of heparin therapy after total joint arthroplasty. J Bone Joint Surg 71A: 1130. 1989 25. Sidawy AN. Menzoian JO : Distal migration and deformation of the Greenfield vena cava filter. Surgery 99 :369. 1986
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26. Stulberg BN. Insall IN . Williams GW. Ghelman B: Deep-vein thrombosis following total knee replacement. J Bone Jo int Surg 66A: 194. 1984 27. Trulock EP: Venous thromboembolism: prophylaxis. diagnosis. and therapy in surgical patients. Surgical rounds for orthopedics. p. 28. October. 1987 28. Turpie AGG. Levine MN. Hirsch J et al: A randomized controlled trial of a low-molecular-weight heparin to prevent deep-vein thrombosis in patients undergoing elective hip surgery . N Engl J Med 315 :925. 1986 29. Woolson ST. Harris WH: Greenfield vena caval filter for management of selected cases of venous thromboembolic disease following hip surgery. Clin Orthop 204 :20 L 1986
Roger H. Emerson, Jr., MD, Richard Cross, MD, and William C. Head, MD
Abstract: The orthopaedic literature does not provide clear guidelines for the protection of the extremely high-risk thromboembolic patient undergoing hip and knee total joint or related reconstructive surgery. Nor is there agreement of how to protect the immediate postoperative patient with thromboembolic complications. The authors. believing that routine anticoagulation measures are ill-advised in these two circumstances. elected instead to place a Greenfield vena cava filter for prevention of life-threatening thromboembolism. Using prospective selection criteria, 47 patients could be followed over a 24-76-month period. There were no clinical embolic episodes in either group and no late complications of the filter placement. The few complications in this series were related to insertion, only one of which lead to minor long-term disability. The caval patency rate was 96%. The authors have concluded that such prophylactic use of the Greenfield vena cava filter is justified since it contributes to safer and more reliable total hip and total knee surgery with only minor morbidity. Key words: deep vein thrombosis, pulmonary embolism, vena cava interruption, hip/knee arthroplasty.
Perioperative prophylaxis of venous thromboembolic disease has become widely accepted for major reconstructive joint surgery (4, 5, 8, 9, 17, 18, 21, 26). However, the methods shown to be efficacious for patients without significant risk factors for deep vein thrombosis (DVT) or pulmonary embolism (PE) have not been studied widely in the exceptionally high-risk situation, and probably are not sufficient in this latter setting (13, 17, 20). While lower extremity deep vein thrombosis can lead to permanent venous insufficiency (4, 5), pulmonary emboli can be fatal (8, 17, 19, 20, 24, 28). The reported incidence of fatal pulmonary emboli in
the setting of lower extremity joint replacement surgery is 1-5% (8,17,28). Most ofthese are not heralded by clinical DVT (1, 3, 19,24, 26). Donaldson et al. have shown that two-thirds of those sustaining a fatal PE die within 30 minutes of the event (6), and Patterson et al. found that five of six patients dying from pulmonary embolism after total joint surgery did so before anticoagulation could be instituted (24). What to do, therefore. for the total hip or total knee patient with a significant history of major thromboembolic disease, or what to do for the fresh postoperative patient with a major thromboembolic event? Full intravenous anticoagulation might be protective, but has an excessive complication rate, as reported recently by Patterson et al. (24). Mechanical
From the Department of Orthopaedic Surgery. Southwest Medical School. Dallas, Texas. Reprint requests: Roger H. Emerson. Jr .. MD. 8230 Walnut Hill Lane, Suite 106. Dallas, TX 75231.
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devices such as cyclic compression boots are appealing, but have not been shown to be effective in this exceptionally high-risk setting (16), are unable by design to be protective from emboli, and, in fact, compression devices on the leg may be contraindicated where there is semiactive thrombotic disease . Careful surveillance might be an option, but, again , is not protective from emboli and does not address the issue of profound cardiovascular collapse from an embolism where even full anticoagulation will not suffice. Using a prospective protocol. the authors have identified two groups of exceptionally high-risk hip and knee reconstructive patients. One group received an elective Greenfield vena caval filter prior to their orthopaedic surgery, to provide prophylactic embolic protection. The other group received a filter after operation, following development of an extensive deep vein thrombosis where full intravenous anticoagulation was felt to be contraindicated, as documented by Patterson et al. (24) , for prevention of embolic complications. The purpose of this study is to establish the safety and efficacy of prophylactic or early postoperative vena cava interruption with the Greenfield filter in this special cohort of patients.
Materials and Methods Since 1983, all patients with (1) chronic deep vein thrombosis; (2) prior deep vein thrombosis or pul monary embolism with a major complication of an ticoagulation; (3) a major prior pulmonary embolism; or (4) deep vein thrombosis or pulmonary embolism within the first 7 postoperative days, were considered candidates for a Greenfield Filter. Groups 1- 3 received filters before operation, and group 4 received the filter after operation. Patients with a remote history of thromboembolic disease underwent routine thromboembolic prophylaxis with low -dose warfarin followed by careful sur veillance with either venogram or ultrasound. A preoperative venogram was done on all of the study patients until 1986, at which time venous doppiers and B-mode ultrasound were done on some of the patients, although most continued to have rou tine venography. If these studies were entirely normal, no filter was placed , unless the patient was in the group that could not receive any prophylactic oral anticoagulation. After surgery, a venous doppler was done three times a week while in the hospital. followed by a venogram if abnormal. No systematic venous imaging was done after hospital discharge.
The filters were placed by three different vascular surgeons who were consulted concerning the overall anticoagulation management of the patient. In this series, all but one of the filters was placed 1 or more days prior to the orthopaedic procedure. Between January 1983 and October 1987, in the course of a busy adult reconstructive orthopaedic practice, 50 patients met this criteria for Greenfield filter insertion. One patient refused the filter, and in one patient it could not be placed from either the neck or inguinal approach. This leaves a final series of 48 patients, with 48 filters placed. The average age was 69 years (range, 33-86 year s), with 27 women and 21 men. Thirty-three were placed prophylactically and 15 for treatment. Four of the treatment group were part of a staged reconstruction, so the filter was placed for both treatment of an acute thromboembolic event and prophylaxis, anticipating subsequent surgery. The final series was made up of 37 prophylactic filters (70%) and 11 purely treatment filters (30%). Twenty-one patients underwent primary THA, 4 primary TKA, 13 revision THA, 5 revision TKA, and 5 other procedures (tendon allograft to knee, hip disarticulation, 3 Girdlestone procedures). All of the orthopaedic procedures on these patients were performed by the senior authors. Follow-up period of this series has been 24-76 months, average 44 months. Thirty -nine filters were placed under general anesthesia and 9 under local. The practice is now to place most under local anesthesia, with anesthesia standby. All were placed via the right internal jugular vein, except two, which were placed via the cornmon femoral when the jugular approach could not be used (Fig. I) . One patient had a failed attempt at insertion in the neck and the other patient had had a previous vascular bypass performed in the neck. Ideal position of the filter was below the renal veins, usually opposite the L 2-3 interspace (Fig. 2,3). The technique of insertion is published elsewhere, but the general principle is to position the filter introducer at the level desired, as determined by fluoroscopy with a venacavagrarn. to determine the location of the renal veins, and then withdraw the introducer leaving the filter in place. A guide wire through the filter maintains a vertical orientation of the filter in the vena cava uo. 22) (Fig. 2). No routine antithrombotic treatment was used in conjunction with the filter when it was placed prophylactically prior to surgery. In the group receiving the filter in the first postoperative week, all patients were taking prophylactic warfarin; the warfarin dose
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which were prophylactic filters. Five of these patients are on chronic anticoagulation, three following postfilter thigh thrombosis. Two use vascular stockings routinely. All but one of these seven pat ients had some preoperative vascular symptoms. All of these seven had good relief of their joint symptoms, however, and would have the surgery again. There were two documented vena cava occlusions, by venography during hospitalization, for a patency rate of 96 %, only one of which is cau sing ongoing symptoms. The latter has typical post phlebitic cornplaints of swelling and leg discomfort with standing, but continues to work. He has no venous dermatitis. The other den ies an y vascular symptoms at th is time , but required a long course of anticoagulation, and experienced 6 months of leg swelling. In this group of 48 patients, there were no woundhealing complications of the hip or knee surgery. There was no mortality from thromboembolic disease and no clinical incidence of postfilter pulmonary emboli. In addition, there was no significant loss of ambulatory function in those few patients who had ongoing vascular symptoms. There are, however. insufficient numbers of pat ients in this series, assuming even a 5% mortality, to make the statistical claim that the use of the filter has prevented a death.
Fig. 1. The usual insertion route for the Greenfield filter is via the right jugular vein, placing the filter below the renal veins.
was gradually increased to full anticoagulation levels, with careful observation of the wound.
Results This group of patients is actively being followed in the author's office as part of an ongoing total joint follow-up protocol. One ofthe patients had deceased of unrelated causes over a year after the implanting of his filter. He had a history of a PE and had no postoperative vascular symptoms. Of the remaining 47 patients, many complained of mild foot and ankle swelling, usually no more than they had before operation. Only seven found their symptoms subjectively worse than before surgery, four of which were treatment and three of
Fig. 2. The preferred location of the Greenfield filter is below the renal veins. During placementof the device, the filter is maintained at the desired level and the introducer pulled back. Theguide wire remains to maintain the filter's vertical position.
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A Fig. 3. (A) AP and (B) lateral radiographs showing typical position in the Greenfield filter opposite the L2-13 interspace.
Complications The complications associated with insertion of the filter reponed here are worthy of note. One patient developed a post-general anesthesia bronchitis requiring antibiotic treatment, and postponement of orthopaedic reconstruction. There was one placement error, slightly above L2ratherthan below, and therefore, possibly above the renal vein, but producing no symptoms or problems. There was one hemothorax requiring a chest tube, resolving with no sequela. Surprisingly, there were two instances of vagus nerve injury from the internal jugular ap-
preach, by the same consulting vascular surgeon, one transient for 3 weeks, and one with permanent hoarseness requiring injection treatments to the chords to regain a more audible voice. The vagus nerve is in the same sheath as the internal jugular vein, and needs to be carefully separated from the other structures and protected during insertion. This should be avoidable and occurred early in the series. There was no clinical evidence in this series suggestive of migration of the filter. Only patients with bothersome vascular symptoms have been further studied clinically, by means of plain abdominal x-ra y and venous doppler and B-mode ultrasound.
Greenfield Filter in Hip and Knee Arthroplasty
Discussion In the recent literature, the scope of venous thromboembolic disease has become well-defined (4-6,8, 9,17,18,21,23,27). In essence, the research to date has been divided into the following areas: defining the risk factors, assessing different prophylactic regimens, assessing different detection methods, and finally, looking at cost-effectiveness. The area least investigated is determining groups at special risk, and how best to treat each of them. Hip and knee reconstructive patients, even without a history of thromboembolic problems, are considered high-risk categories (7, 14, IS, 26). In fact, the incidence of thromboembolic complications is the highest in this type of surgery compared to others (17).
That prophylactic treatment can reduce the incidence of thromboembolic disease and make surgery safer, especially in the orthopaedic surgical groups, is now well-documented (18, 26). The purpose in this setting is "primary prevention" or preventing the occurrence of the disease, as discussed by Paiement (23). At the same time, controversy still abounds since there is no ideal prophylactic method (9) but, rather, it would appear that the method used should be tailored to fit the category of risk for the patients being treated (9, 17). The studies establishing the efficacy of the various prophylactic methods have been done for the most part on patients with no history of thromboembolic disease, since it is universally accepted that this latter group is at extreme risk of recurrent thrombosis, thereby skewing the results. The efficacy of most prophylactic methods in this patient category has not been established (17, 20, 23). These patients are already suffering from thromboembolic disease, and conceptually the goal of "prophylaxis" is to limit the extent of the disease rather than prevent its occurrence. Gold advocates full warfarin anticoagulation for these patients (9). Acceptance of this mode of treatment in the past has been hampered by frequent postoperative wound or gastrointestinal hemorrhage (23, 24, 29).
Little has been written in the orthopaedic literature about vena cava interruption. Brooks et al. (1) recently reported on a hip fracture patient with documented preoperative extensive deep venous thrombosis who underwent insertion of a Greenfield filter prior to uneventful hemiarthroplasty surgery. Woolson and Harris (29) have reported a series of
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5 patients in whom a Greenfield filter was used after operation after full intravenous anticoagulation produced wound bleeding. This bleeding occurred within the first 10 days after surgery. One of these patients, who was bleeding into the hip on full intravenous anticoagulation, requiring angiographic embolization, died of complications of a recurrent pulmonary embolism that occurred before the filter was placed. Woolson and Harris come short of recommending prophylactic filter placement, but acknowledged that earlier filter insertion in this case would have prevented a death. Golueke et al. (10) have made cogent arguments for expanding the use of Greenfield filters, citing an overall 4.6% morbidity rate and 0% mortality rate. Only 23% of their filters were placed prophylactically, for both orthopaedic and nonorthopaedic cases. Current indications from the literature for Greenfield filter placement are clinical circumstances where anticoagulation is either contraindicated, failed, or inadequate (11, 20). Recent experience with the Greenfield filter reported elsewhere has been positive. In particular, ease of insertion, excellent patency rate, and minimal morbidity has made the Greenfield filter the method of choice for vena caval interruption (20). The conical design enhances caval patency, reported as 97%, by Greenfield et aI. (20). Our own data is in general agreement, with a patency rate of 96% in our series. Recurrent emboli have been reported, up to 4% (11), although none occurred in this series, using only clinical criteria for detection. Distal migration of Greenfield filters has been reported (25), although it is a rare occurrence. Frank dislodgement of the filter is rare, although embolization to the right ventricle has been reported (2). In our series, no systematic radiographic study of the filters was undertaken in the total absence of abdominal or other catastrophic clinical events, making any such investigation necessary. That the retrieval of Greenfield filters can be accomplished when indicated is of note (12), although we have made no recommendation or attempt to do so in any of our patients. A word of caution must be raised about insertion complications, however, which caused most of the morbidity in this series. While all of our complications were minor and few in number, they nonetheless caused increased patient inconvenience and some disability. Insertion of these filters should only be undertaken by experienced personnel. These complications should be avoidable. Deep vein thrombosis continues to be a problem after filter placement, with serious persisting venous
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symptoms in 15% (7/47) of this series. Obviously, vena cava filters have no antithrombotic role, and if it is safe to do so, the literature supports the continued use of anticoagulation measures, for 3-4 months (20). This might have diminished the number of postfilter thromboses (3) that we saw in our series. It is our practice at this time to follow this recommendation.
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Conclusion We believe that the data reported here support the expanded use of Greenfield filters in these two patient populations. Since we were able to safely perform complex hip and knee reconstructions without any pulmonary emboli and with minimal morbidity and no mortality, in a group at the highest risk of these complications, we conclude that our protocol using the Greenfield filter should be advocated to others involved in this type of surgery. The literature does not provide a comparable series of patients for comparison with other methods, so other protective measures may prove equally effective. We believe that it is likely that we have prevented a major embolic event, and possibly a death, in our series of patients. In the circumstance of a patient requiring full intravenous anticoagulation within the first week after surgery, especially a revision case with a large wound surface, we recommend that a filter be placed to protect the patient from embolism, and then treatment of the thrombotic event with a slowly increasing anticoagulation regimen, not reaching full therapeutic levels until the wound is mature, at least 10 days from surgery. This is a technically demanding procedure and should be performed only by those skilled in its use. Most of our complications were related to insertion. These should be avoidable. Follow-up study in this series, up to 76 months, has shown no late deterioration in the clinical status.
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References 20. I. Brooks RL, Winslow MC, Kenmore PI: The week-old hip fracture: indication for prophylactic use of a vena cava filter? Orthopedics 10:1287, 1988 2. Castaneda F, Herrera M, Cragg AH et al: Migration
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of a Kimray-Greenfield filter to the right ventricle. Radiology 149:690, 1983 Culver 0, Crawford JS, Gardiner JH, Wiley AM: Venous thrombosis after fractures of the upper end of the femur. J Bone Joint Surg 52B:61, 1970 Dalen JE, Paraskos JA, 'Ockene IS et al: Venous thromboembolism: scope of the problem. Chest 89:370S, 1986 Dalen JE, Alpert JS: Natural history of pulmonary embolism. Prog Cardiovasc Dis 16:259, 1975 Donaldson GA, Williams C. Scannell JG: A reappraisal of the Trendelenberg operation for massive fatal embolism. N Engl J Med 268: 171, 1963 Dorr LD, Sakimura L Mohler JG: Pulmonary emboli following total hip arthroplasty: incidence study. J Bone Joint Surg 61A:I083, 1979 Eskland G, Solheim K. Skjorten F: Anticoagulant prophylaxis, thromboembolism and mortality in elderly patients with hip fractures. Acta Chir Scand 131: 16, 1966 Gold EW: Prophylaxis of deep venous thromboembolism. Orthopedics 1I: 1197, 1988 Golueke PJ, Garrett WV, Thompson JE et al: Interruption of the vena cava by means of the Greenfield filter: expanding the indication. Surgery 103: 111, 1988 Greenfield LT, Peyton R, Crute S, Barnes R: Greenfield vena cava filter experience. Arch Surg 116: 1451, 1981 Greenfield U, Crute SL: Retrieval of the Greenfield vena cava filter. Surgery 88:719, 1980 Harris WH, Salzman EW, Athanasoulis C: Comparison of warfarin, low-molecular-weight dextran, aspirin, and subcutaneous heparin in prevention of venous thromboembolism following total hip replacement. J Bone Joint Surg 56A: 1552, 1974 Harris WH, Salzman EW, Desanctic RW: The prevention of thromboembolic disease by prophylactic anticoagulation. J Bone Joint Surg 49A:81, 1967 Hartman JT, Altner PC, Freeark RJ: The effect of limb elevation preventing venous thrombosis. J Bone Joint Surg 52A:1618, 1970 Hartman JT, Pugh JL, Smith RD et al: Cyclis sequential compression of the lower limb in prevention of deep venous thrombosis. J Bone Joint Surg 64A: 1059, 1982 Hull RD, Raskob GE, Hirsh J: Prophylaxis of venous thromboembolism: an overview. Chest 89:374S, 1986 Hull RD, Raskob GE: prophylaxis of venous thromboembolic disease following hip and knee surgery. J Bone Joint Surg 68A: 146, 1986 Johnson R, Green JR. Charnley J: Pulmonary embolism and its prophylaxis following the Charnley total hip replacement. Clin Orthop 127:123, 1977 Jones TJ, Barnes RW, Greenfield U: Greenfield vena caval filter: rationale and current indications. Ann Thorac Surg 42:S48, 1986 Lowe LW: Venous thrombosis and embolism. J Bone Joint Surg 63B:155, 1981
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22. Menzoian JO . LoGerfc FW. Doyle JE et al: Technical modifications in the placement of inferior vena caval filter devices. Am J Surg 142:216. 1981 23. Paiement GD. Bell D. Wessinger SJ. Harris WH: New advances in the prevention. diagnosis. and cost effectiveness of venous thromboembolic disease in patients with total hip replacement. Proceedings of the Hip Society. Chapter 8. p. 94. 1986 24. Patterson BM. Marchand R. Ranawat C: Complications of heparin therapy after total joint arthroplasty. J Bone Joint Surg 71A: 1130. 1989 25. Sidawy AN. Menzoian JO : Distal migration and deformation of the Greenfield vena cava filter. Surgery 99 :369. 1986
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26. Stulberg BN. Insall IN . Williams GW. Ghelman B: Deep-vein thrombosis following total knee replacement. J Bone Jo int Surg 66A: 194. 1984 27. Trulock EP: Venous thromboembolism: prophylaxis. diagnosis. and therapy in surgical patients. Surgical rounds for orthopedics. p. 28. October. 1987 28. Turpie AGG. Levine MN. Hirsch J et al: A randomized controlled trial of a low-molecular-weight heparin to prevent deep-vein thrombosis in patients undergoing elective hip surgery . N Engl J Med 315 :925. 1986 29. Woolson ST. Harris WH: Greenfield vena caval filter for management of selected cases of venous thromboembolic disease following hip surgery. Clin Orthop 204 :20 L 1986
