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Thromboembolic complications after arthroscopy of the knee
Arthroscopy: The Journal of Arthroscopic and Related Surgery 9(5):570-573
Published by Raven Press, Ltd. © 1993 Arthroscopy Association of North America
Thromboembolic Complications After Arthroscopy of the Knee Kristian Aagaard Poulsen, M.D., Lars C Borris, M.D., and Michael R. Lassen, M.D.
Summary: Arthroscopy of the knee has always been associated with a low risk of complications, including thromboembolism. Therefore, few studies have been concerned with the matter. We present two case reports and a review of the available literature concerning thromboembolic complications after arthroscopy. Key Words: Thromboembolism--Thrombophlebitis--Pulmonary emboli--Review.
Since the introduction of endoscopic technique -75 years ago, the use of arthroscopy has become more and more common and is now very popular in orthopedic practice. Knee arthroscopy is the most common procedure, but in theory all joint cavities can be examined arthroscopically (1). Although the complication rate of arthroscopy is lower than that of arthrotomy, a number of complications have been previously reported, the most common of which are minor articular cartilage damage; hemarthrosis; equipment breakage; injury of ligaments, nerves, or vessels; compartment syndrome; and infectious and thromboembolic complications [i.e., deep vein thrombosis (DVT) and pulmonary embolism (PE)] (1-18). Even though the absolute rate is low, PE represents one of the most life-threatening complications. Apart from this, the postphlebitic limb resulting from acute DVT due to destruction of venous valves (causing swelling, varicose veins, eczema, and chronic ulceration) is a difficult condition to treat. Having seen cases of DVT/PE after arthroscopy of the knee in our own department, we found it interesting to review the literature on this issue in order to estimate the extent of the problem, identify
possible risk factors, and make recommendations for prophylaxis and treatment. CASE REPORTS Case 1 A 31-year-old man underwent arthroscopy of the knee due to clinical suspicion of a lesion of the medial meniscus. The operation lasted 60 min (tourniquet time 65 min) and was performed under regional (epidural) anesthesia. Thromboprophylaxis was not used. On the first postoperative day, the patient experienced increasing pain in the operated limb. On the second postoperative day, he developed fever of 38.8°C. The day after, the patient developed chest pain with cough and clinical signs of DVT of the operated limb. Chest radiographs and electrocardiographs were both normal. Ventilation-perfusion lung scintigraphy showed a high probability for an embolus in the basal part of the left lung. Treatment with heparin and dicoumarol was started, and the patient was discharged from the hospital 9 days after the operation. Anticoagulation treatment was stopped 3 months later, and the patient had no further symptoms in the chest or leg.
From the Venous Thrombosis Group, Department of Orthopedics, Aalborg Hospital, Hobrovej, Aalborg, Denmark. Address correspondence and reprint requests to Dr. Kristian Aagaard Poulsen, Venous Thrombosis Group, Department of Orthopedics, Aalborg Hospital, Hobrovej, DK-9100 Aalborg, Denmark.
Case 2 A 58-year-old man underwent arthroscopy due to a suspected lesion of the medial meniscus of the right knee. He was in good general condition and 570
THROMBOEMBOLIC COMPLICATIONS
without any symptoms of vascular disease. Arthroscopy with a tourniquet was performed on an outpatient basis under general anesthesia (45 min duration) and showed a flap tear lesion of the medial meniscus, a large lesion of the cartilage of the medial femoral condyle, a partial lesion of the anterior cruciate ligament, and arthrosis of both the medial and lateral compartments. Partial resection of the medial meniscus was performed. Thromboprophylaxis was not used. Five days postoperatively, the patient developed symptoms of DVT of the operated limb. Ultrasound examination showed a thrombus in the popliteal vein. The patient was treated with anticoagulation (heparin and dicoumarol) and he was discharged from the hospital a few days later. During treatment, the patient developed hemarthrosis and had several evacuations. Six months later, the patient had fully recovered. DISCUSSION The pathogenesis of venous thrombus is unknown, but the common opinion is that it is multifactorial. One hypothesis is that damage to the endothelium either by inflammation or instrumentation initiates coagulation by release of specific mediators. Venous stasis or the combination of a reduced blood volume and low velocity and turbulence at the valve cusps are considered to be major preconditions for the development of DVT. Postoperative swelling of the knee may reduce blood flow and result in venous stasis. Properties of the blood may be thrombogdnic factors such as thrombocytosis, polycytemia with increase in hematocrit, and disturbances in the coagulation and fibrinolytic systems [decrease in tissue plasminogen activator (tPA), antithrombin III (AT liD, or protein C and S or an increase in plasminogen activator inhibitor (PAI)I (19). Despite the early mobilization that arthroscopic surgery makes possible, there is still a risk of development of postoperative thromboembolic complications. Arthroscopy of the knee has always been associated with a low rate of complications, particularly of thromboembolism, although few studies have addressed the issue until now. The Committee on Complication of the Arthroscopy Association of North America published two retrospective surveys in 1985 and 1986, one of which showed that 752 of 2,215 complications (34%) were thromboembolic (DVT and/or PE) after 375,069 ar-
571
throscopies (1,2), which clearly is an underestimate because these figures were based on clinical symptoms only. Furthermore, retrospective data on thromboembolism are not reliable without regular follow-up because many cases of DVT and PE are diagnosed and treated by the general practitioner, internist, or medical department and therefore are not registered as postoperative complications. The reported incidence of DVT after arthroscopy of the knee ranges between 0 and 7.3% and of PE between 0 and 3.2% in previous studies (Table 1). The incidence of phlebographically verified DVT was 4.2% in a study by Stringer et al. 1989 (4), which was the only study using an objective diagnostic method for screening in all patients and using a prospective design (Table 1). It is important to keep in mind that thromboembolism, especially DVT, may pass subclinically, for which reason screening with objective methods is mandatory. Thus, Kakkar et al. 1970 reported that clinical symptoms were present in only one third of patients with confirmed PE (20). Many noninvasive diagnostic techniques have been developed, but still phlebography is the standard in the diagnosis of postoperative DVT (4,5,9). PE is usually diagnosed by ventilation-perfusion lung scintigraphy (5,6,9) or by pulmonary angiography. It is prudent to make further investigations to diagnose PE when a patient with a verified DVT develops even slight chest pain. The importance of this policy is underlined in our first case report. A number of risk factors have been identified for the development of thromboembolic complications after operative procedures of the lower extremities, the most important of which are age, obesity, proTABLE 1. Incidence of thromboembolic complications
after arthroscopy of the knee in previous studies Investigators (reference)
Incidence of DVT
Incidence of PE
Stringer et al. (4) Sherman et al. a (3) Carson (6) Collins (7) DeLee (2) Small (15) McGinty et al. (18) Jackson (13) Lysholm et al. (17) Dandy and O'Carrol (10) Rand (11) Guhl (12)
4.2% (0.8%) (4.9%) (0.3%) (0.1%) (0.2%) (7.3%) (1.4%) (1.0%) (0.3%) (3.4%) (1.0%)
(0) (0.8%) 1.6% (0.06%) (0.03%) (0.03%) (0) (0.5%) (0) (0) (0) (0)
Incidences in parentheses are based on clinical diagnoses. a Sherman et al. did not distinguish between DVT and PE.
Arthroscopy, Vol. 9, No. 5, 1993
572
K. A. P O U L S E N E T A L .
longed operation and/or tourniquet time (>30 min), previous DVT/PE, cardial insufficiency, varicose veins, and prolonged immobilization (4,19,20). Even though DVT and PE are thought to be the most common and dangerous complications after arthroscopy, few risk factors have been identified. The most commonly reported risk factors are age and duration of operation/tourniquet time (37,9,18). Age is highly suspected of being a risk factor. Age >40-50 years seems to carry a higher risk of DVT/ PE after arthroscopy, possibly due to a reduced level of plasminogen activators (3-7,21). Stringer et al. showed an overall DVT incidence of 15-20% in patients 51-70 years of age, but there were only two cases of DVT in 48 patients having arthroscopy (4). The patient in our second case report was 58 years of age and therefore had a main risk factor but received no thromboprophylaxis. Duration of operation/tourniquet time may be an important risk factor, and several studies have found a higher risk of thrombosis after a tourniquet time of >60 min (3-7). However, tourniquet time was not reported in all previous studies. In both of our cases, tourniquet time exceeded 40 min. There is no agreement on the possible importance of the tourniquet. Fahmy et al. (22) in a study of patients undergoing knee arthrotomy showed an increase in systemic fibrinolytic activity before tourniquet release that peaked 15 min after release and was normalized after 30 min. Identical changes were detected in the operated leg, which was thought to be due to hypoxia and venous occlusion. In this study, an incidence of DVT of 10% in the tourniquet patients and of 35% in the nontourniquet patients was reported (22). In a study by Sherman et al., use of a tourniquet had no effect on the rate of DVT (3), whereas Price et al. found that tourniquet use was associated with ipsilateral DVT in orthopedic patients undergoing operative procedures other than arthroscopy (23); No studies have investigated possible benefit of the use of regional anesthesia in patients undergoing arthroscopy. In patients undergoing hip or knee arthroplasties, regional anesthesia was shown to reduce the incidence of DVT compared with general anesthesia (24,25). This may be due to an increased bloodflow, reduced coagulability, and enhanced fibrinolytic activity. When there is a previous history of DVT/PE the risk of thromboembolic complications increases significantly. Kakkar et al. reported an incidence of Arthroscopy, Vol. 9, No. 5, 1993
DVT of 100% in a group of patients with a history of previous PE (20). We believe that patients scheduled for arthroscopy of the knee should be considered at high-risk for thromboembolism when they are >50 years of age, when the operation or tourniquet time exceeds 60 min, or when they have a history of previous DVT/PE. No studies have addressed thromboprophylaxis in patients undergoing arthroscopy, and little is mentioned of it in the literature. Carson et al. gave thromboprophylaxis with a nonsteroidal antiinflammatory drug (NSAID) (ascriptin) after operation, but the efficacy of this regimen was not reported (6). It may be effective to give high-risk arthroscopy patients thromboprophylaxis. We use some of the methods found to be effective in other kinds of orthopedic surgery, i.e., low molecular weight heparin started before operation and continued for 7-10 days after the operation depending on the degree of mobilization. In addition, consideration should be given to reducing the operating time, using a tourniquet only if necessary, using regional anesthesia if possible, abandoning postoperative splinting, and encouraging early mobilization, as well as diagnosing cases of DVT/PE and treating them properly. The risk/benefit and cost-effectiveness of such measures should be evaluated in a proper study. There is no consensus on whether calf vein thrombi should be treated with anticoagulants or elastic compression stockings and NSAIDs (46,8,9). When initiating anticoagulation, it is important to be aware of the adverse effects that may occur. The international normalized ratio (INR) should be in the range of 2.5-3.5. Our second case report emphasizes the risk of bleeding complications that may develop during anticoagulant therapy. The patient was overdosed, resulting in an actual INR of 4.3 and hemarthrosis. In conclusion, more studies are needed to evaluate the extent of thromboembolic complications in patients undergoing arthroscopy of the knee in order to institute proper prophylactic measures in these patients. Acknowledgment: Case report 1 was supplied by the Department of Orthopaedics, Aarhus County Hospital, courtesy of Dr. Peter Faun¢.
REFERENCES 1. Small NC, Committee on Complications of the Arthroscopy Association of North America. Complications in arthroscopy: the knee and other joints. A r t h r o s c o p y 1986;2:253-8.
THROMBOEMBOLIC C O M P L I C A T I O N S 2. DeLee JC, Committee on Complications of Arthroscopy Association of North America. Complications of arthroscopy and arthroscopic surgery: results of national survey. Arthroscopy 1985;1:214-20. 3. Sherman OH, Fox JN, Snyder SJ, et al. Arthroscopy--"noproblem surgery". An analysis of complications in two thousand six hundred and forty cases. J Bone Joint Surg [Am] 1986;68:256--65. 4. Stringer MD, Steadman CA, Hedges AR, Thomas EM, Morley TR, Kakkar VV. Deep vein thrombosis after elective knee surgery. J Bone Joint Surg [Br] 1989;71:492-7. 5. Walker RH, Dillingham M. Thrombophlebitis following arthroscopic surgery of the knee. Contemp Orthop 1983;6:29-33. 6. Carson RW. Arthroscopic meniscectomy. Orthop Clin North Am 1979;10:619--27. 7. Collins JJ. Knee-joint arthroscopy--early complications. Med J Aust 1989;150:702-3,706. 8. Jackson RW, Rouse DW. The results of partial arthroscopic meniscectomy in patients over 40 years of age. J Bone Joint Surg lBr] 1982;64:481-5. 9. Dunn PM, Post RH, Jones SR. Thromboembolic complications of knee arthroscopy. West J Med 1984;140:291. 10. Dandy DJ, O'Carrol PF. Arthroscopic surgery of the knee. Br Med J 1982;285:1256--8. 11. Rand JA. Arthroscopic management of degenerative miniscus tears in patients with degenerative arthritis. Arthroscopy 1985; 1:253-8. 12. Guhl JF. Operative arthroscopy. Am J Sports Med 1979;7: 328-35. 13. Jackson RW. The role of arthroscopy in the management of disorders of the knee. J Bone Joint Surg [Br] 1972;54:310-22. 14. Pellacci F, Verni E, Lucaccini C, Marchiodi L, Poli G. Ar-
15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
573
throscopic medial meniscectomy. Ital J Orthop Traurnatol 1988;14:157--66. Small NC. An analysis of complications in lateral retinacular release procedures. Arthroscopy 1989;5:282-6. Morgan CD, Casscells SW. Arthroscopic meniscus repair: a safe approach to the posterior horns. Arthroscopy 1986;2:312. Lysholm J, Gillquist J, Liljedahl S-O. Arthroscopy in the early diagnosis of injuries to the knee joint. Acta Orthop Scand 1981 ;52:111--8. McGinty JB, Geuss LF, Marvin RA. Partial or total meniscectomy. J Bone Joint Surg [Am] 1977;59:763-6. Bergquist D. Postoperative thromboembolism. Frequency, etiology, prophylaxis. New York: Springer-Verlag, 1983. Kakkar VV, Howe CT, Nicolaides AN, Renney JTG, Clarke MB. Deep vein thrombosis of the leg: is there a "high risk" group. Am J Surg 1970;120:527-30. Johnson RH, Mansfield A. A new method for the detection of plasminogen activator content of vein walls. Acta Haematol 1978;60:243. Fahmy NR, Patel DG. Hemostatic changes and postoperative deep-vein thrombosis associated with use of a pneumatic tourniquet. J Bone Joint Surg [Am] 1981;63:461-5. Price AJ, Jones NAG, Webb PJ, Mistry FM, Kakkar VV. Do tourniquets prevent deep vein thrombosis? J Bone Joint Surg [Am] 1973;55:106. Modig J. The role of lumbar epidural anaesthesia as antithrombotic prophylaxis in total hip replacement. Acta Chir Scand 1985;151:589-94. Nielsen PT, JCrgensen LN, Albrect-Beste E, Leffers AM, Rasmussen LS. Lower thrombosis risk with epidural blocade in knee arthroplasty. Acta Orthop Scand 1990;61:29--31.
Arthroscopy, Vol. 9, No. 5, 1993
Published by Raven Press, Ltd. © 1993 Arthroscopy Association of North America
Thromboembolic Complications After Arthroscopy of the Knee Kristian Aagaard Poulsen, M.D., Lars C Borris, M.D., and Michael R. Lassen, M.D.
Summary: Arthroscopy of the knee has always been associated with a low risk of complications, including thromboembolism. Therefore, few studies have been concerned with the matter. We present two case reports and a review of the available literature concerning thromboembolic complications after arthroscopy. Key Words: Thromboembolism--Thrombophlebitis--Pulmonary emboli--Review.
Since the introduction of endoscopic technique -75 years ago, the use of arthroscopy has become more and more common and is now very popular in orthopedic practice. Knee arthroscopy is the most common procedure, but in theory all joint cavities can be examined arthroscopically (1). Although the complication rate of arthroscopy is lower than that of arthrotomy, a number of complications have been previously reported, the most common of which are minor articular cartilage damage; hemarthrosis; equipment breakage; injury of ligaments, nerves, or vessels; compartment syndrome; and infectious and thromboembolic complications [i.e., deep vein thrombosis (DVT) and pulmonary embolism (PE)] (1-18). Even though the absolute rate is low, PE represents one of the most life-threatening complications. Apart from this, the postphlebitic limb resulting from acute DVT due to destruction of venous valves (causing swelling, varicose veins, eczema, and chronic ulceration) is a difficult condition to treat. Having seen cases of DVT/PE after arthroscopy of the knee in our own department, we found it interesting to review the literature on this issue in order to estimate the extent of the problem, identify
possible risk factors, and make recommendations for prophylaxis and treatment. CASE REPORTS Case 1 A 31-year-old man underwent arthroscopy of the knee due to clinical suspicion of a lesion of the medial meniscus. The operation lasted 60 min (tourniquet time 65 min) and was performed under regional (epidural) anesthesia. Thromboprophylaxis was not used. On the first postoperative day, the patient experienced increasing pain in the operated limb. On the second postoperative day, he developed fever of 38.8°C. The day after, the patient developed chest pain with cough and clinical signs of DVT of the operated limb. Chest radiographs and electrocardiographs were both normal. Ventilation-perfusion lung scintigraphy showed a high probability for an embolus in the basal part of the left lung. Treatment with heparin and dicoumarol was started, and the patient was discharged from the hospital 9 days after the operation. Anticoagulation treatment was stopped 3 months later, and the patient had no further symptoms in the chest or leg.
From the Venous Thrombosis Group, Department of Orthopedics, Aalborg Hospital, Hobrovej, Aalborg, Denmark. Address correspondence and reprint requests to Dr. Kristian Aagaard Poulsen, Venous Thrombosis Group, Department of Orthopedics, Aalborg Hospital, Hobrovej, DK-9100 Aalborg, Denmark.
Case 2 A 58-year-old man underwent arthroscopy due to a suspected lesion of the medial meniscus of the right knee. He was in good general condition and 570
THROMBOEMBOLIC COMPLICATIONS
without any symptoms of vascular disease. Arthroscopy with a tourniquet was performed on an outpatient basis under general anesthesia (45 min duration) and showed a flap tear lesion of the medial meniscus, a large lesion of the cartilage of the medial femoral condyle, a partial lesion of the anterior cruciate ligament, and arthrosis of both the medial and lateral compartments. Partial resection of the medial meniscus was performed. Thromboprophylaxis was not used. Five days postoperatively, the patient developed symptoms of DVT of the operated limb. Ultrasound examination showed a thrombus in the popliteal vein. The patient was treated with anticoagulation (heparin and dicoumarol) and he was discharged from the hospital a few days later. During treatment, the patient developed hemarthrosis and had several evacuations. Six months later, the patient had fully recovered. DISCUSSION The pathogenesis of venous thrombus is unknown, but the common opinion is that it is multifactorial. One hypothesis is that damage to the endothelium either by inflammation or instrumentation initiates coagulation by release of specific mediators. Venous stasis or the combination of a reduced blood volume and low velocity and turbulence at the valve cusps are considered to be major preconditions for the development of DVT. Postoperative swelling of the knee may reduce blood flow and result in venous stasis. Properties of the blood may be thrombogdnic factors such as thrombocytosis, polycytemia with increase in hematocrit, and disturbances in the coagulation and fibrinolytic systems [decrease in tissue plasminogen activator (tPA), antithrombin III (AT liD, or protein C and S or an increase in plasminogen activator inhibitor (PAI)I (19). Despite the early mobilization that arthroscopic surgery makes possible, there is still a risk of development of postoperative thromboembolic complications. Arthroscopy of the knee has always been associated with a low rate of complications, particularly of thromboembolism, although few studies have addressed the issue until now. The Committee on Complication of the Arthroscopy Association of North America published two retrospective surveys in 1985 and 1986, one of which showed that 752 of 2,215 complications (34%) were thromboembolic (DVT and/or PE) after 375,069 ar-
571
throscopies (1,2), which clearly is an underestimate because these figures were based on clinical symptoms only. Furthermore, retrospective data on thromboembolism are not reliable without regular follow-up because many cases of DVT and PE are diagnosed and treated by the general practitioner, internist, or medical department and therefore are not registered as postoperative complications. The reported incidence of DVT after arthroscopy of the knee ranges between 0 and 7.3% and of PE between 0 and 3.2% in previous studies (Table 1). The incidence of phlebographically verified DVT was 4.2% in a study by Stringer et al. 1989 (4), which was the only study using an objective diagnostic method for screening in all patients and using a prospective design (Table 1). It is important to keep in mind that thromboembolism, especially DVT, may pass subclinically, for which reason screening with objective methods is mandatory. Thus, Kakkar et al. 1970 reported that clinical symptoms were present in only one third of patients with confirmed PE (20). Many noninvasive diagnostic techniques have been developed, but still phlebography is the standard in the diagnosis of postoperative DVT (4,5,9). PE is usually diagnosed by ventilation-perfusion lung scintigraphy (5,6,9) or by pulmonary angiography. It is prudent to make further investigations to diagnose PE when a patient with a verified DVT develops even slight chest pain. The importance of this policy is underlined in our first case report. A number of risk factors have been identified for the development of thromboembolic complications after operative procedures of the lower extremities, the most important of which are age, obesity, proTABLE 1. Incidence of thromboembolic complications
after arthroscopy of the knee in previous studies Investigators (reference)
Incidence of DVT
Incidence of PE
Stringer et al. (4) Sherman et al. a (3) Carson (6) Collins (7) DeLee (2) Small (15) McGinty et al. (18) Jackson (13) Lysholm et al. (17) Dandy and O'Carrol (10) Rand (11) Guhl (12)
4.2% (0.8%) (4.9%) (0.3%) (0.1%) (0.2%) (7.3%) (1.4%) (1.0%) (0.3%) (3.4%) (1.0%)
(0) (0.8%) 1.6% (0.06%) (0.03%) (0.03%) (0) (0.5%) (0) (0) (0) (0)
Incidences in parentheses are based on clinical diagnoses. a Sherman et al. did not distinguish between DVT and PE.
Arthroscopy, Vol. 9, No. 5, 1993
572
K. A. P O U L S E N E T A L .
longed operation and/or tourniquet time (>30 min), previous DVT/PE, cardial insufficiency, varicose veins, and prolonged immobilization (4,19,20). Even though DVT and PE are thought to be the most common and dangerous complications after arthroscopy, few risk factors have been identified. The most commonly reported risk factors are age and duration of operation/tourniquet time (37,9,18). Age is highly suspected of being a risk factor. Age >40-50 years seems to carry a higher risk of DVT/ PE after arthroscopy, possibly due to a reduced level of plasminogen activators (3-7,21). Stringer et al. showed an overall DVT incidence of 15-20% in patients 51-70 years of age, but there were only two cases of DVT in 48 patients having arthroscopy (4). The patient in our second case report was 58 years of age and therefore had a main risk factor but received no thromboprophylaxis. Duration of operation/tourniquet time may be an important risk factor, and several studies have found a higher risk of thrombosis after a tourniquet time of >60 min (3-7). However, tourniquet time was not reported in all previous studies. In both of our cases, tourniquet time exceeded 40 min. There is no agreement on the possible importance of the tourniquet. Fahmy et al. (22) in a study of patients undergoing knee arthrotomy showed an increase in systemic fibrinolytic activity before tourniquet release that peaked 15 min after release and was normalized after 30 min. Identical changes were detected in the operated leg, which was thought to be due to hypoxia and venous occlusion. In this study, an incidence of DVT of 10% in the tourniquet patients and of 35% in the nontourniquet patients was reported (22). In a study by Sherman et al., use of a tourniquet had no effect on the rate of DVT (3), whereas Price et al. found that tourniquet use was associated with ipsilateral DVT in orthopedic patients undergoing operative procedures other than arthroscopy (23); No studies have investigated possible benefit of the use of regional anesthesia in patients undergoing arthroscopy. In patients undergoing hip or knee arthroplasties, regional anesthesia was shown to reduce the incidence of DVT compared with general anesthesia (24,25). This may be due to an increased bloodflow, reduced coagulability, and enhanced fibrinolytic activity. When there is a previous history of DVT/PE the risk of thromboembolic complications increases significantly. Kakkar et al. reported an incidence of Arthroscopy, Vol. 9, No. 5, 1993
DVT of 100% in a group of patients with a history of previous PE (20). We believe that patients scheduled for arthroscopy of the knee should be considered at high-risk for thromboembolism when they are >50 years of age, when the operation or tourniquet time exceeds 60 min, or when they have a history of previous DVT/PE. No studies have addressed thromboprophylaxis in patients undergoing arthroscopy, and little is mentioned of it in the literature. Carson et al. gave thromboprophylaxis with a nonsteroidal antiinflammatory drug (NSAID) (ascriptin) after operation, but the efficacy of this regimen was not reported (6). It may be effective to give high-risk arthroscopy patients thromboprophylaxis. We use some of the methods found to be effective in other kinds of orthopedic surgery, i.e., low molecular weight heparin started before operation and continued for 7-10 days after the operation depending on the degree of mobilization. In addition, consideration should be given to reducing the operating time, using a tourniquet only if necessary, using regional anesthesia if possible, abandoning postoperative splinting, and encouraging early mobilization, as well as diagnosing cases of DVT/PE and treating them properly. The risk/benefit and cost-effectiveness of such measures should be evaluated in a proper study. There is no consensus on whether calf vein thrombi should be treated with anticoagulants or elastic compression stockings and NSAIDs (46,8,9). When initiating anticoagulation, it is important to be aware of the adverse effects that may occur. The international normalized ratio (INR) should be in the range of 2.5-3.5. Our second case report emphasizes the risk of bleeding complications that may develop during anticoagulant therapy. The patient was overdosed, resulting in an actual INR of 4.3 and hemarthrosis. In conclusion, more studies are needed to evaluate the extent of thromboembolic complications in patients undergoing arthroscopy of the knee in order to institute proper prophylactic measures in these patients. Acknowledgment: Case report 1 was supplied by the Department of Orthopaedics, Aarhus County Hospital, courtesy of Dr. Peter Faun¢.
REFERENCES 1. Small NC, Committee on Complications of the Arthroscopy Association of North America. Complications in arthroscopy: the knee and other joints. A r t h r o s c o p y 1986;2:253-8.
THROMBOEMBOLIC C O M P L I C A T I O N S 2. DeLee JC, Committee on Complications of Arthroscopy Association of North America. Complications of arthroscopy and arthroscopic surgery: results of national survey. Arthroscopy 1985;1:214-20. 3. Sherman OH, Fox JN, Snyder SJ, et al. Arthroscopy--"noproblem surgery". An analysis of complications in two thousand six hundred and forty cases. J Bone Joint Surg [Am] 1986;68:256--65. 4. Stringer MD, Steadman CA, Hedges AR, Thomas EM, Morley TR, Kakkar VV. Deep vein thrombosis after elective knee surgery. J Bone Joint Surg [Br] 1989;71:492-7. 5. Walker RH, Dillingham M. Thrombophlebitis following arthroscopic surgery of the knee. Contemp Orthop 1983;6:29-33. 6. Carson RW. Arthroscopic meniscectomy. Orthop Clin North Am 1979;10:619--27. 7. Collins JJ. Knee-joint arthroscopy--early complications. Med J Aust 1989;150:702-3,706. 8. Jackson RW, Rouse DW. The results of partial arthroscopic meniscectomy in patients over 40 years of age. J Bone Joint Surg lBr] 1982;64:481-5. 9. Dunn PM, Post RH, Jones SR. Thromboembolic complications of knee arthroscopy. West J Med 1984;140:291. 10. Dandy DJ, O'Carrol PF. Arthroscopic surgery of the knee. Br Med J 1982;285:1256--8. 11. Rand JA. Arthroscopic management of degenerative miniscus tears in patients with degenerative arthritis. Arthroscopy 1985; 1:253-8. 12. Guhl JF. Operative arthroscopy. Am J Sports Med 1979;7: 328-35. 13. Jackson RW. The role of arthroscopy in the management of disorders of the knee. J Bone Joint Surg [Br] 1972;54:310-22. 14. Pellacci F, Verni E, Lucaccini C, Marchiodi L, Poli G. Ar-
15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
573
throscopic medial meniscectomy. Ital J Orthop Traurnatol 1988;14:157--66. Small NC. An analysis of complications in lateral retinacular release procedures. Arthroscopy 1989;5:282-6. Morgan CD, Casscells SW. Arthroscopic meniscus repair: a safe approach to the posterior horns. Arthroscopy 1986;2:312. Lysholm J, Gillquist J, Liljedahl S-O. Arthroscopy in the early diagnosis of injuries to the knee joint. Acta Orthop Scand 1981 ;52:111--8. McGinty JB, Geuss LF, Marvin RA. Partial or total meniscectomy. J Bone Joint Surg [Am] 1977;59:763-6. Bergquist D. Postoperative thromboembolism. Frequency, etiology, prophylaxis. New York: Springer-Verlag, 1983. Kakkar VV, Howe CT, Nicolaides AN, Renney JTG, Clarke MB. Deep vein thrombosis of the leg: is there a "high risk" group. Am J Surg 1970;120:527-30. Johnson RH, Mansfield A. A new method for the detection of plasminogen activator content of vein walls. Acta Haematol 1978;60:243. Fahmy NR, Patel DG. Hemostatic changes and postoperative deep-vein thrombosis associated with use of a pneumatic tourniquet. J Bone Joint Surg [Am] 1981;63:461-5. Price AJ, Jones NAG, Webb PJ, Mistry FM, Kakkar VV. Do tourniquets prevent deep vein thrombosis? J Bone Joint Surg [Am] 1973;55:106. Modig J. The role of lumbar epidural anaesthesia as antithrombotic prophylaxis in total hip replacement. Acta Chir Scand 1985;151:589-94. Nielsen PT, JCrgensen LN, Albrect-Beste E, Leffers AM, Rasmussen LS. Lower thrombosis risk with epidural blocade in knee arthroplasty. Acta Orthop Scand 1990;61:29--31.
Arthroscopy, Vol. 9, No. 5, 1993