Vol 9, No 4, July/August 2001 253 Arterial complications after total knee arthroplasty (TKA) are quite rare, and the scant literature regard- ing this topic consists mainly of case reports. 1-13 Calligaro et al 14 reviewed 4,097 TKAs performed at their hospital and found that 7 patients (0.17%) had acute ischemia after the procedure. On analysis of 9,022 arthroplasties, Rand 15 found 3 cases of postoperative arterial com- plications (incidence of 0.03%). A tourniquet was used in almost all reported cases. In all of these re- ported cases, the patients had acute thrombosis rather than vessel lacer- ation. Because of these and other associated complications, there have been concerns about the use of a tourniquet during TKA. 16-18 Arterial ischemia following TKA can lead to serious complications, such as problems with wound heal- ing, infection, and limb loss. Be- cause of the relatively poor vascu- larity of the skin surrounding the knee, arterial injury can compromise wound healing in an already disad- vantaged limb and can lead to deep infection. In already ischemic limbs, further arterial injury or deep infec- tion can necessitate amputation. 19 In one review of the data on 44 patients with arterial complications after TKA, 11 (25%) required an amputa- tion. 1 In a study of 14 patients with arterial complications after TKA, Kumar et al 20 found that amputation was necessary for 6 patients (43%), and 1 patient died as a result of over- whelming sepsis. Understanding the vascular risks associated with TKA, especially those associated with the use of tourniquets, can po- tentially decrease morbidity by encouraging appropriate preopera- tive workup and prompt postopera- tive recognition. Risk Factors Of the many risk factors predispos- ing to arterial injury that have been identified, one of the most impor- tant is a history of arterial insuffi- ciency. 1,4,12,14,15,20,21 Any patient with a history of intermittent clau- dication, rest pain, and previous arterial ulcers should be considered at risk for arterial complications during or after TKA. 1,4,15,21 Previ- ous vascular surgery should alert the orthopaedist to refer the patient for a complete vascular assessment because of the risk of graft occlu- sion. 1,4,15,20,21 Absent or asymmetri- cal pedal pulses are also risk factors that should be investigated. 1,12,15,20-22 Calligaro et al 14 reported that arterial injuries occurred only in patients with identifiable preexisting atherosclerotic disease. DeLaurentis et al 21 demonstrated an increased prevalence of arterial complications Dr. Smith is Research Associate, Department of Orthopaedics, University of British Columbia, Vancouver, Canada. Dr. McGraw is Professor, Division of Reconstructive Orthopaedics, Department of Orthopaedics, University of British Columbia. Dr. Taylor is Associate Professor and Head, Division of Vascular Surgery, Department of Surgery, University of British Columbia. Dr. Masri is Associate Professor and Head, Division of Reconstructive Orthopaedics, Department of Orthopaedics, University of British Columbia. Reprint requests: Dr. Masri, Department of Orthopaedics, Third Floor, 910 West 10th Avenue, Vancouver, BC, Canada V5Z 4E1. Copyright 2001 by the American Academy of Orthopaedic Surgeons. Abstract Arterial complications after total knee arthroplasty (TKA) are rare; however, the sequelae can be disastrous. Infection and the need for amputation or vascular reconstructive surgery are not uncommon. A thorough preoperative assess- ment can identify at-risk patients, many, if not all, of whom have preexisting peripheral arterial disease. In the presence of peripheral arterial disease, the use of a tourniquet during TKA has been implicated in subsequent arterial compli- cations. Following the guidelines that have been established regarding preoper- ative assessment, the role of the vascular surgeon, and the use of a tourniquet before and during TKA can assist the orthopaedic surgeon in assessing candi- dates for TKA and reducing the risk of arterial complications. J Am Acad Orthop Surg 2001;9:253-257 Arterial Complications and Total Knee Arthroplasty Donna E. Smith, MD, Robert W. McGraw, MD, David C. Taylor, MD, and Bassam A. Masri, MD in patients with chronic lower- extremity ischemia. Only 24 (2%) of 1,182 patients who underwent TKA in their series had underlying pe- ripheral vascular disease, but 6 (25%) of the 24 patients had vascular injuries, compared with no vascular injuries in the patients without peripheral vascular disease. The rare presence of a popliteal aneurysm puts patients at risk for arterial complications with the use of a tourniquet. 4,21 Radiographic evidence of calcification of the distal superficial femoral artery (Fig. 1) or popliteal arteries may also be a har- binger of increased risk. 1,6,12,15,20,21 Preoperative Assessment A thorough preoperative vascular assessment is of paramount impor- tance to determine whether a pa- tient is at risk for arterial injury, par- ticularly if there is concern about the vascularity of a limb or the abili- ty of the limb to withstand the stress imposed by the tourniquet. 4,22 The minimum assessment can be done quickly by the orthopaedic surgeon at the first consultation. A focused history should seek symptoms of intermittent claudication or ische- mic rest pain. Occasionally, because of the immobility imposed on the patient by the local knee condition, such a history may be difficult to obtain. Previous vascular operations such as coronary artery bypass, carotid endarterectomy, and abdom- inal aortic aneurysm repair indicate substantial risk of peripheral arterial disease. 1 Physical examination should include inspection of the skin of the lower extremities to identify changes associated with chronic ischemia. Skin discoloration, ab- sence of hair, and dystrophic nail abnormalities other than fungal and psoriatic changes may all be sugges- tive of poor circulation. 22 The pop- liteal fossa should be palpated to rule out popliteal artery aneurysm. 1 Pedal pulses should be palpated and compared with those in the con- tralateral foot. 12,22 Radiographs should be inspected for evidence of calcification below the level of the femoral artery (Fig. 1). 1,12 If there is any suspicion of arteri- al insufficiency, the ankle-brachial index (ABI) should be determined with the use of Doppler ultrasound. Any patient with an ABI less than 0.9 is at increased risk for arterial complications and should be as- sessed preoperatively by a vascular surgeon. 21 In patients with severe ischemia and an ABI less than 0.5, a preoperative angiogram is required because immediate surgical revas- cularization may be necessary. 14 The vascular surgeon may recom- mend that bypass surgery be per- formed before TKA. If the ABI is greater than 0.5, the patient may also be at increased risk for arterial complications, but preoperative angiography is not necessary. A vascular surgeon should also be consulted preoperatively if there has been previous peripheral vas- cular surgery or angioplasty in the affected limb. A previous arterial bypass should be assessed for patency and function with duplex ultrasound before TKA. The failure of a femoropopliteal bypass graft at the time of TKA can be limb- threatening. John et al 23 reported a 64% rate of amputation due to graft failure in a group of 99 patients. Arterial Complications and TKA Journal of the American Academy of Orthopaedic Surgeons 254 Figure 1 Radiograph showing calcification of the femoral artery and the superficial femoral artery (arrows) in the distal third of the thigh. A pulsatile fullness or mass in the popliteal fossa may be an aneu- rysm. Baker’s cysts are also com- mon in this patient group. Both popliteal aneurysms and Baker’s cysts can be distinguished with ultrasonography if the clinical as- sessment is equivocal. Most periph- eral atherosclerotic aneurysms are popliteal aneurysms (Fig. 2), which are often bilateral. 24 The most com- mon sequelae of these aneurysms are thrombosis and embolization; either or both occurred in 33 (61%) of 54 patients in one study. 24 The reported rates of amputation neces- sitated by thrombosis of a popliteal aneurysm vary from 20% to 50%. 4 The consequences of thrombosis and embolization are devastating; therefore, repair is always indicated before TKA. Mechanisms of Injury Most arterial complications follow- ing TKA are associated with tourni- quet use and are related to indirect vessel injury and thrombosis, espe- cially in the previously diseased artery. 4,7,15,20,25 The documented mechanisms of injury can be classi- fied into four general categories: arterial occlusion, arterial sever- ance, arteriovenous fistula forma- tion, and arterial aneurysm forma- tion. 4 Arterial occlusion—probably the most common mechanism of arterial injury—can result from thrombosis of the popliteal artery due to manipulation and low flow because of tourniquet use. 1,4,21 Manipulation can also cause intimal tears that lead to thrombosis. 4,9,21 Because an atheromatous popliteal vessel has decreased elasticity, injury may result due to the distor- tion, traction, and fracture of the atherosclerotic plaque that may oc- cur when the knee is manipulated during TKA. 12,26 Essential collateral vessels may also be disrupted at the time of TKA. 13 Another mechanism of injury is trauma at the level of the superficial femoral artery due to tourniquet use. Mechanical pressure can trau- matize atherosclerotic plaques, lead- ing to distal embolization of plaque fragments (Fig. 3). 1,4,9,10,12,13,21 The tourniquet can also cause thrombo- sis of the superficial femoral artery, resulting in ischemia of the knee and leg. 9,12,13,21 With correction of exten- sive flexion contractures, compres- sion of the artery between musculo- tendinous and osseous structures may also occur. 1,9,13,21 Preexisting popliteal aneurysms may develop thrombosis due to the low flow state caused by tourniquet inflation. 1 In- jury to the popliteal artery or one of the collateral arteries can result in false aneurysms, thrombosis, and arteriovenous fistulas. 1,4,21 Throm- bosis and occlusion of a preexisting bypass graft can also occur. 4 Release of the tourniquet before wound clo- sure allows the surgeon to rule out direct laceration to the vessels. 22 Furthermore, release of the tourni- quet just prior to the insertion of the polyethylene insert allows visualiza- tion of the posterior aspect of the wound and easier control of any obvious arterial complications. Postoperative Assessment At the end of the procedure, while the patient is still anesthetized, the vascularity of the affected limb should be assessed. 1,12 Ischemia is present if previously palpable pulses are absent. Once the patient is awake, other signs of arterial insuffi- ciency, such as pallor with poor or absent capillary refill, pain, pares- thesias, and paralysis, can be demon- strated. 1,12 The neurologic status of the affected limb may be difficult to assess because of the residual effects of a spinal anesthetic. Measurement of the ABI will define the degree and presence of ischemia. A vascular surgeon should be consulted immediately if there are any concerns. 1,12 Emergency arteri- ography of an ischemic limb is war- ranted, and revascularization should be undertaken as soon as possible. 14 If a distal bypass is required, con- tralateral saphenous vein grafts are preferred. The prognosis is poor if diagnosis or management is de- layed. 9 Recommendations Regarding Tourniquet Use The use of a tourniquet during TKA is controversial. There are many potential risks, including arterial compromise, pulmonary edema, 27 cardiac arrest, 28 neurologic injury, 29,30 pulmonary emboli, 31 and muscle injury. 29,30 These are rare but poten- tially limb- and life-threatening risks. The primary advantage of the Donna E. Smith, MD, et al Vol 9, No 4, July/August 2001 255 Figure 2 A 79-year-old man who under- went TKA had diminished pulses postop- eratively. An urgent angiogram revealed an aneurysm in the popliteal artery (white arrow) and occlusion of the popliteal artery (black arrow) distal to the aneurysm. Urgent vascular surgery resulted in suc- cessful limb salvage. The aneurysm is not visible on the angiogram. tourniquet is the bloodless field, 22 which should facilitate cementing; however, the clinical relevance of this has not been established. Two small prospective, random- ized studies have been conduct- ed, 16,18 both of which had similar numbers of patients (77 and 80, respectively) and study design. Wakankar et al 18 demonstrated no difference in blood loss, wound healing, or range of motion after 6 weeks, but reported difficulty with cementing due to bleeding in 13 (33%) of 40 patients. Abdel-Salam and Eyres 16 found no difference in blood loss or technical difficulty when a tourniquet was not used. The group that underwent TKA without a tourniquet were able to do a straight leg raise at 2.4 days, compared with 4.6 days for the tourniquet group, which was a sta- tistically significant difference (P<0.05). However, there was no significant difference between the two groups in regaining range of motion and in the Hospital for Special Surgery knee score at 1 year. Operating time and overall blood loss were similar in both groups. Presumably, there was less postoperative pain when a tourni- quet was not used, because those patients required significantly fewer analgesic injections in the first 2 days after the procedure (P<0.05). The incidence of wound infection when a tourniquet was used was higher, but the difference was not statistically significant. Wound infections developed in 5 patients in the tourniquet group, but in none of the patients in the no-tourniquet group. Four of the wound infec- tions were superficial. No patients in either study had any tourniquet- related complications. Overall, these two studies sug- gest that it is safe to perform TKA without a tourniquet. However, larger studies are needed to evalu- ate possible differences in wound healing, range of motion, and com- plication rates after TKA performed with and without a tourniquet. Because of the potential limb- and life-threatening risks, consider- ation should be given to not using a tourniquet in those patients with factors that increase their risk of arterial complications. Several rec- ommendations have been made for patients who require TKA but have identified vascular risk factors. There are two options for patients with a preexisting femoropopliteal bypass graft. There is evidence that TKA can be performed safely with- out a tourniquet. 4,21 If a tourniquet is deemed necessary, a 5,000-U intravenous bolus of heparin can be administered prior to tourniquet inflation and reversed with prot- amine sulfate at the end of the proce- dure. Before making any decisions about the use of a tourniquet, the patient should be assessed by a vas- cular surgeon, and graft function should be evaluated with duplex ultrasound. Arteriography is also warranted if there is any concern about graft function. Graft prob- lems should be corrected before TKA. Prosthetic arterial bypasses may be especially at risk for throm- bosis if a tourniquet is used. In the patient with chronic arter- ial insufficiency, the ABI is a useful tool for preoperative assessment. If the ABI is greater than 0.5, the patient can safely undergo TKA without the need for further inves- tigation. The patient should, how- ever, be informed of the risk of postoperative ischemia and should be advised that revascularization may be required. If the ABI is less than 0.5, arterial bypass should be performed either before or immedi- Arterial Complications and TKA Journal of the American Academy of Orthopaedic Surgeons 256 Figure 3 An 82-year-old woman had painful blue toes after TKA with tourniquet control. Pedal pulses were not palpable. An urgent angiogram revealed atherosclerotic lesions in the superficial femoral artery (arrows) and popliteal artery. Fragmentation of these athero- sclerotic plaques with distal embolization had occurred, resulting in “blue toes syndrome.” ately after TKA. Alternatively, TKA can be performed without a tourniquet. 21 If there is radiographic evidence of calcification of the distal superfi- cial femoral artery or popliteal ar- tery, it has been recommended that TKA should be performed without a tourniquet. 21 A similar recom- mendation has been made for the patient with no palpable pedal pulses or with known peripheral atherosclerotic disease. 4,9,12,21 Summary The incidence of arterial complica- tions after TKA is low, but the se- quelae can be devastating. Most patients at risk have identifiable peripheral arterial disease, which must be sought preoperatively. The risk factors include (1) a history of arterial insufficiency, (2) absence of pedal pulses, (3) a suspected popli- teal aneurysm, and (4) radiographic evidence of calcification of the super- ficial femoral artery or popliteal artery. If any of these factors is pres- ent at the preoperative assessment, a vascular surgeon should examine the patient, and the TKA may have to be performed without a tourniquet. Recent studies have shown that TKA can be performed safely without use of a tourniquet. With detailed preop- erative assessment, patients at risk for arterial complications can be iden- tified, and precautions can be taken to avoid complications. Donna E. Smith, MD, et al Vol 9, No 4, July/August 2001 257 References 1. Holmberg A, Milbrink J, Bergqvist D: Arterial complications after knee ar- throplasty: Four cases and a review of the literature. Acta Orthop Scand 1996; 67:75-78. 2. Dennis DA, Neumann RD, Toma P, Rosenberg G, Mallory TH: Arterio- venous fistula with false aneurysm of the inferior medial geniculate artery: A complication of total knee arthroplas- ty. Clin Orthop 1987;222:255-260. 3. Hagan PF, Kaufman EE: Vascular complication of knee arthroplasty under tourniquet: A case report. 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