A case of popliteal artery injury associated with multiligamentous knee injury successfully managed with endovascular stenting after thrombotic occlusion following vein graft revascularization

Abstract

Autologous vein grafting is a common method for revascularization in cases of traumatic limb arterial injuries. However, no clear guidelines have been established regarding the use of tourniquets following vascular reconstruction. We report a case of graft thrombosis that occurred during a planned orthopedic surgery one week after the initial revascularization. The patient was a 56-year-old man with a complex ligament injury of the left knee accompanied by a popliteal artery injury. After admission to our hospital, he underwent emergency popliteal artery reconstruction using an autologous vein graft. On postoperative day 8, the patient underwent ligament reconstruction under tourniquet control, which resulted in the thrombotic occlusion of the graft. Although repeat vein grafting was attempted intraoperatively, blood flow could not be restored. Ultimately, an endovascular stent was deployed in the popliteal artery, which successfully restored perfusion. At one-year follow-up, the stent remained patent without evidence of fracture or vascular stenosis. This case highlights the potential risk of tourniquet-induced graft thrombosis, particularly in the early postoperative period. Excessive pressure and dilation of a harvested vein may damage the intimal layer, thereby increasing thrombosis risk. In patients with recent vascular reconstruction, especially those at high-risk, the use of tourniquet should be carefully considered. When necessary, meticulous planning and prophylactic strategies are crucial to minimize the risk of graft failure.

Highlights

• •High-pressure dilation (preparation) of vein grafts can cause intimal injury andrisk of subsequent thrombosis.
• •Analyzed an adverse event involving tourniquet use after lower limb revascularization in a plausible scenario.
• •Reported the usefulness of endovascular treatment for limb arterial injury under specific conditions.

Introduction

Fractures around the knee joint and knee dislocations are often associated with popliteal artery injuries, which, if not promptly treated, may lead to permanent functional impairment or even limb amputation [[1], [2], [3]]. Several revascularization methods are available. However, when end-to-end anastomosis is not feasible, autologous vein grafting is typically the first-line option due to its lower infection rate and higher long-term patency rates [1]. Although the great saphenous vein is most commonly used for grafting, it is narrower than the popliteal artery. In clinical practice, the harvest site and dilation procedures before anastomosis are often selected based on the surgeon's experience and judgment.

Following successful revascularization, further additional surgical intervention is often required to manage associated fractures, or, ligament injuries, or, in some cases, soft tissue reconstruction may be required. Although tourniquets should not be used during such procedures [4,5], no clear current guidelines have been established regarding the use of a tourniquet in these situations. Consequently, decisions regarding tourniquet use and technique remain at the discretion of the operating surgeon.

Recent studies have reported on endovascular stenting for traumatic arterial injuries of the extremities. However, in the case of popliteal artery injuries, many aspects, such as long-term outcomes, remain unclear, and endovascular treatment is not yet considered the standard of care [6].

Herein, we report a case of below-knee arterial injury where a thrombotic occlusion occurred in a vein graft following revascularization during subsequent ligament reconstruction. Ultimately, endovascular stenting was successfully performed, saving the limb. This report aims to share the lessons and insights gained from this experience.

Case report

A 56-year-old man was transported to the emergency department after a fall left him trapped under a snowmobile, resulting in left knee hyperextension and associated pain. On examination, peripheral pulses in the left lower limb were not palpable. X-ray imaging revealed an avulsion fracture of the proximal fibula, and contrast-enhanced computed tomography detected an interruption of the popliteal artery, necessitating emergency surgery (Fig. 1).

Fig. 1.

Initial X-ray imaging and lower limb contrast-enhanced computed tomography (CT) at the time of injury.

(a) X-ray imaging at the time of injury showing an avulsion fracture of the fibular head.

(b) Contrast-enhanced 3D CT image demonstrating the interruption of the left popliteal artery.

A posterior approach in the prone position was employed to expose the popliteal region. The popliteal artery was stretched and found to be completely occluded. Using the same prone position, the great saphenous vein was harvested from the distal thigh of the contralateral leg and used for the reconstruction of the popliteal artery. Postoperative contrast-enhanced CT revealed stenosis at the anastomosis site. On postoperative day 2, a thicker segment of the great saphenous vein was harvested from the proximal thigh and used for the second reconstruction (Fig. 2). During this procedure, the 16-mm long graft vein graft was dilated under pressure before the anastomosis.

Fig. 2.

Post-revascularization contrast-enhanced computed tomography (CT) and intraoperative photographs.

(a) CT after the first revascularization on the day of injury, showing stenosis at the distal portion of the vein graft (red arrow). The peripheral arterial pulses were also weak.

(b) On postoperative day 2, a second vein graft was performed. The peripheral pulses became easily palpable.

(c) Intraoperative photograph showing reconstruction of the stretched and injured segment using a great saphenous vein. The reconstructed segment was 16 mm long.

On postoperative day 8, extraarticular repair of the medial and lateral ligaments was performed for the multiligamentous injury. A tourniquet was applied for 97 min during this surgery. However, after the tourniquet release, the peripheral pulses were no longer palpable. The patient's position was changed back to prone, and the graft site was re-explored, revealing that the thrombosis completely occluded the grafted vein (Fig. 3a). Additional vein grafting was attempted twice using the contralateral great saphenous vein; however, blood flow could not be restored distally.

Fig. 3.

Intraoperative angiography during ligament reconstruction and following stent placement.

(a) After ligament reconstruction, contrast enhancement was not absent at the site of the vein graft following tourniquet release; the absence of a contrast agent proximally was due to the timing of imaging.

(b) As two additional vein graft attempts failed to achieve revascularization, a stent was placed at the graft site, resulting in popliteal artery recanalization.

Consequently, further vein graft attempts were abandoned, and the cardiology department was consulted. An endovascular arterial stent, 4 cm in length and 6 mm in diameter (post-dilated to 5 mm), was deployed at the graft site (Eluvia™ Drug-Eluting Stent, Boston Scientific, Marlborough, MA, USA), which successfully restored blood flow (Fig. 3b).

Postoperatively, the patient was started on clopidogrel and edoxaban orally. Knee range-of-motion rehabilitation was initiated 3 weeks after surgery. The patient had an uneventful recovery, and no occlusion was observed at the stent site at the 1-year follow-up (Fig. 4a). The maximum knee flexion range was limited to 110°. Within this range, even at full flexion, no significant arterial stenosis was detected at the stent site (Fig. 4b).

Fig. 4.

Angiographic findings one-year after the injury.

(a) The stented segment of the popliteal artery remained patent without stenosis.

(b) Angiography at maximum knee flexion (110°) showed only mild flexion-induced stenosis slightly proximal to the stented segment, with no stent deformation (the red line indicates the extent of the stent placement).

Discussion

Here, we reported a case of thrombotic occlusion of a vein graft during ligament reconstruction surgery following revascularization using a vein graft for a multiligamentous knee injury associated with popliteal artery injury. In this case, risk management to prevent graft thrombosis was inadequate. Conversely, when thrombotic occlusion occurs in a revascularized popliteal artery, endovascular arterial stenting was found to be a useful salvage option.

Graft thrombosis in this case was mainly believed to be caused by the thrombotic tendency due to intimal injury to the vein graft and the blood flow stagnation resulting from the use of a tourniquet. In autologous vein grafting, dilation under pressure is often performed to reduce the size discrepancy with the recipient artery. However, this preparation can damage the endothelium, increasing the thrombosis risk. Pimentel et al. reported that intimal injury increased particularly when preparation was performed at pressures >100 mmHg [7]. When endothelial injury and blood flow stasis are present, platelets are more likely to adhere to the damaged areas, and coagulation factors such as thrombin and fibrinogen are less dispersed, allowing rapid thrombi formation [8,9].

To reduce the risk in such situations, the vein graft should be harvested from a site with as large a diameter as possible, and dilation under pressure should be avoided. In an arterial environment, the vein graft expands by 20 %–30 % [10]; thus, it may be safer to accept a certain degree of diameter mismatch. In addition, if tourniquet use is unavoidable, effective countermeasures may include limiting the duration of continuous use and administering systemic heparin just before application [5].

In this case, despite multiple attempts at repeat revascularization using vein grafts after thrombosis, blood flow could not be restored distally. The most suspected cause was an arterial spasm [11]; however, intraoperative interventions such as the local application of lidocaine failed to achieve sufficient blood flow recovery. Even if the spasm was temporary, thrombosis could reoccur in the graft if blood flow was not promptly restored. Therefore, ensuring definitive revascularization was necessary.

Endovascular arterial stenting for traumatic limb vascular injuries is not feasible in cases of complete arterial transection and is contraindicated in open fractures because of infection concerns. However, it is minimally invasive, and its short-term outcomes have been reported as generally favorable in recent years [12]. On the other hand, stenting near joints, such as the knee, is challenging due to the risk of stent fracture; indeed, cases of fracture have been reported [13]. However, the hinge point of the popliteal artery during knee flexion is located at the distal femur, and in our case, because the stent was placed posterior to the tibia, the effect of flexion was relatively limited [14]. In addition, highly flexible stents that are resistant to sharp bending and fracture have recently been developed [15]. In the future, the indications for the endovascular treatment of popliteal artery injuries may expand as device technology advances.

To our knowledge, there have been no previous reports of cases similar to ours. It is unclear whether such thrombotic occlusions are relatively common but underreported or truly rare. Rather than simply concluding that tourniquet use should be avoided after revascularization, we focused on strategies to reduce the risk of adverse events when tourniquet use is deemed necessary.

Conclusions

Performing autologous vein graft revascularization for traumatic popliteal artery injuries requires multiple strategies to prevent thrombotic occlusion of the graft during subsequent surgeries. Furthermore, in cases where vascular occlusion occurred following revascularization, endovascular stenting was found to be a useful option for limb salvage.

CRediT authorship contribution statement

Kazuo Sato: Writing – review & editing, Writing – original draft, Visualization, Methodology, Data curation, Conceptualization. Tatsuhiro Ishijima: Data curation. Kenichi Kusunoki: Data curation. Toshiki Yoshino: Data curation. Mizuki Minegishi: Data curation. Yoshio Nishida: Data curation. Hiroko Murakami: Writing – review & editing. Yoshihiko Tsuchida: Writing – review & editing. Hiroki Bota: Resources, Data curation. Yuta Izawa: Data curation.

Ethical consideration

This case report was conducted in accordance with the ethical standards of our institution. Written informed consent for publication, including the use of anonymized images, was obtained from the patient. According to the policy of our institution, ethical review board approval was not required for single-patient case reports.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

The authors declare no competing interests.