Popliteal artery transection injury can have fatal effects for patients, since irreversible ischemia can occur in as little as 6–8 h. The prevalence of popliteal artery injury in lower extremity fractures after violent trauma is 1.04% ^[1]. Acute popliteal artery thrombosis can occur as a result of direct trauma to the knee in cases of knee dislocations, distal femur fractures, and tibial plate fractures. Traction injury can induce indirect trauma, including popliteal artery laceration. According to the literature on arterial injury, the most prevalent types of arterial injury are transection, occlusion, intimal injury, pseudoaneurysm, and fistula formation ^[2]. The most prevalent type of arterial injury is transection ^[3]. Popliteal artery thrombosis is rare, since the literature reports that only one popliteal artery thrombosis was detected in 32 cases of popliteal artery injury over a 10-year period ^[4]. The most common cause of popliteal damage is an open wound, such as a gunshot, stab, open fracture, or surgical procedure. Closed injuries caused by displaced fractures or dislocations around the knee are the second most common ^[5]. We report a rare case of closed displaced medial condyle fracture of tibia with popliteal artery thrombosis that was detected postoperatively.

A 21-year-old male patient reported to the casualty after sustaining a high energy trauma to left knee due to road traffic accident. The patient reported being in casualty at midnight 6 h after trauma. On examination, the limb was swollen, tense, tenderness was present with ecchymosis over the posterior and posteromedial aspect of knee. On examination of neurovascular, there was foot drop, dorsalis pedis pulsation was present but volume was less compared to opposite side. Pin prick on the toes was present. The patient was stabilized in casualty, and skeletal traction was applied. The limb was elevated on Bohler-Braun splint. He was given analgesics along with magsulf dressing to reduce the edema of limb. The evaluation of the fracture was done with X-ray and computed tomography (CT) scan which suggested a displaced medial condyle of tibia fracture. We did not plan any imaging of the arterial or venous system of the lower extremity as dorsalis pedis pulsation and pin prick to the toes are present (Fig. 1).

Posteromedial plating of the displaced medial condyle was planned as per fracture geometry evaluated from CT scan. Surgery was planned after 3 days when the soft tissue condition was favorable. Surgery was done under tourniquet with a posteromedial plate applied through posteromedial approach. Careful dissection and blunt retractors are used to prevent injury to posterior neurovascular structures. Torniquet time was 50 min and closure was done after deflating the torniquet. Careful hemostasis was done, and wound was closed under a negative suction drain. Immediately after the surgery, the dorsalis pedis pulsation was present and the volume was same as in the pre-operative period (Fig. 2).

In the post-operative rounds around 6 h after surgery, the dorsalis pedis pulsation was found absent though pin prick to the toes was present. Temperature of the limb was maintained, and the patient reported no paresthesia. Immediately, color Doppler was done. Reduced flow was appreciated in dorsalis pedis and anterior tibial artery on color Doppler. A thrombus was noted by the consultant radiologist in the popliteal artery following which the patient was urgently transferred for urgent interventional radiologist opinion and management. CT angiogram was done which was suggestive of acute thrombotic narrowing in left popliteal artery. Intra-arterial thrombolysis was planned. The lesion was crossed with 0.035 Fr Terumo guidewire followed by check angiogram and selective catheterization of distal popliteal artery confirmed. Ev3 Cragg Mc Namara catheter is placed in thrombotic arterial segment. Check the shot taken and the position confirmed. Injection alteplase 3 mg stat is given, followed by infusion at 1 mg/h (total 20 mg given) through spray catheter. Injection of heparin 1000 IU/h is given through sheath. In post-thrombolysis period, tablet aspirin 150 mg/day and tablet clopidogrel 75 mg/day were given (Fig. 3).

The patient was kept in intensive care unit for 5 days for further monitoring. The patient was discharged on 6^th day and the surgical wound was healthy with no soakage. Limb was warm and distal pulse was feeble and foot drop was present. Static ankle foot orthosis was given to prevent contracture formation. Suture removal was done on post-operative day 15. Patients were followed at regular intervals. Fracture united at 3 months and the patient had excellent functional outcome according to rasmussen functional score (Fig. 4).

The prevalence of popliteal artery injury in blunt lower limb fractures is 1.04% ^[5]. When the fracture line advances posteriorly in the proximal tibial plateau and the medial and posterior columns are involved, posterior bone pieces compress the popliteal artery, resulting in contusion or rupture. The lateral and posterior columns will fracture, and the popliteal artery may sustain damage, if the knee joint is put under axial and valgus stress during flexion or semi-flexion. Compared to the lateral articular surface, the medial articular surface is stronger and bigger. Therefore, medial plateau fractures – which are frequently caused by significant trauma – are likely to result in ligament, vascular, and nerve injury ^[6]. According to Moore et al. ^[7], Schatzker type IV fractures have the highest risk of vascular and nerve damage. The distal segment of the popliteal artery is located toward the posterior aspect of the proximal tibia, where the hard connective tissue septa holds the vessel in place against the knee capsule. As a result, the popliteal artery is anchored proximally to the popliteal fossa. Once misplaced fractures or dislocations occur, the popliteal artery has little buffering area and is thus vulnerable to harm ^[8]. A true end artery, the popliteal artery arises from the femoral artery and is rather short with a weak collateral supply network. The collateral supply does not provide enough blood flow to keep the lower limbs healthy. Despite the clear symptom of popliteal artery occlusion, if the patient is not thoroughly evaluated, the diagnosis may go unnoticed ^[3]. Another helpful method for evaluating popliteal artery damage is duplex ultrasonography. To detect arterial stenosis and occlusion, it has a sensitivity of 95–100% and a specificity of 99–100% ^[9]. Penetrating trauma is the most frequent cause of vascular damage in the extremities. Penetrating vascular injuries can be attributed to a number of circumstances, including alcohol and drug addiction, warfare, suicide attempts, and attacks. Blunt trauma, which includes falls from a height, automobile accidents, and crush injuries, is the second most frequent cause ^[10]. About 30–50% of individuals with knee dislocation have popliteal artery occlusion (Wright et al., 2004) ^[11]. Imanaka et al. ^[12] and Kovacs et al. ^[13] have documented instances of total knee arthroplasty-related popliteal artery thrombosis leading to blockage. Wagner et al. ^[14] reported blunt popliteal artery trauma in their study of 100 patients in cases of fractures around knee and dislocations. Li et al. ^[5] reported a case of popliteal artery occlusion in fracture of posteromedial condyle of tibia along with PCL avulsion injury that developed 6 h postoperatively. They treated the patient with percutaneous thrombectomy. Prophylactic fasciotomy was done and infusion of heparin was given for 2 days followed by oral aspirin for 1 months. Currently available treatments for popliteal artery obstruction include systemic thrombolysis and anticoagulant medication, surgical embolectomy, interventional thrombolysis, and mechanical thrombectomy (Wright et al., 2004) ^[11]. Systemic thrombolytic and anticoagulant medication might worsen bleeding at the site of fractures and knee dislocation, hence it is not recommended for individuals with high-energy injuries. To decrease bleeding and trauma, combining treatment with interventional intra-arterial local thrombolysis and thrombectomy has been documented in the literature ^[3]. Popliteal artery blockage can have frightening consequences. Amputation can be prevented with close observation, prompt diagnosis with a CT angiography, prompt treatment, and aggressive application of various therapeutic techniques ^[3]. An algorithmic approach to popliteal artery injury after knee fracture and/or dislocation has been proposed by Hsieh et al. ^[15] (Fig. 5).

Popliteal artery thrombosis though a rare complication should be suspected and ruled out by imaging techniques in cases of blunt trauma to knee leading to tibial plateau fractures along with some neurological deficit and echymosis posterior to knee that suggest high intensity of trauma. Dorsalis pedis pulsation may be present in cases of incomplete occlusion or progressive thrombus following trauma and other signs of ischemia may be masked. A pulsation with reduced volume should suggest for vascular imaging with initial color Doppler scanning as it is a limb-threatening complication if not detected early and also management is dictated by the presence of associated vascular injury.

The clinical message of this article is the critical importance of suspecting and ruling out popliteal artery thrombosis in cases of blunt trauma to the knee leading to tibial plateau fractures. Despite being a rare complication, popliteal artery thrombosis should be considered, especially when there are signs such as neurological deficits and ecchymosis posterior to the knee, which suggest high-intensity trauma. Early detection through imaging techniques like color Doppler scanning is crucial, as this condition can be limb-threatening if not identified and managed promptly.