Inferior medial genicular artery pseudoaneurysm after primary total knee arthroplasty. A case report

Abstract

Background: Small genicular vessel injuries during primary total knee arthroplasty could pass unnoticed during surgery and present late postoperatively. Case report: We present a female patient 65 years old, who presented three weeks after primary TKA with fresh bleeding from the lower end of the surgical wound, CT angiography showed a pseudoaneurysm of the inferior medial genicular artery which was treated at the same session by coil embolization. Conclusion: A pseudoaneurysm of the inferior medial genicular artery could complicate primary TKA. Mutual help from an intervention radiologist is necessary for diagnosis and management.

Full Text

Background:

Vascular complications after total knee arthroplasty (TKA) are uncommon, occurring at an incidence of 0.03 to 0.5%, which is more in revision surgeries (1, 2). However, if occurred and is diagnosed early, it could be managed sufficiently by percutaneous intervention maneuvers; however, if it is severe or missed, it might need vascular surgery intervention and could end up in limb amputation (2, 3).

Pseudoaneurysm formation after TKA most likely results from iatrogenic trauma during tibial cut either by the saw blade or a bluntly placed instrument (4). Such trauma could affect one of the major vessels, such as the popliteal artery, or one of the smaller branches, such as one of the genicular arteries, as reported in the literature (2, 4, 5).

We present a case of inferior medial genicular artery (IMGA) injury presented by pseudoaneurysm three weeks after primary TKA, which was performed for primary knee osteoarthritis.

Case report:

History and patient information:

Female, 65 years old, healthy, complaining of chronic right knee pain, and was diagnosed with advanced primary knee OA. The patient underwent TKA under spinal anesthesia and tourniquet control. Surgery was performed through a medial parapatellar approach, using a manual instrument (intramedullary rod to guide the distal femoral cuts, while the tibial cuts were performed using an extramedullary guide), and a cemented posterior stabilized prosthesis was implanted. The wound was closed in layers, and a suction drain was inserted. No intraoperative adverse events were reported. Postoperatively, the patient stayed in the hospital for two days; the drain was removed on the second postoperative day (the draining amount was 400 cc), and there was no need for a blood transfusion. Before discharge, the wound was checked, and no abnormality was detected. Anticoagulation in the form of Aspirin 75 mg tablets twice daily was prescribed for three weeks.

Clinical findings:

The patient showed up in the clinic after two weeks for suture removal; she reported committing to the postoperative rehabilitation protocol under the supervision of a physiotherapist, and there was a gradual improvement in pain and knee motion. However, later on, after a week, she presented with fresh bleeding from the lower end of the wound; she denied any history of trauma or changing of the anticoagulation medication. The distal pulse was intact. There was a global knee swelling, no hotness, a positive patellar tap test, and mild tenderness over the knee joint line. The wound was healed except for the lower end, where blood oozing was coming from.

Diagnostic assessment and therapeutic intervention:

After consultation with an intervention radiologist colleague, he advised an immediate computed tomography angiography (CTA) with contrast, which revealed a contrast-filled lesion near the anteromedial border of the tibial insert, diagnosed as pseudoaneurysm originating from the IMGA which was treated at the same session by endovascular coil embolization (Figure 1).

Follow up and outcomes:

The patient was advised to continue the rehabilitation protocol. A weekly evaluation of the knee for the first month was performed. The lower end of the wound healed without any further complications, and the knee swelling resolved within the first two weeks. No incidence of bleeding or swelling was reported till the last follow up.

Discussion:

Genicular arteries (laterally and medially, including the IMGA) represent the main blood supply of the knee joints and originate mainly from the popliteal artery (PA) and the superficial femoral artery (SFA) (6).

Thankfully, vascular injuries during TKA are rare and occur more commonly during revision surgery, which could be a direct injury of one of the major vessels (PA and SFA) or any of the smaller genicular branches, presenting as a pseudoaneurysm (2, 3). Risk factors for pseudoaneurysm formation are not well documented; however, previous vasculopathy (in diabetic patients or with peripheral vascular disease), atherosclerosis, and female gender were proposed as possible predisposing factors (2, 4).

Clinical presentation could be recurrent knee swelling (hemarthrosis), bruising, pulsatile mass, or fresh bleeding, which could be acute, subacute, or chronic (commonly occurring if small vessels are involved) (1). In the current case, we believe that the initial IMGA injury was plugged by a small clot that was dislodged after the patient increased her activities after suture removal, leading to recurrent bleeding.

Proper management involves accurate diagnosis by early suspicion and the help of a vascular surgeon or interventional radiologists. Definitive management relies mainly on the type and the vessel injured. It could range from direct vascular repair or bypass if a major vessel was involved to percutaneous procedures such as cauterization, stenting, and embolization, which (was performed in the current case) (1, 5, 6).

Conclusion:

Although vascular injuries post total knee arthroplasty are rare, if passed unnoticed, they could be devastating, leading up to limb amputation. Injury of the smaller branches, including the inferior medial genicular artery, could occur, which might present with knee swelling and fresh bleeding. Minimally invasive management techniques such as percutaneous embolization in collaboration with the interventional radiology team are safe and effective.