Delayed-Onset Pseudoaneurysm of the Superior Lateral Genicular Artery Following Total Knee Arthroplasty: A Case Report.

Background: Pseudoaneurysm of the superior lateral genicular artery (SLGA) is a rare vascular complication following total knee arthroplasty (TKA), with an incidence ranging from 0.03% to 0.2%. Most cases occur in the immediate postoperative period while delayed presentation months after surgery can be often misdiagnosed as infection or hemarthosis. Case Presentation: A 62-year-old male smoker with previous TKA presented to the emergency department with knee pain and a palpable pulsatile mass on the lateral side of the right knee. Clinical evaluation with doppler ultrasonography and CT scan showed the presence of a 1.5 cm pseudoaneurysm of the SLGA. Initial conservative management with manual compression proved ineffective thus given the high risk of rupture, definitive surgical exclusion was performed with no post-procedural complications. Conclusion: Delayed SLGA pseudoaneurysms typically present with nonspecific symptoms like pain, swelling and limited ROM. Diagnosis relies on imaging while surgical ligation proved to be an effective treatment. Pseudoaneurysm should be considered in post-TKA patients with unexplained knee swelling and pain, even months after surgery. Early diagnosis through second level imaging, multidisciplinary collaboration and timely surgical intervention are crucial for preventing complications.