Iliofemoral deep vein thrombosis after tibial plateau fracture fixation related to undiagnosed May-Thurner syndrome: a case report

BACKGROUND: May-Thurner Syndrome (MTS) represents an anatomic variation of the iliac vessels, in which the left common iliac vein is compressed by an overriding iliac artery. Patients with this abnormality are predisposed to the formation of a left-sided iliofemoral deep venous thrombosis (DVT). While DVT is a familiar complication in the setting of lower extremity trauma, there are no previous reports of MTS complicating the care of patients requiring orthopaedic surgery. CASE PRESENTATION: We present the case of an extensive limb-threatening DVT in a patient with previously undiagnosed MTS, resulting after internal fixation of a left tibial plateau fracture. Four days after surgery, despite standard prophylactic anticoagulation, the patient developed an extensive occlusive DVT, extending from the common iliac vein to the popliteal vein. Successful diagnosis required a CT venogram in addition to standard lower extremity ultrasound exam. Severe lower extremity edema continued to worsen despite formal anticoagulation. Urgent mechanical thrombolysis was undertaken, followed by staged catheter-directed thrombolysis with recombinant tissue plasminogen activator (rTPA) and intraluminal stenting. Following this treatment, the patient was noted to have gradual but dramatic resolution of his lower extremity edema and swelling. CONCLUSION: The present case demonstrates the potential danger that may accompany MTS in the setting of lower extremity trauma. When an extensive left lower extremity DVT complicates the care of a patient with extremity trauma, clinicians should have a low threshold to pursue the diagnosis of MTS with advanced imaging studies. Venography remains the gold standard in diagnosis, but CT and MRI venography are less invasive and should allow for accurate diagnosis. In this case, formal anticoagulation proved to be ineffective, and endovascular intervention was required.