LAUSR

© BMJ Publishing Group Limited 2022. No commercial reuse. See rights and permissions. Published by BMJ. DESCRIPTION A male patient in his late 30s presented to the outpatient department with reports of pain and swelling around the knee with blood stained discharge since 2 weeks. On eliciting history, it was noted that the patient had sustained a closed fracture of the right proximal tibia (Schatzker type V) following a road traffic accident. Subsequently, the patient underwent open reduction and internal fixation, the intraoperative and postoperative period were uneventful and he was subsequently mobilised. The patient, however, started to develop pain and swelling around the knee approximately 2 months after the procedure. He then noticed a sinus with bloody discharge. General physical examination was unremarkable. On local examination, a 15 cm surgical scar healed by primary intention was noted on the anterolateral aspect of the proximal tibia. A diffuse nonpulsatile swelling measuring 8*5 cm was present over the lateral aspect of the proximal tibia with a wound of 1*0.5 cm with bloody discharge (figure 1). Mild local rise of temperature was noted in the vicinity. The range of movement at the knee was restricted and painful. Distal pulses were palpable but feeble. There were no distal neurological deficits. Initially it was suspected to be a case of osteomyelitis and the patient was planned for surgical management. However, a preoperative arterial Doppler done in view of feeble distal pulses showed monophasic flow in the dorsalis pedis and the anterior tibial artery. A subsequent CTangio showed a saccular outpouching arising from the anterior tibial artery suggestive of a pseudoaneurysm (figure 2). Patient was then taken up for excision of pseudoaneurysm. Postoperatively the peripheral pulses returned to normal and arterial Doppler showed triphasic flow distally. There have been numerous reports of pseudoaneuryms encountered in orthopaedics. They are most often seen as a complication of the placement of an implant or following trauma by displaced fracture fragments. 2 Occasionally their appearance may mimic soft tissue tumours. Patients usually present with a progressive pulsatile swelling and profuse bleeding from the wound site. Distal pulses are usually normal. The mechanism of injury usually dictates progression of symptoms. Fracture fragments often cause an acute presentation of a pseudoaneurysm, whereas a chronic presentation is often associated with prolonged impingement or erosion of the artery by protruding fixation that results in loss of integrity of the arterial wall. In this case, it was noted that the pseudoaneurysm was caused by the fracture as the CT image showed that the hardware was not directly in contact with the vessel. It is vital to elicit a detailed history of mode of injury, site of injury and previous operative procedures. Such patients must be approached with a high index of suspicion and imaging techniques such as the arterial Doppler and CT angiography must be employed prior to any operative procedures.