Knee osteoarthritis is a common disease in the elderly causing painful ambulation, motion limitation and ultimately disability.4, 5 In 2015, Yang et al. suggested that PFO could relieve pain and improve the varus alignment of medial compartment knee OA by redistributing loads between the medial and lateral compartments.2 The authors proposed that PFO is as a simpler, less invasive and cost-effective intervention compared to other common surgeries. A further biomechanical cadaveric study in 2018 proved the decompression of the medial compartment after the intervention of PFO.1 In the early literature (from 2015 to 2018), relatively low rate of complications was mentioned, and most of them occurred as nerve palsy. The original authors reported 3.6% lower leg numbness due to common peroneal nerve palsy and superficial peroneal nerve injury.2
Compared to the suggested level (6–10 cm below the fibular head), an adjustment with a more distal osteotomy (10–15 cm below the fibular head) had been made after some transient drop toes or numb dorsal feet encountered in our clinical practice. Similar effect in pain relief was obtained without mentioned neurologic compromise. Considering the different level of fibular osteotomy in this case and few complications mentioned in prior PFO literature, we searched reported vascular injuries following the harvest of fibular graft, a similar surgery to PFO removing a fibular segment as bone graft. Related complications to fibular harvest consist of nerve injury (3 ~ 12%), compartment syndrome, weakness of the extensor hallucis longus (3 ~ 10%), and ankle instability (2–12%)6–9 while vascular complications are relative rare with a prevalence less than 1%. Among the vascular complications, some were thromboembolic events, and some intraoperative vascular injuries were repaired immediately, and no delayed presentation had been mentioned.7
Anatomically, the ATA is most vulnerable while penetrating through the interosseous membrane (IOM) at around 5.4cm below fibular head to the anterior compartment.6 At the anterior compartment, the ATA runs down anterior to the IOM medial to the fibula.10 Therefore, to secure surrounding neurovascular structures of the middle fibula, the osteotomy should start at the posterolateral corner of the fibula and aim toward the anterior tibia.In the literature, the incidence of ATA pseudoaneurysms is relatively low and common events associated with ATA pseudoaneurysms were trauma, vascular and orthopaedic procedures. Reported causative orthopedic procedures included the insertion of interlocking bolt in tibial nailing and Steinman pin insertion while performing skeletal traction.11
Limb pseudoaneurysms frequently present with pain, swelling, ecchymosis, pulsating masses and compressive neurological symptoms. However, it may take hours to years to be clinical symptomatic depending on the size and site of the pseudoaneurysm.10, 12, 13 Therefore, once the mentioned vascular symptoms become prominent, any history of nearby surgeries should raise clinical suspicion and warrant prompt investigation.
Currently, this is the only case report that describes ATA pseudoaneurysm after partial fibula osteotomy and which was successfully managed with endovascular stenting. Presentation of painful swelling and ecchymosis at nearby surgical sites are alarming signs indicating the vascular imaging like CT angiography for potential vascular injuries. Referral to interventional radiologist or vascular surgical team should be done promptly.