TRAUMATIC PSEUDOANEURYSM/FALSE ANEURYSM OF PERONEAL ARTERY

Definition:   An injury to the intimal lining of the peroneal artery that can occur, although extremely rare, during an inversion and/or plantar flexion injury to the ankle^{1,2, 3,4}.   The resultant injury leads to a pseudo/false aneurysm on the lateral aspect of the ankle.  This will produce a palpable and pulsatile mass on the lateral ankle and can result in severe pain.  It can be associated with ATFL, CFL and talocalcaneal ligament injuries³ and sural nerve neuropathy secondary to compression ⁴.
Injury Mechanism:  May occur iatrogenically after ankle surgery^5,6or after an inversion and or plantar flexion injury to the ankle.^1,2,3

Differential Diagnoses:  Hematoma, ATFL injury, longitudinal peroneal tear, peroneal subluxation, High ankle sprain, ankle fracture, True aneurysms (mycotic, or secondary to connective tissue disease or Behcet’s disease)².
Exam: 
Initially gait may involve antalgic gait.  The gait may resolve without resolve of the aneurysm.  Ankle will appear swollen over the postero-inferior aspect of lateral malleolus.   It will warm to touch, and pulsatile ^1,2.  The skin overlying the aneurysm may be necrotic ².   May be associated with decreased sensation in the sural nerve distribution.
Investigations:  
Ultrasound Doppler – Dilated vessel, mixed flow within vessel.
CT Angiogram and MR Angiogram with gadolinium are more definitive and should be ordered prior to surgical intervention².
Management: 
Surgical:   Vascular surgery to excise hematoma and repair intimal injury either with vein graft or stent.^1,2
Interventive Radiology: 
May include coil embolization, stent insertion or thrombin injection.²

Dr. Neil Dilworth (Aug 18, 2014)

References:

1.  Retrospective Case Report from SMS, 2012 CT angiogram confirmed and surgically repaired (hematoma excised and vein graft).

2.  Ramdass MJ. Traumatic false aneurysm of the distal peroneal artery with associated anatomic anomaly: a case report. Cases journal 2009;2(1):8605-8605.

3. Maguire DW, Huffer JM, Ahlstrand RA, Crummy AB., Jr Traumatic aneurysm of perforating peroneal artery. Arterial bleeding – cause of severe pain following inversion, plantar flexion, ankle sprains. J Bone Joint Surg Am. 1972;54(2):409–412.

4.  Rainey RK, Andersen C, Sehorn S, Sears S. Traumatic false aneurysm of the ankle. A case report.Clin Orthop Relat Res. 1983;176:163–165.

5.  Pai VS. Traumatic aneurysm of the perforating peroneal artery following ankle fracture. J Foot Ankle Surg. 1999;38(6):417–419.

6.  Shah AR, Khan SK, Adair W, Chatterji U. Peroneal artery pseudoaneurysm after surgical stabilisation of a Weber C trimalleolar ankle fracture: A case report and review of literature. Trauma 2014;16(1):51-55.