Arteriovenous Fistula Secondary to Recurrent Metacarpophalangeal Joint Dislocation: A Case Report

Introduction

Acquired arteriovenous fistula (AVF) is rare compared to congenital lesions in the upper limbs, where the former is secondary to penetrating or blunt trauma, surgery, invasive procedures, infection, arterial aneurysm or inflammation between large to medium-sized vessels.1–3 Most traumatic AVFs are a result of penetrating injury (82%–98%).4–9 Traumatic vascular injury after fractures, dislocations, or both of the upper limbs is rare, with a reported rate of 0.3% to 6.5%.5 A careful search of the literature revealed seven upper limb AVFs secondary to blunt trauma: four phalanges,3,4,6 two thumbs,7,10 and one wrist.9 The mechanism of each is shown in Table 1. Common sites for most AVFs are seen in the radial and ulnar arteries; those distal to these are extremely rare.1,4 It has been postulated that the small caliber of a digital vessel makes a partial disruption difficult, and blunt trauma is more likely to produce a thrombus, whereas a penetrating injury is more likely to sever the vessel.8

Case Report

A 65-year-old woman was referred with a gradually enlarging swelling over the dorsum of her left hand over the course of a few years with a preceding history of recurrent left third metacarpophalangeal (MCP) joint dislocation. This was associated with a 1 cm swelling on the dorsum of her left hand at the level of the distal third between the third and fourth metacarpal bones, and a palpable thrill. The ultrasound scan confirmed an AVF (Figure 1). Operative intervention was offered because it was enlarging and was becoming symptomatic with an ache.

Under general anesthetic, an incision was made over the dorsum of her left hand (Figure 2). Intraoperative Doppler was used to identify the feeding vessel, and this was then ligated. Total operative time was 30 minutes, and there was minimal blood loss. She was discharged the next day after an uncomplicated recovery. Histopathology confirmed an arterialized vein consistent with the diagnosis of traumatic AVF secondary to repeated dislocation. Her subsequent follow-up at 1 month showed complete resolution of her symptoms.

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Figure 1 Ultrasound scan showing arteriovenous fistula on the radial aspect of the left third metacarpophalangeal joint. Multiple dilated veins demonstrate arterialized waveforms within the dorsal aspect of the left hand overlying the second and third metacarpal head region.

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Figure 2 Incision over dorsum of left hand and the arteriovenous fistula isolated.

Discussion

Hunter was the first to describe AVF clinically in 1757.10 The presentation of traumatic AVF varies depending on the subtypes, location, and extent of the vessels.11 Disfigurement, pain, heaviness, edema, arterial insufficiency (paresthesia, pallor, pulselessness, hypothermia, cold intolerance), increased skin turgor, pulsation, and thrills have been reported.1,4,8,10,12 Complications such as rupture and hemorrhage have not been described in the AVF of digital arteries.8

In traumatic AVF of the upper limbs, the progressive dilatation of the feeding artery and vein involved in the hyperdynamic circulation has resulted in reports of late sequalae such as congestive heart failure, proximal arteriovenous dilatation, and the risk of endocarditis.5,10 Cardiac decompensation may occur gradually over several years because of increased cardiac output secondary to increased flow in the AVF.12,13 Pain in the hand is often due to the proximity of the digital nerves but may be severe secondary to the steal phenomenon.1,12,13 AVF may cause sensory disturbances due to the pressure effect on the contiguous nerves, and in addition, it may also exert pressure on other vital structures in the upper limb.1,12,14 Acute muscle compartment syndrome has been reported in lesions of the arm and forearm, rather than the hand.12

Conclusion

Traumatic AVF of the distal upper limb is rare, and only a few cases have been reported. This is the first known report of a traumatic AVF in the dorsum of the hand secondary to blunt trauma from recurrent MCP dislocation. It should be considered as a differential diagnosis when there is a persistent palpable lesion after the traumatic swelling has resolved. Complete and early surgical excision is the treatment of choice as it is effective and safe and often provides definitive cure and prevents complications.4,5,8,14