CHRONIC RING EROSION OF A FINGER.

Editor,

Ring erosion of a digit is a rare injury that develops insidiously over many months or years. The risk factors include psychiatric illness, poor social support and self-neglect. The majority of patients deny direct trauma as a cause. We present a case of ring erosion of a digit with significant bone destruction.

A 59-year-old man was admitted for investigation of sepsis, following a fall. His comorbidities included obesity, recurrent lower leg cellulitis and restricted mobility. He had no psychiatric illness or known substance abuse. On admission, he was unkempt, pyrexial and tachycardic. The finding of an embedded ring on his right middle finger warranted plastic surgery review due to concerns that it could be the source of sepsis. On further questioning, the ring had been present for over 3 years and removal had been recommended. However, due to fear that it would result in finger amputation, the patient declined treatment.

The finger was swollen proximally without significant erythema or discharge. It was well perfused and had a reduced range of movement and stiffness. The ring freely rotated in the bony tract which had formed over the years. Radiographic examination of the affected finger showed significant bone erosion of more than 50 % of the proximal phalanx (Figure 1,2)

Photograph showing dorsum of right hand with the ring embedded in the middle finger.

Lateral radiographs of the right hand showing erosion of the proximal phalanx of the right middle finger before and after ring removal

The external part of the ring was cut with a ring cutter and the internal part was then easily removed by rotating it out through the formed tract.

DISCUSSION

Ring erosion of a digit involves a combination of repetitive trauma over a long period of time and predisposing factors. Initially, oedema and skin hypertrophy develop distal to the ring, subsequently, an epithelial bridge forms over the ring on the palmar surface, leaving the dorsal surface intact. The clinical picture at presentation is usually either chronic or acute-on-chronic with superadded infection and neurovascular compromise.

To our knowledge, there is no case of digital amputation in the literature as a consequence of ring embedment. This could be explained by the fact that the involved digits, develop collateral circulation around the rings.,

In one review of the literature in 2002, Leung reported 11 cases with a similar presentation. Over 50% of patients had a mental illness and 72% were female between the ages of 7-73 years. Another author reported multiple rings removed from the same digit without the need for amputation.

The management entails removal of the ring and wound care. It may be possible to remove the ring with a ring cutter as a minor procedure, especially when the ring is freely mobile within the tissue plane formed., A foreign body granuloma may develop if a saw is used for ring removal as small ring fragments can remain in the tissue. In more complicated cases, a hand surgeon should be consulted for consideration of removal in a controlled theatre environment., In advanced cases, exploration and reconstruction of the defect may be required.,

The learning point is that early intervention is the key to preventing the associated morbidity caused by chronic destruction and loss of function.