Subungal Exostosis

A subungal exostosis is a relatively uncommon condition where a benign bone growth extends from the small bone at the tip of the toe. This prominent bone growth usually disrupts the toenail and often creates localized discomfort and deformity. Subungal exostoses are more common in relatively young patients, but can occur at any age. They often involve the great toe, although any toe can be affected. The exact cause of a subungal exostosis is unclear, although localized repetitive trauma has been proposed as a possible cause.

Symptoms associated with a Subungal Exostosis

Many subungal exostoses create a deformity of the toenail and toe, but otherwise have minimal symptoms. However, as the deformity associated with the tip of the toe gets larger symptoms of pain and local irritation are common. Symptoms are often aggravated by constrictive shoes.

Imaging studies

X-rays of the toes will demonstrate a prominent growth of bone extending from the last bone of the affected toe (the distal phalanx). Plain x-rays will usually confirm the diagnosis. However, if the exact cause of the deformity is in question, an MRI may be beneficial.

Treatment

Non-operative Treatment of a Subungal Exostosis

Many subungal exostoses create a deformity of the toenail and the tip of the toe, but otherwise are not painful. If this is the case, no specific treatment is required.  Other cases of subungual exostosis have symptoms that can be improved or eradicated by using comfort shoes with lots of space in the toe box, or by adding padding or a soft gel sleeve to the toe.

Surgical Treatment of Subungual Exostoses

For some patients with a subungual exostosis, the deformity will be symptomatic and worsen to the point where the condition will need to be addressed with surgery. Fortunately, surgery is usually straightforward and effective. Surgery often requires removing part of, or all of, the toenail. This is followed by removal of the excessive bone growth. Healing often requires a number of weeks, and longer for the toenail to grow back.

July 11th, 2024