Nail Unit Reconstruction After Surgery for Refractory Retronychia

Commentary on “Nail Unit Reconstruction After Surgery for Refractory Retronychia”

“…Whereas most cases are due to chronic repeated minor trauma that often goes unnoticed, 4,5 other cases develop after a single heavy trauma as in the case commented here. 6 Most cases described were acute with massive swelling and violaceous discoloration of the proximal nail fold leading to loss of the Lovibond angle, granulation tissue protruding from under the fold, yellow nail plate, and very extensive onycholysis. Besides this acute form, a chronic retronychia variant exists that may rarely develop from an untreated acute one or appear without obvious prior inflammatory alterations.…”

“…Clinically, the nail is thick, discolored, and often looking like an oyster shell, the back of a shrimp, or a horseshoe crab with marked onycholysis and longitudinal overcurvature, a big distal bulge, and a disappeared nail bed. All cases have in common that the proximal nail remains attached to the lateral matrix horns, whereas the median portion is detached, 6 and this association of attachment to the lateral matrix horns and central detachment is most probably the mechanism of retronychia. The nail is programmed to grow forward in both the matrix and the nail bed.…”

“…Light-to-moderate cases may respond to high-potency topical steroids or intralesional steroid injection, 7,8 whereas moderate-to-severe cases require nail avulsion. 6 Postavulsion complications in the big toe are frequent, but often neglected. Apart from the rare event of simple nail dystrophy due to matrix damage, the most common and refractory problem is the development of a distal bulge that is always associated with a disappearing nail bed impeding the outgrowth of the nail plate.…”

“…Distal embedding is a consequence of the lacking or short nail plate as explained. The insertion of the saved nail into the nail pocket 6 can prevent a pterygium if there is an open wound on both the undersurface of the proximal nail fold and the underlying matrix. Furthermore, it also covers denuded areas of the matrix and proximal nail bed, facilitating wound healing and reducing postavulsion pain.…”