Delta formation in foot polydactyly

Abstract

Congenital triangular deformity of the foot bones may occur in phalanges and metatarsals. As it resembles the Greek letter delta it is called "delta phalanx" and "delta metatarsal". We report on 19 delta formations in ten patients with foot polydactyly. Our long-term follow-up of these patients indicates four stages in the ossification process: no ossification of the epiphysis; appearance of single or multiple ossification centers; unification of the ossification centers with nonosseous tissue between the diaphysis and the epiphysis; and, finally, complete ossification. Pathogenetically, the delta formation may represent an intermediate stage in the bifurcation process of a polydactylic ray. Splitting longitudinally in a direction from distal to proximal, it is the root of the bifurcated toe ray.

Bifurcate Metatarsal Causing Foot Deformity: A Case Report

“…Olason and Dohler 1 reported nineteen cases of a "delta metatarsal," which may represent an intermediate stage in the bifurcation process of a polydactylic ray but these all involved patients with concurrent polydactyly. 1 We did not find any references in the literature to a bifurcate metatarsal without polydactyly.…”

Longitudinal epiphyseal bracket

“…A radiographic staging of the longitudinal epiphyseal bracket has been described in plain radiography [11, 12] (Fig. 3).…”

Hands

“…The phalangeal shape is reminiscent of the Greek letter D (delta), which explains the designation. This bizarre configu-ration results from a 90°tilt of a diaphysis-metaphyseal osseous unit that is longitudinally bracketed by an abnormal, C-shaped epiphysis (Olason and Dohler 1988;Ogden et al 1981). The proximal phalanx of the 1st digit and the middle phalanx of the 5th digit are the most commonly affected.…”