The outcome of conservative treatment of spiral metacarpal fractures and the role of the deep transverse metacarpal ligaments in stabilizing these injuries.

We carried out a prospective study to assess the outcome of spiral metacarpal fractures treated with early mobilization even in the presence of malrotation. We treated 30 patients of whom we assessed 25. Of these, 23 had an excellent outcome and two had good outcomes. Objectively all the fractures united with some shortening of between 2-5 mm. Only two cases reported mild dysfunction: one patient had a residual malrotation of 5° and one had some discomfort when boxing. We also carried out simple biomechanical studies on a cadaver and two patients undergoing ray amputations. These showed that, as the distal fracture fragment migrates proximally, any malrotation in a closed injury with intact deep transverse metacarpal ligaments corrects with flexion, which also helps to limit the shortening. Spiral metacarpal fractures, whether central or border, whether single or multiple, can usually be treated reliably with early mobilization as any malrotation corrects with flexion and the degree of shortening is limited.