Two Cases of Radial Ray Deficiency With Absence of First Metacarpus and 2 Tiny Fingers

We report 2 cases showing both radial ray deficiency and thumb duplication. The common features of these cases were absence of the first metacarpus and presence of 2 tiny fingers. The features of our cases may have been due to continuous abnormality of the mesenchymal cells before limb bud formation and apical ectodermal ridge at the established limb bud. In 1 case, we created a 5-finger hand using 2 tiny floating fingers. Two fingers as vascularized bones with growth potential were useful to make 1 thumb. Two tendon transfers at 2 years of age were effective to allow gripping and pinching of objects. At 6 years of age, the thumb was lengthened by an iliac bone graft and a reverse forearm flap. At 27 years of age, the patient showed grip power of 20 kg in the affected hand. The Quick-DASH (the Japanese Society for Surgery of the Hand version) score was 4.6. The patient was satisfied with the appearance and function of the hand, although size discrepancy between the thumbs remained.