[Surgical management of the Blauth 1 to 3A thumb hypoplasia].

Thumb hypoplasia is a sequence of congenital abnormalities, from minor hypoplastic thumb with a preserved function to complete thumb aplasia. We only discuss in this chapter on the management of the thumb hypoplasia type 1 to 3A according to the modified Blauth's classification. Their common feature is the conservative treatment, in opposition with severe hypoplastic thumbs usually treated by index pollicisation. Whatever is the degree of hypoplasia, patients should be carefully examined for bilaterality, other anomalies and syndrome. Surgical treatment, when indicated, requires systematically widening of the first web space, stabilization of the metacarpophalangeal joint and restoration of opposition and extension. Reconstruction of the infant thumb should be started in the first year of life. Functional result depends on the degree of hypoplasia and differs dramatically whether if the thumb hypoplasia is isolated or associated with a radial club hand.