Thumb Hypoplasia

Abstract

Hypoplasia of the thumb refers to a spectrum of clinical abnormalities ranging from a slightly small digit to complete absence (or aplasia) of the thumb unit. As a component of radial dysplasia, thumb hypoplasia can be either an isolated entity or seen in conjunction with other elements of radial longitudinal deficiency. Treatment of this condition initially involves identifying and addressing co-morbid anomalies in other body systems. The severity of thumb hypoplasia is then graded so that appropriate treatment methods can be instituted. The goal of treatment is ultimately to provide the child with a stable and functional thumb unit.

A Case of a 5-Year-Old Boy with a Blauth Type IIIB Hypoplastic Thumb Reconstructed with a Nonvascularized, Hemilongitudinal Metatarsal Transfer

“…As a common treatment option, type I follow-up is performed. Meanwhile, for types II and IIIA, opponensplasty is performed, such as the Huber opposition or flexor digitorum superficialis tendon transfers [4, 5]. Finally, for types IV and V, pollicization is performed [4, 6, 7].…”

“…Meanwhile, for types II and IIIA, opponensplasty is performed, such as the Huber opposition or flexor digitorum superficialis tendon transfers [4, 5]. Finally, for types IV and V, pollicization is performed [4, 6, 7]. Treatment for these types has generally been well-received; however, the treatment methods used for type IIIB hypoplastic thumbs are controversial [8] and reflect the desire of parents to preserve the thumb [7].…”

“…Meanwhile, additional treatment methodologies (e.g., bone grafting) must be utilized in addition to opponensplasty to establish a stable thumb. In order to establish a stable thumb, bone grafting with the use of a metatarsal bone, toe joint, or fibula is necessary [4]. Furthermore, two-term opponensplasty is required.…”

“…However, it is difficult to perform vascularized bone grafting, particularly in children. In addition, large bone defects occur after surgery and so growth disorders and toe deformities have been reported as complications of toe joint transplantation and general metatarsal bone grafting [4, 8].…”

Bilateral congenital absence of flexor pollicis longus with thumb hypoplasia and thenar atrophy

“…[2345678] According to Blauth et al ., thumb hypoplasia may be classified as isolated minor hypoplasia (type 1), associated with thenar hypoplasia and metacarpophalangeal (MCP) joint instability (type 2), musculotendinous/osseous deficiency with absent active motion at MCP or IP joint (type 3), floating thumb (type 4), and complete absence of the thumb (type 5). [10]…”