Thumb Hypoplasia

Lohrasb Sayadi, BS; Mustafa Chopan, BS; Donald Laub, MD

ePlasty. 2015;15

Introduction

Description

N.D. presented at 8 weeks of age because of concern over her small right thumb. She was unable to actively flex or oppose this thumb, and the first carpometacarpal joint was unstable. Radiographs showed a hypoplastic digit with undeveloped carpometacarpal joint (Fig. 1). The remainder of her examination showed normal findings.

(Enlarge Image)

Figure 1.

Radiograph of N.D. preoperatively, demonstrating thumb hypoplasia and an unstable carpometacarpal joint.

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Introduction
Discussion
References
Sidebar

Table 1. Modified Blauth classification of thumb hypoplasia ^*
Type	Description	Treatment
Type I	Minor hypoplasia	No treatment required
Type I	All musculoskeletal and neurovascular components of the digit are present but small in size	No treatment required
Type II	All of the osseous structures are present (may be small)	Stabilization of the MCP joint
	MCP joint ulnar collateral ligament instability	Release of the first web space
	Thenar hypoplasia	Opponensplasty
Type IIIA	Musculoskeletal and osseous deficiencies
	CMC joint intact
	Absence of active motion at the MCP or IP join
Type IIIB	Musculoskeletal and osseous deficiencies
	Basal metacarpal aplasia with the deficient CMC joint
	Absence of active motion at the MCP or IP joint	Thumb amputation and pollicization
Type VI	Floating thumb
Type VI	Attachment of the hand by the skin and digital neurovascular structures
Type V	Complete absence of the thumb