Congenital clasped thumb

Diagnosing the congenital clasped thumb is difficult in the first three to four months of life, as it is normal when the thumb is clutched into the palm in these first months.^[6] Diagnoses that cause the same flexion or adduction abnormalities of the thumb are:

• Congenital clasped thumb
• Congenital Trigger thumb (flexion of the interphalangeal joint) - Trigger finger
• Spasticity: overstimulation of muscles

Syndrome associated flexion-adduction of the thumb:

• Freeman–Sheldon syndrome (a congenital, heritable affection of the face, the hands, the feet and some joints)^[5][7]
• Distal arthrogryposis^[5][8]
• MASA syndrome^[5][9]
• X-linked hydrocephalus^[5][10]
• Adducted thumb syndrome^[5]
• Waardenburg syndrome^[5]
• Whistling face syndrome (Freeman–Sheldon syndrome)
• Digitotalar dysmorphism^[11]
• Multiple pterygium syndrome

There are a few different classifications conceived to categorize the spectrum of variety of congenital clasped thumb. In literature, X classifications have been described for clasped thumb. The two most relevant of the existing classifications, to our opinion, are the classifications of McCarrol^[12] and Tjuyuguchi et al.^[13]

The most global format is the classification of McCarrol, which divides the congenital clasped thumbs into two groups. Group I includes the supple clasped thumb, when the thumb is only passively correctable. While complex clasped thumbs, thumbs which cannot be moved neither passively or actively, belong to group II.^{[citation needed]}

Tjuyuguchi et al. designed a classification existing of three groups:^{[citation needed]}

• Group I: The supple clasped thumb, where the thumb is passively abductable and extendable against the resistance of thumb flexors, without other digital anomalies.
• Group II: The clasped thumb with hand contractures, where the thumb is not passively extendable and abductable, with or without other digital anomalies.
• Group III: The clasped thumb which is associated with arthrogryposis.

Treatment of congenital clasped thumb includes two types of therapy: conservative and surgical.

Treatment of all categories of congenital clasped thumbs should start with either serial plaster casting or wearing a static or dynamic splint for a period of six months,^[5] while massaging the hand. Extension by splinting shows reduction of the flexion contracture. To gain optimal results, it is important to start this treatment before the age of six months. The result of this therapy is better in less severe deformities.^[14] In most uncomplicated cases, a satisfactory result can be gained when splint therapy starts before the age of six months.^[15] Splinting should be tried for at least three months and possibly for as long as six months or longer. If the result of splint therapy stagnates, surgery treatment is indicated.^[16]

Surgical treatment should be considered in patients who have not been treated at younger age or when conservative therapy fails. Surgery is recommended during the age of three to five years.^{[citation needed]}

Techniques

• Release the thumb web space: it is possible to widen and deepen the area between the thumb and the index finger when it is too tight. To achieve this, a transposition flap or four-flap or five-flap Z-plasty can be used.
  • Transposition flap:^[17] skin flaps of the index finger and/or the thumb are moved to the web space.
  • Four-flap or five-flap Z-plasty:^[5] the web space is widened and deepened with skin of the web space itself.

• Tendon transfer:^[5] a technique usually considered for young children, in which tendons of index finger or little finger are used to make an adequate new extensor tendon for the thumb.

Other procedures

• Arthrodesis: fixing the metacarpophalangeal joint of the thumb in a more extension position.