Clasped thumb is a condition that causes the child’s thumb to lose its normal appearance and movements.
The structure which helps to bend the thumb is known as tendon. Thumb has tendons to straighten it and bend it. In children with clasped thumbs, there is a problem in the development of tendons to straighten ( extend ) the thumb.
The diagnosis of clasped thumb is often delayed because an infant frequently holds the thumb within the palm for the first 3-4 months. Children may have problems in straightening the thumb and it may remain inside the palm. Depending on the severity of disability clasped thumb is divided into 3 types
Type 1 : Child’s thumb joints are loose. Children may have problems in lifting their thumb due to problems in the tendons alone.
Type 2 : Child will have features of type 1 with additional problems in ligaments of joints and muscles of the palm.
Type 3 : Associated with other congenital disorders ( Arthrogryposis, mental retardation, Aphasia, Shuffling gait )
In children with type 1 clasped thumb, splinting the thumb is an important part of treatment. Full time splinting for 6 months has been shown to be effective.Many studies have shown that good results are obtained in 70% of children who are splinted within 12 months of birth. In contrast, splinting was effective in only 21% of children older than 1 year and in none older than 2 years. So identifying the problem and starting early splinting prevents contractures in the thumb.
Surgery is warranted for children who have failed splinting or are initially seen when older than 2 years.
The precise timing of surgery is dependent on multiple factors, including the age of the child, degree of deformity and patience of the family. A delay in surgery upto 2 years of age in a child is not detrimental .