Functional classification

One functional classification of cleft hand relies upon the utility remaining in the residual thumb and first web space. As the cleft becomes more severe in this system, it merges with the first web space and ultimately can result in the absence of all radial hand structures. The function of the thumb and first web will largely determine the function of key activities like pinch grip and the strategy for reconstruction:

• type 1: normal web space that is not narrowed
• type 2a: narrowed web space but mild deficit
• type 2b: severely narrowed web space
• type 3: syndactylized web space; thumb and index finger are syndactylized; the web space is obliterated
• type 4: thumb web space is merged with the cleft; index ray absent
• type 5: no thumb; ulnar rays remain but thumb web space no longer present

For example, a type 1 defect would only require closure of the cleft by excision of bone and reconstruction of the transverse metacarpal ligament. However, an absent thumb might require a toe-to-hand free tissue transfer.

Ref: Manske PR (1993) Plast Recon Surg 91(1): 196.