Polydactyly is a hand or foot condition where there are more than ten fingers or toes present. Although not indicative of the presence of other genetic conditions, polydactyly usually presents as extra fingers or toes that sometimes alter the function of the hand or foot. Most cases, in fact, do not occur based on family history or genetics. Sometimes, the additional digit may get in the way of normal function in addition to the obvious cosmetic difference.
Extra fingers or toes can occur adjacent to any digit, but seem to occur more routinely with border digits (eg, the small finger or thumb).
Several characteristic problems are present:
- the extra digit can split at the level of one of the bones
- the duplication can involve the joint
- curvature of the remaining digit can occur
- the duplicated digits are themselves underdeveloped
Treatment is usually surgical. The extra finger or toe will need to be removed all the way to the level of the split, whether bone or joint. Once the digit is removed, the residual finger or toe will likely need to be straightened. Ligaments around duplicated joints are tightened, and bone is straightened as necessary for the final result. Surgical treatment is advocated as early as 6 months of age in some cases. Early correction can have long-term functional benefits.
Occasionally, a residual curvature deformity may persist or develop over the next several years. Secondary surgery may be required to correct this problem, should it develop.