Congenital hand defects are very common affecting 1 in every 1000 live births.
Polydactyly: Most common hand defects are polydactyly or extra fingers. These fingers may be fully formed or rudimentary. Poorly formed fingers can be removed in clinics or bedside at birth only. I remove such fingers early after birth as they may get gangrenous due to thin stalk. Fully formed fingers need a full-fledged operation theater setup with magnification facilities.
Saving adjacent fingers both form and function is important. At times I use parts from the extra finger to strengthen the existing fingers.
Syndactly: Fused fingers or syndactly is common 1 in every 2000 live births. Most commonly 2 fingers are fused. Sometimes all 4 or 5 fingers may be fused. Two-finger fusions can be corrected in a single surgery. Multiple fused fingers need more than 1 procedure. Excellent functional recovery is expected after the procedure.
I prefer to separate 2 fingers in a single session, both hands/feet can be done in the same sitting for children. Adults one hand is done at a time.
Aplasia or Absent thumb: Thumb accounts for 40% of hand function. Absent or non-functional thumb disables a person. Absent thumb since birth is a rare occurrence. It can be managed by pollicization where the index finger is transposed to the thumb joint and works as the thumb. The second option is toe to thumb transfer where the great toe is transferred to the thumb for function.
Both procedures give excellent results, I prefer to do pollicization wherever possible. However, if conditions permit then toe to thumb transfer also gives very good results.