February 11, 2026
Mirror hand syndrome, clinically known as ulnar dimelia, is one of the rarest congenital differences of the hand. Children with this condition are born with extra fingers, no thumb, and in some cases, differences in the forearm and elbow as well.
Over the past decade, Charles Goldfarb, MD, has performed surgical reconstruction for approximately one child with mirror hand each year – an extraordinary level of expertise for such a rare diagnosis.
Dr. Goldfarb explains, “Over the years, I have learned so much from caring for children with mirror hand syndrome. No two children are exactly alike – the hand, wrist, and elbow can all vary significantly. Still, I believe strongly that four guiding principles shape the best care."
- Create the most functional hand possible. “My goal is to create a hand that allows a child to grasp, pinch and explore confidently. That usually means creating a new thumb and shaping the hand around the strongest fingers.”
- Straighten and strengthen the wrist. “The wrist is often bent because the lifting muscles are weak. During surgery, I use available tendons to help power wrist extension so the wrist can rest in a straight, functional position.”
- Address the elbow early when needed. “When the elbow is involved, early surgery gives the joint – still largely cartilage in young children – a chance to remodel. Removing the bony block to bending can improve long-term motion.”
- Focus on long-term function and adaptability. “Children are incredibly adaptable. If we can provide a good hand, a straight wrist and an elbow that bends, the future is very bright.”
Learn more about congenital hand and arm differences.
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