Lengthening a finger or thumb may be a good treatment option for a number of conditions including symbrachydactyly, constriction band syndrome, and ulnar deficiency. Essentially any congenital or traumatic condition that leads to a shortened digit (or digits) may interfere with function. If lengthening that digit will help pinch or large object grasp (i.e., soda can), then the procedure is considered. Typically it is one metacarpal or one phalanx bone that is lengthened although it can be done for more than one digit. Typically we lengthen the most distal bone (i.e., the farthest bone out) if it is long enough to allow the fixator to be safely placed (more later).
I believe in lengthening for function. It can really make a huge difference because it will simply increase the number of activities that the child can accomplish with the affected hand. I do NOT believe in lengthening for appearance. There is some information on the web and some things I have heard from patients about “growing” new fingers. This does not make a lot of sense to me for a lot of reasons. I use lengthening devices for 1 or 2 digits with a specific functional goal in mind.
The procedure has some risks, the most common being skin infection. Most kids treated with a lengthener will have a skin infection but usually it can be treated with antibiotics by mouth. Some have more serious infections. The next most common issue is that the bone may not form as fast as we would like or as fully as we would like and additional surgeries may be required to help this process.
Fixators are not just used for fingers and we commonly use them in the forearm for radial deficiency https://congenitalhand.wustl.edu/2012/05/fixator-for-radial-longitudinal.htmland sometimes for ulnar deficiency https://congenitalhand.wustl.edu/search/label/Fixators.
The idea is that we can place a fixator on a short bone and then slowly grow that bone. Typically less than 1mm a day. A family member turns a dial 3-4x/ day to gradually make the bone longer. We have to carefully watch the xrays to make sure the body is responding by growing bone. This process is painless and if the child is having pain, something is usually wrong. We grow the bone as long as possible to help function. The fixator is on during the lengthening process (may be months but depends on how much bone we grow) and then stays on a bit longer while the bone truly heals (after we stop turning the dial). More information is always available through our website at http://ortho.wustl.edu/content/Patient-Care/3220/SERVICES/Hand-Wrist/Congenital-Hand-Disorders.aspx
Here is one example.
|This is an unusual form of cleft hand (central deficiency). There is no thumb except the floppy “nubbin.”|
|Another picture of unusual cleft hand with absent thumb|
|This is the xray. Notice the lack of the thumb. The thumb metacarpal measures 22mm- good enough to support a fixator.|
|We have placed the fixator to allow a gradual lengthening of the bone.|
|Another view of fixator for cleft hand lengthening of a thumb.|