Symphalangism is an uncommon diagnosis related to lack of joint motion at one or more joints in the fingers or toes. It can be associated with other diagnoses such as brachydactyly but in my experience is most often an isolated diagnosis. It is not painful. Depending on the joint involved, it can be frustrating when the joint does not move. Parents certainly worry about function with a stiff joint although generally kids figure things out and work ‘around’ this issue. While the toes can absolutely be involved, those joints are rarely if ever treated because their stiffness does not cause problems.
This can be a genetic condition where it is passed down from a parent but most of the children I have seen and treated do not have a parent with symphalangism. One type is ‘Cushing Proximal Symphalangism’ which affects the PIP joints (the middle knuckle in the finger). OMIM (online mendelian inheritance in man) is a great resource. Read the report. There are other types including a distal type (last joint in the finger) as well.
Treatment of symphalangism is difficult. I have not found than therapy or splinting to be helpful. Depending on which joint is involved, no treatment at all may be required. Surgery was, for many years, thought to not have a role. But, Drs Baek and Lee in South Korea have written about their good results with surgical treatment of the condition. Their manuscript on 36 joints in 17 children can be found here.
There are a few things to look for. First, the child will not have creases on the top or bottom of the affected joint because the creases develop with joint motion. Obviously, the joint will not move (or only move a very slight amount. And finally, X-rays can be helpful. The younger the child, the more difficult it can be to interpret the X-rays. And comparison fingers can help.
In a child with a PIP joint symphalangism and in a family this is highly concerned about this, surgery can be helpful. My experience has been that surgery is helpful and can improve motion in many but not all kids. The surgery releases tight joint structures including the capsule and the ligaments. It requires a great deal of family participation after the surgery because even if we gain motion in the operating room, keeping the motion requires therapy at home multiple times each day. And the therapy is not fun because it will be painful in the first days and weeks after the surgery. But, with a successful surgery and good therapy, we have seen patients can 40-65 degrees of motion. I prefer operating on younger children as I believe that they have a great chance of joint remodeling.
Here is one example with symphalangism of the little finger PIP joint (the middle joint). The main knuckle (the MCP joint) and the last joint (the DIP joint are working fine. However, the PIP joint has no creases on top (or bottom). The X-rays are subtle but show slight narrowing of the joint. This child was improved after surgery.
Another example example is a middle finger PIP joint symphalangism. In this case, the middle finger stayed straighter and seemed to be in the way. We were able to operate at 4 months of age which is my preference because, as I noted above, remodeling of the joint can better take place. These two pictures show the lack of skin creases for the PIP joint of the middle finger, both on the top and palm sides of the finger. In this child, we obtained 90 degrees of motion in the operating room and 6+ months later motion remained more than 60 degrees.
Symphalangism is an are condition which may be genetic and may affected the hands and/ or the feet. There is not pain and function is typically excellent. But when certain joints are involved, especially in the hands, the stiff joint can cause the finger to get in the way with function. This is especially true if multiple fingers are involved. In those children, and with ideal family support and commitment to therapy, surgery can be helpful to release the tight joint structures and improve motion.