Congenital radial head dislocation is an unusual congenital anomaly of the elbow. It is undoubtably present at birth but is rarely discovered until children get a bit older. This is mainly because the limitations of radial head dislocation are not life- altering for most (including the motion limitations). X- rays are usually the best way to discover a joint dislocation but may not be diagnostic in a young child. Much of the elbow is cartilage in a young patient and the cartilaginous elbow is difficult to understand because cartilage is not visible on x- ray.
So, congenital radial head dislocation often presents as children the reach an age of increased activities- typically 4-8 years of age but often even older. They usually complain of a lack of motion- specifically limited rotation of the forearm. Rarely, elbow flexion or extension limitations may be noted. Pain is rare in the younger patients but pain can be a problem in the teenager with a marked deformity . When the dislocated radial head is bumped- it hurts.
Some basics. First, children with congenital radial head dislocation have it for both elbows. Second, it can be associated with syndromes- including nail- patella syndrome: http://ghr.nlm.nih.gov/condition/nail-patella-syndrome. Others may include Klinefelters and Cornelia de Lange. Third, most dislocations are posterior or posterior- lateral but some may be anterior or truly lateral.
One of the biggest issues with the diagnosis of congenital radial head dislocation is separating it from trauma causing a radial head dislocation. It can be confusing. There may be several tricks to separate the two. First, if both sides are involved, it is a birth (congenital) problem. And second, the x- rays can help. Typically the capitellum is rounded and the radial head is concave and round. If these shapes are not present- the radial head and capitellum have not developed normally because it is a problem present since birth (i.e., not a trauma). Third, most radial head dislocations in kids are accompanied by an ulna fracture (Monteggia injury)- make sure ulna is ok! And fourth, radial head dislocation may be a part of proximal radioulnar synostosis. This is a different issue altogether.
In most cases, we do not surgically treat congenital radial head dislocations. If discovered in a young child, there have been thoughts about putting it back in place but most believe this will not succeed. In older kids, attempts to put radial head back in place are even less likely to succeed because the anatomy is altered. So, given that most kids have few if any complaints- we do not recommend surgery. However, in older kids, typically teenagers, pain can be an issue. If the pain is a real issue, surgical excision of the radial head can be considered. It should ideally be delayed until the growth plates are closed. I have been very happy with our results with this operation but there are a couple of issues for families to consider. First, the radius can move slightly proximally (away from wrist). If it does, the ulna becomes prominent at the wrist and can be painful. This can, in a small percentage of patients, require another surgery. Second, we worry about the stability of the elbow and possibility of development of arthritis. And third, excision of the radial head may improve elbow motion (best for rotation) but obviously does not make it normal. We have published our results in this area with good outcomes: http://www.ncbi.nlm.nih.gov/pubmed/23123151
Here are a few pictures of recent radial head excision in a teen with elbow pain.
|AP x-ray of elbow with congenital radial head dislocation demonstrating deformity of radial head. This teenager had pain.|
|Congenital radial head dislocation. Not the head of the radius is out of place and misshapen.|
|We take an x-ray of the wrist to understand the relationship of the radius and ulna before we remove the radial head. This helps us understand issues later that might develop.|