The elbow is a very complex joint when viewed in three-dimensional (3-D) space. Getting the broken bone lined back up in all three dimensions isn’t always easy. Viewed from the side on X-ray, the fracture might look fine. But viewed from the front, back, or from above, the malalignment remains and is much easier to see.
To help you understand what’s going on, we need to talk about the elbow carrying angle. Straighten your arm and let the forearm drop down to your sides. Now turn your hands so the palms are facing forward. Look at your elbow and notice the angle formed from the shoulder to the wrist with the center at the elbow. This is called the carrying angle of the elbow.
Deformities affecting the carrying angle are equally difficult to correct. Surgery is required and in particular, a supracondylar osteotomy procedure is usually the preferred treatment. There are many different ways to do an osteotomy on the distal humerus (lower end of the upper arm bone).
Some correct the angle in one dimension (i.e., as seen from the side). Others correct in three-dimensions. Using this type of osteotomy, the surgeon can correct for deformities in all three planes. The result is to correct the carrying angle, reduce the excess elbow extension, and realign the internal rotation malunion.
Loss of correction after a three-dimensional ostetomy may occur as a result of an unstable osteotomy from the way the bones were cut and arranged. Pins were used to hold everything together until complete bone union took place. But the decrease in contact area between the bones makes it difficult to stabilize the osteotomy site.
There may be some other reason for your child’s loss of correction. The best thing to do is make a follow-up appointment with the surgeon to take a look at what’s going on. If the change in the elbow carrying angle isn’t causing any problems, then it may not be necessary to do anything at this time.