Our four-year-old fell down the stairs in our split-level home. She broke her arm just above the elbow. They put her in a cast and later had to do surgery becaude the break separated inside the cast. Does this happen very often?

At the time of the injury, X-rays are used to view broken bones with the specific idea in mind to plan the safest and most effective treatment. If the two ends of the broken bone line up and have not separated apart, then a cast can be applied. In the case of the elbow, a long-arm cast is often needed (from hand to shoulder) to prevent the bones from shifting apart.

Sometimes, the surgeon makes a judgement call. There may be a minor amount of separation called displacement seen on the X-ray. In an effort to avoid surgery, a cast is applied with a wait-and-see approach. The arm is re-Xrayed to check on alignment and bone healing.

If the bones continue to drift apart (and especially if the ends of the bone separate and shift so that they no longer line up), then the cast is removed and surgery is done.
Long-arm casting for elbow fractures is used whenever possible to avoid the invasiveness of surgery.

In a recent large study of lateral condyle elbow fractures, 14 patients of the 39 who were put in a long arm cast without surgery ended up with a gap in the fracture site. This shift in bone alignment required surgical fixation within the first two weeks of casting. That’s almost half of the group, a fairly high percentage.

Future studies may look into predicting who will have separation and require surgery to hold the bone together but for now, the wait-and-see approach has its merits.