It sounds like the type of fracture was a lateral condylar fracture of the distal humerus. The distal humerus is at the bottom of the upper arm.
The humerus flares at the bottom on both sides forming a part of the bone called the condyle. The lateral condyle is the bony projection along the outside of the elbow (side farthest away from the body). Fractures of the lateral condyle are fairly common in children. Finding the most effective treatment with the fewest complications is an important goal.
The choices in treatment include: putting the arm in a cast from the hand to the top of the upper arm. That’s called a long arm cast. Casting without surgery is possible when the break is intact and hasn’t separated or displaced.
A second treatment alternative is called closed reduction and internal fixation or CRIF. With CRIF, the break can be lined up (reset) without an incision to cut through the skin and open the arm up. And for fractures that have separated too much and/or shifted so the broken ends no longer line up, the third procedure used is called an open reduction and internal fixation (ORIF). With the open reduction, the surgeon makes an incision down to the bone. The bone is put back together and held in place with wires, plates, and/or screws. The arm is placed in a long arm cast until sufficient healing takes place.
Each of these treatment approaches have their pros and cons in terms of complications. Putting a cast on without wiring or screwing the bones back together has a risk of the bones drifting too far apart. Closed reduction and internal fixation may not bring the bones back as close together as needed. The result can be deformity and change in the carrying angle of the arm. Open reduction with internal fixation (ORIF) is really the most accurate treatment but it is also the most invasive.
A wide range of complications can occur from the treatment of lateral condylar fractures. There can be infections, loss of blood supply to the bone, failure of the bones to knit back together (malunion), or just a very slow process of healing (delayed union).
Sometimes the bones shift even with surgery (CRIF or ORIF). If too much shifting occurs, an elbow deformity can develop that affects the carrying angle of the arm. There are cases where growth is stopped or the opposite (too much bone growth) occurs. Stiffness, loss of motion, weakness, and loss of function are all possible problems that can develop.
The best thing to do is keep your regular follow-up appointments with the surgeon. Periodic X-rays may be needed to track your son’s progress and make sure the bone is healing properly. If you notice anything unusual, don’t hesitate to report this to the surgeon for further evaluation.