In this article, Dr. D. S. Bae, a children’s orthopedic surgeon from Harvard University reviews the treatment of forearm fractures. In particular distal radial forearm fractures are the focus of this report. Distal refers to the end of the bone near the wrist. The bone affected most often is the radius (one of two bones in the forearm). Although children often heal quickly, displaced (separated) fractures and fractures affecting any part of the growth plate can create some very challenging problems.
In the last 10 years, surgeons have revisited the question of whether or not casting is sufficient for these types of fractures. There’s been some suggestion that surgery to pin the healing bones might be a better option than just cast immobilization. The thinking behind this has come as a result of the many cases where the fracture reduction was lost with casting.
Loss of fracture reduction is so common, it appears that at least one-third of all distal radial fractures (and as many as 90 per cent of cases) are affected. The first step in understanding how to keep this from happening is to look for risk factors.
Some of the factors that have been shown to increase the risk of loss of fracture reduction include: 1) type of fracture displacement, 2) amount of displacement (more than 50 per cent), 3) location of the fracture, 3) increased angle of the bone, and 4) fracture of the other forearm bone (ulna).
Other factors that may contribute to the loss of fracture reduction have been suggested. Muscle atrophy (wasting) and decreased swelling while in the cast can make a difference. The arm moves around too much inside the loose cast to keep the fracture firmly in place while healing. Movement of the arm can cause the fractured ends of the bones to separate again.
There’s been some question as to whether a short-arm (below the elbow) versus long-arm (above the elbow) cast makes a difference. Studies show that even more important than the type of maneuver used to reduce the fracture or the type of cast (short versus long) is the casting technique used. Serial X-rays taken once a week can help identify when a problem with reduction is occurring.
At the same time, there were some studies done to look at the results when using surgery to pin the fracture sites. The final outcome was that patients didn’t fare any better after surgical fixation than they did with nonoperative casting.
Reduction with pin fixation isn’t recommended for every fracture. It is considered most appropriate when there is a fracture through the metaphysis (growth plate). Other reasons open surgery might be done include open fractures (bone pokes through the skin), fractures that overlap and can’t be reduced, and fractures that are pressing on nerves or blood vessels.
Open fractures involve more damage to the periosteum (hard, outer covering of bone) and greater disruption of the surrounding soft tissues. The risk of nerve damage and compartment syndromes is much higher with open fractures. When a long nail or pin is placed down through the bone, complete reduction is not done first. Instead, the implant is put in place first while gently reducing the bones as much as possible and finishing the process after the pin is in place.
If the force of injury is strong enough, damage to the triangular fibrocartilage complex (TFCC) can occur along with fractures of the distal forearm. Such injuries can also require surgical repair. The TFCC is an area of strong fibrous cartilage between three of the wrist bones that articulate (move against) the bones of the forearm. Disruption of this soft tissue complex can create a very painful, unstable wrist.
Sometimes open surgery is necessary because the fracture is in such a location that key muscles are in the way. While trying to match the two ends of the bone up, the soft tissue gets caught between the bones. This makes reduction of the fracture difficult, if not impossible, with closed techniques. In all cases, when pin fixation is required, the surgeon tries to avoid or spare the growth plate.
Disrupting the growth plate can result in physeal arrest. This means the bone stops growing. When it’s not possible to avoid the areas of growth at the end of the fractured bone, then pins are placed through the physeal structures rather than across them. Plates and screws are another option to avoid drilling through or across the growth zones.
In younger children, the bone remodels itself nicely without complications or loss of skeletal growth. Older children with less potential for bone remodeling may benefit more from plate fixation. Growing children must be followed closely with periodic X-rays to make sure growth has not been stopped. Any child reporting wrist pain should be evaluated carefully for deformity that suggests loss of fracture reduction.
Even with good treatment (including surgery when needed), complications can occur. The most common problems are fracture malunion, fracture nonunion, disruption of growth, and nerve damage. There’s a high rate of late complications with loss of reduction. Surgeons are advised to keep this in mind and always follow pediatric patients who have distal forearm fractures carefully until complete healing is seen on X-ray.
With proper care, children may only experience a small loss of motion. Usually this is not enough to be noticeable during everyday movements or activities. Open fractures are at risk for infection and must be monitored closely.
Some angulation or malrotation of the bone may occur after healing. Most children aren’t affected by this, and there is little deformity actually visible. If the forearm looks too crooked or there is loss of function, further surgery to re-align the bones may be needed.
Because fractures of the distal radius are so common, an update and review of this kind is important. The wide range of surgical techniques available that might be needed keep the surgeon on his or her toes. Growing children with unpredictable bone remodeling add another dimension to the decision-making process in planning an optimal treatment approach. In addition, increased sports participation and the need for better functional outcomes, along with greater patient and family expectations create new challenges for the surgeon.