Forearm Fractures in Children

Forearm Fractures in ChildrenDistal forearm fractures in children are most common, and those involving the metaphysis usually involve both bones. Diaphyseal fractures are common in girls ages 10 to 12 years and in boys ages 12 to 14 years.

Evaluation

Consider the possible complicating factors. Look for concurrent nerve injuries, vascular compromise, and compartment syndromes.

Open fractures significantly increase the risk of complications, with about 10% of cases having nerve injuries or compartment syndromes. Delayed or nonunion, refracture are frequent in type 2 and 3 fractures. Nerve injuries recover spontaneously, but compartment syndromes require urgent release.

Ulnar styloid fractures are usually not solitary injuries. Look for other associated fractures.

Angulation Conventional AP radiographs may not show the greatest degree of angulation. Oblique views or fluoroscopy are helpful.

Diaphyseal Fractures

Management can be guided by a flowchart. It is often helpful to use finger traps and gravity to support and aid in maintaining reduction following manipulation. Immobilize most by flexible IM fixation. Open reduction becomes increasingly likely with increasing age. Accurate reduction is necessary at the end of growth to avoid malunion and limited forearm rotation.

Anesthesia Options include general, local, regional, or even no anesthesia. The option of no anesthetic is appropriate for fractures that can with absolute certainty be reduced with one deft manipulation. The child is given the choice of this option. The other methods require several injections and prolonged emergency department or hospital stays. The child usually accepts and later appreciates this choice.

Greenstick fractures are contained within the periosteum. Complete the fracture, place in finger traction, and immobilize in a long-arm cast with the forearm in a position assumed naturally with traction.

Plastic deformation often involves the ulna. Look for a dislocation of the radial head, making it a Monteggia equivalent. Most simple deformation occurs in early childhood when remodeling will correct malunion. Immobilize for 3 weeks. For more severe angulation, gradual but forceful manipulation may be necessary to correct the deformity.

Complete fractures Manage most by performing a manipulative reduction and then applying finger traction during cast application. Immobilize in the position of rotation naturally assumed by the forearm when traction is applied. Diaphyseal fractures in late childhood and adolescence often require operative reduction.

Radius fractures Isolated injuries may be difficult to align, as the proximal fragment is uncontrollable. Rotate the forearm to align the forearm with the free proximal radius fragment. Use fluoroscopy to make this match.

Preventing reduction loss Molding the cast to provide a snug fit will help. Repeat radiographs at weekly intervals for 3 weeks. Union of these diaphyseal fractures can take several weeks.

Acceptable alignment Side-to-side alignment is acceptable for children under the age of 8 years. In children over 10 years of age, do not accept malalignment greater than 10°. Malposition in the older child is an indication for operative reduction.

Refracture This occurs in about 10% of fractures. Try to prevent it by a good reduction and immobilization until bridging callus is seen on both sides of the fracture.

Malunion Remodeling will correct nearly any degree of malunion in the child under age 5 years. Malunions of greater than 10° in the older child or adolescent cause limitation of forearm rotation. This loss of motion is readily apparent on physical examination but is rarely noticed by the patient. This disparity between motion loss and disability is a source of confusion when assessing outcomes of forearm fractures.

Closed Reduction of Forearm Fractures

These fractures are common childhood fracture. Midshaft fractures require more accurate reduction, as remodeling is much less than for distal forearm fractures.

Distal Forearm Fracture Reduction

Bayonette apposition may be accepted if angulation <20° and 2 years of growth remain. For fractures requiring reduction, follow several steps. Provide anesthesia for displaced fractures. Local, regional, or general anesthesias are acceptable options.

Distraction Apply firm traction to overcome the shortening.

Hyperextend Extend the fracture to accentuate the deformity. The distal fragment is brought into a position that allows reduction.

Align cortical margins With thumb pressure and traction, the cortical margins are approximated to achieve appositional alignment.

Straighten arm This completes the reduction.

Midshaft Fractures

Midshaft fractures require an accurate reduction due to the greater distance between the fracture and the adjacent joint. Residual malalignment reduces forearm rotation.

Plastic deformation bowing may be straightened by manipulation.

Green-stick consider either completing the green-stick fracture or simply aligning the fragments.

Complete fractures in children may be reduced by the same general maneuver as for distal fractures.

Position for Immobilization

Distal forearm fractures are placed in slight wrist flexion and supination for the common dorsal angulated fractures.

Midshaft fractures are immobilized in the position of rotation that occurs when traction is applied to the arm.

Proximal fractures are immobilized in supination.

Immobilization

Immobilize the arm in a long-arm cast or splint-cast combination. The splint-cast accommodates forearm volume changes that occur from the increase and decline of soft-tissue swelling. First apply padding, place anterior and posterior splints, overwrap the forearm with an elastic bandage, secure with a circumferential cast above, and then apply molding while the cast material hardens.

Post-Reduction Management

Obtain radiographs at 1 and 2 weeks to be certain the reduction is maintained. Cast immobilization is discontinued at 6 weeks for distal and 8 weeks for midshaft fractures. Be aware of the risk of refracture of midshaft fractures.

Flexible IM Fixation of Forearm Fractures

Manage most forearm fractures by closed reduction. Those that require internal fixation are best fixed with flexible intramedullary pins or rods. This fixation was detailed by Metaizeau. Several recent studies confirm the effectiveness of this fixation.

Percutaneous K Wire Fixation

Reduction Under anesthesia and on a radiolucent table, attempt closed reduction. If unsuccessful, perform an open reduction through a 2-cm incision directly over the fracture site. At least 50% apposition is required for fixation.

Fixation Perform percutaneously using 1.6 mm K wires guided by imaging. Entry points are radial styloid or olecranon. For both-bone fractures, reduce and fix the radius first. Drive the pins just short of the growth plates.

Immobilization Place a long-arm cast and the forearm rotated based on fracture level and best alignment as determined by imaging. Remove the cast and wires in 4–6 weeks in the clinic. Others recommend burying the pins and leaving them in place for 3–4 months to reduce the risk of refracture.

Titanium Nail Fixation

Select nails about a third the diameter of the medullary canal. Nails are usually 2–3 mm. Open the medullary canal with an awl distal to the epiphyseal plate. Bend an elastic titanium nail and insert it into the medullary canal. Make a small incision on the dorso–radial side of the radius proximal to the epiphyseal plate and insert the second titanium nail. This nail should be bent so the convex side is radial to maintain the interosseous space. Position the nails under imaging to achieve optimal reduction and alignment. Cut off the nails at skin level. A cast is usually not necessary.

After treatment Remove the nails at about 12 weeks under local anesthesia.

Single Bone Fixation

Single bone fixation maintains forearm alignment and is suitable for most children. Usually the ulna only is rodded. Supplement the IM fixation with a long-arm cast.

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