Pediatric Distal Radius Fractures

Joshua M. Abzug

Scott H. Kozin

INTRODUCTION

Distal radius fractures are one of the most common injuries sustained during childhood, accounting for 21% to 31% of all pediatric fractures (1, 2, 3). These fractures are more common in boys and typically occur as a result of a fall during activities such as sports or play (4). Following the fall, patients complain of pain at the level of wrist, have tenderness to palpation in that region, and may have swelling and/or decreased range of motion. It is important to assess the remainder of the extremity as well in order to identify any associated fractures or injuries such as a supracondylar humerus fracture. Standard posteroanterior (PA) and lateral radiographs of the wrist should be obtained to evaluate the distal radius region. In cases when the fracture is slightly more proximal, suspected fractures in the metadiaphyseal region, forearm PA, and lateral radiographs should also be obtained.

Pediatric distal radius fractures are divided into two main types, physeal fractures and extraphyseal fractures. The physeal fractures are further classified using the Salter-Harris classification system, with Salter-Harris type II fractures being the most common type (5).

Treatment options for pediatric distal radius fractures can range from simple removable splint application, often provided for torus fractures (6), to formal open reduction and internal fixation. Additional options include closed treatment with cast immobilization, short arm or long arm, closed reduction and casting, closed reduction and percutaneous pinning, and, very rarely, external fixation application. Pediatric distal radius fractures are one of the most common skeletal injuries in children that require surgical intervention (7).

CLOSED TREATMENT WITH OR WITHOUT REDUCTION

Indications/Contraindications

Closed treatment of pediatric distal radius fractures is the most common type of treatment performed for these injuries. For example, torus or buckle fractures can be treated with a removable splint for 3 weeks without any need for further imaging or treatment (7, 8, 9). Specific parameters regarding acceptable alignment criteria for closed treatment vary greatly in the literature regarding coronal and sagittal alignment (7, 10, 11) (Table 7-1). Typically, up to 50% displacement is considered acceptable. Most authors agree that no rotational deformity is acceptable as this will not remodel; however, Noonan and Price noted that up to 45 degrees of malrotation in children less than 9 years of age and up to 30 degrees of malrotation in children greater than 9 years of age will not lead to functional loss (12). Fractures that do not meet these criteria may be candidates for attempts at closed reduction maneuvers.

Specific contraindications to closed management alone include fractures with substantial displacement, open fractures, and fractures with median neuropathy that does not improve following closed reduction.

Preoperative Preparation

It is ideal to gather all needed cast material and additional supplies prior to beginning to place a cast on a child with a distal radius fracture. These materials include the following:

2 in. stockinette

2 in. cast padding

TABLE 7-1 Acceptable Parameters for Closed Treatment of Pediatric Distal Radius Fractures

Age in Years	Coronal Alignment	Sagittal Alignment	Reference
<5		Up to 35 degrees	Lovell and Winter
5-12		Up to 25 degrees
>12		Up to 15 degrees
4-9	15 degrees	15-20 degrees	Rockwood and
9-11	5 degrees	10-15 degrees	Wilkins
11-13	0 degree	10 degrees
>13	0 degree	0-5 degrees
4-9	5-10 degrees	15-20 degrees	Bae
Data from Bae DS. Pediatric distal radius and forearm fractures. J Hand Surg Am. 2008;33(10):1911-1923; Waters PM, Bae DS. Fractures of the distal radius and ulna. In: Beaty JH, Kasser JR, eds. Rockwood and Wilkin’s Fractures in Children. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2010:292; Skaggs DL, Frick S. Upper extremity fractures in children. In: Weinstein SL, Flynn JM eds. Lovell and Winter’s Pediatric Orthopaedics. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:1760.

2-in. fiberglass
Large basin
Room temperature water
Scissors
Nonsterile gloves

We have found that it is easier to apply casts utilizing smaller cast padding and fiberglass, especially in younger children, to avoid wrinkles. The use of room temperature water instead of warm water will permit more time to work with the cast material and limit any potential for burns due to the exothermic reaction of the cast material that occurs during hardening (13).

If a closed reduction procedure is being performed, our preference is to have the child receive conscious sedation. Additionally, one should enlist a health care worker to aid in holding the limb while a long arm cast is applied.

Surgical Procedure

Cast application is a skill that requires practice in order to prevent potential complications and optimize management. The steps are as follows:

Apply stockinette to injured limb leaving 1 to 2 in. of extra length proximally and distally from where cast will ultimately end.
Apply two to three layers of cast padding evenly without wrinkles (material should overlap previous layer by 50% and be rolled to avoid excessive tightness) (Video 7-1).
Stop cast padding distally at level of distal palmar crease to permit full metacarpophalangeal joint flexion.
Stop cast padding proximally at proximal third of forearm for short arm casts and proximal third of arm for long arm casts (ensure elbow is flexed to 90 degrees for long arm casts) (Fig. 7-1).
Dunk fiberglass in room temperature water, and squeeze some but not all of the excess water out.

Apply fiberglass in similar manner as cast padding (Video 7-2) (during the fiberglass application, fold back the excess stockinette to ensure no rough edges of fiberglass are against the skin).

FIGURE 7-1 Application of cast underpadding. Note the elbow is flexed 90 degrees and the cast underpadding stops of the level of the distal palmar flexion crease to permit full digital motion. (Courtesy of Joshua M. Abzug, MD.)

FIGURE 7-2 A. Application of the fiberglass cast material around the thumb by cutting the fiberglass. B. Stretching of the fiberglass around the thumb to permit full thumb range of motion following cast application. (Courtesy of Joshua M. Abzug, MD.)

Mold cast utilizing a three-point or interosseous mold.
Full thumb motion should be present (Fig. 7-2).

If a closed reduction maneuver is being performed, it should be done prior to placement of any casting material. With the child under conscious sedation (our preference is with the use of ketamine), the injury pattern is recreated and the reduction performed. Therefore, in the more common extension-type injuries, the distal radius is extended, traction is applied, and then the distal radius is translated volarly to perform the reduction (Video 7-3). Once the reduction is completed, the assistant can apply traction to maintain the reduction, and the cast can be applied. A three-point mold is placed in the cast to help maintain the alignment and the cast is permitted to harden. We have not found it necessary to bivalve the cast. If no assistant is available, the child’s limb can be placed in finger traps applied to an IV pole; however, this may not be optimal due to the difficulty in finding the appropriately sized finger traps, the potential to place traction across the physis, and the potential for the limb to fall out of the finger traps.

EDITOR’S NOTE

Successful closed reduction management of distal radius fractures in children requires exacting detail to molding of the cast. Numerous studies have identified poor cast molding as a risk factor for loss of reduction after closed reduction of distal radius fractures. The cast index and gap index have been used to measure the adequacy of molding at the fracture site. The apex of the three-point mold should be at the fracture site with pressure applied broadly. Gaps between the inside of the cast and the skin, overpadding at the fracture site, molding at the wrong point, and straight casts without molding can contribute to loss of reduction. In addition to looking at the fracture alignment on postreduction radiographs, the adequacy of molding should be assessed (MSK).

Postoperative Management

Immobilization is typically maintained for 3 to 4 weeks. It is important to counsel patients/parents that the cast should not get wet, unless a waterproof cast padding has been used. Additionally, patients and parents should be counseled to avoid placing objects inside the cast. Cast removal is also a technical skill that requires practice in order to avoid potential injury to the patient. The cast saw should be stabilized with one to two fingers against the cast, and the saw should be used with an in-out motion to avoid cutting or burning the patient (14).

Patients who undergo a closed reduction should be assessed 3 to 5 days later with repeat radiographs to ensure maintenance of alignment. If the alignment remains acceptable, the patient should be assessed again 5 to 7 days later with repeat radiographs. Worsening alignment at either visit is indicative of fracture instability and should be treated with either closed reduction and percutaneous pinning or open reduction and internal fixation.

Complications to Avoid

Proper casting technique is vital to the successful nonoperative management of pediatric distal radius fractures, especially those that are displaced. Optimal cast application can be assessed utilizing both the cast index and gap index that indirectly assess the amount of cast padding placed and molding performed, with high indices correlating with increased redisplacement rates due to poor molding of the cast or excessive padding (15, 16, 17). Furthermore, excessive padding can lead to a cast being too loose permitting shear stress to occur at the skin/padding interface and ultimately lead to skin irritation. In contrast, insufficient padding can lead to skin irritation at sites of bony prominences or pressure sore development due to focal areas of increased pressure with resultant decreased perfusion (13). Cast removal also has the potential to cause complications, including permanent scars due to lacerations or burns (18).

Pearls and Pitfalls

Closed treatment with or without a closed reduction is the most common treatment for pediatric distal radius fractures.
Ensure proper cast application technique utilizing small-sized cast padding and fiberglass.
Use only two to three layers of cast padding, each overlapping the previous layer by 50%.
Assess alignment 3 to 5 days following a closed reduction and again 1 week later to ensure maintenance of alignment.
Remove cast utilizing in-out technique with a blade that is not dull to avoid burns and/or lacerations.