Salter–Harris Classification

Within the broader category of physeal fractures, a subcategorization system proposed by Salter and Harris in 1963 is widely used to further specify the extent of physeal involvement. ¹⁴ This classification is based on five primary designations, aptly termed Salter–Harris types I to V (SH I–V). An SH I fracture does not involve any ossified bone, with the fracture line traversing solely through the physis. Type II fractures are the most common type, accounting for nearly three-quarters of all distal radius physeal fractures in children. ¹⁴ These fractures are characterized by a fracture line, which extends through the physis and into the metaphysis. An SH III fracture extends from the physis into the epiphysis. Type IV fractures encompass all three of these sections, with a fracture line extending from the epiphysis to the metaphysis, through the physis or vice versa. An SH V fracture is rare and is notably different than the earlier types. These fractures are most often caused by crushing mechanisms or repeated compression and are associated with significantly increased rates of physeal arrest. ¹⁴

Nondisplaced Fractures

Nondisplaced and minimally displaced fractures do not often require operative intervention. Given the proximity to the physis, particularly for fractures in younger children, distal radius fractures have tremendous potential for remodeling and are often able to be treated conservatively with casting or splinting. In the case of SH types I and II fractures, those that are minimally displaced or nondisplaced can typically be managed conservatively. In particular, fractures with less than 50% displacement and those that limited angulation are often casted and closely followed during the early stages of healing. ¹⁵ Current literature describes that fractures with less than 15° of sagittal plane angulation and/or 1 cm of shortening will remodel without substantial functional impairment. ^{16 , 17}

Torus/buckle fractures are inherently stable and can typically be treated nonoperatively. However, there is a lack of consensus as to what is truly classified as a buckle/torus fracture. ¹⁰ For a stable torus/buckle fracture, immobilization for approximately 3 weeks is recommended in a short-arm cast or splint. For older patients, splints may be utilized for immobilization and weaned as the patient’s symptoms improve.

Displaced Fractures

General guidelines indicate that in children under 9 years of age, any amount of displacement and up to 15° of angulation and 45° of malrotation may be treated nonoperatively. ^{8 , 16 , 17} However, some authors recommend that up to 20 to 25° of flexion/extension angulation and 10° of radial/ulnar deviation are acceptable in the younger population. ¹⁸ Acceptable amounts of displacement and angulation for nonoperative treatment decrease with age as the remodeling potential diminishes with maturation and closure of the physes. In children 9 years and older, dorsal angulation greater than 20° should be treated with an intervention that improves the alignment. ⁸ It is important to note that complete fractures and fractures that are not inherently stable should be closely followed with weekly radiographs for up to 3 weeks to ensure maintenance of acceptable alignment.

Additional Indications for Surgical Intervention

Fracture patterns consistent with SH II to IV fractures often require a closed reduction to improve the alignment. Surgical intervention may also be indicated in cases of additional concurrent injuries, open fractures, floating elbows, suspected neurovascular injury, and/or intra-articular involvement. ¹⁹ In these cases, additional preoperative imaging such as computed tomography (CT) or magnetic resonance imaging (MRI) may be ordered to better assess the injury and plan for surgery. Additional surgical indications include complete extraphyseal fractures, which are inherently unstable, an inability to obtain an acceptable reduction with closed means, and the need for correction of a deformity due to insufficient remodeling.

Furthermore, socioeconomic factors need to be considered when evaluating the need for operative intervention, particularly in cases where the angulation, displacement, and/or malrotation are borderline, as the socioeconomic factors may lead to poor compliance regarding the need for close follow-up to monitor for loss of acceptable alignment.

Closed Reduction under Anesthesia

Closed reduction under some sort anesthesia is most often the first-line treatment for fractures that are not in acceptable alignment. However, it is important to note that repeated attempts at reduction increase the potential for physeal injury and subsequent growth disturbance, and therefore, we recommend no more than two attempts at reduction in the emergency department followed by no more than two attempts at closed reduction in the operating room. Additionally, late attempts at reduction can also lead to an increase in physeal damage, and therefore, attempts at closed reduction of physeal fractures should be limited to about 2 weeks from the time of injury. If a physeal fracture presents following this time frame, the fracture should be allowed to heal and remodel, even if a malunion develops, as the deformity can be corrected later on if needed without damaging the physis.

The method of anesthesia may vary based on where the closed reduction is taking place (i.e., emergency department vs. operating room) and physician preferences. Commonly, distal radius fractures can be reduced under anesthesia by means of a hematoma or intravenous block, axillary block, self-administered 50/50 nitrous oxide mixture, conscious sedation, general anesthesia, or some combination of these methods. ^{20 , 21 , 22 , 23 , 24 , 25} To perform a closed reduction, traction should initially be applied to unlock the fracture ends. Subsequently, the distal fragment should be translated in the direction opposite the angulation (i.e., volar translation for a dorsally angulated fracture). While maintaining the fracture in a reduced position, the extremity should be immobilized in either a sugar tong splint or long-arm cast. Proper casting technique, including either a three-point or interosseous mold and an optimal cast index, is imperative to optimize the potential to maintain the reduction. Follow-up radiographs over the first 2 to 3 weeks after reduction are imperative to ensure maintenance of acceptable alignment.

Closed Reduction with Percutaneous Pinning (CRPP)

Percutaneous pinning can provide stabilization following a reduction under anesthesia. This procedure is performed in cases of inherently unstable fractures, fractures that have failed prior attempts at closed reduction, and when stabilization of a fracture is needed without the aid of a cast/splint (i.e., open wounds, a floating elbow injury that one does not want to apply a circumferential dressing, or an associated vascular injury that requires close observation). A CRPP procedure minimizes surgical time and invasiveness while providing substantial stability to the fracture.

The procedure is performed utilizing the semisterile technique directly on an inverted large fluoroscopy unit (▶Fig. 24.1). Alternatively, one can use a hand table or a mini C-arm. Following the closed reduction and confirmation of acceptable alignment in both the coronal and sagittal planes using fluoroscopy, Kirschner wires (K-wires) of appropriate size for the patient’s age and size can be inserted either percutaneously or using a small longitudinal incision over the radial styloid. The wire is placed on the radial styloid for physeal fractures or just proximal to the physis for extraphyseal fractures and is driven retrograde, crossing the fracture site in a bicortical manner as confirmed with fluoroscopic imaging. An additional K-wire can be inserted, either in a divergent or crossed manner, if additional stability is thought to be necessary (▶Fig. 24.2). Once the K-wire(s) have been appropriately placed, they should be bent 90° with the bend approximately 1 cm from the skin surface and then cut such that only about 1 cm of the K-wire persists past the bend. Additional fluoroscopic images should be obtained to ensure there was no loss of alignment during this process. Sterile dressings are then applied followed by application of a well-molded long-arm cast. Follow-up radiographs should be obtained within 1 week following the procedure to ensure that the reduction has been maintained. Additional radiographs are obtained 4 to 6 weeks postoperatively, and if the fracture is healed, the K-wire can be removed in the outpatient setting without any need for anesthesia. Additional follow-up radiographs should be obtained over the course of the next year until either longitudinal growth is confirmed or a physeal bar is apparent.