Radial shortening and positive ulnar variance caused by metaphyseal impaction of the distal radius increase tension on the triangular fibrocartilage complex and load on the distal radioulnar joint (DRUJ), potentially leading to articular surface damage, pain, and restricted forearm rotation. Specifically, compared with normal anatomy, a radial shortening of 2.5 mm increases the load on the distal ulna by approximately 18%–42% [5], and a shortening of 10 mm may result in a loss of 47% of pronation and 29% of supination [6].

Improper reduction of intraarticular fractures is a representative cause of posttraumatic arthritis and subsequent limitation of joint motion and pain. Even 1–2 mm of intraarticular incongruity is known to induce arthritis and lead to poor outcomes. Knirk and Jupiter [7] reported that >1 mm of intraarticular incongruity resulted in radiographic arthritis in 91% of cases, and that all patients with ≥2 mm of incongruity developed radiographic arthritis.

Abnormal volar or dorsal tilt of the distal radius in the sagittal plane is associated with wrist range of motion, particularly flexion and extension. As dorsal tilt increases, the load-bearing area shifts from the volar-radial side to the dorsal-ulnar side, leading to compensatory flexion at the midcarpal joint. This can result in painful synovitis and a form of dorsal intercalated segment instability [8,9]. Conversely, excessive volar tilt reduces wrist extension and may cause dorsal subluxation of the ulnar head and restricted supination [10].

Changes in radial inclination affect grip strength, radial and ulnar deviation, and load distribution across the wrist. It has been reported that patients with radial inclination less than 5° experience poor outcomes in 100% of cases [11].

To consider nonoperative treatment immediately after injury, criteria that predict the likelihood of subsequent displacement are necessary, and numerous studies have been conducted on this topic. Weber [12] defined unstable fractures as those in which dorsal cortical comminution exceeds 50% of the anteroposterior diameter of the fracture site on the sagittal view. Cooney [13] classified fractures as unstable if initial radiographs demonstrated >25° of dorsal tilt, >10 mm of radial shortening, or bilateral radius fractures. Lafontaine et al. [14] proposed more specific criteria, widely used for assessing instability, including: >20° dorsal tilt, >5 mm radial shortening, >50% dorsal comminution, intraarticular displacement, associated ulnar metaphyseal fracture, shear fracture of the distal radius, DRUJ fracture-dislocation, and early loss of reduction after initial reduction—meeting three or more of these conditions suggests an unstable fracture.

Radiographic criteria for determining whether to proceed with operative treatment after successful reduction have also been extensively studied. With advances in surgical techniques and implants, operative treatment has shown improved outcomes, narrowing the indications for conservative management, especially in younger patients with high functional demands. Radial shortening of >2 mm, DRUJ subluxation, and significant anteroposterior translation of the distal ulna are generally considered unsuitable for conservative treatment. However, acceptable thresholds for intraarticular incongruity (<1 mm vs. <2 mm) and dorsal tilt (allowing up to 10° vs. allowing only neutral alignment) remain controversial (Fig. 1) [15-19]. Randomized controlled trials comparing conservative and operative treatment for displaced distal radius fractures have consistently demonstrated superior radiographic alignment following surgical fixation, particularly with respect to volar tilt and radial inclination at final follow-up [20]. Several studies have also reported modest advantages in early functional recovery and grip strength in surgically treated patients during the initial postoperative period [21,22]. However, long-term follow-up data in elderly populations indicate that these early advantages do not persist over time. Large prospective studies have shown that although volar locking plate fixation may facilitate faster early recovery, it does not confer superior patient-reported outcomes at 12 months when compared with cast immobilization [23,24]. In line with these findings, a comprehensive systematic review and meta-analysis by Gutierrez-Espinoza et al. [25] concluded that while statistically significant differences in radiologic and functional outcomes favor volar plate fixation, these differences do not exceed minimal clinically important difference thresholds. Furthermore, ulnar variance did not differ significantly between treatment groups, and radiographic parameters showed limited correlation with long-term clinical outcomes (Table 1) [20,22,24,26-28]. Collectively, these data suggest that despite the potential for radiographic malunion in conservatively managed cases, long-term functional recovery is not inferior to surgical intervention, supporting nonoperative management as a viable primary treatment option.

Rather than applying strict radiographic criteria uniformly across all patients, more stringent criteria may be appropriate for younger, active individuals, while more flexible thresholds may be suitable for elderly patients with comorbidities or low functional demands. In particular, several studies have reported that unsatisfactory radiographic results do not always correlate with unsatisfactory functional outcomes in elderly patients [29,30]. Kyung et al. [31] reported that dorsal metaphyseal comminution did not significantly affect radiographic or functional outcomes in patients treated nonoperatively. Kim et al. [32] compared elderly patients (≥65 years) treated nonoperatively versus operatively for unstable distal radius fractures and found that although radial shortening was more pronounced in the nonoperative group, functional evaluation and wrist range of motion did not differ significantly between groups. A recent randomized trial of intraarticular fractures found that intraarticular incongruity did not significantly affect functional outcomes, even though radiographic differences were present (Fig. 2) [16]. These findings support the premise that in elderly patients with lower functional demands, nonoperative treatment can achieve satisfactory outcomes even when anatomical restoration is not perfect.

In addition to radiographic findings, clinical features such as concomitant fractures in the ipsilateral upper extremity, carpal fractures or dislocations, severe soft-tissue damage, or associated neurovascular injury warrant consideration of operative treatment as a priority [15].

When dorsal metaphyseal comminution is mild, radial length is relatively preserved, or angulation/displacement is minimal, additional fracture reduction is not required. In displaced fractures, longitudinal traction is applied along the forearm with adequate pronation of the hand while directing the distal fragment opposite to the direction of displacement in order to achieve reduction. Typically, the wrist is immobilized in approximately 20°–30° of flexion with ulnar deviation. If needed, local injection of lidocaine at the dorsal aspect of the fracture may be used before attempting reduction to provide pain relief and allow effective traction.

Elevation of the hand is essential to prevent swelling after injury. The use of a sling is not recommended because it positions the hand below the level of the heart; instead, the hand should always be kept above the elbow. Continuous finger motion is necessary. Importantly, finger motion must include full metacarpophalangeal (MCP) joint flexion and full interphalangeal (IP) joint extension rather than motion limited to the IP joints alone (Fig. 3). If active exercise alone is insufficient, assisted active exercise using the contralateral hand should be performed so that the patient can fully clench the fist and achieve full finger extension. Assisted exercises should apply sustained, gentle pressure rather than abrupt force to the joints. Additionally, during prolonged immobilization, contractures may develop in nonimmobilized joints such as the shoulder or elbow; therefore, these joints should be moved regularly from the time of injury [33].

Because considerable swelling is present immediately after injury, excessive compression during initial bandage or plaster application should be avoided. Joints not requiring immobilization—such as the shoulder and the MCP joints—should remain as mobile as possible. In particular, excessive pressure during plaster wrapping can lead to circulatory compromise, and improper molding before the plaster sets may result in pressure over bony prominences (e.g., radial or ulnar styloid, posterior ulna), causing skin necrosis, nerve palsy, or vascular insufficiency [33].

Various immobilization techniques for conservative treatment of distal radius fractures include sugar-tong splints, long-arm splints or casts, short-arm double splints, short-arm splints or casts, and radial gutter short-arm splints. Among these, sugar-tong splint is most commonly used immediately after injury. It partially restricts elbow motion while preventing forearm rotation in an effort to reduce loss of reduction [34]. However, sugar-tong splints may be uncomfortable during elevation due to their weight, and restriction of elbow motion can lead to elbow stiffness [35,36].

Randomized controlled trials have demonstrated that immobilization methods not involving the elbow provide stability comparable to elbow-including methods, with fewer immobilization-related complications [17,37]. Therefore, the necessity of elbow immobilization in conservative management of distal radius fractures remains controversial. Grafstein et al. [38] also reported no significant differences in redisplacement rates or functional recovery among sugar-tong splints, short-arm double splints, and short-arm casts in displaced distal radius fractures, recommending that physicians use the method they are most familiar with. The American Academy of Orthopaedic Surgeons (AAOS) clinical practice guideline similarly states that there is insufficient evidence to determine the superiority or necessity of elbow immobilization in conservative treatment of distal radius fractures [39].

Emerging technologies such as 3D-printed custom splints have been introduced as alternatives to conventional immobilization. These patient-specific devices, designed based on forearm surface scanning and fabricated using additive manufacturing, offer potential advantages including reduced weight, improved ventilation, and water resistance. A recent randomized controlled trial comparing 3D-printed splints to fiberglass casts in minimally displaced distal radius fractures demonstrated equivalent patient satisfaction and clinical effectiveness, although minor complications such as pressure points and splint breakage occurred more frequently in the 3D-printed group and required design modifications [40].

Regardless of the immobilization technique, it is essential to avoid crossing the metacarpal heads with the distal end of the splint or cast to permit MCP flexion to 90° and to prevent finger stiffness. After splint or cast application, the patient should be instructed to move the MCP joints to confirm absence of discomfort.

The recommended duration of immobilization is generally 3–4 weeks for impacted or minimally displaced fractures and 5–6 weeks for displaced fractures [33,35,41]. Recent evidence suggests that shorter immobilization periods may be appropriate for stable fractures. Multiple studies have demonstrated that 1 week of cast immobilization is safe and feasible for nondisplaced or minimally displaced distal radius fractures, potentially resulting in better functional outcomes and faster return to activities [42]. In displaced fractures, long-arm immobilization using a sugar-tong splint or long-arm cast is applied for the first 2–3 weeks, followed by a short-arm cast for an additional 3–4 weeks; however, actual duration may vary depending on fracture characteristics, patient status, and progression of bone healing [19,43,44]. In cases requiring reduction, weekly radiographs for the first 2–3 weeks are necessary to detect redisplacement or deformity, and if present, treatment should be converted to operative management [33].

After planned immobilization is completed, active mobilization is required to restore wrist range of motion. With the elbow flexed and the upper arm supported on the table, the patient performs wrist flexion, extension, pronation, and supination through active and assisted active exercises [33]. Pain during early rehabilitation is common after prolonged immobilization; nonsteroidal anti-inflammatory drugs and heat therapy may help alleviate symptoms [33].