Distal radius fractures are among the most common fractures in adults, with an incidence of 20 per 10,000 people per year [1, 2]. Women are more likely to suffer a distal radius fracture than men [3]. Most distal radius fractures can be treated conservatively with immobilization, while displaced fractures often require surgery [4].
The treatment of fractures with open reduction and internal fixation (ORIF) has significantly increased over the past decade [3]. Percutaneous pinning, external fixation, spanning plate osteosynthesis, and intramedullary nailing are additional options for stabilizing distal radius fractures [5, 6]. The method of fracture treatment varies depending on the patient (age, activity, or additional conditions) [7], local standards [8], and fracture patterns [9].
Classifications
Distal radius fractures are divided into different categories. The AO classification is commonly used to describe distal radius fractures and is based, like the Frykman classification, on fracture assessment in conventional X-rays [10]. The "four corner concept" with the radial, palmar, dorsal, and ulnar "corners" or fragments is described by axial computed tomography (CT) images [11]. As described by Bain et al. [12], the "corners" on the radius correlate with the attachments of the radiocarpal and radioulnar ligaments. According to Brink et al., there are eight common fracture patterns of the distal radius [11]. In the sagittal CT reconstruction, the lunate bone is often subluxated with either the dorsal or palmar fragment. This fragment, which subluxates the lunate bone, is referred to as the key fragment and should be addressed at the beginning of osteosynthesis [11]. In their classification, Hintringer et al. describe a fracture pattern-specific fragment and derive the surgical strategy from it [13].
Principle and Goal of Surgery
Conservative treatment can be performed for stable, non-displaced fractures. This usually involves immobilization in a forearm cast for 4 to 6 weeks [1]. Surgery is required when displaced fractures cannot be reduced closed or are unstable and re-dislocation is expected (Table 1). Functional follow-up treatment of a non-displaced fracture may be considered in exceptional cases, such as bilateral upper extremity injury. Despite good fracture alignment and lack of instability criteria, plate osteosynthesis may be recommended in this case after consultation with the patient.
| Table 1 Instability Criteria of Distal Radius Fractures |
| dorsal comminution zone [14, 15] |
| age > 60 years [15] |
| female gender [15] |
| dorsal tilt > 20° [14] |
| associated distal ulna fracture (excluding avulsion of the tip of the ulnar styloid process) [15] |
| radial shortening > 5 mm [14, 16] |
| palmar tilt [17] |
The goal of surgical treatment is to achieve bony healing with correctly restored axis, rotation, radial/ulnar length ratio, and radial inclination, as well as anatomical reconstruction of the joint surface in intra-articular fractures. The fixation of the fragments should allow for functional postoperative treatment. If fixation principles such as Kirschner wire osteosynthesis are not functionally stable, additional immobilization with a cast is required, making functional follow-up treatment impossible.
Plate osteosynthesis requires open fracture reduction. The majority of distal radius fractures are treated with palmar angle-stable plate osteosynthesis. The palmar approach, however, does not allow visual control of the joint surface and requires ligamentotaxis of the dorsal radiocarpal ligaments for the reduction of dorsal fragments. A dorsal approach should be performed when centrally impressed joint fragments or dorsal fragments cannot be reduced by ligamentotaxis. The dorsal approach also allows for the treatment of ligamentous or bony concomitant injuries of the proximal carpal bones. According to the literature, the dorsal approach has no negative impact on functional or radiological outcomes [18].
In cases of central impression of the joint surface, arthroscopically assisted reduction and fixation of the fragments can also be performed. Certain fractures, such as fractures of the radial styloid process, can be treated percutaneously or arthroscopically assisted with lag screws.
Absolute Indications for surgery include:
- open fractures
- fracture-dislocations
- concomitant vascular and/or nerve injuries.
The relative indication for surgical treatment of distal radius fractures strongly depends on the patient's needs. The indication is more liberally made in younger, active patients than in older patients with fewer functional demands. Fractures with fewer than 3 instability criteria (Table 1), where good fracture alignment has been achieved through closed reduction, can be primarily treated conservatively. To timely recognize secondary dislocation, radiological follow-up is required after about 1 and 2 weeks. Fractures that exhibit dislocation according to Table 2 and either cannot be adequately reduced or have more than three instability criteria should normally be treated surgically.
| Table 2 Limits of Acceptable Fracture Dislocation in Distal Radius Fractures |
| palmar tilt |
| radial shortening with ulna plus > 2 mm |
| intra-articular step ≥ 1 mm |
| intra-articular gap ≥ 2 mm |
| dorsal tilt > 10° |
| radial inclination < 15° |
| coronal shift |
| pathological carpal alignment |
Two additional, often less considered radiological criteria indicating operable instability are carpal alignment and coronal shift [19, 20, 21]. In a lateral X-ray, carpal alignment is assessed based on the radial axis in relation to the position of the capitate bone [22]. There are two methods to determine carpal alignment. In the first method, a line is drawn along the longitudinal axis of the radius and the capitate bone. Proper alignment is present if these two lines intersect within the carpus. In the second method, a line is drawn along the inner border of the palmar cortex of the radius. If this line intersects the center of the capitate bone, proper alignment is also present [20, 22]. A d.-p. X-ray is used to assess the coronal shift. In this case, an ulnar radial boundary line is drawn and extended distally. This line should cross the lunate bone in the middle 2/4 (26–75% of the width of the lunate lies ulnar to the intersection in healthy individuals) [21].
Indications for the Palmar Approach
- fractures tilted palmar
- fractures tilted dorsal that can be reduced by ligamentotaxis
Indications for the Dorsal Approach
- fractures with intact palmar lip
- a central impression ("Die-Punch Fragment")
- need for visual control of the radiocarpal joint
- concomitant ligament injuries (such as the scapholunate ligament)
- fractures of the proximal carpal bones.
Outcomes
Even when acceptable fracture alignment could be achieved through closed reduction, prospective randomized studies have shown better functional outcomes after palmar plate osteosynthesis compared to conservative therapy for both displaced intra- and extra-articular distal radius fractures [23, 24]. Patients aged 18 to 75 years were included in these studies. It is controversial whether plate osteosynthesis and anatomical restoration are actually beneficial in older patients aged 65 years and older [25]. Older patients who have undergone either surgical or conservative therapy appear to have the same long-term outcomes (over 12 months) [26, 27, 28]. However, surgical therapy facilitates recovery and leads to better functional outcomes in the first months [27, 28]. Therefore, it is important to consider the patient's age and health status when determining the indication for surgery.
Plate osteosynthesis is a safe operation with a postoperative complication rate of 9–15% [29, 30]. The most common complications are tendon irritations or ruptures. A meta-analysis has shown that there is no difference in complication rates between surgical and conservative therapy of distal radius fractures [25]. No difference was found between palmar and dorsal plate osteosynthesis of AO type C3 fractures in terms of complications and functional outcomes [18]. Therefore, the chosen surgical approach should be aligned with the fracture pattern to achieve anatomical reconstruction.