Distal radius fractures are among the most common fractures in adulthood with an incidence of 20 per 10,000 persons per year [1, 2]. Women suffer a distal radius fracture more frequently than men [3]. Most distal radius fractures can be treated conservatively through immobilization, dislocated fractures often require surgery [4].
Fracture management with open reduction and internal fixation (ORIF) has increased significantly in the last ten years [3]. Percutaneous Kirschner wire osteosynthesis, external fixator, bridging plate osteosynthesis ("spanning plate") and intramedullary nailing are additional options for stabilizing distal radius fractures [5, 6]. The way a fracture is treated varies depending on the patient (age, activity or additional diseases) [7], local standards [8] and fracture patterns [9].
Classifications
Distal radius fractures are divided into various categories. The AO classification is frequently used to describe distal radius fractures and, like the Frykman classification, is based on the fracture assessment in conventional X-ray images [10]. The "four corner concept" with the radial, volar, 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. Therefore, 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 not uncommonly subluxated either with the dorsal or volar fragment. This fragment that subluxates the lunate bone is referred to as the key fragment and should be addressed at the beginning of the osteosynthesis [11]. In their classification, Hintringer et al. describe a fracture pattern-specific fragment and derive the operative strategy from it [13].
Principle and Goal of the Surgery
Conservative treatment can be performed for stable, non-dislocated fractures. This usually involves immobilization in a forearm cast for 4 to 6 weeks [1]. Surgery is required if dislocated fractures cannot be closed reduced or are unstable and re-dislocation is to be expected (Tab. 1).A functional aftercare of a non-dislocated fracture can be considered in exceptional cases, such as in the case of bilateral injury to the upper extremity. Despite good fracture position and absence of instability criteria, plate osteosynthesis can be recommended in this case after consultation with the patient.
| Tab. 1 Instability criteria of distal radius fractures |
| dorsal comminution zone [14, 15] |
| Age > 60 years [15] |
| female gender [15] |
| dorsal angulation > 20° [14] |
| associated distal ulna fracture (excluding avulsion of the tip of the ulnar styloid process) [15] |
| Radial shortening > 5 mm [14, 16] |
| volar angulation [17] |
The goal of operative management is to achieve osseous healing with correctly restored axis, rotation, radius/ulna length ratio and radial inclination as well as anatomical reconstruction of the joint surface in intra-articular fractures. The fixation of the fragments should enable functional postoperative treatment. If fixation principles such as Kirschner wire osteosynthesis are not functionally stable, additional immobilization by cast is required, which makes functional aftercare impossible.
Plate osteosynthesis requires open fracture reduction. The vast majority of distal radius fractures are managed with volar locking plate osteosynthesis. However, the volar approach does not allow visual control of the joint surface and requires ligamentotaxis of the dorsal radiocarpal ligaments for reduction of dorsal fragments. A dorsal approach should be performed if centrally impacted joint fragments or dorsal fragments cannot be reduced by ligamentotaxis. The dorsal approach also allows concomitant treatment of ligamentous or osseous concomitant injuries of the proximal carpal bones. According to the literature, the dorsal approach has no negative influence on the functional or radiological outcome [18].
In the case of central impression of the joint surface, arthroscopically assisted reduction and fixation of the fragments can also be performed. Certain fractures can be managed percutaneously or arthroscopically assisted with lag screws, such as the fracture of the radial styloid process.
Absolute indications for surgery include:
- open fractures
- dislocation fractures
- concomitant injuries to vessels and/or nerves.
The relative indication for operative management of distal radius fractures depends heavily on the patient's needs. The indication is more generously made in younger, active patients than in older patients who have fewer functional demands. Fractures with fewer than 3 instability criteria (Tab. 1), in which a good fracture position was achieved by closed reduction, can be treated primarily conservatively. To detect secondary dislocation in time, radiological follow-up after about 1 and 2 weeks is required. Normally, fractures that exhibit dislocation according to Tab. 2 and either cannot be adequately reduced or have more than three instability criteria should be treated operatively.
| Tab. 2 Limits of acceptable fracture dislocation in distal radius fractures |
| volar angulation |
| Radial shortening with ulna plus > 2 mm |
| intra-articular step ≥ 1 mm |
| intra-articular gap ≥ 2 mm |
| dorsal angulation > 10° |
| radial inclination < 15° |
| coronal shift |
| pathological carpal alignment |
Two other radiological criteria that are often less considered and indicate instability warranting surgery are the carpal alignment and the coronal shift [19, 20, 21]. In a lateral X-ray, the carpal alignment is evaluated based on the radius axis in relation to the position of the capitate bone [22]. There are two ways to determine carpal alignment. In the first variant, a line is drawn along the longitudinal axis of the radius and the capitate bone. Normal 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 volar cortex of the radius. If this line intersects the center of the capitate bone, normal alignment is also present [20, 22]. An a.p. X-ray is used to evaluate the coronal shift. In this case, an ulnar radius 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 lie ulnar to the intersection in healthy individuals) [21].
Indications for the volar approach
- volarly angulated fractures
- dorsally angulated fractures that can be reduced by ligamentotaxis
Indications for the dorsal approach
- Fractures with intact volar rim
- a central impression ("die-punch fragment“)
- Necessity of visual control of the radiocarpal joint
- concomitant ligament injuries (such as the scapholunate ligament)
- Fractures of the proximal carpal bones.
Results
Even if an acceptable fracture position could be achieved by closed reduction, prospective randomized studies have shown better functional results after volar plate osteosynthesis compared to conservative therapy for both dislocated 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 restoration of anatomy in older patients over 65 years is actually advantageous [25]. Older patients who have undergone operative or conservative therapy apparently have the same long-term results (over 12 months) [26, 27, 28]. However, operative therapy facilitates convalescence and leads to better functional results in the first months [27, 28]. Therefore, it is important to consider the patient's age and health status when indicating 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 was no difference between operative and conservative therapy of distal radius fractures in terms of complication rate [25]. No difference was found between volar and dorsal plate osteosynthesis of AO type C3 fractures in terms of complications and functional results [18]. Therefore, the chosen surgical approach should be aligned with the fracture pattern to achieve anatomical reconstruction.