Introduction

Distal radius fractures (DRF) are very common and have two peaks of incidence [1,2,3,4,5,6,7,8,9,10]. First, young patients who typically sustain high-energy trauma and second elderly patients with low-energy trauma, like falls. In the past, DRFs were treated conservatively by casting, K-wire stabilization, or external fixator [11,12,13,14,15,16,17,18,19]. Due to the introduction of palmar angular stable plate systems, a fixation of dorsally displaced DRF became possible from the palmar aspect of the distal radius. Palmar fixation ensures sufficient stability to allow early active wrist mobilization without immobilization/splinting [13, 20,21,22,23,24].

Literature has still found no consensus which fixation technique is the most advantageous. A recent network meta-analysis concluded that plate fixation offers the best results in terms of early functional outcome and lower complication rate. The long-term outcomes, however, show no stabilizing technique to be superior to any other [2, 3, 9, 14, 25,26,27,28].

This article reviews the current evidence with respect to indications for surgery, surgical approaches, and reduction and fixation techniques.

Indications for surgery

The choice of conservative or surgical treatment might be difficult as there are several variables that need to be considered. These include age, gender, occupation, dominant hand, bone quality, co-morbidities, medication, and functional and mental health. In combination with many different fracture types, the decision process for the best treatment for each individual is very complex [29]. The most common form of treatment for DRF is closed reduction and cast immobilization [30,31,32]. Unfortunately, the risk for re-displacement is about 64% in conservative treatment [31, 33]. The majority of treating surgeons consider a dorsal angulation > 15°, radial shortening > 3 mm, or an intra-articular step-off > 2 mm as an indication for surgery [34].

Surgical treatment should be recommended to patients with a high-risk for re-displacement. However, identification of these patients, who are prone to loss of reduction under conservative treatment, is challenging [29]. In 1989, Lafontaine et al. [35] determined five predictors for instability: dorsal angulation > 20° at presentation, dorsal comminution, intra-articular fractures, associated ulnar fracture, and age over 60 years. If three of these five predictors exist, the fracture is considered to be potentially unstable and, therefore, surgical treatment is advisable. Since then, several studies have confirmed these five predictors as risk factors for a loss of reduction under conservative treatment [36]. Recently, Walenkamp et al. [37] pooled the published data in a systematic review and meta-analysis. They observed that only dorsal comminution, females, and patients over 60 years have an increased risk for secondary re-displacement. There is uniform consensus that palmarly displaced (Smiths fracture) or palmar/dorsal shear fractures (Barton’s, reverse Barton’s fractures) are unstable and require surgery [38].

To complicate matters further, strong evidence exists that patients over 60 years of age might not even benefit from operative treatment [39]. Arora et al. [30] and Ergo et al. [40] compared conservative treatment with palmar locking plate fixation in patients over 65 years of age, and found no significant differences in range of motion (ROM), pain, or patient-reported outcome measurements 12 months after surgery. Although the surgically treated group showed a significantly better radiological result than the conservatively treated group. Chen et al. [41] performed a systematic review and meta-analysis and demonstrated similar findings, but no significant differences in functional outcome or higher risk for complications. Apart from age, another recent meta-analysis has shown that surgical treatment does provide a better radiological outcome, but no significant differences in functional outcome or complication rates between the operative and conservative treatment methods were demonstrated [42].

Ultimately, no unanimous solution exists, for treating DRF. The primary concern of the patients’ needs and demands of everyday living will determine the choice of treatment. Restoring the distal radius to an acceptable radiological alignment (dorsal tilt ≤ 10°, radial shortening < 2 mm, and intra-articular step-off < 2 mm) is both mandatory and critical in young and active patients [29].

Preoperative planning

Preoperative planning for surgery of the DRF includes an exact anamnesis and clinical examination of the patient. Evaluation of ROM, circulation, and neurology is essential. Every patient with a DRF must also be evaluated for CTS. An acute CTS has to be treated intraoperatively by immediate carpal tunnel release. As CTS is very common in elderly patients, and particularly elderly female patients have a higher DRF rate, a latent, pre-existing CTS has to be excluded [43]. In these cases, the latent CTS should also be released whilst treating the DRF. Although there is no general recommendation in the literature, the high postoperative complication rate of CTS [44] supports this approach.

Standard wrist radiographs for diagnosing a DRF include images in both planes (anterior–posterior and lateral view) [45, 46]. The standard radiographs of DRF in all intra-articular and displaced fractures should be augmented by a CT-scan to evaluate the complexity, comminution, dislocation, and involvement of the joint [47]. Cole et al. [48] confirmed the improved diagnostics of articular congruity compared to plain radiographs. Identification of an articular involvement or step-off is critical, as post-traumatic osteoarthritis occurs in 91% of cases with any degree of incongruity and 100% where the articular step-off is over 2 mm [49]. In addition, a 3D reconstruction of the wrist can be helpful for further surgical planning and confirming a decision [50, 51]. In most cases, the indication for surgical treatment of a DRF should be based on the CT-scan. The axial CT images allow the identification of key fragments and the appropriate surgical approach can be planned.

The significance of the axial CT-scan and the different types of “key fragments” is discussed by Hintringer et al. in the article “Biomechanical Considerations on a CT based treatment-oriented classification in radius fractures” [52].

Surgical approaches

Surgical approach for palmar plating

The most common approaches to the distal radius are the Henry approach and modified Henry approach, also known as trans-FCR approach. The difference between them is that the latter is through the FCR tendon sheath, whereas the classic one is between the FCR tendon and the radial artery, without opening the FCR tendon sheath [53].

An approximately 7 cm longitudinal skin incision is made, beginning at the wrist crease and extends over the tendon of the flexor carpi radialis muscle. If necessary, the incision can be extended distally towards the scaphoid’s tubercle (Fig. 1). After coagulation of small subcutaneous vessels, sharp preparation up to the FCR tendon takes place. Then, the forearm fascia is released. The FCR tendon sheath should only be opened distally, when there is a need to access to ulnar part of the distal radius, like in ulnar palmar rime factures and incised on the radial side to prevent damage to the nearby cutaneous branch of the median nerve.

Fig. 1
figure 1

Palmar approach to the distal radius. An approximately 7 cm longitudinal skin incision is made over the tendon of the flexor carpi radialis muscle. If necessary, the incision can be extended distally or proximally

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The flexor muscles are bluntly divided and held to the ulnar side using blunt hooks, thus protecting the median nerve. The pronator quadratus muscle is visualized, incised lengthwise on the radial side, and pushed away from the radius with a blunt rasp. Thus, direct access and reduction of the fracture are possible (Fig. 2) [54,55,56,57,58].

Fig. 2
figure 2

Deep palmar preparation to the distal radius. After releasing the forearm fascia, the flexor muscles are bluntly divided and held to the ulnar side. The pronator quadratus muscle is visualized, incised lengthwise on the radial side, and pushed away from the radius

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To position the plate on the fracture site, the pronator quadratus muscle needs to be detached and released, from its distal–radial aspect [59]. The conventional approach involves a routine repair of the muscle, but it still remains debatable in the literature. Some surgeons postulate that a repair restores pronation strength and protects the flexor tendons by covering the hardware [5, 60, 61]. However, in a systematic review by Mulders et al. [61], no significant benefit in the functional outcome for repairing the pronator quadratus muscle was found. Even in minimal invasive plate osteosynthesis (with preservation of the pronator quadratus muscle), no significant differences in wrist function was observed when compared to the conventional palmar plating.

Surgical approach for dorsal plating

Dorsal approach

If a dorsal plate position is necessary, a longitudinal skin incision is made ulnar and proximal to the Lister's tubercle (Fig. 3). After coagulation of smaller subcutaneous vessels, dissection down to the extensor retinaculum takes place and full skin flaps with subcutaneous tissue are raised to prevent injury of the dorsal branches of the ulnar nerve as well as the superficial branch of the radial nerve [55, 62, 63]. The forearm fascia and the third extensor tendon compartment are opened to radially retract the extensor pollicis longus tendon. The fourth extensor tendon compartment is mobilized subperiosteally in an ulnar direction [9]. If necessary, it can also be opened like a door wing (Figs. 4, 5). The posterior interosseous nerve lies under the fourth extensor tendon, which can be neurectomized proximally if a dorsal wrist capsule denervation should be necessary [55, 63].

Fig. 3
figure 3

Dorsal approach to the distal radius. The dorsal aspect of the distal radius is accessed by 7 cm longitudinal skin incision ulnar to the tuberculum lister

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Fig. 4
figure 4

Opening of the extensor tendon sheets. The fourth extensor tendon sheet is opened like a door wing

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Fig. 5
figure 5

Dorsal approach axial view. Temporary shift of the extensor pollicis longus tendon to the radial side. If necessary, the extensor carpi radialis tendons can be mobilized subperiosteal radially

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Dorsal–ulnar approach

For the dorsal–ulnar approach the radioulnar joint is palpated and a longitudinal incision is made accordingly. The fifth extensor tendon compartment is then opened, and the underlying radioulnar joint can be accessed [55, 63].

Approach to distal radioulnar joint and treatment of instability is discussed in the article by Spies et al. “Distal radioulnar joint instability – current concepts of treatment” [64].

Palmar or dorsal fixation of distal radius fractures?

A recent network meta-analysis concluded that plate fixation offers the best results in terms of early functional outcome and minimizing fracture healing complications [25, 26]. As yet, none of the fixation methods have shown their superiority and which approach is preferable is still open to debate [62].

Not only the direction of the fragment displacement will influence the decision for palmar or dorsal fixation, but also the surgeon’s experience/preference [65]. An advantage of dorsal plating is the direct visibility of the fragments and articular surface. In addition, the plate can act as a buttress against dorsal collapse [66, 67]. Since the introduction of palmar locking plate systems, not only palmar displaced fractures can be fixed successfully. However, the locking screws also prevent dorsal collapse of the fracture. Due to the span between the palmar cortex and flexor tendons, palmar plate fixation reduces the risk of tendon irritation.[65].

Wei et al. [68] compared complications of dorsally and palmarly stabilized DRF in a meta-analysis. No significant differences in the overall complication rate could be determined, but a dorsal fixation showed higher rates of tendon irritation and a palmar one, a higher risk for carpal tunnel syndrome, and neuropathy. As earlier meta-analyses included not only studies using low-profile plates, the more recent research found no significant differences in functional outcome and complication rate between palmar and dorsally stabilized DRF [65, 69, 70].

The fracture type and surgeon's experience should determine the optimal approach, fixation technique, and plate type. In our opinion, indications for dorsal plating are limited to dorsal shear fractures or severe dorsally comminuted fractures, where palmar plating does not ensure adequate stability.

Reduction techniques for distal radius fractures

When treating a DRF, a basic distinction must be made between dorsal or palmar dislocation, central impression, comminution zone, or combination of them all.

Strongly dissociated fractures are generally treated with the extension technique. In a supine position, the arm is placed on the hand table and traction of 2–3 kg is attached to the thumb, index, and ring finger using Chinese finger traps (Fig. 6). Thereby, the same principle as the conservative reduction of DRF is applied, except along the horizontal axis. After the extension is attached, and traction in direction of dislocation applied, reduction of the fracture fragments in their anatomical position can be performed.

Fig. 6
figure 6

Horizontal traction using Chinese finger traps. Presents the patient lying in a supine position with the affected arm positioned on the operating hand table. Sterilized Chinese finger traps are used to generate horizontal traction of 2–3 kg. Thereby, reduction of the fracture is facilitated

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Arthroscopic fracture reduction and treatment of concomitant injuries of DRF is discussed in detail by Kastenberger et al. [71]

Dorsal dislocation

Large dorsally dislocated fragments can be reduced by closed reduction under traction. If the reduction is unstable, intramedullary k-wires, 1.4–1.6 mm in diameter, are inserted from the dorsal and radial aspect into the fracture site according to the technique of Kapandji (Fig. 7) [72]. A small incision is made to insert the blunt end of the K-wire into the bone; thereby, avoiding possible injury to the extensor tendons or sensory nerve branches. Intramedullary K-wires can also be inserted from the radial side to reduce radial dislocation of the distal fragment and maintain reduction. Another useful trick is to use the K-wires as dorsal joysticks to manipulate the fracture element and stabilize the reduction. To lower the tension on the radial styloid and facilitate anatomical reduction, the tendon of the M. brachioradialis can be released distally [73].

Fig. 7
figure 7

Kapandji reduction technique. Seventy-nine-year-old female patient with a dorsally displaced distal radius fracture (a). Closed reduction was achieved using intramedullary K-wires from the dorsal and radial aspect according to Kapandji (b)

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Palmar dislocation

A palmar dislocation can be manually reduced under longitudinal traction and applying palmar pressure with the surgeon’s thumb. Conservative reduction uses a similar technique. But as a rule, surgery is necessary to stabilize a palmar dislocation. To visualize and directly reduce the fracture, a palmar approach has to be used (Fig. 8). In these cases, a secondary dislocation is very unlikely due to the immediate support of the palmar plate. However, it is important to identify smaller palmar edge fragments, which can usually be reduced directly, but require a very far distal plate positioning or special plates for permanent stabilization. The hook, lunate facet, or rim plates are options to stabilize these specific fracture types. In very distal fractures, which require plate positioning distally to the watershed line, irritation or rupture of the FPL tendon can occur in the long-term due to pressure of the plate on the tendon. Therefore, in these cases, an early plate removal should be planed. To protect the FPL tendon and prevent these complications, special plates were designed [8, 13, 74].

Fig. 8
figure 8

Palmar dislocation. Fifty-one-year-old male patient with a palmar dislocated distal radius fracture (a). Tension using Chinese finger traps was applied to the thumb, index, and ring finger. Thereafter, the fracture was directly reduced using the palmar approach and a plate was applied (b). One year after surgery, the X-ray shows an anatomically aligned healed fracture of the articular surface (c)

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Central depression

A central depression zone cannot be reduced by a closed approach. Using a palmar approach, the radius is dissected. Depressions of the articular surface can then be lifted with an intramedullary k-wire (Fig. 9) before or after the plate is applied. If there is a pronounced dorsal comminution zone, the impression can also be elevated using a combined approach (Fig. 10) and then stabilized by palmar plating. Temporary fixation with K-wires distal to the plate directly on the palmar rim provides temporary stability.

Fig. 9
figure 9

Small depression of the articular surface, reduction over the plate. A distal radius fracture in a 71-year-old female patient with a central depression zone (a). The plate was applied with the palmar approach, and reduction was achieved using an intramedullary K-wire through a plate hole. The reduction was temporarily stabilized with multiple K-wires, and finally, the screws were inserted (b). c Radiological outcome 6 months after surgery

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Fig. 10
figure 10

Severe central depression of the articular surface. A distal radius fracture in a 53-year-old male patient with a severe central depression and dorsal comminution zone (a). Using a dorsal approach, the depression was elevated with an osteotome. Prior to screw insertion, the reduction was temporarily stabilized with multiple K-wires (b). c Outcome on X-ray and CT 6 months after surgery

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Comminuted fracture

When treating a comminuted fracture, a combination of the above-mentioned procedures is usually necessary. First, the extension is attached to the hand as previously described. The larger dorsally dislocated elements can then be stabilized temporarily by medullary k-wires according to Kapandji. The fracture elements are presented via a palmar approach, reduction can then be maintained directly or by the plate. If palmar stabilization is not sufficient, an additional dorsal plate is recommended.

Tips and tricks for DRF reduction

After using these tricks for indirect reduction, there are also different helpful tricks to assist direct reduction of the fracture.

K-wires as joysticks distal to the plate (Fig. 11)

Fig. 11
figure 11

Temporary K-wire reduction and fixation. After reducing the fracture using both dorsal and radial K-wires according to Kapandji (a), the plate is stabilized on the radius through the gliding hole in a palmar approach. The articular surface is supported with K-wires distal to the plate (b). These are used as joysticks for direct manipulation, to realign the anatomic shape of the articular surface

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The plate is positioned palmary under image intensification and fixed onto the distal radius using the gliding hole. In case of a persistent step-off of the articular surface, k-wires can be inserted into specific fracture fragments distal to the plate. Using this method, fracture elements can be manipulated and positioned directly using the k-wires. Thus, malrotation of these parts, which could occur during drilling or screw insertion, can be avoided. Care has to be taken for precise subchondral positioning of the K-wires. After reduction of the fragments, the angular stable screws are inserted and the K-wires removed.

K-wire reduction through the distal holes of the plate (Fig. 12)


Fig. 12
figure 12

Fracture reduction using the distal holes of the plate. Twenty-three-year-old male patient with a palmar dislocated distal radius fracture (a). Reduction was achieved by a palmar approach and fracture compression through the plate (c). Multiple K-wires provided temporary stabilization prior to screw placement, which were then removed at the end of surgery (b)

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Smaller as well as larger fracture fragments can be reduced and stabilized with temporary K-wire fixation, through the distal plate holes. This method prevents malrotation during drilling or screw insertion.

Additional screw fixation with headless compression screws (HCS) (Fig. 13)


Fig. 13
figure 13

Additional stabilization using a headless compression screw. Thirty eight-year-old female patient with a fracture of the left radius (a). Two headless compression screws joined the distal fragment to a larger unit, and the final stabilization was achieved with a long palmar plate. c Radiological outcome after 6 months

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The smaller fracture elements that cannot be grasped by the available screws of the plate need separate stabilization with HCS that can be inserted before or after applying the plate. This method can fix smaller fragments to larger units, which in turn are stabilized with the plate. If additional screws are used, the guide wires can be used as joysticks for temporary fixation, after which the screw can be threaded over these K-wires.

Fixation of the styloid with headless compression screws (Fig. 14)

Fig. 14
figure 14

Fixation of the radial styloid using a headless compression screw. Forty-eight-year-old male patient with a fracture of the radial styloid and a palmar rim fragment (a). The intra-articular step-off was elevated with a K-wire from palmar, the radial styloid was then fixed with a headless compression screw using a radial mini-open approach, and finally, a palmar plate was placed to stabilize the rim fragment (b). c Radiological result 6 months postoperatively

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Especially radial styloid fragments can be stabilized using HCS, which are inserted through the radial styloid in a proximal–ulnar direction. To prevent a lesion of the superficial branch of the radial nerve or the tendons in the first extensor tendon compartment, a mini-open approach is used. If the distal radioulnar joint is unstable, the ulnar styloid should be fixed. Therefore, an intraoperative instability check has to be carried out after stabilization of the distal radius [75,76,77]. Details about the approach and treatment of distal radioulnar joint instability are described by Spies et al. “Distal radioulnar joint instability – current concepts of treatment” [64].

Temporary transfixation of the distal radius to the lunate (Fig. 15)

Fig. 15
figure 15

Temporary transfixation of the radius to the lunate. Thirty-year-old male patient with a high-energy distal radius fracture including dorsal subluxation of the carpus and multiple small rim fragments (a). Traction was applied using Chinese finger traps. Thereafter, a palmar approach was used to stabilize the small palmar rim fragments with a small hook plate. A second low-profile plate was applied via a dorsal approach. The dorsal subluxation of the carpus was prevented by a temporary radio-lunate transfixation using a K-wire (b). The K-wire was removed 5 weeks after surgery (c). d Radiological result 6 months after the first operation

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In very distal palmar rim fractures, where even special plates are unable to incorporate the small fragments, or if a high risk for palmar subluxation of the carpus exists, a temporary K-wire transfixation can be used. The K-wire is drilled from the distal radius into the lunate in a dorsal-to-palmar direction. The K-wire is clipped just under the skin and left in situ for 5 weeks [43]. Therefore, secondary fragment dislocation palmary and subluxation of the carpus can be prevented.

Conclusion

Indications of DRFs are dependent on many factors that influence the choice of surgical treatment. These include co-morbidities, medication, and functional and mental health. Especially in elderly patients, with low demands and osteoporosis, an operation must be carefully considered.

If surgery is necessary, then the majority of DRF can be stabilized by a palmar approach. Our center prefers the Henry approach and the sheath of the FCR tendon should only be opened if access to the ulnar part of the radius is necessary. In the surgical standard setting, the aforementioned traction with Chinese finger traps has become an established method. Ideally, manual correction of the dislocation should be performed before the skin incision. A DRF can be reduced directly or indirectly, particularly with the aid of k-wires. Persistent instabilities may require either temporary transfixation of the carpus or a small hook plate to reinsert bony avulsed ligaments.