Treatment of distal radius fractures with locking plates: an update
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Internal fixation with volar locking plates has revolutionized the treatment of distal radius fractures. Manufacturers have introduced plate designs that closely follow the anatomy of the distal radius. However, use of volar plates has also led to the emergence of new types of complications. While the use of monoaxial or polyaxial locking screws and of minimally invasive techniques (arthroscopy, preservation of pronator quadratus) increases the cost of the surgical procedure, it results in a tangible benefit for patients, allowing them to move their wrist almost immediately after surgery and to quickly regain their autonomy. We reviewed the literature to analyze the level of proof.
KeywordsDorsal plate Volar plate Secondary displacement
There has been an exponential growth in the use of volar plates for treating distal radius fractures: from 42% of plate-treated fractures in 1999 to 81% in 2007 . The direct additional cost of using these plates versus pinning the fracture with K-wires is estimated at 2000 Euros per case . In patients above 65 years of age, there is no correlation between the fracture’s anatomical reduction and the functional outcome . However, the risk of a poor outcome increases greatly in that age group. Patients above 65 years of age have a higher relative risk of having a poor outcome due to inadequate reduction or malunion, when compared with perfectly reduced fractures. In the subset of patients who experience secondary displacement after reduction, the outcomes are even worse. Thus, starting from a “certain reduction” or at the point where the displacement does not surpass a “certain value”, better reduction does not lead to better outcomes—as long as the fracture does not shift again! Unfortunately, 50% of reduced and immobilized fracture undergo secondary displacement . Anatomical reduction and fixation do not necessarily lead to better outcomes; instead, they help to avoid poor ones. This is where plate fixation comes into play.
The downsides of pinning and external fixation—even when performed correctly—led to the development of dorsal internal fixation techniques . This internal fixation method seems logical: Since it is generally agreed that anterior displacement can be controlled by volar plate fixation, why not apply this same reasoning to posterior displacements since the posterior cortex of the distal radius is thinner and weaker than the anterior cortex? A dorsal plate can maintain the reduction of the posterior tilt.
There are two broad types of dorsal plates that follow two principles: console-type plates (which oppose or maintain) and column plates (which repair). Console-type plates are like T-plates in which the shape, material and dimensions have been modified to make them more suitable to the posterior aspect of the radius. The primary objective of these plates is to counter any posterior displacement, with some plates having the option of reducing the fracture “on the plate”. Column plates are based on Rikli’s column theory: When fractured, the radial and ulnar columns—the two cortical bone columns of the radius—must be reconstructed with one or more anatomical plates that match each of these columns anatomically . These two theories should be complementary: preventing recurrent displacement and restoring the anatomy are two complementary goals. Three comparative biomechanical studies suggest these results can be extrapolated to patients. The Peine study validated the column theory by showing that using two separate plates to fix the two columns was superior. In their cadaver study, the biomechanical results were better with two column plates than with the Pi plate (which is like a column plate) and the Forte plate . Hahnloser et al. confirmed that double plates were stronger than the Pi plate in a clinical study . The third biomechanical study of console plates compared the T-plate and the “rake-like” Gesensway plate . The latter was shown to be twice as rigid and three times stronger; this was a precursor to locked plates. Anterior cortical contact is crucial; without it the loads on the posterior aspect are very high . However, this biomechanical validation does not mean we should forget the clinical reality of difficult placement, the functional consequences of stiffness and especially the complications.
Most published studies focus on a certain type of dorsal plate or compare different models with each other. The types of fractures studied are not homogeneous, and the study design may lump extra-articular fractures together with comminuted intra-articular fractures. Even if the fracture is not “complex”, bone fragility may make it challenging to apply several plates on the radius. Studies, like the Hahnloser study , reporting little to no complications are rare—typically the complication rate is 30%. The theoretical disadvantage of dorsal plates is their bulkiness in an anatomical area in which nerves or extensor tendons could be damaged . Lister’s tubercle cannot be left intact with “console-type” plates—a technical detail that authors tend to forget. Resection of Lister’s tubercle does not lead to complications in our experience . Tendon-related complications such as tendinitis or tendon rupture mainly affect the extensor pollicis longus (EPL). However, this complication is rare in nearly every published study with dorsal plates. Carter does not report any such case . EPL tendinitis was reported in 25% of patients treated with first-generation Pi plates; this was attributed to the plate’s “aggressive” design. Published dorsal plate studies have a mean follow-up of 40.6 months and involve about 20 patients. The posterior approach allows better reduction of the joint surface according to Letsch et al. . The clinical and functional outcomes were statistically better with dorsal plates than with volar plates. One case of over-reduction was reported with the Forte plate . Several authors recommend removing dorsal plates once the fracture has healed . One appropriate indication of dorsal plate is treating comminuted intra-articular distal radius fractures with fragment specific fixation.
Volar plates: a French revolution
Anterior comminution sometimes (often?) associated with posterior displacement motivated Nonnenmacher to use a volar plate (bowl fixation) since posterior pinning could not “always solve everything” . This technique requires multiple surgical approaches. In our experience, many patients subsequently develop stiffness, although it is difficult to determine whether this is due to the technique or the type of fracture (which is sufficiently displaced or comminuted for the surgeon to consider doing bowl fixation). Volar plate fixation avoids the damaged side of the radius in favor of the intact areas where the cortical bone is stronger. For many years, Orbay has insisted that a “volar plate” is the best solution for “posterior displacement” .
The anterior approach (Henry’s approach) is well known and extensively taught. The pronator quadratus is scraped or detached with an electrocautery tip on the side of the radius; it can be reattached later on. The radial epiphysis is exposed to the joint capsule. In dorsally displaced fractures, the fragments are reduced with the wrist in hyperflexion; a periosteal elevator can be introduced in the fracture site. The brachioradialis can be detached if necessary to make reduction easier and allow the dorsal epiphysis to be evaluated . The plate is first attached to the diaphysis with a screw in an oval hole, which is present on most plates. C-arm fluoroscopy is used to confirm the correct plate size and position on the radius. The plate is then screwed to the epiphysis with wrist hyperflexion maintained by the surgical assistant. Reduction may also be performed on the plate after fixation on the epiphysis. An intraoperative oblique lateral view is taken to detect whether any screws protrude inside the joint. The wrist is X-rayed laterally with the elbow slightly flexed to make the joint space visible.
The main—and maybe sole—advantage of volar plates in dorsally displaced fractures is the ability to reduce the anterior cortex anatomically under direct visual control. This is vital to the stability of distal radius fractures, even with intra-articular fractures . To avoid an iatrogenic event due to volar plate fixation, bicortical screws more than 18 to 20 mm long should not be used in Lister’s tubercle and the diaphyseal screws must not protrude from the cortex (10- or 12-mm screws normally). Screw size has become problematic since the diameter was reduced from 3.5 to 2.4 mm .
Advances in volar plate design
The second generation of plates opened up the possibility of using locking screws. The option of locking the screws to the plate expanded the indications for volar fixation (fixation of dorsally displaced fractures without posterior intrafocal pinning; ignoring posterior comminution). Three screws in the epiphysis and three in the diaphysis were sufficient to make the construct stable. Several studies have confirmed the mechanical benefits of a locked plate system in osteoporotic bone, where even small axial stresses can cause the screw to move in the plate. One of the benefits of locked plate systems is that the construct’s strength is increased by more than four times. The absence of movement between the screw and plate means that stresses can be transmitted to the subchondral bone, especially in cases of weakened or comminuted bone .
In a cadaver model of a circumferential bone defect mimicking comminution, Levin et al. showed that two different locked plates with three distal screws were stronger than a conventional volar T-plate . The increased rigidity and stable alignment between the metaphysis and diaphysis with the locked volar plate allow immediate mobilization. According to Levin, this scenario is difficult to imagine with an unlocked volar plate, a dorsal plate or external fixation .
However, two other studies [18, 19] found no significant difference in rigidity and failure strength between locked and unlocked plates. The screw position is also important. In an extra-articular fracture model, Drobetz et al.  showed that when the 2.4-mm screws were in the subchondral zone (area 4 mm above the joint surface), the strength of the construct was better than with a row of more proximal screws (more than 4 mm) due to fracture site collapse and four times more radial shortening [1.38 vs 0.36 mm]. Although a plate with solid epiphyseal screws rarely loosens, it has not been shown that a screw that holds in a plate is better than a screw that holds in the bone!
This led to the development of third-generation plates which incorporate polyaxial screw technology. This allows the surgeon (not the plate) to decide the screw direction. The polyaxial nature of the screws (± 10° or 20°) challenged manufacturers: the screws must remain buried, and the plate cannot be more than 2 mm thick; otherwise, flexor apparatus complications can develop. The advantage of this polyaxial (variable angle) feature is that it allows the surgeon to drive a screw into the styloid.
The fourth generation of plates was introduced thanks to collaborative work between implant manufacturers and surgeon designers. The redesign of these plates allows them to be placed in the optimal anatomical location on the radius surface, since the lateral (ulnar) column is more distal than the medial (radial) column. Many published studies provide evidence of consistently good functional outcomes for epiphyseal fixation with various types of volar plates. Volar plate-specific complications impact the flexor tendons (plate is too distal) or the extensor tendons (screws are too long). However, the rate of complications with volar plates is lower in published studies than with dorsal plates or pins. The main advantages of volar plates are that secondary displacement is no longer a concern and patients can immediately move their wrist.
Published studies on volar plates, like those on dorsal plates, have looked at one type of plate to treat all dorsally displaced distal radius fractures. In most cases, the sagittal tilt is reduced with anteversion of 6° or less. Volar plates described in published studies are mainly used for internal fixation . This type of plate is indicated in the presence of significant posterior comminution or associated with anterior comminution. With this plate, a graft is not necessary in osteoporotic patients with comminuted fractures or in younger patients following high-energy trauma. In the Huard et al. study , bone substitute or graft was not used to fill the metaphyseal comminution when volar plates were applied, despite circumferential comminuted fractures in 60% of the cases. There was no loss of sagittal tilt. The articular surfaces are reduced indirectly. If a graft is needed, a small dorsal incision is made, which increases morbidity. Carpal tunnel release is performed when symptoms are present . In our practice, we release the carpal tunnel in patients who have symptoms of median nerve compression in the carpal tunnel before the fracture occurred or since the fracture.
Several orthopedic implant manufacturers now offer volar locked plates. The resulting rigid construct means that patients can—in theory—move their wrist immediately after surgery. One of the benefits is that secondary displacement is no longer a concern in pure metaphyseal fractures or metaphyseal–epiphyseal fractures with circumferential comminution. However, this is not yet sufficient to justify the extra cost of self-stabilizing screws, which is 10 times higher than standard screws.
Open reduction with direct plate fixation does not lead to better functional outcomes than external fixation.
Volar plate fixation leads to better short-term functional outcomes than dorsal plate fixation.
For distal radius fractures treated with volar plates, there is no significant difference in the functional outcomes between those in which the tip of the ulnar styloid is fractured and those in which it is not fractured.
The presence of a fracture at the base of the styloid has no effect on the functional outcomes or the long-term outcomes in distal radius fractures treated by plate fixation.
Fractures treated by plate fixation have better short-term outcomes (up to 3 months) in terms of range of motion and functional scores. However, there is no difference in the long-term outcomes (DASH score) between plates and between various types of fixation systems (plates, pinning, external fixator).
Early mobilization (starting at week 2) provides no long-term benefits compared with delayed mobilization (starting at week 6) after plate fixation.
In a randomized study of patients above 70 years of age treated with a plate or by casting, there was no significant difference between groups in terms of range of motion, strength or activity scores (DASH, PRWE), despite 89% of the patients treated by casting having malunion and 77% having a deformity . When a study extends beyond 6 months, there is no difference between these treatment methods, despite the methodological power of these randomized studies. A difference may or may not be found depending on whether the endpoint of the study is before or after 1 year postoperative. Thus, weekly assessments must be performed during the first 6 months post-fracture to detect a true difference. A composite score is needed to show that plates are better.
While no differences have been found between surgical and functional (conservative) treatment after 6 months or 1 year in randomized head-to-head studies, the outcomes are clearly worse in patients who suffer deformities, malunions or secondary fracture displacement.
We performed a retrospective comparison between volar plates and pinning using a composite score: to have a “good outcome,” patients needed to have a good result on every objective and subjective measure. The results were similar for the mean subjective scores, but the composite score showed that the number of patients satisfied overall (good PRWE, DASH and Herzberg scores) was greater for plate fixation than pinning. Dissatisfied patients (one of the above three scores was poor) were the ones who had experienced secondary displacement or malunion . In another study comparing volar plate fixation to pinning, we showed that during the first 6 weeks postoperative, plates allow faster resumption of activities of daily living , which was also reported by Voigt’s group .
Patients treated with plate fixation had better short-term functional scores, up to 12 weeks, but not at the final follow-up visit (1 year). The grip strength was not higher after plate fixation .
Surgical plate fixation of displaced distal radius fractures allows patients to regain their autonomy faster and prevents the poor functional outcomes associated with secondary displacement. Immediate mobilization does not result in better long-term range of motion. In patients above 65 years of age, lack of anatomical reduction does not lead to worse outcomes than does good reduction with plate fixation after 1 year of follow-up. Nevertheless, in this population, internal fixation leads to faster recovery, which is evident in studies focused on this topic. Unfortunately, this population is difficult to follow over time. Fracture registries would be very valuable in developing more personalized treatments.
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Conflict of interest
One of the co-authors has no conflicts of interest directly related to this article, but has conflicts of interest with the following companies: FX solutions, Zimmer Biomet, Medartis, Evolutis, Wright, Lilly, Elsevier, Springer
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