In this study, we analyzed the efficacy of volar locking plating in the distal radius fractures with DMC. Compared with the extra-articular fracture group, no significant fracture re-displacement or reduced wrist ROMs was observed in the intra-articular distal radius fractures with a simple articular component (C2 fractures). However, a significant decrease of the volar tilt as well as the extension/flexion ROMs were observed in the intra-articular fractures with multi-fragmentary articular component (C3 fracture) during follow-up.
Previously, biomechanical studies using extra-articular fracture models have confirmed that the volar locking plating could provide an equivalent or slightly less stability compared with dorsal plating in distal radius fractures with DMC[7–9]. In clinical studies, Guillou reported 22 patients with a dorsally comminuted extra-articular distal radius fracture fixed with volar locking plate. Most (95.4%) of the patients maintained the stability without secondary displacement at 6 months postoperatively. We observed similar radiological results in our study, wherein no significant radiographic change in volar tilt, radial inclination, radial height, or ulnar variance was found in the A3 fracture group during the 12 months’ follow-up. Our findings provided extra clinical evidence for the application of volar locking fixation in the extra-articular distal radius fractures with DMC.
Considering the intra-articular fractures with DMC, no straightforward biomechanical studies could be found in literature. In clinical studies, Khamaisy compared the outcome of volar locking plating in the dorsally comminuted (DC) and the dorsally intact (DI) distal radius fractures. The vast majority of the cases included in Khamaisy’s study were AO/OTA type C fractures, and a satisfied fracture reduction was preserved in the DC fractures compared to the DI ones with no significant difference observed in radial inclination, volar tilt, and radial length. These results implied that volar locking plating could provide sufficient stability for the intra-articular fractures despite of the occurrence of DMC. However, the authors didn’t compare the outcome among different sub-types of intra-articular fractures due to limited sample size. In our study, volar locking plating was testified to preserve fracture reduction in the C2 fractures, but not in the C3 fractures.
Our results were in contrast to Chou’s study, wherein 41 patients with AO/OTA C3 dorsally comminuted distal radial fractures were treated using either dorsal (n = 22) or volar (n = 19) locking plate . In both groups, no significant re-displacement was observed in terms of radial inclination, volar tilt, and ulnar variance. Compared with Chou’s study, a larger number of cases were included in our study, and the significant loss of volar tilt in the C3 fractures in our study was possibly caused by a compromised subchondral support of the thin and displaced dorsal fragment provided by the distal row of screws with inadequate length (Fig. 3 )[22–24]. The subsequent loss of fracture reduction was also observed by Gogna’s study, wherein 33 dorsally comminuted distal radius fractures were fixed with volar locking plate and followed for over a year[15, 20, 25]. Totally three cases of C3 fractures (18.7%) were reported to present a dorsal subluxation of the carpus or a loss of dorsal tilt after one-year follow-up. These results were comparable with our study, and called for attention to the usage of volar locking plate in the C3 fractures with DMC, especially for the fractures with the occurrence of radiocarpal fracture dislocation or dorsal rim fractures.
To prevent the loss of reduction in C3 fractures, different solutions were reported in literature. An appropriate length of the distal row of locking screws was proven crucial for the single volar plating construct. However, the risk of extensor tendon irritation would increase with longer distal radius screws. Multi-row of volar locking screws was considered more stable than the single row screw construct. However, little evidence was provided to support the use of two rows of distal screws over one row in the fixation of distal radius fractures. Besides, the combined usage of volar and dorsal plating was recommended to provide extra buttress for the dorsal fragment[9, 28, 29].
With regard to the recovery of wrist function, Chou reported a progressive improvement of wrist range of motion following volar plating of C3 dorsally comminuted distal radius fractures. After one-year follow-up, the patients showed an 89% recovery of flexion-extension and a 97% recovery of supination-pronation compared with that of the contralateral healthy wrists. Compared with Chou’s study, the patients with C3 fractures achieved comparable recovery of supination-pronation range of motion in our study. The relatively lower percentage of flexion-extension recovery in our study was possibly associated with the loss of volar tilt in radiological findings. Even so, the majority (87.9%) of the patients with C3 fractures achieved an excellent or good Gartland and Werley wrist score. Four patients (3.1%) with a significant loss of volar tilt resulted in decreased flexion-extension range of motion and a fair functional outcome (Fig. 4). This was consistent with Gupta and Perugia’s findings that volar tilt was one of the most important radiographic parameters affecting the functional outcome of distal radius fractures [30, 31].
There are several limitations to our study. First, the study was based on retrospective data, which could harbor confounding sources of bias. Second, the length of the follow-up in our study was reported to be sufficient for the conclusion of radiological and functional outcome, but relatively short for the record of long-term complications.
In conclusion, the volar locking plate fixation provided sufficient stability for distal radius fractures with DMC, and resulted in similar radiological and functional outcomes in all of the C2 fractures as those in the extra-articular fractures. Considering the C3 fractures, despite of the subsequent loss of volar tilt, the majority of the patients achieved good to excellent wrist function following volar locking plating. Attention should be paid to the subchondral support of the thin and displaced dorsal fragment using locking screws with appropriate length.