The Effect of Displaced Dorsal Rim Fragment in a Distal Radius Fracture

Size and fixation options of dorsoulnar fragments in distal radius fractures

PURPOSE

This study aimed to investigate the influence of size and fixation options of dorsoulnar fragments on the clinical outcomes of distal radius fractures (DRFs).

METHODS

This retrospective analysis was performed on 94 patients with DFR accompanied by dorsoulnar fragments, spanning the period from October 2018 to November 2022. Mean follow-up was 15.5 (range, 12-20) months. Patients were divided into small- (<5 %, n = 28), middle- (5-15 %, n = 50), and large- (>15 %, n = 16) sized groups according to articular involvement of dorsoulnar fragments determined by three-dimensional (3D) computed tomography (CT) modeling. Subdivision also took place for the presence of postoperative fragment displacement (>2 mm) and fixation methods including volar locking plate (VLP), VLP combined with dorsal hollow compression screw (VDS), and VLP combined with dorsal low-profile mini plate (VDP). The radiographic parameters (volar tilt, radial inclination, and radial height) and functional outcome measures of wrist range of motion, wrist function (DASH, PRWE), and wrist pain (VAS) were evaluated and compared between groups.

RESULTS

Fracture healing was observed in all patients at final follow-up. No instances of dorsoulnar fragment displacement were observed in patients undergoing VDS and VDP treatment and the incidence of the dorsoulnar fragment displacement was 35 % (n = 8) in small-sized group, 21 % (n = 7) in middle-sized group, and 7 % (n = 1) in large-sized group when patients were treated with VLP. In small-sized group, no significant differences were found between patients with and without dorsoulnar fragment displacement in dorsiflexion restriction (10.6 ± 2.8°, 9.1 ± 2.3°, P = 0.159), pronosupination restriction (9.6 ± 2.1°, 8.6 ± 1.7°, P = 0.188), DASH (11.5 ± 4.1, 10.7 ± 3.2, P = 0.562), PRWE (11.9 ± 4.2, 10.6 ± 3.6, P = 0.425), and VAS (1.1 ± 1.1, 0.9 ± 1.0, P = 0.528). In middle-sized combined with large-sized group, the functional outcome measures of dorsiflexion restriction (12.5 ± 3.7°, 9.8 ± 2.9°, P = 0.022), DASH (14.6 ± 5.2, 11.4 ± 3.7, P = 0.030), and PRWE (15.0 ± 4.5, 11.3 ± 3.9, P = 0.016) were superior in patients without dorsoulnar fragment displacement. In patients treated with VLPs, no significant differences were found in dorsiflexion restriction (9.8 ± 2.5°, 10.8 ± 3.5°, 9.4 ± 2.5°, P = 0.299), pronosupination restriction (9.2 ± 1.9°, 10.1 ± 2.8°, 8.9 ± 1.5°, P = 0.200), DASH (11.1 ± 3.5, 12.9 ± 4.3, 11.1 ± 3.6, P = 0.162), PRWE (11.1 ± 3.9, 12.8 ± 4.2, 10.8 ± 3.9, P = 0.188), and VAS (1.0 ± 1.0, 1.4 ± 1.1, 0.9 ± 0.9, P = 0.151) between small-sized, middle-sized, and large-sized groups. In middle-sized group, no significant differences were found in dorsiflexion restriction (10.8 ± 3.5°, 9.4 ± 2.2°, 9.4 ± 2.4°, P = 0.316); pronosupination restriction (10.1 ± 2.8°, 8.8 ± 1.9°, 9.0 ± 2.5°, P = 0.314), DASH (12.9 ± 4.3, 10.3 ± 3.7, 10.5 ± 3.7, P = 0.133), PRWE (12.8 ± 4.2, 10.4 ± 3.8, 10.6 ± 4.1, P = 0.199), and VAS (1.4 ± 1.1, 0.8 ± 0.7, 1.0 ± 1.1, P = 0.201) between subgroups of VLP, VDS, and VDP. No significant differences were found in radiographic parameters between all groups compared.

CONCLUSION

This study indicated that the strict reduction and fixation of a dorsoulnar fragment might be not essential when its articular involvement was less than 5 %. The volar locking plate (VLP) fixation was commonly effective in treating distal radius fractures accompanied by a dorsoulnar fragment involving over 15 % of the articular surface. Additionally, the use of an additional dorsal hollow compression screw or a dorsal low-profile mini plate can get good wrist function in the early-term follow-up when the dorsoulnar fragment involve 5-15 % of the articular surface.

Complications of operatively treated distal radial fractures

Distal radial fractures represent the most common fractures of the upper extremity. Operative treatment is performed for approximately one-third of distal radial fractures in the adult population. Complications following operative treatment of distal radial fractures vary depending on the treatment modality and can be stratified into preoperative and postoperative complications. Complications can occur in the near, intermediate and long term. The most common complications seen are tendon irritation and rupture, chronic regional pain syndrome (CRPS), carpal tunnel syndrome, ulnar or radial neuropathy, compartment syndrome, malunion, inadequate fixation or loss of fixation, symptomatic hardware, post-traumatic arthritis, stiffness and infection. Careful planning, treatment and patient selection can help to mitigate these complications.Level of evidence: V.

Volar versus combined dorsal and volar plate fixation of complex intraarticular distal radius fractures with small dorsoulnar fragment - a biomechanical study

Complex intraarticular distal radius fractures (DRFs), commonly managed with volar locking plates, are challenging. Combined volar and dorsal plating is frequently applied for treatment, however, biomechanical investigations are scant. The aim of this biomechanical study was to investigate volar plating versus double plating in DRFs with different degrees of lunate facet comminution.Thirty artificial radii with simulated AO/OTA 23-C2.1 and C3.1 DRFs, including dorsal defect and lunate facet comminution, were assigned to 3 groups: Group 1 with two equally-sized lunate facet fragments; Group 2 with small dorsal and large volar fragment; Group 3 with three equally-sized fragments. The specimens underwent volar and double locked plating and non-destructive ramped loading in 0° neutral position, 40° flexion and 40° extension.In each tested position, stiffness: (1) did not significantly differ among groups with same fixation method (p ≥ 0.15); (2) increased significantly after supplemental dorsal plating in Group 2 and Group 3 (p ≤ 0.02).Interfragmentary displacements between styloid process and lunate facet in neutral position were below 0.5 mm, being not significantly different among groups and plating techniques (p ≥ 0.63).Following volar plating, angular displacement of the lunate facet to radius shaft was significantly lower in Group 1 versus both Group 2 and Group 3 (p < 0.01). It decreased significantly after supplemental dorsal plating in Group 2 and Group 3 (p < 0.01), but not in Group 1 (p ≥ 0.13), and did not differ significantly among the three groups after double plating (p ≥ 0.74).Comminution of the lunate facet within its dorsal third significantly affected the biomechanical outcomes related to complex intraarticular DRFs treated with volar and double locked plates.Double plating demonstrates superior stability versus volar plating only for lunate facet comminution within its dorsal third. In contrast, volar plating could achieve stability comparable with double plating when the dorsal third of the lunate facet is not separated by the fracture pattern. Both fixation methods indicated achievable absolute stability between the articular fragments.

Size and stabilization of the dorsoulnar fragment in AO C3-type distal radius fractures

INTRODUCTION

Volar locking plate (VLP) fixation has become the gold-standard treatment for distal radius fractures (DRFs). Especially, internal fixation of the volar lunate facet fragment is essential for the treatment of AO C3-type DRFs. On the other hand, the necessity of the fixation of the dorsal lunate facet fragment (dorsoulnar fragment) remains unclear. The purpose of the present study was to measure three-dimensionally the size of the dorsoulnar fragments in AO C3-type DRFs using computed tomography (CT) images in detail, and to reveal relationships of the size and stabilization of the dorsoulnar fragment with postoperative fracture displacement after VLP fixation.

MATERIALS AND METHODS

We retrospectively reviewed the 101 consecutive Japanese patients who underwent surgical treatment for AO C3-type distal radius fractures. If patient had dorsoulnar fragment, the three-dimensional size of this fragment and the occupying ratio to the radiocarpal joint (RCJ) and the distal radioulnar joint (DRUJ) were anatomically evaluated using the preoperative CT images. In addition, we investigated the relationship of the size and stabilization of the dorsoulnar fragment with fracture displacement after VLP fixation. We statistically compared the size parameters and occupying ratio of the dorsoulnar fragment between the displaced group and the stable groups using a two-tailed t-test. We also statistically compared the numbers of screws inserted into the dorsoulnar fragments between the displaced and stable groups using a chi-square test.

RESULTS

The mean dorsoulnar fragment size was 9.4 mm × 7.9 mm × 11.0 mm and the occupying ratio to the DRUJ and RCJ was 50% and 10%, respectively. The number of patients treated with volar locking plate fixation was 77, of which 12 patients had postoperative displacements. Although the size of the dorsoulnar fragment was not associated with postoperative displacement, stabilization following screw insertion into the dorsoulnar fragment was significantly associated with displacement.

CONCLUSION

Stabilization of the dorsoulnar fragment with at least one screw of the volar locking plate was necessary to prevent postoperative fracture displacement regardless of dorsoulnar fragment size in AO C3-type distal radius fractures.

Dorsal Lunate Facet Fracture Reduction Using a Bone Reduction Forceps

Background  The dorsal lunate facet fragment represents part of a complex articular injury of the distal radius and is challenging to reduce through a standard volar approach. We propose reduction through a standard volar approach and intraoperative dorsal lunate facet reduction using a bone forceps. To evaluate the postoperative reduction, we used computed tomography (CT) scan. Methods  We retrospectively included 60 patients with a median follow-up of 44 weeks. Fracture reduction was evaluated using pre- and direct postoperative CT scans of the wrist, measuring the articular gap and step of the sigmoid notch. The range of motion was evaluated clinically by the treating physician. Bivariate analysis was performed to compare pre- and postoperative radiographic measurements and to compare wrist range of motion. Results  When comparing the injured with the uninjured wrist, there was a significant difference in flexion, extension, pronation, and supination. In 87% of the patients, there was complete radiographic reduction of the fracture. Conclusion  This study shows that dorsal ulnar lunate facet fracture fragments in distal radius fractures can be reduced through a standard volar approach with the help of an intraoperative bone reduction forceps. Using wrist CT, we showed that 87% of the patients with a dorsal ulnar lunate facet fragment had a postoperative articular step or gap of <1 mm. Level of Evidence : This is a level IV, therapeutic study.

Fragment-Specific Fixation in Distal Radius Fractures

PURPOSE OF REVIEW

Fragment-specific fixation can be a useful tool in treating distal radius fractures. In order to best utilize these techniques, surgeons require an understanding of the normal anatomy, fracture patterns, approaches, and fixation strategies.

RECENT FINDINGS

Fragment-specific fixation may be appropriate for certain fracture patterns particularly when monoblock plating techniques are not sufficient. Radial styloid, volar rim, dorsal wall, dorsal-ulnar corner, and impacted intraarticular fragments may be secured with implants designed specifically for each individual fragment. Although more technically demanding, advantages include accurate articular reconstruction, minimal hardware irritation, and reliable functional outcomes.

Comparison of Locking and Frag-Loc Screws for Fixation of Die-Punch Fragments

Background  The Frag-Loc (FL) compression screw system was designed to stabilize dorsally displaced intra-articular dorsoulnar (die-punch) fragments in distal radius fractures. Purpose  Comparison of the biomechanical properties of fixation of the die-punch fragment (stiffness, ultimate strength, and displacement ratio of the fragment), using the FL and traditional locking screw (LS), and using simulated distal radial fractures in cadaveric specimens under axial compressive loading. Both screws were used with a volar locking plate (VLP). Materials and Methods  Eight matched pairs of formalin-fixed cadaveric specimens of the radius were used to simulate distal radius fractures with die-punch fragments. The die-punch fragment was fixed using VLP with either FL group or LS group. Biomechanical properties for the two fixation systems were evaluated under axial compression loading, applied at a constant rate of 0.5 mm/min until failure. Load data were recorded and the ultimate strength and change in the gap between the die-punch and proximal fragments measured, with the displacement ratio calculated by dividing the value of the gap before loading by the gap after loading. Failure was defined as 10 mm or more of fragment displacement, or screw failure. Results  There were no differences in ultimate strength ( p  = 0.47) or stiffness ( p  = 0.061) between the two fragment fixation systems. However, the displacement ratio was lower for the FL than for the LS system ( p  = 0.049). Conclusion  Compared with LS, the FL system lowers the displacement of die-punch fragments under compressive loading. Clinical Relevance  The FL system is effective for the treatment of distal radius fractures with die-punch fragments.