Volar Fixed-Angle Plating of Distal Radius Extension Fractures: Influence of Plate Position on Secondary Loss of Reduction—A Biomechanic Study in a Cadaveric Model

doi:10.1016/j.jhsa.2006.01.011

The Journal of Hand Surgery

Volume 31, Issue 4, April 2006, Pages 615.e1-615.e9

https://doi.org/10.1016/j.jhsa.2006.01.011 Get rights and content

Purpose

Treatment of extension fractures of the distal radius with volar fixed-angle plates has become increasingly popular in the past 2 years. It has been observed clinically that placement of the distal screws as close as possible to the subchondral zone is crucial to maintain radial length after surgery. The purposes of this study were (1) to evaluate radial shortening after plating with regard to plate position and (2) to evaluate whether plate position has an influence on the strength and rigidity of the plate–screw construct.

Methods

An extra-articular fracture (AO classification, A3) was created in 7 pairs of fresh-frozen human cadaver radiuses. The radiuses then were plated with a volar distal radius locking compression plate. Seven plates were applied subchondrally; 7 plates were applied 4.5 mm to 7.5 mm proximal to the subchondral zone. The specimens were loaded with 800-N loads for 2,000 cycles to evaluate radial shortening in the 2 groups. Each specimen then was loaded to failure.

Results

Radial shortening was significantly greater when the distal screws were placed proximal to the subchondral zone. The amount of shortening after cyclic loading correlated significantly with the distance the distal screws were placed from the subchondral zone. Rigidity of the plate systems was significantly higher in radiuses in which the distal screws were placed close to the subchondral zone.

Conclusions

To maintain radial length after volar fixed-angle plating, placement of the distal screws as subchondral as possible is essential. The subchondral plate–screw–bone constructs showed significantly greater rigidity, indicating higher resistance to postoperative loads and displacement forces.

Section snippets

Specimen Selection and Preparation

Seven matched pairs of fresh-frozen human cadaver forearms were prescreened using a mini C-arm (MiniView 6800; GE OEC Medical Systems Inc., Salt Lake City, UT) to exclude previous fractures, anatomic abnormalities, and positive ulnar variance. Bone mineral density (BMD) was obtained in all specimens by use of multislice micro computed tomography (μ-CT 20; Scancom Medical Ltd, Bassersdorf, Switzerland). The specimens’ characteristics are outlined in Table 1. Biologic variability was limited

Cyclic Testing

Descriptive data pertaining to change in length (mm) for pins A, B, and C for the proximal and subchondral specimens after cyclic loading (800 N) are presented in Table 2. Statistical analysis showed that the subchondrally plated radiuses had significantly less shortening compared with the proximally plated radiuses (F = 8.402; p = .027). When the displacement data were pooled across pins A, B, and C there was a 73.9% increase (1.38 mm vs 0.36 mm, respectively) in radial shortening under 800-N

Discussion

The results of this study show that the distal radius metaphysis settled significantly more under cyclic loading in radiuses in which the distal screws of the locking compression plate were placed at least 4 mm proximal to the subchondral zone compared with radiuses in which the plate–screw system was applied maximally close to the subchondral zone. Moreover the distance the screws are placed away from the subchondral zone correlates strongly to the amount of settling (ie, radial shortening).

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Cited by (103)

Can we safely place the distal volar locking plate screws into the subchondral zone of a distal radius fracture using a 45° supination oblique view under fluoroscopic guidance?
2023, Injury
Careful distal locking screw insertion into the subchondral zone is necessary to obtain proper mechanical strength of unstable distal radius fractures using volar locking plating. However, subchondral zone screw insertion increases the risk of intra-articular screw penetration, which may remain unrecognized during surgery due to complex distal radial anatomy. The purpose of this study was to evaluate the role of fluoroscopic guidance with a 45° supination oblique view technique for placing distal screws into the subchondral zone during volar locking plating for unstable distal radius fractures and to explore the factors associated with poor screw placement.
We retrospectively analyzed 171 wrists of 169 patients treated with variable-angle volar locking plates for unstable radius fractures. The subchondral zone was defined as the metaphyseal area within 4 mm of the articular margin of the distal radius. The location of the distal locking screws and radiographic parameters, including the teardrop angle, were measured using computed tomography scans and X-rays. Clinical and radiographic factors were examined to determine their possible associations with screw placement failure.
Of 581 distal screws inserted, 559 screws (96.2%) were inserted into the subchondral zone and 17 screws into the metaphyseal zone (2.9%). Five screws (0.7%) in three wrists showed intra-articular placement: four screws were placed into the lunate fossa and one into the scaphoid fossa. These three wrists also exhibited significantly reduced teardrop angles. The distal screws were significantly closer to the joint line in the lunate fossa than the scaphoid fossa (1.9 ± 0.9 mm vs. 2.8 ± 1 mm, P < 0.000).
The 45° supination oblique view technique is a useful fluoroscopic guiding technique for accurate and safe distal screw placement in the subchondral zone in volar locking plate fixation for distal radial fractures. However, a decreased teardrop angle or extended lunate fossa should be corrected before distal screw insertion to avoid intra-articular screw placement.
Changes in Distance Between the Flexor Pollicis Longus Tendon and Volar Locking Plate: An Ultrasonographic Study
2023, Journal of Hand Surgery
Flexor pollicis longus rupture is a major complication after volar locking plate fixation of distal radius fractures. Although the distance between the flexor pollicis longus tendon and the plate (plate–tendon distance) measured by ultrasonography is used to predict tendon rupture risk, the timing of the ultrasonography can affect the measurements. Therefore, this study aimed to analyze the chronological change of the plate–tendon distance between the tendon and plate.
A total of 166 wrists underwent the plate–tendon distance measurement twice or more times within 15 months after surgery. Longitudinal ultrasonography scans with the wrist in a neutral position and the thumb flexed were used to measure the plate–tendon distance. The plate–tendon distances at 0–5 months, 5–10 months, and 10–15 months after surgery were compared. A multiple linear regression analysis was performed to evaluate the influence of the interval between surgery and examination, Soong grade, and plate type on the plate–tendon distance.
The plate–tendon distance decreased as the interval between surgery and examination increased. The plate–tendon distance was an average of 2.0 ± 1.1 mm, 1.4 ± 0.9 mm, and 1.2 ± 0.9 mm at 0–5 months, 5–10 months, and 10–15 months after surgery, respectively. Significant differences were observed between 0–5 months and 5–10 months and between 5–10 months and 10–15 months after surgery. A multiple linear regression showed that significant predictors of the plate–tendon distance were the intervals between surgery and examination and Soong grade.
The plate–tendon distance decreased as the time since surgery increased. When ultrasonography is used for the assessment of tendon rupture risk, it should be considered that the plate–tendon distance decreases as the interval between the surgery and examination increases.
Prognosis IV.
Three-dimensional imaging of the distal radius with reference to volar locking plate surgery
2022, Orthopaedics and Traumatology: Surgery and Research
The watershed line is widely accepted as the distal limit of the volar locking plate (VLP); however, the VLP placement could vary depending on the plate contour and morphology of the distal radius. The aim of this study was to investigate the morphology of the distal radius and VLP fitting using 3D images.
We hypothesized that attachment of the VLP would affect the contour of the volar prominence of the distal radius.
Variable-angle LCP two-column volar distal radius Plate 2.4 and 16 formalin-fixed cadavers were studied. The plate and forearm were scanned using a computed tomography scanner. The plate was fixed to the radial shaft in the most distal position without flexor pollicis longus tendon contact. Postero-antero and lateral radiographs were obtained using fluoroscopy. Postero-antero radiographs were superimposed on a 3D image of the distal radius. The virtual plate was attached to the distal radius in the computer simulations and the plate was adjusted in the sagittal plane. In the postero-antero radiographs, the distance between the plate and distal end of the radius (DPR) was measured. In the sagittal plane, the height of the volar lunate facet (VLF) and the plate-to-bone distance of each locking screw hole was measured. The volar cortical angle (VCA) was measured as the angle formed by a line drawn along the volar surface and a line drawn on the radial shaft on the sagittal plane at each locking screw plane.
A significant correlation was observed between the height of the VLF and the DPR and between the height of the VLF and the VCA. The plate-to-bone distance at the ulnar screw hole was significantly smaller than that of the other screw holes.
Our study revealed that the higher the VLF, the more proximal is the VLP. The plate fits on the bone surface at the ulnar side, whereas the radial side has more space between the plate and bone.
III, diagnostic Level.
Biomechanics of Distal Radius Fractures
2021, Distal Radius Fractures: Evidence-Based Management
Cartilage and subchondral bone distributions of the distal radius: a 3-dimensional analysis using cadavers
2020, Osteoarthritis and Cartilage
To quantify the spatial distributions of cartilage and subchondral bone thickness of the distal radius.
Using 17 cadaveric wrists, three types of 3-dimensional models were created: a cartilage-bone model, obtained by laser scanning; a bone model, rescanned after dissolving the cartilage; and a subchondral bone model, obtained using computed tomography. By superimposing the bone model onto the cartilage-bone and the subchondral bone models, the cartilage and subchondral bone thickness were determined. Measurements along with the spatial distribution were made at fixed anatomic points including the scaphoid and lunate fossa, sigmoid notch and interfossal ridge, and compared at each of these four regions.
Cartilage thickness of the interfossal ridge (0.89 ± 0.23 mm) had a larger average thickness compared to that of the scaphoid fossa (0.70 ± 0.18 mm; p = 0.004), lunate fossa (0.75 ± 0.17 mm; p = 0.044) and sigmoid notch (0.64 ± 0.13 mm; p < 0.001). Subchondral bone was found to be thickest at the scaphoid (2.18 ± 0.72 mm) and lunate fossae (1.94 ± 0.93 mm), which were both thicker than that of sigmoid notch (1.63 ± 1.06 mm: vs scaphoid fossa, p = 0.020) or interfossal ridge (1.54 ± 0.84 mm: vs scaphoid fossa, p = 0.004; vs lunate fossa, p = 0.048). In the volar-ulnar sub-regions of the scaphoid and lunate fossa, the subchondral bone thickened.
Our data can be applied when treating distal radius fractures. Cartilage thickness was less than 1 mm across the articular surface, which may give an insight into threshold for an acceptable range of step-offs. The combined findings of subchondral bone appreciate the importance of the volar-ulnar corner of the distal radius in the volar locking plate fixation.
Volar Locking Plate Fixation for Distal Radius Fractures by Intraoperative Computed Tomographic–Guided Navigation
2020, Journal of Hand Surgery Global Online
Unstable distal radius intra-articular fractures require restoration of alignment. Exact fixation of intra-articular fragments is ideal. Here, we employed intraoperative computed tomography (CT) navigation to insert screws accurately in the intra-articular dorsal fragments during treatment with a volar locking plate for distal radius intra-articular fractures. The main purposes of this study were to evaluate the accuracy of this procedure and the postoperative stability of the articular fragments through CT findings, as well as to assess clinical outcomes.
This study included 26 patients with distal radius fractures, who were treated with a volar locking plate using intraoperative CT navigation with a minimum follow-up of 12 months. Mean patient age was 63 years and mean follow-up was 16 months. We examined the position of the inserted distal screws and articular displacement on preoperative, intraoperative, and post–bone union CT images. The 3 distal ulnar screw positions that influence the stability of the dorsoulnar articular fragment were evaluated. The Mayo wrist score and Disabilities of the Arm, Shoulder, and Hand score were also clinically evaluated.
Computed tomography evaluation revealed that the distal locking screws were appropriately inserted at the subchondral position, with sufficient length to stabilize the dorsal fragments, and reduction and stability of the articular fragment were acceptable. At the final follow-up, mean Mayo wrist score was 90.8 and mean Disabilities of the Arm, Shoulder, and Hand score was 9.6.
Intraoperative CT navigation was successfully used for volar locking plate fixation of intra-articular distal radius fractures. Computed tomography evaluation revealed that the screws were precisely inserted for articular fragments and bone union was achieved, maintaining good intra-articular alignment. The findings demonstrate the accuracy of volar locking plate fixation assisted by intraoperative CT navigation and the good clinical outcomes of this procedure.
Therapeutic IV.

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Distal radiusVolar Fixed-Angle Plating of Distal Radius Extension Fractures: Influence of Plate Position on Secondary Loss of Reduction—A Biomechanic Study in a Cadaveric Model

Purpose

Methods

Results

Conclusions

Section snippets

Specimen Selection and Preparation

Cyclic Testing

Discussion

Injury

J Hand Surg

J Hand Surg

J Hand Surg

J Hand Surg

J Hand Surg

J Hand Surg

J Hand Surg

J Hand Surg

J Hand Surg

J Hand Surg

J Hand Surg

J Hand Surg

Bone

J Hand Surg

J Hand Surg

J Hand Surg

Fractures of the distal radiusclassification of treatment and indications for external fixation

Injury

Distal radius
Volar Fixed-Angle Plating of Distal Radius Extension Fractures: Influence of Plate Position on Secondary Loss of Reduction—A Biomechanic Study in a Cadaveric Model