Intraoperative imaging of the distal radioulnar joint using a modified skyline view

Common Complications of Distal Radial Fractures

Distal radial fractures are associated with good outcomes; however, although they occur at low rates, complications can significantly impair treatment success. Therefore, the treating surgeon should be aware of potential complications associated with each treatment type and how to best prevent them. Although certain patient-specific and fracture-specific factors may increase the risk of adverse outcomes, most are nonmodifiable risk factors at the time of presentation, so it is imperative that every effort is made to mitigate these risk factors to prevent long-term morbidity. Patients should be well-informed about these complications and potential symptoms so that they can be addressed expeditiously.

Reliability of the Dorsal Tangential View in Assessment of Distal Radioulnar Joint Reduction in the Neutral, Pronated, and Supinated Positions in a Cadaver Model

PURPOSE

Intraoperative assessment of distal radioulnar joint (DRUJ) alignment is often based on lateral radiographs whose interpretation is dependent upon positioning the forearm in neutral rotation. The dorsal tangential view (DTV) is a near-axial view of the dorsal wrist used in assessing dorsal screw penetration during radius fixation. The purpose of this study was to determine whether the DTV can also reliably assess DRUJ alignment in multiple forearm positions.

METHODS

Four transhumeral cadaveric specimens were used to simulate an unstable DRUJ. The stabilizing soft tissue structures of the DRUJ were sectioned. Fluoroscopic DTV images were obtained with the DRUJ of each specimen held in 5 positions: dorsally dislocated, dorsally subluxated, reduced, volarly subluxated, and volarly dislocated. In each position, images were taken with the forearm in neutral rotation, full pronation, and full supination. Three observers independently assessed DRUJ position on DTV images. Intra- and interobserver reliability were assessed in each forearm position.

RESULTS

Observers correctly identified DRUJ position as reduced, volarly malreduced, or dorsally malreduced on 94% of the DTV images (97%, 95%, and 92% in the neutral, supinated, and pronated forearm positions, respectively). Weighted kappa values for intraobserver reliability were 0.965, 0.964, and 0.965 for the 3 observers. The mean kappas for intraobserver reliability were 1.000, 0.967, and 0.930 with the forearm in neutral, supinated, and pronated positions, respectively. Weighted kappa values for interobserver reliability between paired observers were 0.948, 0.912, and 0.929. The mean kappa for interobserver reliability was 0.926, 0.931, and 0.930 for the forearm in neutral, supinated, and pronated positions, respectively.

CONCLUSIONS

The DTV reliably demonstrated the position of the DRUJ independent of forearm rotation in a cadaveric model.

CLINICAL RELEVANCE

Surgeons may consider the DTV as another tool for fluoroscopic verification of the DRUJ reduction in the operating room or clinic.

The Sigmoid Notch View for Distal Radius Fractures

PURPOSE

This study defines the sigmoid notch view of the distal radius. Specifically, we tested the null hypothesis that there is no relationship between the subchondral stripe of bone seen on a sigmoid notch view of the distal radius and the articular surface of the sigmoid notch.

METHODS

We used 44 wrist specimens for anatomic and fluoroscopic analysis. We measured the articular depth of the sigmoid notch from its deepest point and classified the shape of the sigmoid notch. We then placed a radiopaque marker at the nadir of the articular surface and quantified the fluoroscopic depth of the sigmoid notch. A sigmoid notch view, which was a tangential fluoroscopic view of the volar and dorsal lips of the sigmoid notch, was obtained. The relationship of the articular surface to the stripe of subchondral bone seen on this view, called the sigmoid stripe, was determined.

RESULTS

Anatomic analysis revealed sigmoid notch types with proportions similar to those in previous descriptions. The marker for the articular surface was superimposed or just ulnar to the sigmoid stripe in all specimens. In flat face and ski slope notches, this was coincident with the volar and dorsal lips of the sigmoid notch. In C- and S-type notches, there was a measurable distance from the articular surface marker to the edges of the bone of the volar and dorsal lips of the sigmoid.

CONCLUSIONS

The articular surface marker at the nadir of the sigmoid notch is always coincident or ulnar to the sigmoid stripe in the sigmoid notch view.

CLINICAL RELEVANCE

Surgeons can use the sigmoid notch view as a reliable method to (1) evaluate the integrity of the articular surface, (2) ensure hardware is not placed in the distal radioulnar joint, and (3) guide placement of volar locking plates in the coronal plane.

Distal radius fluoroscopic skyline view: extension-supination versus flexion-supination

The aim of our study was to compare the vertical fluoroscopic view of the wrist in extension and supination (ES) to the view in flexion and supination (FS) and determine which of the two views allowed the best visualization of four selected anatomical landmarks SDLR (radial styloid, dorsal radius cortex, Lister's tubercle and distal radioulnar joint). Our case series included 50 patients who had suffered a distal radius fracture and undergone an open reduction and internal fixation procedure with a volar locking plate. For each case, two fluoroscopic views were taken: ES (wrist extension and supination) (group I) and FS (wrist flexion and supination) (group II). Ten observers had to recognize the SDLR anatomical landmarks on 100 fluoroscopic skyline views (time 1) and 15 days later (time 2). The rate of recognition of the four anatomical landmarks was 78% in group I and 66% in group II (p < 0.001). The concordance rate of recognition of the four anatomical landmarks was mediocre (κ = 0.411). In conclusion, the vertical fluoroscopic skyline view in wrist extension and supination seems to be the most adequate view to assess the quality of the fracture reduction, the distal radioulnar joint and the length of the screws in open reduction and internal fixation of distal radius fractures with volar locking plates.

Comparing Dorsal Tangential and Lateral Views of the Wrist for Detecting Dorsal Screw Penetration after Volar Plating of Distal Radius Fractures

BACKGROUND

The dorsal tangential (DT) view has been shown to improve the detection of dorsal screw perforation during volar distal radius fracture fixation. Here we performed a cadaveric imaging survey study to evaluate if the DT view was uniformly beneficial for all screws.

METHODS

Standardized placement of fixed-angle volar distal radius plates was performed on two cadavers. Fluoroscopic images depicting variable screw perforation of each of the four screw holes on the plate were generated. A 46-image survey was distributed at a large academic medical center. Respondents were asked to answer if the screw was perforating through the dorsal cortex in each image. Statistical analysis was performed using Fisher's exact test. A p value < .05 was considered significant.

RESULTS

The DT view offered a significantly more reliable determination of dorsal screw penetration than traditional lateral imaging for the radial-most screw at all degrees of perforation and the middle two screws at 2 mm of perforation. Residents and attendings had more accurate screw readings overall using the DT view.

CONCLUSIONS

The DT view is superior to traditional lateral imaging in the detection of small amounts of dorsal perforation of the radial-most three screws of a fixed-angle volar plate.

Review of the Clinical Use of Fluoroscopy in Hand Surgery

Fluoroscopy is a commonly used tool in hand surgery. There have been recent advances in the technology and its clinical utilisation. Indications include assessment of joint and fracture fixation and stability, particularly when combined with minimally invasive techniques. Recent developments include surgeon operated mini C-arm image intensifiers. We present a review of the clinical utilisation of fluoroscopy in hand surgery including recent developments, Australian legislation, safety issues, strategies to reduce radiation exposure and clinical examples for imaging distal radius and scaphoid fracture fixation.