Intraoperative imaging of the distal forearm

Fluoroscopic visualization of anatomical fracture reduction and correct implant placement for the distal forearm can be significantly facilitated using the following views:

• AP and lateral views of the distal forearm (including tangential views)
• Oblique views (supination and pronation)
• Dorsal views (dorsal tangential and skyline views)

The following represents ideal imaging with the patient in the supine position with the arm resting on an arm table. The wrist is adjusted in different positions to acquire the respective views.

The C-arm is usually oriented vertically. Only dorsal views need some adjustments.

• The forearm is in full supination or full pronation
• The beam is placed vertically

Use additional tangential views to clear the radiocarpal joint space. The radiocarpal joint space is slightly tilted by 5°–10°.

In full supination, the elbow should be lifted by this degree. Alternatively, the C-arm may be adjusted.

The following lines and landmarks can be observed:

1. Proximal carpal row (scaphoid, lunate, and triquetrum)
2. Distal radioulnar joint (DRUJ)
3. Dorsal rim
4. Palmar rim

Central reference point (CRP) 

The optimal view is obtained when the image is centered over the DRUJ. The joint space of the DRUJ is then usually visible.

Correct intraoperative AP view 

Left image: Incorrect intraoperative view, not centered on DRUJ

Right image: Postoperative view, same patient, centered on DRUJ, revealing malposition of the implant

This view is particularly useful for identifying:

• Böhler’s angles
• Radiocarpal joint and DRUJ congruency
• Correct plate position
• Rule out screw penetration into the radiocarpal joint or the DRUJ

• The forearm is in neutral rotation
• The beam is typically placed vertically

Use additional tangential views to clear the radiocarpal joint space.

Usually, raise the forearm by about 20°–25° to adjust for the radial inclination.

This series of images shows the representation of the radiocarpal joint surface depending on the angle of the beam.

The following lines and landmarks are seen:

1. Lunate and scaphoid
2. Distal ulna
3. Dorsal rim
4. Palmar rim

The optimal view is obtained when the pisiform projects onto the middle/distal third of the scaphoid.

1. Scaphoid
2. Lunate
3. Radial styloid
4. Capitate
5. Pisiform
6. Ulnar head and styloid

Correct intraoperative lateral view 

Different intraoperative lateral tangential views 

This view is particularly useful for identifying:

• Böhler’s angles
• Radiocarpal joint congruency
• Position of the distal ulna relative to the radius
• Correct plate position
• Correct screw position

• With the beam oriented vertically, the hand is pronated supinated about 45° out of the neutral position.

The following lines and landmarks can be observed:

1. Lunate
2. Lunate facet
3. Dorsoradial (radial styloid)

The following lines and landmarks can be observed:

1. Scaphoid
2. Scaphoid facet
3. Dorsoulnar (“dorsal corner”)

• Dorsoradial view: lunate, lunate facet, and dorsoradial contour of radial styloid visible
• Dorsoulnar view: scaphoid, scaphoid facet, and dorsoulnar contour (“dorsoulnar fragment”, “dorsal corner”) visible

Left: correct intraoperative dorsoradial (supination) view 

Right: correct intraoperative dorsoulnar (pronation) view 

This view is particularly useful for identifying:

• Dorsoradial view: lunate facet, palmar ulnar fragment (“palmar corner”); dorsoradial contour of radial styloid: screw penetration of 2nd compartment

• Dorsoulnar view: scaphoid facet, dorsoulnar fragment (“dorsal corner”); screw penetration of 3rd and 4th compartment

• The C-arm beam is usually in a vertical position
• Lift the forearm upright at a ca 20° angle to the beam
• Flex the wrist to obtain the dorsal tangential view
• Extend the wrist to obtain the skyline view

The following lines and landmarks can be observed:

1. Lunate
2. Sigmoid notch
3. Scaphoid
4. Dorsal rim
5. Scapholunate joint space

The following lines and landmarks can be observed:

1. Palmar rim
2. Sigmoid notch
3. Radial styloid
4. Dorsal rim

The optimal view is obtained when the following is visible:

• Dorsal rim of the radius
• Sigmoid notch

Correct intraoperative dorsal tangential view 

Correct intraoperative skyline view 

This view is particularly useful for identifying:

• Screw penetration of dorsal compartments, especially the 3rd
• Screw penetration of sigmoid notch

Intraoperative dorsal tangential view: screw penetration of 3rd compartment 

Intraoperative skyline view: screw penetration of 3rd and 2nd compartment