First and second year — the floor first, then every step
Describe the fracture and give the four radiographic parameters — radial inclination, radial height, palmar/dorsal tilt and ulnar variance — plus articular step-off; then look at the scaphoid, the scapholunate interval and the DRUJ.
Orient first
Normal parameters are the reference against which reduction is judged: radial inclination about 22°, radial height about 11 mm, palmar (volar) tilt about 11°, and ulnar variance compared with the other wrist.
The articular surface has two facets (scaphoid and lunate); a step between them is intra-articular displacement.
The distal radioulnar joint and the triangular fibrocartilage complex are part of the injury; an ulnar styloid BASE fracture can destabilise the DRUJ.
Acquire the study
PA and true lateral of the wrist (pisiform overlying the distal pole of the scaphoid on the lateral); post-reduction views in the same projections.
The manoeuvre
PA: RADIAL INCLINATION — the angle between a line from the radial styloid tip to the ulnar corner of the radius and a line perpendicular to the radial shaft axis.
PA: RADIAL HEIGHT — the distance between two lines perpendicular to the shaft axis, one at the radial styloid tip and one at the ulnar corner of the articular surface, in mm.
Lateral: TILT — the angle between a line joining the dorsal and volar rims of the articular surface and a line perpendicular to the shaft; volar tilt positive, dorsal tilt negative.
PA: ULNAR VARIANCE — the distal articular surface of the ulna relative to the ulnar corner of the radius, in mm, compared with the other wrist if available.
Intra-articular extension: articular step-off and gap in mm; die-punch fragment of the lunate facet.
Scaphoid, the scapholunate interval, carpal alignment on the lateral (lunate and capitate), the ulnar styloid (tip versus base).
What confirms it
Two views; intra-articular extension confirmed on the PA/lateral or CT.
What licenses you to exclude it
A normal radiograph with snuffbox tenderness does not exclude a scaphoid fracture (see the scaphoid card).
The classic misread
Measuring tilt on a rotated lateral view.
Missing a scaphoid fracture or scapholunate widening in the same wrist.
Reporting the injury
Classification to use
Describe (extra-/intra-articular, dorsal/volar angulation, comminution) and give the AO/OTA 23 code if your centre uses it; eponyms (Colles, Smith, Barton, chauffeur) are shorthand, not a substitute.
Measurements — and how to take them
Radial inclination (normal about 22°), radial height (normal about 11 mm), volar tilt (normal about 11°), ulnar variance (in mm, against the other side).
Articular step-off and gap in mm (a step-off > 2 mm is widely used as the threshold for operative consideration — verify).
What to report
Extra- or intra-articular; direction of displacement; the four parameters; articular step-off and gap; comminution (dorsal metaphyseal).
Ulnar styloid (base versus tip), DRUJ, scaphoid and scapholunate interval, carpal alignment.
How to report it
X-ray: "Intra-articular fracture of the distal radius with dorsal angulation: dorsal tilt 18°, radial inclination 12°, radial height 6 mm, ulnar variance +3 mm. 2 mm articular step-off between the scaphoid and lunate facets. Fracture of the base of the ulnar styloid. Scapholunate interval normal."
What not to report
Do not write "acceptable position" — give the parameters; acceptability depends on age and function.
Associated injuries to look for
Scaphoid fracture, scapholunate ligament injury, perilunate injury, ulnar styloid base fracture with DRUJ instability.
What changes management
Loss of the parameters beyond local acceptability, articular step-off, DRUJ instability, a volar lunate facet fragment — operative fixation.
Reference values
Each value carries the caveat that keeps it from being misused. Normal limits and diagnostic criteria are kept apart on purpose: a disease cut-off read as a normal range is the more dangerous mistake.
Normal limits
Distal radius · Radial inclination15–25°
PA wrist radiograph. The angle between a line from the tip of the radial styloid to the ulnar corner of the distal radial articular surface, and a line perpendicular to the radial shaft axis.
⚠️ FOREARM ROTATION ALTERS THIS MEASUREMENT — a malpositioned film gives a wrong angle, so assess rotation before reporting loss of inclination after a distal radial fracture.
X-ray · CT
Distal radius · Volar (palmar) tilt
7–15°, mean about 11° (some texts accept 2–20°)
TRUE lateral wrist radiograph. The angle between a line through the dorsal and volar rims of the radial articular surface and a line perpendicular to the radial shaft axis.
Requires a true lateral — obliquity invalidates it. Dorsal angulation (a negative value) is the typical post-Colles deformity and is a surgical planning number, so state it explicitly rather than as "loss of volar tilt".
X-ray · CT
Distal radius · Radial height (length)approximately 10–13 mm
PA wrist radiograph. The distance between two lines perpendicular to the radial shaft axis — one through the tip of the radial styloid, the other through the distal ulnar articular surface.
Loss of radial height after a distal radial fracture is one of the acceptance criteria for reduction, together with radial inclination and volar tilt — all three are reported, not one.
X-ray
See it on real cases
Direct links to Radiopaedia — the reference article and worked cases with their images. Each opens on Radiopaedia.