- See:
-
Radiology of the Wrist
-
Distal Radius Fx
- Discussion:
-
radiographic measurements:
- articular step off: most important determinant of outcome;
-
radial shortening second most determinant of outcome;
-
dorsal angulation
-
radial inclination
-
unstable vs stable frx;
- stable frx are usually extra articular w/ mild to moderate displacement, & when reduced do not redisplace to the original deformity;
- in stable extra-articular fractures, there will often be frx extension into the
DRUJ, which is the most likely source of symptoms;
-
intra-articular frx:
- displacement can be measured by applying a series of circular templates to the curvature of the greatest remaining
articular surface of the distal radius;
- depressed areas off of the circle template are measured for step off;
-
comminution:
- if comminution extends volar to midaxial plane of radius, then cast immobilization will frequently fail;
- as noted by Trumble et al 1998, in younger patients,
external fixation provided consistently better
results when there was comminution in 2 or more cortices or when there was comminution of one
surface which was greater than 50% of the metaphyseal diameter;
- in older patients, external fixation provided better results if there was comminution in only one cortex;
- references:
-
An effective treatment of comminuted fractures of the distal radius.
- Intrafocal (Kapandji) pinning of distal radius fractures with and without external fixation.
TE Trumble et al.
J. Hand Surg. Vol 23-A. No 3. May 1998. p 381.
-
rotational alignment:
- in the study by Tornetta et al (15 th Annual Meeting of the Orthopaedic Trauma Association, 1999), the authors point out that
there can be up to 38 deg of mal-rotation can be present before a step off can be appreciated on the lateral view;
- PA views were even less sensitive for determining malrotation;
- it was determined that over pronation of the distal fragment was associated with a more volar position of the ulna
on a true lateral view (where as it is normally slightly dorsal on a true lateral view);
-
classification:
-
Frykman Classification
-
Melone Classification
-
Universal Classification
- Routine Views:
-
PA View
-
radial inclination
-
radial length: (
ulnar variance)
-
radial ulnar joints:
- distal radioulnar joint should measure approximately 2 mm;
- if there is a of a radio-ulnar joint disruption consider CT scan;
-
lateral view
-
fat pads: (in the case of occult injury)
-
dorsal tilt:
- look for dorsal tilt of the lunate (
DISI deformity);
- misc: consider use of a 20-25 deg tilted lateral to better profile the radial articular surface;
- ref: Tilted lateral radiographs in the evaluation of intra-articular distal radius fractures.
DW Lundy MD et al.
J. Hand Surgery. Vol 24-A. 1999. p 249.
- Specialized Studies:
- Ulnar Deviation
PA View;
-
Pronated Olblique (STT joint) 
- Ulnar Deviation Lateral View:
- normally ulnar deviation will cause the lunate to dorsiflex and shift volarly, and the radio-luno-capitate
alignment resembles a
DISI pattern;
- volar shift of the lunate helps maintain the normal co-linear relationship of the radius and the capitate;
- w/
mid carpal ulnar instability, the lunate will dorsiflex,
but will not have normal palmar translation;
- hence, the longitudinal axis of the capitate lies above the axis of the radius;
- this "zig zag" deformity would be expected to cause symptoms following distal radial
fractures even if the loss of volar tilt was minimal;
-
CT scan: can help assess the step off of intra-articular fractures and comminution;
Fractures of the distal radius. Intermediate and end results in relation to radiologic parameters.
Computerized tomographic evaluation of acute distal radial fractures.
Colles fracture: does the anatomical result affect the final function
Colles' fracture. How should its displacement be measured and how should it be immobilized.
Factors affecting the outcome of Colles' fracture: an anatomical and functional study.
Radiographic evaluation of osseous displacement following intra-articular fractures of the
distal radius: reliability of plain radiography versus computed tomography.
