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Duke Orthopaedics
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Wheeless' Textbook of Orthopaedics

Radiographic Findings of Distal Radius Frx


- 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  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.
    - rotational alignment:
           - in the study by Tornetta, et al (15th 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.


- 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.




Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, August 7, 2012 2:18 pm