- Anatomy:
-
Tunnel V:
- overlies distal ends of radioulnar articulation on dorsum of wrist, contains
EDM;
-
Tunnel VI:
- in groove between the apex of ulnar styloid process & ulnar head, contains
ECU tendon which is palpable from
where it passes over ulnar styloid process to its insertion into the side of 5th metacarpal base;
- Exam:
- ulnar styloid process: on the distal tip of the ulnar styloid process, you should feel small, shallow dorsal groove running longitundinally;
-
ECU tendon runs thru this groove;
- it is most easily palpated when hand is radiallly deviated & tendon is contracted;
- ECU is more palpable when wrist is extended & ulnarly deviated;
- tenderness in area of ulnar styloid process may be due to either pathology w/ in process itself or to a
Colles frx w/ assoc frx
of the distal end of ulnar styloid process;
- Management of Frx:
- frxs of ulnar styloid process are assoc w/
frxs of distal radius;
-
avulsion frx:
- frxs involving lesser portions of ulnar styloid do not seen to be associated w/ significant instability
of distal
radioulnar joint;
- w/ minimally displaced frx involves ulnar styloid, place upper extremity in long arm posterior splint in mid supination for 3-4 weeks;
- supination is the normal anatomic position of the forearm and reduces subluxation of the ulnar head;
-
base frx:
- ulnar styloid fractures at its base disrupt the major stabilizing ligaments of the distal ulna and
TFCC and
may lead to instability of the distal radioulnar joint (see
RU joint instability);
- closed reduction and pinning:
- fixation is achieved with 0.035 inch K wire or with use of a cannulated screw;
- open reduction:
- a displaced ulnar styloid frx which occurs along w/ a unstable distal radius frx, should be considered for ORIF;
- surgical approach: incision is made between the ECU and the FCU;
- consider intra-osseous wiring or a tension band construct;
Repair of the triangular ligament in Colles' fracture. No effect in a prospective randomized study.
