- Discussion:
- most frequent radiocarpal instability;
- the lunate is translocated ulnarly, and therefore is not supported by the radius;
- ulnar translationn is also commonly seen in disease such as
RA or in
Madelung's deformity;
- in RA, may occur along w/
caput ulnae syndrome;
- abnormal translation of lunate in ulnar direction is pathognomonic of
ulnar translocation;
- Clinical Presentation:
- clinically the carpus and hand are offset ulnarward;
- Radiographs:
- on x-ray, lunate is positioned just distal to the ulna and a large space between the radial styloid and the scaphoid;
-
two types according to position of scaphoid:
-
Type I:
- entire carpus, including scaphoid, is displaced, & distance between radial styloid process & scaphoid is widened;
-
Type II:
- distance between scaphoid & radial styloid process, remains normal, but the scapholunate space is widened;
- its important to distinguish between the two types of ulnar translocation since appearance of a wide scapholunate
gap may lead to the erroneous dx of
scapholunate dissociation;
- Treatment:
- late identification of ulnar translation deformity or dorsal or volar translation deformity reponds poorly to ligament repairs;
- acutely consider, radiolunate fusion;
- consider relocation of carpus & maintenance of reduction by radiolunate arthrodesis may be a more reliable and satisfactory technique;
-
Darrah's Procedure:
- the main limitation with this procedure in the rheumatoid wrist, is that there is nothing to prevent continued
ulnar and palmar translocation of the carpus;
-
Sauve Kapandji Procedure:
- may allow a higher level of wrist function than is seen w/ the Darrah procedure;
Irreducible fracture-dislocation of the distal radioulnar joint secondary to entrapment of the extensor carpi ulnaris tendon.
Congenital radio-ulnar synostosis: surgical treatment.
The Sauv'e-Kapandji procedure.
Post Traumatic Ulnar Translocation of the Carpus.
JM Rayhack, RL Linscheid, JH Dobyns, JH Smith.
J. Hand Surg. Vol 12-A. 1987. p 180-189.
