2.  46yo male presents with  T 98.4 P 74 BP 138/80
chief complaint of left O2 100%
wrist pain. Patient  Gen NAD
slipped on side walk on  MSK pain to dorsum of
sheet of ice and fell left wrist just proximal to
forward, landing on 3rd metacarpal. 2+ distal
outstretched hand. Pain pulses. Pain with wrist
has been lingering for rotation
past two days, and pt
endorses “clicking”  Neuro: motor 5/5 nl
sound with certain wrist sensation
movements

4.  scapholunate dissociation
 scaphoid impaction syndrome (SIS)
 occult ganglion cyst
 posterior interosseous nerve neuroma
 physiologic scapholunate (compare to other hand)
 perilunate dislocation
 non-displaced scaphoid fx

5. White arrow: "Terry Thomas"sign gap between scaphoid and lunate, normal 1-2 mm
(abnormal 3mm) Progressive flexion and foreshortening of the scaphoid leads to the scaphoid
ring sign, seeing scaphoid end on.
Black arrow: Signet Ring sign- seen with abnormal palmar flexion of scaphoid.
Right Image: Scapholunate angle nl 30-60 degrees, >80 degrees diagnostic of DISI (dorsal
intercalated segment instability) signifying carpal instability

6.  Orthopedic follow up, for most cases will need
operative repair of interosseous ligament.
 Can place patient in thumb spica splint and have
patient f/u with ortho within one week.
 Untreated, SLD can lead to DISI, defined by SL angle
>80 degrees due to abnormal flexion of
scaphoid, indicating wrist instability, and if further
untreated, can lead to severe arthritis; thus prompt
ortho f/u necessary

7.  MCC of carpal instability
 Assoc. injuries: simultaneous radial styloid fx is relatively
common w/ carpal dislocation; also always consider non-
displaced scaphoid fx.
 Mechanism is similar to that of scaphoid fx, w/ stress
loading of extended carpus, except it is usually in ulnar
rather than radial deviation
 SL angle greater than 80 degrees indicative of DISI, which
can occur with SLD left untreated, and is indicative of
worsened carpal instability.
 DISI can lead to scapholunate advance collapse (SLAC), a
specific pattern of osteoarthritis and subluxation which
results from untreated chronic SLD.

9.  http://www.wheelessonline.com/ortho/scapholunate_
instability
 http://fhs.mcmaster.ca/surgery/documents/scapholu
nate_dissociation.pdf
 http://www.rcsed.ac.uk/fellows/lvanrensburg/classific
ation/hand/scapholunate_diss.htm
 http://emedicine.medscape.com/article/1244215-
overview
 http://www.radsource.us/clinic/0906
 http://www.wheelessonline.com/ortho/x_ray_findings
_in_sld