Wrist Instabilities Flashcards
Carpal instability
dislocation or loss of contact between bones of the distal carpal row over the proximal carpal row in relation to the radioulnar joint
Radioulnar motion - radial deviation
distal row - radial
proximal row - ulnar
Radioulnar motion - ulnar deviation
distal row - ulnar
proximal row - radial
DTM
Dart Throwing Motion
involves a combination of wrist extension in radial deviation and flexion with ulnar deviation
DTM and SLIL
DTM pattern produces minimal elongation and thus minimal tension the the volar and dorsal SLIL
Load distribution on the carpus during gripping
80% on the radiocarpal joint
20% on the ulnocarpal region
of the 80% radial load: 60% on scaphoid and 40% on lunate
Stages of scapholunate instability (3)
- predynamic instability
- dynamic instability
- static instability
Pre-dynamic instability
earliest sign of SLIL pathology
SL membrane attenuated or partially torn, producing abnormal motion between the scaphoid and the lunate
produces wrist synovitis and pain
Dynamic instability
ligamentous tears of either the palmar and/or dorsal portions of SLIL
Static instability
SL gap can be seen on radiograph (>3mm abnormal)
SL angle greater than 60-70 deg on lateral radiograph
lunate rotated dorsally (DISI)
Signs and symptoms SL injury
- typically result of a FOOSH
- acute injury present with painful and swollen wrist
- with time, pain becomes more localized of the SL ligament dorsally
- Terry Thomas sign
- signet ring sign
- DISI deformity
- degenerative changes to radial styloid and capitolunate joint
Pre-dynamic and dynamic instability therapeutic management
- cast immobilization 7-10 days
- prefabricated orthosis to be used during aggravating activities for additional 2-6 weeks
- AROM exercises/DTM
- once pain free, orthosis discontinued and strengthening exercises as tolerated 10 weeks and beyond
- most resolve within 6 months without surgical intervention
Static SL dissociation therapeutic management
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Signs and symptoms LT injury
- typically occurs secondarily to injury to ulnar side of wrist
- pain over the ulnar aspect of their wrist that is exacerbated by power grip and ulnar deviation
- VISI deformity
- lateral radiograph: lunate more palmarly flexed
- normal SL angle
Midcarpal instability
instability between the proximal and distal carpal rows
can be intrinsic or extrinsic
Intrinsic MCI
characterized by generalized wrist ligament laxity outside of the carpus
can be classified as dorsal, palmar, or combined
Extrinsic MCI
secondary to bone abnormalities outside of the carpus like radius fracture malunions and extrinsic ligament injuries found in association with ulnar minus variance
Signs and symptoms MCI
sense of wrist instability, significant wrist pain, an abrupt painful click/clunk/snap during wrist motion, and weakness with gripping
DISI
dorsal intercalated segment instability
lunate dorsiflexed 15 degrees or greater in relation to capitate
VISI
volar intercalated segment instability
volar rotatoion of the scaphoid and lunate can be seen on lateral radiograph
capitolunate angle of greater than 30 degrees
Op/NonOp management of wrist ligament injury
- edema and pain control
- maintenance of ROM to uninvolved joints
- initiation of controlled, protected mobilization to the uninvolved structures
- avoidance of exercise or activity that may compromise tissue healing or place undue load to healing/repaired structures
- overall achievement of stable wrist with functional ROM
Functional wrist ROM
5 degrees flexion
30 degrees extension
10 degrees radial deviation
15 degrees ulnar deviation
