Management of the scaphoid during four-corner fusion-a cadaveric study.
OBJECTIVE
To examine the effects of scaphoid retention, inclusion, and excision on wrist motion and radiolunate contact characteristics in a cadaveric model after simulated 4-corner fusion with rigid internal fixation.


METHODS
Seven fresh-frozen cadaveric upper extremities were examined. For all surgical manipulations the motion was measured and contact characteristics were assessed using ultra-low prescale pressure-sensitive film.


RESULTS
Compared with the intact specimen, simple 4-corner fusion with scaphoid retention led to a significant decrease in extension, radial deviation, and ulnar deviation, but no change in radiolunate contact characteristics. After 4-corner fusion there was no significant difference in motion or radiolunate contact characteristics between scaphoid retention and scaphoid inclusion. After 4-corner fusion scaphoid excision allowed significantly greater radial deviation compared with scaphoid retention and scaphoid inclusion. Compared with the intact specimen 4-corner fusion with scaphoid excision also led to a significant increase in radiolunate contact area and mean contact pressure.


CONCLUSIONS
When performing 4-corner arthrodesis in the absence of radioscaphoid arthritis, scaphoid excision may improve motion at the cost of increased mean radiolunate contact pressure.
Kobza
Paul E
PE
Department of Orthopaedic Surgery, Baylor College of Medicine and the Houston Veteran's Affairs Medical Center, Houston, TX, USA.
Budoff
Jeffrey E
JE
Yeh
Ming Long
ML
Luo
Zong Ping
ZP
D001174:Arthrodesis; D001696:Biomechanical Phenomena; D002348:Carpal Bones / Q000502:physiology / Q000601:surgery*; D006801:Humans; D016059:Range of Motion, Articular; D021361:Scaphoid Bone; D014955:Wrist Joint / Q000502:physiology*