Chapter 95 - Hand Trauma

Question 1

angular deformity > 30 degrees in the metacarpals leads to what?

Answer 1

extensor lag at the PIP joint
(typically an apex dorsal angulation of the MCP)

Question 2

why are metacarpal neck fractures inherently unstable?

Answer 2

volar comminution

Question 3

what XR view helps with cmc fracture dislocations?

Answer 3

supinated oblique

Question 4

what ligament holds the small fractured pice in place in a bennets fracture?

Answer 4

the volar oblique ligament

Question 5

what mm is the deforming force in a bennett’s fracture?

Answer 5

abductor pollicis longus (proximal pull and abduction/supination of the proximal end of MC)
adductor pollicis (adduction of distal mc)

Question 6

reduction maneuver for a bennett’s fracture

Answer 6

longitudinal traction, extension, abduction and pronation of the metacarpal

Question 7

how to reduce a dorsal MCP dislocation

Answer 7

DO NOT pull longitudinal traction!!! (this will pull the volar plate into the articular space)
flex the wrist and the mcps
push the base of the dislocated proximal phalanx palmar then slide it distal

Question 8

open reduction of an irreducible MCP dislocation - what approach do you take?

Answer 8

dorsal
volar approach puts the digital neurovascular bundles at risk bc they are push superficially into the palm by the metacarpal head

Question 9

deforming forces of a proximal phalanx fracture

Answer 9

apex palmar
- central slip of the extensor tendon pulls the distal fragment distal
- interossei flex the proximal fragment

Question 10

proximal phalanx heals in significant angulation - what is the consequence?

Answer 10

PIP extensor lag

Question 11

shortening of the middle phalanx causes what?

Answer 11

DIP extensor lag

Question 12

dorsal PIP dislocation treatment (no fracture)

Answer 12

most are stable following reduction
if stable - buddystrap and early movement - prevents stiffness as much as possible

Question 13

palmar PIP dislocation treatment (no fracture)

Answer 13

more rare
represents central slip injury
treat with extension splinting of the PIP for 6 weeks (DIP should be free)

Question 14

dorsal PIP fracture dislocation tx

Answer 14

dorsal extension blocking splint in 60-70 degrees of flexion
unstable - orif
chronic - hemihamate

Question 15

gamekeeper’s thumb pathoanatomy

Answer 15

same as skiiers thumb
UCL gets avulsed off the proximal phalanx
the ligament +/- a bony fragment gets trapped by the adductor aponeurosis

Question 16

mallet finger

Answer 16

edc rupture off dosral distal phalanx
caused by forceful DIP flexion
tx - extension splinting of the DIP if the fragment <40%
bigger fragment - ORIF

Question 17

jersey finger

Answer 17

FDP rupture off the palmar Distal phalanx surface after hyperextension
these are pretty much always operative