Two categories
Based on number of fracture lines
Type I
non displaced, no matter how many fracture lins
Type II
single displaced fracture line – 2 part
Type III
two displaced fracture lines – 3 part
Type IV
comminuted
Based on position of main fracture line
A: lateral 1/3 of joint
B: middle 1/3 of joint
C: medial 1/3 of joint