The Dorr classification for bone quality of the proximal femur depends on radiographic and other findings. The qualities of the proximal femur are important when choosing and placing the stem of a femoral implant.
There are 3 types: A, B and C
Type A:
(1) bone of the proximal femoral shaft show thick cortices in radiographs
(2) narrow diaphyseal canal
(3) funnel shape of the canal at the level of the lesser trochanter
(4) a lateral radiograph shows a thick curved posterior cortex ("fin")
(5) classically seen in a young, muscular male
Type B:
(1) cortices of the proximal femur are not as thick as type A but greater than type B
(2) wider diaphyseal canal
(3) a lateral radiograph shows erosion of the proximal fin with flattening of the cortex
Type C:
(1) bone of the proximal femoral shaft show thin cortices
(2) wide diaphyseal canal
(3) the canal may be compared to a stovepipe
(4) cortical bone shows decreased bone definition ("fuzzy")
(5) a lateral radiograph shows the loss of the posterior fin
(6) classically seen in a thin, elderly female
