Classification of the AO-ASIF Group for Fractures of the Proximal Femur

Description

The AO-ASIF (Arbeitsgemeinschaft fur Osteosynthesefragen, Association for the Study of Internal Fixation) developed a classification system for fractures, based on location and type of fracture.

Code for location: 31 (femur, proximal)

Locations:

(1) trachanteric area (A)

(2) neck fracture (B)

(3) head fracture, with or without neck (C)

Trochanteric Area	Type of Fracture	Fracture Code
pertrochanteric simple	along the intertrochanteric line	A1.1
	through the greater trochanter	A1.2
	below the lesser trochanter	A1.3
pertrochanteric, multi-fragmentary	with one intermediate fragment	A2.1
	with several intermediate fragments	A2.2
	extends more than 1 cm below the lesser trochanter	A2.3
intertrochanteric	simple, oblique	A3.1
	simple. transverse	A3.2
	multifragmentary	A3.3

where:

• A pertrochanteric fracture relates to both the greater and lesser trochanters. An intertrochanteric fracture runs between the two trochanters.

Neck Region	Type of Fracture	Fracture Code
subcapital, with slight displacement	impacted with valgus >= 15°	B1.1
	impacted with valgus < 15°	B1.2
	non-impacted	B1.3
transcervical	basicervical	B2.1
	midcervical adduction	B2.2
	midcervical shear	B2.3
subcapital, non-impacted, displaced	moderate displacement in varus and external rotation	B3.1
	moderate displacement with vertical translation and external rotation	B3.2
	marked displacement	B3.3

Head Region	Type of Fracture	Fracture Code
split	with avulsion of the ligamentum teres	C1.1
	with rupture of the ligamentum teres	C1.2
	large fragment	C1.3
fracture with depression	posterior and superior	C2.1
	anterior and superior	C2.2
	split-depression	C2.3
head and neck fractures	split head and transcervical neck	C3.1
	split head and subcapital neck	C3.2
	depression head and neck fracture	C3.3

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Description

Specialty

ICD-10