Femur Fractures

Intracapsular Fractures of the Proximal Femur

Blood supply to the head of the femur

ref: Crock " An atlas of the arterial supply of the head and neck of the femur in man"
CORR 152: 1727, 1980
Chung JBJS 58A: 961970, 1976

4 groups 1. Extracapsular arterial ring

= trochanteric anastomosis
major contributions posteriorly from the horizontal br of the med circumflex femoral , and, anteriorly from ascending br of the lat femoral circumflex artery

2. Ascending cervical branches

( = retinacular br's) arise from 1.
pass up beneath the synovial and capsular reflections in their passage they give branches to the metaphysis of the femoral neck
there is a free intramedullary anastomosis bw branches of the superior nuttrient artery system,br's of the extracapsular ring, br's of the ascending cervical branches, and the subsynovial ring
4 groups sup, inf, med, lat the lateral supplies most of the blood to femoral head
at the margin of the artic cartilage these vessels form a second ring the

3. Subsynovial intracapsular ring ( Chung)

( = circulus articuli vasculosis Hunter, 1743). This ring may be complete or incomplete (complete more often in males). From this ring epiphyseal branches arise that enter the femoral head

4. Artery of the lig teres

from the lat br of the obturator artery supplies small area about the fovea in the vast majority

Epidemiology

increased freq with
age
dementia
malignancy
chronic illness

decreased freq with
long term physical activity
supplemental Vit D3 and Cain elderly women
HRT

Classification

Garden R.S. " Reduction and Fixation of subcapital fracturesof the femur"
OCNA 5: 683712, 1984
Types

an incomplete or impacted fracture
a complete but undisplaced fracture
a complete partially displaced fracture
a completely displaced fracture

Eliasson etal "Displacement in femoral neck fractures"
Acta Orth Scand 59:359371, 1988
Displaced ( = Garden 1+2)
Undisplaced (= Garden 3+4)

Treatment

based on pt age and grade of fracture

Pt less than 65
and do not have a chronic illness, poor life expectancy ® ORIF

Pt bw 65 and 75
those with high functional demand ® ORIF
those with low demand , chronic illness® arthroplasty

Pt more than 75
arthroplasty

pts of any age with less than 1 yr life expectancy® hemiarthroplasty
pts less than 75 with a limited life expectancy of more than 1yr®bipolar

Internal fixation

Timing of treatment
reduction of a displaced fracture of the femoral neck improves blood supply to the femoral head reduction within 8 12 hrs minimises risk of AVN if reduce within 8 hrs risk of AVN in a displaced fracture is ~ 20%.
2448 hrs risk is ~ 40%
ref: Swiontkowski etal JBJS 66A: 837846, 1984

Closed Reduction
Leadbetter ( ref : JBJS 20:108113, 1938)
affected hip flexed to 90 deg in slight adduction, traction then applied, then the thigh is internally rotated , then while maintaining IR the thigh is abducted and brought down to level in extension
Open Reduction
indicated if CR fails
anterolat approach bw TFL + G medius, open capsule, disimpact and reduce
Method of fixation
3 cannulated screws
CHS not recommended as is too large an implant and if placed incorrectly can jeopardise blood supply
If CHS used use a derotation screw to control rotation

Arthroplasty

AMP for pts more than 70
THR for pts less than 70

Complications

AVN

undisplaced fracture ~ 10%
displaced fracture up to ~ 80% either partial or complete (variable reporting)

late segmental collapse occurs in
~ 10% undisplaced fracture
~ 30% displaced fracture

Failure of fixation

Nonunion
rare in undisplaced fracture
~ 30% in displaced fracture
treat with either a valgus osteotomy or an arthroplasty

DVT/PE
DVT ~ 40%
low dose warfarin in pts who justify risk of anticoagulation

Prognosis

ref: LuYao etal " Outcomes after displaced fractures of the femoral neck"
JBJS 76A: 1525, 1994
Metaanalysis of 116 papers

At 2 yrs after primary ORIF
nonunion in 33%
AVN in 16%
reoperation rate 2036% ( ie 2.5 times that for hemiarthroplasty)

At 2 yrs from hemiarthroplasty
dislocation 2%
reoperation rate 618%

At 2 yrs from THR
dislocation 11%


Intertrochanteric Fractures

classification

AO

proximal femur type
A1 pertrochanteric simple
A2 pertrochanteric multifragmentary
A3 intertrochanteric

Kyle, Gustilo and Premer JBJS 61A: 216221, 1979

type 1: stable undisplaced , no comminution
type 2: stable displaced , min comminuted. Reduction ®stable construct
type 3: unstable , large posteromed comminuted area
type 4: also have a subtrochanteric component

Treatment

Type 1,2,3: ORIF with CHS
Type 4: CHS if pyriformis fossa not intact, supplemental BG

2nd generation nail if pyriformis fossa intact
no advantage to use osteotomies if using a sliding screw device
ref : Hopkins , Nugent and Dimon "Medial displacement Osteotomy for unstable intertrochanteric fractures" CORR 245: 169172, 1989

Complications/ Prognosis

Mortality
~ 30% at 1 yr , after this the expected normal curve is followed

Infection
~1%

Nonunion
rare

Mechanical / technical failures
nail cutting out
pin penetration
fracture below implant seen esp in gamma nail


Subtrochanteric fractures

Classification

Type 1
High: fracture line extends into the lesser trochanter

Type 2
Low: lesser trochanter remain