Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Lower extremity - bones
Lower Extremity Tolerances based
on PMHS experiments
Standards
Pelvis
Mechanical axis:
5 degree to
vertical axis
Anatomy
Long bones fractures - classification
Bone tolerances
Injury mechanisms
Injury criteria and levels, standards
Countermeasures
Thigh
Leg
New Delhi, December 4, 2010
Foot
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Movement directions
Classification of joints
z Flexion
z Extension
z Adduction
z Abduction
z Rotation
• Fully movable joint
– the hip and ankle
• Partially movable joint
– the inter metatarsal joint
• Immovable joint
– the sacroiliac joint
– the pubic symphysis
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Frontal view of the male and
female pelvis
Anatomy of the hip joint
Main anatomical structure
Sidan 1
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Moment-angle characteristics of
the hip joint
Anatomy of the knee
failure
of joint
failure
of joint
physiological
movement
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Anatomy of the foot-ankle complex
Movement of the ankle joint
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
The types of fractures
according to loading
Physiological movement of
joints of extremities
Kapandji [1970], White and Panjabi [1978], Frankel and Nordin [1980]
Sidan 2
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Femur strength
Tibia and fibula strength
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Lower extremity injuries in the
front and side car accidents
General injury patterns of
extremities in accidents
•
•
•
•
Bone Fractures
Joint Dislocation
Sprain and Rupture of Soft Tissues
Nerve System Injuries
States 1986
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Motorcycle accidents injury distribution (non fatal accidents)
head fractures
with concussion 7%
Injuries to pelvic region
• pelvic injuries
severe face injuries 7%
severe neck injuries 1%
–
–
–
–
–
upper extremity injuries 40%
soft tissue injuries 5%,
nerve, vessels injuries 2%
avulsions of muscle insertions (sport mainly)
isolated fractures of the pelvic ring (minor impacts)
multiple fractures of fractures-dislocations (common)
injuries to the sacrum and coccyx (not serious but painful)
associated soft tissue injuries (bladder, urethra, vagina,
vascular injuries...)
• hip injuries
– avulsions of the epiphysis
– traumatic hip dislocations and fracture-dislocations
(acetabulum)
– fractures of the neck of the femur
lower extremity injuries 59%
Sidan 3
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Injury mechanisms to lower
extremity in frontal impacts
Pelvis: injury mechanisms
Frontal impact
Factors influencing
lower extremity
injuries
Lateral impact
More factors:
age, belt use,
pre-impact breaking,
car weight,..
Femoral shaft fracture
Car interior deformation
Fractured patella
Knee ligament injury
Toepan local intrusion
Posterior hip dislocation
Intrapelvic (femur neck,
trochanter)fracturedislocations and fractured
pelvis
Fracture - dislocation
Foot pedals, foot entrapment
Sliding and twisting on the pedals
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Major injuries to lower extremity in
car-pedestrian accidents
Injury mechanisms of the knee
joint in pedestrian accidents
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Damage mechanism of knee joint
Fractures of the ankle and
direction of forces
Shearing displacement
Lateral
impact
Compressive force
Medial
impact
Shearing force
Impact force
: Ligament with high risk
of damage
: Bone with high risk
of fracture
Ground reaction force
Bending deformation
Abduction tibial fracture
Kajzer et al. 1997
Sidan 4
Adduction tibial fracture
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Pelvis impact response - tolerances
Force-deflection response of pelvis
• Vertical loading
– 3.7 kN dynamic -> bilateral dislocation of the sacroiliac joint
– 3.5 kN static -> similar kind of injury (Fasola et al. 1955)
• Frontal loading
– 2.7 kN at the pubis -> fracture of the pubic rami (Fasolaet et al. 1955)
– 8.9 - 25.6 kN at the knee -> hip/pelvic fractures (Melvin et al. 1980)
– 37 kN noted -> not fractures (Nusholtz 1982)
• Lateral loading
– Fracture force: 4.9 - 11.9 kN for males, 4.4 - 8.2 kN for females (Ramet,
Cesari 1979 - 1983)
– Average force for AIS 2-3: 8.6 kN for males, 5.6 kN for females
– Impact Force = 193.85 Wc - 4710.6, Wc - body weight ->
for 50th percentile male: 9.8 kN
– even study from UMTRI and University of Heidelberg
Lateral impact to greater trochanter, pendulum diameter 150 mm,
mass 23.4 kg, speed 16.2-33.8 km/h. Peak pelvis acceleration and pelvic
deformation not reliable measures. Ratio of pelvic deformation to pelvic
width correlate with pubic rami fracture:
25% probability of fracture at 27% pelvic compression
Viano et al. 1989
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Test setup and
registered parameters
Studies on pelvis impact tolerance
Biomechanical data in sitting posture which simulates driver
or passenger of a car in the lateral impact situation.
1979
1980
1982
Ramet and Cesari IRCOBI
Cesari et al. 24th STAPP
Cesari and Ramet 26th STAPP
1985
Cesari et al. 9th ESV
Nusholtz et al. 26th STAPP
Haffner 10th ESV
Pelvic Lateral
Deformation
Table
Accelerometer
Wing fixation screw
Pre-load
(400 N)
Distance
between iliacs
Spring
Load cell (1)
Pelvic Force
V=32 km/h
Impact Force
= Ram mass Acceleration
Ram
Styrodure R
(100 120 50)
Load cell (2)
Knee fixation plate
Biomechanical data in standing posture which simulates
pedestrian of car-pedestrian obtained in 2003 (Matsui, Kajzer).
Simulated ground
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Pelvic Fracture Risk Curve
Picture from experiments - top view
1.0
n=11
0.8
0.6
0.4
9.6 kN
0.2
8.9 kN
0.0
0
2
4
8 10 12 14
6
Normalized Impact Force (kN)
Impact force of 8.9 kN — 20% risk of pelvic fracture
Impact force of 9.8 kN — 50% risk of pelvic fracture
Sidan 5
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
PMHS: experiment with bodyparts or tissues
Tolerance levels of upper and
lower leg
• Femur force
EEVC WG 10 ≤ 4 kN
4.23 kN
5.28kN
7.1 - 7.7 kN (static axial compression)
11.6 kN (dynamic axial compression)
• Femur bending moment
EEVC WG 10 ≤ 220 Nm
310 Nm (males static)
• Tibia acceleration
EEVC WG 10 ≤ 150 g
fractures
170 - 270 g (average 222 g)
no fracture 185 - 243 g (average 202 g)
124 - 207 Nm (static bending moment)
280 - 320 Nm (dynamic bending moment)
Set-up in experiments: Tolerance of the knee
joint at lateral impact in shearing.
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Levels of knee force and moment
in various studies
Tolerance levels of the knee
EEVC WG 10 ≤ 6mm at 4 kN
• Shearing
Test setup
Shearing
12 mm (no preload, quasistatic)
16-28 mm (preload, dynamic)
2.4-2.9 kN shearing force
400-500 Nm bending moment
Bending
Study
Kajzer
1999
Kajzer
1997
Impact velocity level
[km/h]
20
40
15
20
Knee shearing force
[kN]
2.4
(SD 0.2)
2.6
(SD 0.5)
1.8
(SD 0.4)
2.6
(SD 0.5)
Knee bending moment
[Nm]
418
(SD 100)
489
(SD 141)
Kajzer et al.
Kajzer
1999
Kajzer
1997
20
40
1.3
(SD 0.5)
1.5
(SD 0.6)
307
(SD 147)
331
(SD 79)
Kajzer et al.
15
20
101
(SD 21)
123
(SD 35)
• Bending
EEVC WG 10 ≤ 15°
11° (dynamic) - 19° (quasistatic, no prelad)
15-16° (preload dynamic)
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Setup of four-point knee bending
test
Bhalla’s results compared with
response os FLEX-PLI and TRL-PLI
• Konosu and Tanahashi 2003
Bhalla et al., 2003
Sidan 6
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Tibia injury criterion
Tibia Index (TI)
Femur Injury Criterion (FIC)
TI=(M/Mc) + (F/Fc) < 1.0 and Fmax <8 kN
F (kN) =23.14 - 0.71 T (ms), for T<20 ms
where:
F (kN) = 8.9 kN, for T>=20 ms
Mc=225 Nm and Fc=35.9 kN
where:
Basis: Static bending tests of tibia (Yamada)
F is the axial compressive force
Bone properties:
T the primary load pulse duration.
ultimate compressive stress = 210 Mpa
ultimate tensile stress = 150 MPa
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Tolerance levels of the ankle joint
Safety countermeasures
• Ankle moment (quasi -static)
– 33 Nm in dorsiflexion
– 40 Nm in plantarflexion
– 34 Nm in inversion
– 48 Nm in eversion
• Ankle bending angle
– 34 deg. in inversion (quasi -static)
– 32 deg. In eversion (quasi -static)
• Intrusion
- Footwell structural reinforcements
- Toepan padding
- Reinforcement of car body and door
• Pedal modifications
• Knee bolster
- Bolster airbag
• Seat
- Seat cushion restraint system
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Functions of the knee bolster
Methods to reduce foot impact
force
•
•
•
•
• Mechanically retract brake upon impact
- foot may slip off pedal during retraction
• Allow ‘soft’ brake arm to compress into
the toepan
• Brake assembly initially stiff and against
toepan
Sidan 7
to control kinematics
to distribute impact loads
to absorb occupant energy
to maximally protect against injury
of the lower extremities
Janusz Kajzer - Kabimec Consulting
Janusz Kajzer - Kabimec Consulting
Protection of lower extremities of
vulnerable road users
General principle:
• Reduce local stiffness of the car-front components
during an impact
To be implemented by:
• using energy-absorbing material and
structure and pedestrian protection airbag (PPA)
• increasing the clearance between
hood and rigid components underneath eg. engine etc
(moveable hood)
Active safety:
• Accident free driving system, accident avoidance
system
also… speed reduction
and…….
Sidan 8