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Response of the Knee Joint in Lateral Impact: Effect of Shearing Loads
Technical Paper
1990-13-0021
Published September 12, 1990 by International Research Council on Biokinetics of Impact in Switzerland
Sector:
Language:
English
Abstract
During the 80's a new type of cash impact dummy, the
rotationally symmetrical pedestrian dummy (RSPD), suitable for the
assessment of car front aggressiveness in pedestrian impacts was
developed (Aldman, 1985). This dummy enables measurement of
biomechanical parameters, such as moments and forces at the knee
joint level which are related to the injury mechanisms.
To determine the ultimate resistance to shear force or denting
moment of the human knee, it was desirable to make separate
experiments, where only one of those two parameters affects the
biological material at the time.
In this study an experimental method for assessment of the
shearing force int the lateral direction at the knee joint has been
developed. The maximum shearing force in the lateral direction the
knee could bear without injuries was determined. Injuries were
described by measurement of the knee laxity and by dissection of
the knee region.
Nineteen tests with human cadaver legs were carried out under
dynamic conditions, nine at a velocity of 15 km/h and ten at 20
km/h. The results show the necessity of discussing two different
injury mechanisms.
The first injury mechanism, which occurs at about 5 milliseconds
after impact, is directly correlated with the force generated by
the local acceleration of the biological system. The consequences
of this force are injuries at the contact point and extra-articular
injuries. The mean peak force correlated with this injury mechanism
was 180 (± 38) daN for an impact velocity of 15 km/h and 257 (±
45) daN for an impact velocity of 20 km/h.
The second injury mechanism, which occurs at about 15 - 20
milliseconds after impact is correlated with the force transferred
through the knee joint when the thigh was accelerated. The
consequences of this force are intra- articular injuries of the
knee joint. The mean peak force correlated with this injury
mechanism was 257 (± 37) daN at impact velocity of 15 km/h and
322 (± 46) daN at impact velocity of 20 km/h