How
do
you
tear an ACL?
Well the short answer is "all too easily" for me unfortunately; I've torn both within the last couple of years and am currently doing physical therapy from the one I had operated on this last spring. The most common mechanism of injury seems to be during sports in which there is a lot of quick pivoting, rapid decelerations, sudden changes in direction, landing stiff legged from jumps, and sometimes even car accidents that cause large forces to strike the knee (www.sportsci.org)(www.wikipedia.org)
Sports like football, skiing, soccer, floor hockey, and other field sports have high occurrences of ACL tears (www.nlm.nih.gov)(Remer et al, 1992).
The motions that have been most linked to ACL failure (most common motions to least common motions) are (Remer et al, 1992):
1) Internal rotation with valgus (knock kneed; knee bent and pointing inward) stress.
2) Hyperextension of the knee joint.
3) Varus stress with external rotation (bow-legged: knee bent and pointing outward) stress.
90% of the time the ligament will tear in the "middle substance" while the other 10% of the time it will tear at the attachment points (Remer et al, 1992). When it tears, patients often describe a popping noise associated with intense pain and often people will complain that their knee is "going out" on them (www.orthopedics.about.com). The joint often swells up within six hours and
becomes very stiff and painful to bear weight upon (www.medicinenet.com)(www.nlm.nih.gov).
Well the short answer is "all too easily" for me unfortunately; I've torn both within the last couple of years and am currently doing physical therapy from the one I had operated on this last spring. The most common mechanism of injury seems to be during sports in which there is a lot of quick pivoting, rapid decelerations, sudden changes in direction, landing stiff legged from jumps, and sometimes even car accidents that cause large forces to strike the knee (www.sportsci.org)(www.wikipedia.org)
Sports like football, skiing, soccer, floor hockey, and other field sports have high occurrences of ACL tears (www.nlm.nih.gov)(Remer et al, 1992).
The motions that have been most linked to ACL failure (most common motions to least common motions) are (Remer et al, 1992):
1) Internal rotation with valgus (knock kneed; knee bent and pointing inward) stress.
2) Hyperextension of the knee joint.
3) Varus stress with external rotation (bow-legged: knee bent and pointing outward) stress.
90% of the time the ligament will tear in the "middle substance" while the other 10% of the time it will tear at the attachment points (Remer et al, 1992). When it tears, patients often describe a popping noise associated with intense pain and often people will complain that their knee is "going out" on them (www.orthopedics.about.com). The joint often swells up within six hours and
becomes very stiff and painful to bear weight upon (www.medicinenet.com)(www.nlm.nih.gov).
Title Page
How do you tear an ACL?