Influence of a mono-centric knee brace on the tension of the collateral ligaments in knee joints after sectioning of the anterior cruciate ligament--an in vitro study.
OBJECTIVE
To analyze the influence of knee bracing on the tension of the medial and lateral collateral ligaments in anterior cruciate ligament deficiency.


METHODS
The tension of the collateral ligaments in anterior cruciate ligament deficient knees was measured with and without knee bracing using an in vitro model.


BACKGROUND
Anterior cruciate ligament deficiency increases the tension in both collateral ligaments at the knee joint. Therefore knee braces should reduce that tension increase. However, that effect has never been proven quantitatively.


METHODS
After anterior cruciate ligament-transection, the forces of the medial (anterior/posterior part) and lateral collateral ligament were measured in ten fresh human cadaver knees at 0 degrees, 20 degrees, 40 degrees, 60 degrees, 80 degrees and 100 degrees of flexion, with and without application of a mono-centric knee brace. To quantify the ligament forces, strain gauges were fixed at the bony origins of the ligaments.


RESULTS
Bracing led to a significant decrease of ligament forces (20-100 degrees: P < 0.0001) in the anterior part of the medial collateral ligament in all joint positions. In the posterior aspect, this effect was observed only at 40 degrees (P < 0.0001) and 80 degrees (P = 0.001) of flexion. In the lateral collateral ligament, bracing caused a strain reduction from 60 degrees to 100 degrees of flexion (P < 0.0001). Therefore a flexion angle dependent effect of knee bracing on the strain was seen in the posterior aspect of the medial and in the lateral collateral ligament in anterior cruciate ligament deficient knee joints.


CONCLUSIONS
Application of a mono-centric knee brace leads to a significant position dependent reduction of collateral ligament tension after anterior cruciate ligament-rupture.
Research Group for Kinematics and Biomechanics, Department of Orthopedic Surgery, University of Frankfurt, Marienburgstr. 2, 60528 Frankfurt, Germany. stefan.hinterwimmer@ch-i.med.uni-muenchen.de
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Hinterwimmer
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Graichen
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Baumgart
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Plitz
D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D001915:Braces; D002102:Cadaver; D017885:Collateral Ligaments / Q000503:physiopathology*; D006801:Humans; D066298:In Vitro Techniques; D007718:Knee Injuries / Q000503:physiopathology*; D013314:Stress, Mechanical