HOW DONJOY 4-POINTS-OF LEVERAGE PROTECTS ACL
Anterolateral Instability
Patients with an ACL deficient knee have an anterolateral instability that causes the knee to give way.
Rotation Compotent
Ant.
It is very difficult to control instability in an ACL deficient knee in a direct way using a knee brace.
ACL Rupture
ACL
Indirect stabilisation of the knee is achieved with the biomechanical 4 point design of the DonJoy brace.
Lat.
PCL
Med.
The 4-point system is clinically proven to be the most effective way to prevent anterior translation of the tibia.
A DonJoy brace will provide a high level of stability for the ACL deficient knee by effectively reducing or preventing the anterior tibial translation through the use of the 4-points-of-leverage.
Post.
Anterior Compotent
FOURCEPOINT HINGE TECHNOLOGY
Aggressive eccentric contractions of the quadriceps produce significant anterior tibial translation and can injure the ACL or permanently stretch out an ACL graft (DeMorat et al., AJSM, 2004). Additional studies show quadricep-intensive activities should be avoided at joint angles, particularly the last 30 degrees of extension, when strains are at a maximum. Enovis has developed a hinge to address maximising ACL and ACL graft protection in these “at risk” positions. Small knee flexion angles at initial contact during landing tasks may contribute to ACL injuries. The FourcePoint Hinge can be used to control joint range of motion by increasing the knee flexion angle during landing, resulting in a decrease of anterior shear force on the ACL by 9-13% (Garret and Yu, AJSM, 2004).
FLEXION
EXTENSION
The DonJoy FourcePoint utilises a spring mechanism in the hinge to apply gradually increasing resistance during knee extension. The resistance engages in the last 25 degrees of extension (relative to the extension stop). The hinge has three levels of resistance with the option to turn off resistance if appropriate. THE RESISTANCE SERVES THREE CRITICAL ROLES: • First, it reduces the time spent near full extension or in the “at risk” position • Second, it increases the posterior load applied by the brace on the tibia to prevent anterior tibial translation • Third, it eliminates the extension shock felt when a patient extends into a 10 degree standard rigid stop
FourcePoint Hinge Technology works to enhance DonJoy’s 4-Points-of-Leverage design by damping knee joint extension, which improves the mechanical performance of the brace and reduces shear forces at the knee. Addressing the “at-risk” position, the hinge resistance engages in the last 25 degrees of knee extension. The FourcePoint hinge combined with the 4-Points-of-Leverage cuff and strapping design provides a more comfortable brace that reduces anterior shear forces at the knee. This is beneficial for patients as it reduces strain on the healing ACL graft, providing stability to an unstable, ACL deficient knee or for prophylactic use.
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