Chapter 29: Knee orthoses for sports-related disorders Flashcards
What are the three categories of knee orthoses?
Prophylactic braces
Functional braces
Rehabilitative braces
What is femoral rollback?
As knee flexion starts in full extension, the femoral condyle begins to roll without sliding, and with further knee flexion sliding becomes more predominant.
Why does axial rotation occur at the knee?
Because of a differential radius of curvature between the medial and lateral femoral condyles, the convex shape of the medial tibial plateau, the concave shape of the lateral tibial plateau, and the ability of the MCL to stretch more rapidly than the lateral collateral ligament.
So, as the knee flexes, there is inward rotation of the tibia, where the opposite occurs with extension.
What are the most common knee injures?
Injuries to the ACL, PCL, and MCL
The ACL is the primary restraint for what?
Anterior tibial displacement
The PCL is the primary restraint for what?
Posterior tibial displacement
The PCL is the secondary restraint for what?
External rotation
With PCL rupture what occurs?
Posterior subluxation of the tibia on the femur, which results in increased contact pressures in the patellofemoral joint and medial femoral condyle.
What makes the PCL and MCL different from the other ligaments?
They are made of fibroblastlike cells so it has the ability to heal itself.
What percent of knee injuries are PCL injuries?
3-37%
Most knee MCL injuries are due to what?
Significant valgus stress applied to the lateral aspect of the knee
The MCL provides retraint for what?
Valgus loading and external tibial rotation.
Prophylactic braces are mostly used by what to prevent what?
Football and lacrosse players to prevent MCL and ACL injury.
What does the prophylactic knee brace attempt to do?
Limit the strain on the MCL and ACL by redirecting a lateral impact force away from the joint line to points more distal on the tibia or femur.
Prophylactic knee bracing may cause what?
Increased injury and severity to the MCL
