Biomechanics of the Knee Flashcards
Biomechanics
If the frontal plane angle of the knee is less than 170° it is called excessive genu ____, or “knock-knee”.
Knee
Valgum
Biomechanics
If the frontal plane angle of the knee is greater than 180° it is called genu ____, or “bow-leg”.
Knee
Varum
Biomechanics
Describe the articulation at the tibiofemoral joint.
Knee
Two articulations between large, convex femoral condyles (medial and & Lateral) and nearly flat, smaller tibial condyles
Biomechanics
What two muscles dynamize the medial meniscus?
Knee
- Quadriceps Femoris
- Semimembranosus
Biomechanics
What three muscles dynamize the lateral meniscus?
Knee
- Quadriceps Femoris
- Semimembranosus
- Popliteus
Biomechanics
Does complete lateral meniscectomy increase or decrease peak contact pressures at knee?
Knee
Increase.
230%
Biomechanics
During tibial-on-femoral knee extension, arthrokinematically the tibia rolls ____ and glides ____ . The medial condyle rolls (more or less) than the lateral side, causing ____ rotation of the tibia.
Knee
Anteriorly
Anteriorly
More
External
Biomechanics
What benefit does the patella provide during knee extension?
Knee
Improves Mechanical Advantage of Quads
Biomechanics
What are the retropatellar forces during the following activities?
* Walking
* Jogging
* Deep squat
Knee
Walking = 0.5x body weight
Jogging = 7x body weight
Deep Squat = 20x body weight
Biomechanics
During what degree of motion is the ACL most vulnerable? Why?
Knee
15-30° of knee flexion
* Accepts most anterior translation at 30°
* Accepts most IR force at 30°
* Most slack between 20-50°
* Poor hamstring force 20° and under
Biomechanics
The ACL accepts the most load in (flexion or extension); whereas, the PCL accepts the most load in (flexion or extension).
Knee
- Extension
- Flexion
Biomechanics
Which ligament of the knee is best at limiting external valgus forces?
Knee
The Medial Collateral Ligament
Biomechanics
The medial tibial plateau accepts (more or less) weight than the lateral side and has a meniscus that moves (more or less) than the lateral side.
Knee
- More
- Less
Biomechanics
Describe the movement and femoral contact of the patella during knee flexion.
Knee
The patella glides inferiorly in a ‘C’ shape during knee fleixon. Patellar contact against the femoral condyles starts inferiorly, moves superiorly, and finishes laterally.
Biomechanics
Freedom of knee axial rotation ____ with greater flexion, totaling ____ degrees of rotation at 90° flexion.
Knee
Increases
45°
