7. Osteokinematics
(Axial) Rotations Valgus and varus
At 90o flexion
Medial Rotation= 0-15o
Lateral Rotation= 0-30o
In Extension = 6-7o (only
passive)
With 20o knee flexion = 13o
7
Axial rotation increases with knee flexion.
Total rotation in 90o flexion = 40- 45o
External rotation to internal rotation= 2:1
Naming the rotation- based on orientation of tibial
tuberosity
8. Osteokinematics
8
Naming the rotation- based on orientation of tibial
tuberosity with respect to distal anterior femur
Neumann, 2010
18. Automatic or terminal rotation
Coupled motion of lateral rotation and
extension of knee
Non-voluntary (Automatic)
Locks the knee joint
Keeps knee to remain in full extension in
standing
18
19. Non weight bearing
A-P diameter of Lat F condyle < Med F condyle
During last 30° of extension, glide and roll in
Lateral condyle finishes but not in medial
condyle
Lateral condyle serves as an axis for the medial
condyle to rotate backwards i.e. Lateral rotation
of tibia on femur occurs
19
20. Non weight bearing
This is locking of knee or Screw Home
Phenomenon
Locking makes all ligaments taut
20
21. Non Weight Bearing: Unlocking
Knee flexes only if unlocked
It happens with medial rotation of tibia on
femur
Unlocking is brought about by Popliteus
muscle
21
22. Weight bearing
Locking: femur rotates medially on relatively
fixed tibia during last 30° of extension
Unlocking: lateral rotation of femur on tibia
before flexion proceeds
22
23. Factors guiding Screw home Rotation
Shape of Medial femoral condyle
Tension in ACL
Lateral Pull of the Quadriceps
23
25. References:
Norkin C, Levengie P. Joint structure and
function. 4th Edition
Neumann DA. Kinesology of musculoskeletal
system, Foundation for Physical Rehabilitation,
2nd Edition
Kapandji IA. The Physiology of Joints. Volume 2,
Lower Limb. 5th Edition
25
Notes de l'éditeur
Evolute is the curved path… that medial lateral axis takes
Average axis of rotation is close to lateral epicondyle. This movement causes rubbing of the skin in hinged braces + movement of goniometer during joint ROM assessment.
Axial rotation increases with knee flexion. Total rotation of about 40- 45 degrees. External rotation to internal rotation= 2:1
Minimal rotation at 0 degrees of knee extension
Naming the rotation- based on orientation of tibial tuberosity in respect to anterior distal femur
Naming the rotation- based on orientation of tibial tuberosity in respect to anterior distal femur
Posterior rolling in flexion
Posterior rolling in flexion
Anterior glide in flexion and vice versa
Different from the rotation described earlier
In both closed or open kinematic chain, the knee joint laterally rotates (femur internal rotation in closed and tibia external rotation in open KC)
Medial condyle curves about 30 degrees laterally as it approaches intercondylar groove. Also articular surface of medial condyle extends farther anteriorly than lateral condyle, the tibia is obliged to follow the laterally curved path into full tibial on femoral extension.