rection of patellar movement.” (Lee et al, 2003 p.686)
This influence on the patella by the relative motion between the tibia and femur is echoed by Kapandji,
“During movements of axial rotation the patella displacements relative to the tibia occur in a coronal plane. In the neutral position of rotation the patellar ligament runs a slightly oblique course inferiorly and laterally. During medial rotation the femur is laterally rotated with respect to the tibia, dragging the patella laterally, and the patellar ligament now runs obliquely inferiorly and medially. During lateral rotation, the opposite movements take place: the femur drags the patella medially and the patellar ligament now runs inferiorly and laterally with a greater obliquity than in the neutral position.”(Kapandji, pg.106)
“Patella displacements relative to the tibia are therefore indispensable for movement of both flexion-extension and axial rotation.”(Kapandji, pg. 106)
What exactly is happening?
“During lateral rotation of the tibia on the femur the lateral condyle moves forward on the lateral tibial surface, while the medial condyle moves backwards on the medial tibial surface. During medial rotation of the tibia on the femur the converse is true: the lateral condyle moves backwards and the medial condyle forwards on their corresponding tibial surfaces. In reality, the anteroposterior movements of the condyles on their corresponding tibial surfaces are not identical.” (Kapandji, pg. 90)
Because of this unequal movement, the axis of rotation is NOT between the two intercondylar tubercles as many people would think, or what your college professor lead you to believe, but actually through the articular surface of the medial tubercle which serves as the central pivot point of the knee joint.
So now you’ve identified a limitation, how would you treat it?
Treatment Example: Below is an example taken from Greenman (Greenman’s Principles of Manual Medicine, Fourth Edition. Page 453), in an effort to restore normal tibia internal rotation
Position: Tibia Externally rotated
Motion Restriction: Internal rotation of tibia
- Patient is prone on the table with the operator standing at the side of the dysfunctional extremity
- Operator flexes the knee to 90 degrees and grasps the heel and the forefoot of patient.
- Operator dorsiflexes the ankle and internally rotates the tibia to the barrier.
- Patient externally rotates the forefoot against operator resistance for 3-5 seconds and three to five repeitions.
- Following each patient effort, the operator internally rotates the foot to the new barrier.
Are you treating Tibial rotation limitations in multiple stages of flexion?
Considering the obvious fact that the knee experiences a large excursion in flexion angles during sporting activity and also that patella contact pressures change as a result of knee flexion angle, (“Earlier in vitro studies have demonstrated that, in weight bearing, contact pressures within the patellofemoral joint increase as the knee flexes from 0 to 90 and decrease as the knee extends.” Lee, 2003), it is clearly warranted to treat limitations in both normal tibio-femoral along with patella and patellar tendon mobility in these various degrees of motion, and not simply in the traditional supine, table supported manner.
Closing Thoughts: Evaluating knee rotation is a critical part of any comprehensive knee pain evaluation, especially for those evaluations involving pain and swelling of a “non-specific” origin (aka: patellofemoral pain syndrome). For those that are familiar with the SFMA, limitations in multi-segmental rotation can be evaluated in a minimal amount of time and will lead you directly to this rotational component should a limitation exist. Treating this limitation should reflect the knee angle in which the restriction actually corresponds to.
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- Greenman’s Principles of Manual Medicine, Fourth Edi