Osgood Schlatter is a guy that most kids don’t really want to meet. He’s not friendly, and often leads to painful anterior tibial tuberosities in growing kids. While commonly attributed to a “traction” based strain on the tibial tuberosity from the strong contractions on the quadriceps groups during jumping, running, cutting, and landing, however, like with most things, there are other factors that need to be taken into account. A number of theories exist including pronated feet, relative internal roation of the lower extremeities, tibial torsion, and ankle mobility.
Tibial torsion has been implicated by Gigante and colleagues, who found that those with the greatest angles of external tibial rotation the greater shear forces were placed across the tibial tuberosity during knee extension (screw home mechanism), and found that those symptomatic had significantly greater angles to tibial external rotation compared to those who did not have pain.
The significance of tibial torsion is great in considering high quality movement and determining the appropriate selection of exercises. When the tibia is locked in such positions, shifting into the ipsilateral hip becomes significantly more difficult, which ultimately will lead to inefficient gait and places the knee at greater risk of degenerative complications. While not all cases are easily managed, you’ll often find runners with short and stiff TFL and ITB to exhibit greater external tibial torsion.
Naturally, from a movement perspective, we should be sure to address the issue from the hip with by improving hip flexion ability, reduce the tone of the TFL, improving mobility of the ITB over VL, and then we can look to improve from the ground up. There are a number of good MET techniques that can be used to help eliminate exogenous tension at the hip and help restore better interaction of the tibi0femoral joint.
Sarcevic observed in those with OS that the majority of the subjects displayed highly limited dorsiflexion range of motion (most <10 degrees). This lack of dorsiflexion mobility forces greater demand for tibial IR motion, pronation, hip, and knee flexion. As the quadriceps contract eccentrically during the stance phase, requiring more knee flexion is not a recipe for unloading the tibial tuberosity.
Commonly, however, you’ll notice that athletes display both poor talocrural mobility AND the restrictions at TFL and ITB. In this case, it is often that the subtalar joint needs to be addressed as the ankle is locked into inversion.
Should this be the case, a complementary grouping of sound mobility work from the hallux (are they externally rotating the limb to get around a big to restriction?) to the hip seems like it may be a smart play.
As you can tell, everything affects everything, so we should keep that in mind. Simply because a knee is hurting, there are a number of joints (and structures that influence those joints) that may be to blame.