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Tracking Motion in the Patella and Menisci By Mary Ann Foster The cartilage in our knees is like the tread on a tire. If the tires are misaligned, the tread wears down unevenly and prematurely. The same thing occurs in the knees. Over time, and with repeated compressive loading, the underlying patellar cartilage and menisci undergo gradual deterioration. Faulty tracking can hasten this process and prematurely wear down vulnerable structures in the knee. We use the word tracking in two contexts: to describe the actual movement inside the joint, and to describe the clinical skill of observing pathways of movement. Knee-tracking exercises can be used to assess joint mechanics and minimize mechanical stress on the knee during passive movement techniques. In the last column on knee rotations, we tracked axial rotation during knee flexion and terminal rotation during knee extension. In this column, we will look at pathways of motion that occur in two unique structures of the knee: the patella and the menisci. PATELLA MOTION The patella serves as an anatomical pulley to give the quadriceps a corner to pull around. It slides up and down in the intercondylar groove, or notch, along a curved pathway of motion (Image 1). Thick hyaline cartilage underlying the patella protects the knee from extreme compression and friction generated by contraction of the quadriceps during activities such as walking up or down a hill, which places 200–300 pounds of pressure on the patella. You can track patellar motion by lightly holding the kneecap while slowly flexing and extending the knee. Muscular pulls on the knee must be balanced for optimal patella tracking (Image 2). Muscular imbalances can trigger inflammatory conditions that produce scarring in patellar cartilage, restricting its gliding motion along the intercondylar groove. For example, when the lateral quadriceps overpowers the medial quadriceps, the patella is pulled laterally off its ideal track. This can lead to the many painful conditions exacerbated by joint motion, such as arthritis and/or the deterioration of patellar cartilage called chondromalacia. 104 m a s s a g e & b o d y w o r k j u l y / a u g u s t 2 0 1 4 technique THE SCIENCE OF MOVEMENT 2 Lines of pull of the quadriceps. 1 Tracking pathway of the patella in the intercondylar groove. Medial epicondyle Lateral epicondyle 20º 60º 90º 135º Knee flexion