The patella is attached to the quadriceps tendon at its upper pole and attached to the patellar tendon at its lower pole which is inserted into the tibial tuberosity. The centering of the patella in the trochlear groove is related to the strength of the vastus medialis obliqus and the medial patello-femoral ligaments which pull the patella medially while the vastus lateralis and the lateral patello-femoral ligaments pull the knee cap towards the lateral aspect of the knee joint.When all of these factors are in proper alignment, the patella is centered in the trochlear groove of the femur. An understanding of the normal function of the patello-femoral joint is essential for any evaluation involving patello-femoral dysfunction, such understanding results from an integration of the anatomy and biomechanics. Patellar maltracking is a mechanical problem and occurs usually laterally.