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Health Sciences & Medicine
Pages 8 (2008 words)
Introduction: In view of the frequent problems involving the patellofemoral joint, it is interesting and remarkable that for much of the time, the articulating surfaces of this joint are not in contact with each other. While there is no bone-on-bone contact with the femur in full knee extension or while standing or walking on the level ground, the extent of contact between the patella and the femur appears to vary depending on a number of factors, such as, the angle of knee flexion, the location of the contact, the surface area of contact, and the patellofemoral joint reaction force (Ficat and Hungerford, 1977, 85-109).
This increasing force is transmitted by the quadriceps and is somewhat dissipated by the increased patellofemoral contact with increasing flexion. However, because the force increases more rapidly that the available surface area, with increasing flexion, the stress on the patella increases in a significant manner. In this scenario, any muscle imbalance between the lateral and medial quadriceps muscles can affect the patellar alignment and pressure distribution in the lower flexion angles of less than 60 degrees resulting in rotation of the patella in the coronal plane. At higher flexion angles, imbalances are likely to produce a tilt of the patella in the sagittal plane (Lopis and Padron, 2007, 27-43).
Patellofemoral joint reaction force causes compression of the patellofemoral joint. These forces are caused by the increase in patellar and quadriceps tendon tension and the increase in the acquity of the Q angle that occurs during knee flexion. ...
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