الفهرس 
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Abstract
The patellofemoral joint is complex and often misunderstood region of the knee. Knowledge of the anatomy of this joint is continuously evolving and this knowledge is very important to find better methods to treat patients with patellofemoral articulation pathology. (1) Patellofemoral motion requires a complex interaction of the bones and soft tissue structures. Anatomic abnormalities of the bones cause malalignment and may predispose to patella maltracking. Abnormalities of the dynamic and static soft tissue structures have significant effects on patellofemoral biomechanics.
As a sesamoid bone, the patella enhances the mechanical advantage of the extensor mechanism. Functioning as a lever, the patella acts to magnify either force or displacement, depending on the activity and helps to increase the moment arm of the quadriceps. This decreases the amount of quadriceps force necessary to extend the knee. (2)Isolated patellofemoral arthritis is a relatively frequent problem, especially in female patients presenting with knee pain. McAlindon et al, 1992,(3) reported an incidence of 24.3% and 11.0% in women and men aged >55 years with knee pain, respectively. Isolated patellofemoral arthritis was also identified in 3.8% of asymptomatic controls. In a later review, Davies et al, 2002, reported a 9.2% frequency in a consecutive series of 174 patients older than 40 years presenting with knee pain. When looking at patients older than 60 years, the disease was present in 13.6% of women and 15.4% of men.
The causes of isolated patellofemoral arthritis are generally divided into primary and secondary arthritis, the last including trochlear dysplasia, malalignment and post-traumatic. Clinically patellofemoral arthritis may present by pain on grinding the patella crepitation, peripatellar tenderness, pain on compression of the patella, limitation of patellar mobility and Clarke’s test (positive when patients complained of pain during.