الفهرس 
INTRODUCTION
Patellar retinaculumOnly 14 pages are availabe for public view
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Abstract
Patellar fractures account for about 1% of all fractures. They are most
common in people who are 20 to 50 years old. Male to female ratio is
(2:1). Bilateral injuries are uncommon. The aim of the work in this study is
assessment of the results of surgical management of patellar fractures by
different methods.
The patella is the largest sesamoid bone. It is embedded in the tendon of
quadriceps femoris, anterior to the knee joint. The patella is flat, distally
triangular, proximally curved, and has anterior and posterior surfaces,
three borders and an apex.
The main function of the patella is to displace the quadriceps tendon–
patellar tendon linkage away from the axis of knee rotation. This action
increases the effective moment arm of the quadriceps mechanism and
contributes the additional 60% of torque that is needed to gain the last
15°of knee extension .This second action therefore creates a mechanical
advantage analogous to that of a pulley.
Patella fractures result from direct or indirect forces. The majority of
patella fractures occur from direct injuries such as a blow to the patella
from a fall, a motor vehicle crash, or some combination of these. Indirect
injuries occur from a near fall, a fall from a height, or as a combination
injury. This type of injury occurs when the forces from the extensor
mechanism exceed the intrinsic strength of the patella.