Within each type of knee system are
also several different implant
designs. The surgeon chooses the
implant style based on his technique
and the patient's anatomy, but here's
a quick overview of some of the dif-
ferences.
• Implant designs. A surgeon can
choose from 4 different implant
designs, depending on their manu-
facturer's availability within a partic-
ular system: cruciate-retaining (CR),
posterior-stabilized (PS), bicruciate-
retaining (BCR) and unicompartmen-
tal. CR implants let the surgeon pre-
serve the patient's posterior cruciate ligament, if it's still intact.
However, PS implants let the surgeon remove the ligament and replace
it with a cam-and-post system. BCR designs are relatively new to the
market and are designed to save both the anterior and posterior cruci-
ate ligaments. Unicompart-mental knees replace just one side of the
joint and work well in outpatient settings, though they are less common
than total joint replacement.
• Fixation. While some implants are attached using fast-curing bone
cement, cementless prostheses are made of a material that attracts new
bone growth to keep the device in place. Both approaches work well, says
Paul W. Manner, MD, a professor at the University of Washington School
of Medicine and author of AAOS's OrthoGuide to Knee Replacement
IMPLANTS
Which Style Implant to Choose?
• IMPLANT DECISIONS After you choose a knee
system, your surgeons will need to select an implant.
