Installing/Removing The Knee Extender - Otto Bock C-Leg 3C98-3 Instructions For Use Manual

Preparation for use

7.1.4 Installing/removing the knee extender

CAUTION
Using the prosthesis on the patient with the knee extender installed
Falling due to unexpected prosthesis behaviour.
► Before trial fitting the prosthesis on the patient, remove the knee extender.
► Do not use the knee joint with the knee extender inserted under any circumstances during dynamic alignment
optimisation.
4
Mounting the knee extender
The knee extender has to be used for bench alignment of the prosthesis. This ensures the recommended sagittal
positioning of the prosthetic components – the foot, socket and knee joint – relative to each other and therefore
offers the full functionality of the knee joint.
1) Check whether both 8° flexion stops are mounted on the knee joint (see Page 24).
2) Turn the knee extender adjustment screw counter-clockwise, setting the knee extender to the minimum height
(see fig. 4).
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Position the middle of the foot (MF) approx. 30 mm/1.18 inch
anterior to the alignment reference line (A). This applies to all
foot components that are recommended for use with the product,
regardless of the previous alignment specifications in the instruc­
tions for use of those feet!
Noting the alignment recommendation of the foot component,
add 5 mm to the effective heel height (shoe heel height – sole
thickness in the forefoot area) and set the outward rotation of the
foot.
Place the alignment reference point (=knee axis) approx.
0-5 mm/0-0.19 inch anterior to the alignment reference line.
Take into account the knee-ground distance and outward rotation
of the knee (the adapter insert provides for a rotation of approx.
5°). Recommended sagittal positioning of the alignment refer­
ence point: 20 mm/0.79 inch above the medial tibial plateau.
Connect the foot and knee joint using a tube adapter. To do so,
tilt the joint in the correct position and set the required tube
length.
Mark the lateral centre of the socket with a centred, proximal dot
and a centred, distal dot. Mark a line through both dots from the
socket brim to the end of the socket. Use the 4H105 knee
extender (see Page 22).
Now position the socket such that the alignment reference line
passes through the proximal centre dot.
Adjust the socket flexion to 3° – 5°, but take the individual situ­
ation (e.g. hip joint contractures) and the ischial tuberosity-to-
ground distance into account.
The adjustment software helps to determine the socket flexion
precisely.
Connect the socket and modular knee joint using an adapter.
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C-Leg 3C98-3/3C88-3