Taking The Plaster Negative; Fabricating The Test Socket; Determining The Alignment Reference - Ottobock 7E9 Gebrauchsanweisung

Use 2Z11=KIT
INFORMATION: The connection area of the prosthetic knee joint can be protected against
scratches with the protective film of the 2Z11=KIT during alignment in the workshop and testing
in the trial fitting area.
► Use the protective film as illustrated in the accompanying document for the 2Z11=KIT.
► Remove the protective film before the patient leaves the fitting area.

5.1 Taking the Plaster Negative

Recommended equipment:
>
743A11 Casting Apparatus, 743G5 Hip-Cast Casting Apparatus (includes 743Y26 Pressure
Block)
► Take the plaster negative using the Hip-Cast plaster casting technique. Ensure that the anteri­
or pressure block is applied with 5° exterior rotation.

5.2 Fabricating the Test Socket

1) With the help of the plaster negative, cast and model a plaster positive.
2) Vacuum form the test socket and fit it to the patient.

5.3 Determining the Alignment Reference

Determining an alignment reference in a neutral position of the hip prosthesis socket determined
under load is required for the sagittal placement of the hip prosthesis socket in the prosthesis
system. In this neutral position (see fig. 4), the patient perceives virtually no anterior or posterior
tilting moments acting on the hip prosthesis socket in the sagittal plane, and the pelvic tilt position
is as physiological as possible.
Recommended tools:
>
743A29 Reference Determination Tool (see fig. 3)
1) Adjust the height of the casting table to the ischial tuberosity to ground distance of the patient.
2) Place the patient, with optimally applied hip prosthesis socket and without prosthetic compon­
ents, on the casting table with the prosthesis side, observing the following criteria:
- Straight stance, balanced at pelvis height
- Foot and centre of the body are in one line in the a - p direction
3) Lower the plate of the casting table by the height of the reference determination tool
(approx. 4.8 cm).
4) Position the centre of the reference determination tool between the bottom of the hip pros­
thesis socket and the plate of the casting table, subject to the following criteria:
The reference determination tool must be positioned approximately 5 – 6 cm lateral from the
medial socket edge. Align the base plate of the reference determination tool parallel to the
edge of the casting table.
5) Determining the neutral position (TMS: partial mass centre of gravity):
First, place the reference determination tool in the maximal anterior position. The patient will
perceive a backward tilt of the hip prosthesis socket (see fig. 5).
Then place the reference determination tool in the maximum posterior position. The patient
will perceive a forward tilt of the hip prosthesis socket (see fig. 6).
In small increments, reposition the reference determination tool in the sagittal plane between
the maximum positions until the user perceives neither a forward nor a backward tilt (neutral
position) (see fig. 4).
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