Otto Bock 17CF1 Series Instructions For Use Manual page 15

INFORMATION
Orthosis alignment
Ottobock recommends checking the alignment of the orthosis using the L.A.S.A.R. Posture or
L.A.S.A.R. Posture 3D and adapting it as needed.
Fabricating a plaster model
Due to the design of the carbon spring, make sure the plaster cast is taken with slight outward
rotation. Request the information on the plaster casting technique if required (Fabricating a
plaster cast – KAFO (knee-ankle-foot orthosis): 646T5411*). Raise the heel slightly by approx. 15
to 20 mm (see fig. 2) for better positioning of the carbon spring below the foot in the plaster cast.
The enclosed template may be used for the sagittal positioning of the lower leg (use small tem­
plate for sizes 10 to 12).
Installing the carbon spring
Prerequisite: The patient-specific plaster model has been fabricated.
1) Pull a layer of Perlon stockinette over the plaster model and fabricate the lining using 5 mm of
Pedilin (see fig. 4). The 5 mm material thickness can be used for all size models.
2) Mark the fixation zone and movement zone for the carbon spring, dividing the model into the
zones 1 and 2 (see fig. 3, see fig. 5).
3) Mark the carbon spring below the foot, with the length extending up to approx. 20 mm before
the rollover zone of the foot (see fig. 6).
4) Optional: Shorten the carbon spring, at most up to the mark. Deburr and round the cut
edges (see fig. 7).
5) Create the structure for the carbon spring on the lining using several layers of Pedilin and by
sanding (see fig. 8).
6) Align the carbon spring in the foot component in the direction of the second foot ray (see
fig. 9).
7) Contour the Pedilin structure under the carbon spring, avoiding cavities under the carbon
spring (see fig. 10).
8) Secure the carbon spring on the model with PVA adhesive tape and pull on a layer of Perlon
stockinette (see fig. 11).
9) For vacuum forming, use homo-polypropylene with a thickness of 4 mm for all carbon spring
sizes (see fig. 12).
10) Mark the course of the edge and remove the orthosis from the cast. Then separate the calf
component from the foot component according to the markings (see fig. 13).
11) Use a ruler to mark the centre of the bores on the calf component (see fig. 14).
12) Mark the bores on the foot component. The proximal bore runs in front of the curve of the heel
(see fig. 15).
13) For the holes in the orthosis shells, use a 4 mm drill bit for an M4 thread and a 5 mm drill bit
for an M5 thread (see fig. 16).
14) Transfer the bore holes to the carbon spring (see fig. 17).
15) For the 502E3 welding nut, drill a 5 mm hole for an M4 thread and a 6.5 mm hole for an M5
thread (see fig. 18).
16) Deburr the bore with a 726S9=90x11.5 counterbore (see fig. 19).
17) Press in the welding nut (see fig. 20). To achieve an optimal fit of the bores, screw on the
upper section on a trial basis and check the positions of the remaining bore holes. Repeat
steps 14 through 16.
18) Assemble the carbon spring with the orthosis using the supplied screws, countersunk wash­
ers and welding nuts and secure with Loctite 241 (see fig. 21).
19) Ottobock recommends positioning the sagittal load line approx. 15 mm in front of the knee
compromise pivot point according to Nietert (see fig. 22).
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