C-Leg compact Prosthetic System
32 | Ottobock
3.2 Bench Alignment Using an Alignment Tool such as L.A.S.A.R. Assembly
INFORMATION
To align the prosthesis please proceed in two steps:
First make the bench alignment using an alignment tool such as 743L200 L.A.S.A.R. Assembly.
In a second step, the static alignment is optimized with the 743L100 L.A.S.A.R. Posture (see Section 2.5 “Static
Alignment Optimization”).
A
5 mm
2
4
3°-5°
A
M
MF
+ 5 mm
23
1
MF
+ 5 mm
A
30 mm
M
A correct bench alignment (e.g. using the 743L200 L.A.S.A.R. Assembly) ensures that the user can benefit from all the
advantages of the C-Leg compact. The optimal residual limb position must be anticipated when positioning the socket
connector. Plumb lines in the frontal and sagittal planes (drawn from the hip joint’s centre of rotation and marked dur-
ing plaster cast taking and trial fitting of the test socket) will facilitate correct positioning of the lamination anchor or
socket adapter.
•
Position the middle of the foot (MF) approx. 30 mm anterior to the alignment reference line (A). This applies to all
feet that are recommended for use with the C-Leg compact, independently of the specifications in the Instruction for
Use of those feet!
Add 5 mm to the required heel height. Set correct outward rotation of the foot (Fig. 1).
• Clamp the knee joint with the mounted tube adapter into the alignment tool. Place the alignment reference point
(=knee axis) approx. 0 – 5 mm anterior to the alignment reference line (Fig. 2). Consider the knee-floor distance and
outward rotation of the knee (approx. 5° are provided for by the adapter insert in the L.A.S.A.R. Assembly). Recom-
mended positioning of the alignment reference point: 20 mm above the medial tibial plateau.
• Connect the foot to the modular knee joint using a tube adapter. To do so, tilt the joint in the correct position and set
the required tube length (Fig. 2).
•
Mark the centre of the socket proximally (M) and distally on the lateral side. Draw a line through both marks from
the socket brim to the distal end of the socket (Fig. 3).
Now position the socket such that the alignment reference line (A) passes through the proximal centre mark (M).
Set the socket flexion to somewhere between 3° and 5°; however, the individual situation (e.g. hip joint contractures)
must be taken into account and, if necessary, more flexion should be provided. Also pay attention to the ischial
tuberosity-to-floor distance (Fig. 4).
