Determination Of System Height - Otto Bock Genium X3 Setup Manual

3 Determination of system height

Crucical for component selection
In order to take proper positioning into account, Ottobock
specifies an alignment reference point and 2 system heights
for every knee joint. The portion of the total system height
that is situated above the alignment reference point is called
the proximal system height; the portion below the align-
ment reference point is called the distal system height. Mini-
mum and maximum values are specified when using tube
adapters that can be cut to length.
Positioning the alignment reference point 20 mm above the
medial tibial plateau (MTP) is recommended. The distance
between the alignment reference point and floor is also
called the knee axis-floor measurement. It corresponds to
the MTP-floor measurement plus 20 mm.
The minimum distal system height of the knee prosthesis
system (joint and tube adapter) combined with the system
height of the foot is the minimum distal structural height
of the prosthesis. It corresponds to the minimum required
knee axis-floor measurement for the user. For users of
Structural height
measurement
6 Ottobock | Genium X3 Set-up Guide
MTP-floor
smaller stature in particular, this measurement can have a
pronounced impact on the selection of prosthesis compo-
nents and is therefore of great importance.
An example: After measuring from the socket end to the
floor, you have a structural height of 58 cm for various com-
ponents. Then you measure the MTP-floor distance – for ex-
ample 49 cm. Your calculated knee axis-floor distance then
measures 51 cm. To find out whether the available MTP-floor
distance for the user is sufficient to integrate the desired
components, you simply need to check if the knee axis-floor
distance (MTP-floor distance + 20 mm) is greater than/equal
to the minimum distal structural height. Using the figures
from the example above, you can opt for a prosthetic system
with a minimum distal structural height of 51 cm or less.
The overview below not only illustrates the composition
of the minimum distal structural height, but helps you to
select the prosthetic foot.
Proximal structural height
+ 20 mm
Distal structural height
Proximal system height,
Genium X3
Distal system height,
Genium X3
Tube adapter system
height (variable)
Prosthetic foot
system height