Use; Plaster Casting Technique; General Information; Advantages Of The Anatomical Shape - Otto Bock Instructions for us Instructions For Use Manual

6 Use

6.1 Plaster Casting Technique

6.1.1 General Information

The custom-made residual limb socket is of the utmost importance for the quality and wearer comfort of a prosthes­
is. For transfemoral sockets in particular, the lack of residual limb load-bearing capacity due to anatomical reasons
requires the application of special design criteria.
The connecting element between the body of the amputee and the prosthesis has to fulfil the following functions:
• Correct containment of the residual limb volume
• Secure adhesion of the prosthesis on the residual limb
• Favourable load and force transmission
• Secure guidance of the prosthesis
Arterial, venous and lymphatic circulation must not be impaired; non-physiological pressure also has to be avoided.
The various parts of the residual limb socket have to conform to anatomical features; the circumference is reduced
based on functional criteria in order to compress the residual limb.
Using the Anatomical SIT-Cast Casting Apparatus allows a systematic approach for taking plaster casts of the
transfemoral residual limb to be implemented without disregarding individual criteria. In combination with the
743A11 Otto Bock Casting Apparatus and the 743G10 Pneumatic SIT-Cast Casting Device or the 743G1 SIT-
Cast Casting Device, plaster casts are taken under load.

6.1.2 Advantages of the Anatomical Shape

The socket shape has the following advantages:
• Sitting is more comfortable thanks to the gluteus cutout, since the patient is not sitting on part of the socket (no
interference by the plastic material). This offers freedom of movement, an improved and more functional gait
pattern and, very important for the patient, an improved cosmetic appearance.
• The lower brim significantly enhances freedom of movement. Full hip flexion is possible and, depending on the
length of the residual limb and hip flexibility, the patient can achieve virtually normal external rotation up to 90
(sitting cross-legged).
• The appearance of the hip and buttocks while walking is more physiological. There is virtually no apparent dif­
ference compared to the sound side.

6.1.3 Adjustment Possibilities for Taking Casts of Anatomical Structures

The precisely adjustable casting elements serve to precisely capture anatomical structures already while taking the
plaster cast. This makes it easier to produce a custom plaster negative for the patient.
In order to follow the individual anatomy, the elements of the ramus embracing are continuously adjustable in two
dimensions.
1. The ramus angle is precisely captured by the elements of the ramus embracing. These should run parallel to
the ramus branch and are positioned more anterior compared to classic CAT-CAM sockets. At this position,
the angle is approximately 30° for the male pelvis and 40° to 45° for the female pelvis. These values are
guidelines only and should be verified on a case by case basis. During advance adjustment and while taking
the plaster cast, ensure that the elements of the ramus embracing are flush with the ischial tuberosity on the
posterior side.
2. The distance of the elements of the ramus embracing in the medio-lateral direction can be varied, and depends
on the a-p position of the elements as well as the ramus angle.
The frontal support has a recess in the medial direction to relieve pressure on the area over the adductor tendons.
It is also continuously adjustable in the anterior-posterior direction in order to set the precise a-p measurement
(between the adductor tendons and the posterior part of the ischial tuberosity). During advance adjustment ensure
that the elements of the ramus embracing are flush with the ischial tuberosity on the posterior side.
743Y50 Anatomical SIT-Cast
Use
Ottobock | 25