Making the Positive Cast

To make the positive cast, you need two alignment aids. Use alignment aids with a square of 11 x 11 mm for system ankle joints in system widths of 10 and 12 mm. Use alignment aids with a square of 15 x 15 mm for all other system joints. Clean both alignment aids before using them. In addition, you need an awl, a cordless drill, a step drill and a knife.

Prick a hole through the plastered washer at the lateral pivot point at ankle height using an awl. Repeat the procedure at the medial pivot point at knee height.
You can find the steps for positioning the washer under “2 – Preparing the cast”.

Use a step drill to enlarge the hole at the lateral pivot point at ankle height. Bear in mind that the diameter of the hole has to be smaller than the alignment aid’s width in order to ensure a fit that is free of play.
Repeat the procedure at the medial pivot point at knee height.

Cut the hole at the lateral pivot point at ankle height with a knife so the alignment aid can be guided through the plaster.
Repeat the procedure at the medial pivot point at knee height.

Define the alignment of the mechanical axes by pricking a small hole in the opposite plaster layer with the tip of the alignment aid at the medial pivot point at ankle height. Bear in mind that the alignment aids must be positioned at an angle of 90 degrees to the direction of movement and parallel to the ground and to each other. Repeat the procedure with the alignment aid at the lateral pivot point at knee height.

Prick the holes at the medial pivot point at ankle height and at the lateral pivot point at knee height with the help of the markings.

Attention! The alignment aids must not be insulated because otherwise the adhesive connection of the holders with the plaster will not be sufficient later. Stick the alignment aids through the respective holes. Insert a metal bar into the negative cast. Check the parallel alignment of the alignment aids again and fix them with longuettes. Close the cutting edge.

Fix the negative cast and the metal bar to prevent it from tipping over. Fill the negative cast with plaster. Afterwards, access the joint angles of the individual normal posture with e-Cast and make adjustments if necessary. Wait until the plaster has completely hardened. Remove the alignment aids and the e-Cast sensors. Remove the negative cast in order to receive the positive cast.

The square holes at knee and ankle height produced by the alignment aids are at an angle of 90 degrees to the direction of movement and parallel to each other and the ground.