Step-by-Step Lamination
Follow this process for the Proprio Foot battery dummy and Coyote pin system
By Jim Coleman and Jed Newhardt
O&P Almanac, JANUARY 2010

The following will outline the proper placement of the Proprio dummy plate used to laminate a socket resulting in a definite impression for the Proprio Foot battery pack placement on the posterior of a below knee (BK) socket. You may use your shops standard layup for this lamination, although this article will suggest certain materials as well as precautions at particular steps in order to position and laminate the dummy plate unit in its proper position on the posterior of the BK socket.

Photo 1 shows a BK socket made with an inner one-fourth inch Proflex liner formed on the socket with a Coyote unit attached to the distal end of the cast. This is now ready for the lamination layup.

To start the lamination, pull a PVA bag over the cast. Depending on the patient’s weight and activity level, you should start your layup with a double-layered carbon braid pulled over the cast. Follow with 4 inches of nyglass, then tie distally to hold all material in place. Instructions from the Coyote lamination kit should be followed to cut holes to expose the four screws on the bottom of the Coyote unit. At this time, place the Proprio dummy plate on the posterior section of the cast. The bottom of the dummy unit should be approximately three-quarters to 1 inch up from the posterior seat of the cast with the cast sitting upright in a vise with the pipe securing it in place.

As you hold the dummy unit in position, pull another 4 inches of nyglass over the unit and tie the nyglass distally to hold the unit in its proper place for lamination (see photo 2). Recheck the position, as this is very important for a definitive lamination position.

Continue layup with a reflected carbon braid as the outer layer. Then, cut the material over the four screw inserts on the Coyote laminating plate and insert the four screws supplied in the Coyote kit. Also, when placing the dummy in position, make sure the far left stem of the dummy is laying over the edge of the posterior seat on the left side. This will aid in the trimming process, after lamination.

After the lamination cures and the socket is removed from the mold, use a sander to sand the surface of the Proprio dummy to expose the entire surface of the unit (see photo 3).

Remove the dummy unit from the socket. You may need to use a small flat instrument to lightly pry the dummy from the socket. After you remove the dummy unit, notice the two black or dark holes in the center of the dummy. Ossur makes these holes on the unit to help the lamination become saturated with resin through the dummy plate.

You will now notice the discreet outline made by the dummy unit on the posterior section of your socket. Notice in photo 4 that the right side of the dummy stem is over the edge of the posterior seat. This will create the necessary clearance to insert the charging cable into the battery.

As shown in photo 5, grind out the indent on the left side of the dummy socket area to accommodate the power connection cable to the foot from the battery. The best tool for grinding out the indent is a small hand grinder.

After you check for enough space to accommodate the battery, place a Velcro hook and loop on both the socket and back of the battery. Make sure the upper (right side) battery charger connection and the lower (left side) power connection have enough relief to accommodate both cords after installation of battery pack. Photo 6 shows this section of battery installation against the finished socket.

The battery pack will fit snuggly against the relief area to prevent lateral displacement. Photo 7 shows the finished socket in place with the battery and with the Proprio Foot attached. Finally, there are different lamination layups and socket attachments for various patient conditions and needs, but the dummy unit placement will remain with the same finishing procen Technician’s Cornerdures regardless of what the BK socket prescription may require.





Photo 8 shows two very satisfied people: Ken Doe, CPO, and his patient, Stan Zucker.

Ralston (Jim) Coleman has been a prosthetic technician for more than 34 years at Boas Surgical, Inc. in Allentown, Pennsylvania. Reach him at 610/432-6736.

Jeffrey Fussner, CPO, CEO of Boas Surgical Inc.; Matt Perkins, CEO of Coyote Designs; and Kurt Gruben, CPO, regional clinical manager of Ossur Americas contributed to this article.