Preparatory Socket Fabrication

The suggested method of preparatory socket fabrication described below is designed to assist the clinician in constructing a light-weight, durable and functional preparatory prosthetic socket that reduces fabrication time and costs. Once familiar with the properties of the material, the technique may be modified to suit the practitioner's needs allowing the user to incorporate different laminating rings, adapters, connectors and attachments. These devices can be recycled for use in subsequent RPS sockets when residual limb volume and shape has significantly changed and a new socket needs to be fabricated.

1. Apply a silicone suction liner in accordance with standard procedures. Fig. 1
   


2. Apply relief pads on the distal aspect of tibia, fibula head and medial condyle. If there is a prominent patella apply a relief pad which will serve as a channel to facilitate removal. These pads can be made of Plastazote, Aliplast, PPT or felt. The edges of the padding should be feathered.



3. Screw in the distal connector pin that is supplied with the Icecast compact system. Use surgical tubing or other material to fill the void proximal to threads to help facilitate removal. Fig. 2
   


4. Hold pads in place using plastic wrap. Wrap the Saran wrap proximal to the trim lines and as proximal as possible on the thigh.



5. Place a silicone disc "spacer" over the connecting pin and against the end of the liner. Fig. 3
   


6. Pull a post op sock over the plastic wrap taking care to not move the relief pads. Fig. 4
   


7. Place a backing plate with four screws over the silicone disc ensuring the hex screws are in place and oriented properly in both AP and ML directions. Double stick adhesive tape can be used to hold the backing plate in place to maintain the alignment. Fig. 5
   


8. Open an STS Reinforced Preparatory molding sock pouch. Enlarge the distal opening slightly for the connector pin. Immerse the sock in a bucket of room temperature water and message or knead the roll for about 5 seconds to allow water to saturate the water curable resin. Fig. 6
   


9. Condense or slightly tighten the roll of the sock. Fig. 7 This will provide tension to the fabric adjacent to the hole.
   


10. Place the sock over the connector pin threads and roll it up the limb and over the post op sock beyond the proximal trim line. Do NOT pull or stretch the STS sock excessively.



11. The flat bearing surface of the nylon adapter should be coated with petroleum jelly or silicone spray to facilitate removal.


12. Screw the nylon adapter or stabilizing puck fully onto the threads of the connector pin. Fig. 8
    


13. Cut off the excess sock material above the proximal trim lines. Fig. 9
    


14. Inflate the pump bladder to approximately 20 mm Hg to facilitate the application. Reverse the bladder to expose the connector pin lock and secure in position by opening and closing the pressure relief valve. Fig. 10
    


15. Attach the connector pin to the locking mechanism.


16. Roll the bladder onto the residual limb. Maintain the pin alignment with the leg by aligning the pump handle with the long axis of the residuum. Fig. 11
    


17. Inflate pump to the desire pressure between 80 and 100mmHg depending on the type of fit. Remove the pump from the connector mechanism.


18. Support the bladder for approximately five to seven minutes until the sock hardens.



19. Once cured, reattach the pump. Reflect the bladder back over itself exposing the pin lock release button. Press the button and remove from the connector pin. Fig. 12
    


20. Return the bladder to the original position. Fig. 13
    


21. Detach the distal nylon adapter end piece. A channel locking wrench may be necessary. Fig. 14
    


22. Have the patient pull on the silicone liner with the limb relaxed and in slight flexion. Gently pull off the socket. Fig. 15
    

    Steps to finish the Socket



23. Mark the proximal trim lines. Use a Landis trimmer to remove most of the excess material. A sander is then used to remove additional material to the trim line. Fig. 16
    


24. Grind the distal end of the socket in a flat plane until the heads of the screws are visible. Remove the hex screws after cleaning out any residual resin from the screw heads. Fig. 17
    


25. Finish the proximal trim line with split leather or other similar material of your choice.


26. Attach the pin locking mechanism using the appropriate screws. Check the locking mechanism to ensure free movement. Fig. 18
    


27. Attach the lower extremity components to the locking mechanism. Fig. 19
    

The silicone liner is used for protection of the underlying skin from the exothermic reaction during the curing process of the RPS resin. A standard wool or cotton sock may be substituted. Auxiliary suspension such as a BK sleeve or cuff suspension may be used.

SUGGESTIONS FOR THE BEGINNER

It is suggested that for the first two or three times the practitioner uses the RPS sock, an assistant be on hand to cut off excess material after the RPS sock is rolled up the residual limb. This will allow more time and attention to be placed on the application process.

We also suggest that for the first two or three times the practitioner uses the RPS sock, the water temperature should be very cold to prolong curing time thereby allowing more working time. Once familiarity with the system is achieved, water temperature can be increased appropriately. Room temperature water allows 5-7 minutes of working time.

Familiarity with the Ossur IceCast Compact pump will facilitate application. Try a "dry run" (without using the RPS sock) if you are not familiar with this system.

Normal Version