Prosthetic Sock Ply Management 

Prosthetic socks are used to account for volume changes in the residual limb.  Prosthetic socks are measured by the width at the top and bottom of the sock, as well as the overall length.  Socks also come in a variety of thickness, or ply.  A 1 ply sock measures approximately 2 millimeters, while a 5 ply sock measures approximately 10 millimeters.  Of course, the socks do tend to reduce in thickness as they become worn.  These socks can be used in various combinations.  For example, to achieve 6 ply of prosthetic socks, an amputee could use one 6 ply sock or two 3 ply socks.

Prosthetic sockets with flexible interfaces usually require a lower sock ply for comfort.  Conversely, rigid sockets may require a thicker sock ply, to cushion the residual limb.  A new prosthesis is usually fit with one 3 ply prosthetic sock.  Of course, this is a generalization and many sockets are initially fit with less or more socks.  Amputees commonly increase sock ply to account for volume loss in the residual limb.  While this can be a successful approach, excessive sock ply, generally more than 10 ply, can cause instability and undue pressure on the residual limb.

This is a familiar problem with lower extremity amputees and, often times, there is a simple solution.  Throughout the day, the fluid in a human body fluctuates.  This is true for amputees and non-amputees.  In the beginning of the day, a residual limb may be slightly swollen.  Sometimes the swelling can reduce throughout the day, which is often what happens after we sweat. 

Tip of the day:  If the prosthetic socket feels too tight, an amputee may opt for a thinner sock, or reduce the number of socks worn.  If the prosthetic socket feels too loose, an amputee can opt for a thicker sock, or add a sock. 

Amputees need to find the right combination of prosthetic socks and thickness.  If the problem is not resolved and the discomfort continues, the prosthetist should be contacted for input.