Prosthetic sockets stabilized by alternating areas of tissue compression and release

Abstract

Abstract-A prosthetist makes a conventional socket by wrapping plaster bandage around the residual limb and using the resulting shell to create a positive model. After he or she modifies the plaster, it is used to create a laminated socket. Such sockets are almost perfect cylinders that encapsulate the limb. The bone is centered in soft, compressible tissue that must move aside before the bone can push against the socket to transmit force or torque to the prosthesis. In a compression/release stabilized (CRS) socket, three or more longitudinal depressions compress and displace tissue between the socket wall and the bone to reduce lost motion when the bone is moved with respect to the socket. Release areas between depressions are opened to accommodate displaced tissue. Without these openings provided, the CRS socket will not function as intended. Often, the release areas of compression are the struts of a carbon-fiber frame, and the regions between struts are left open. A frame with openings may be modified by the prosthetist adding a thin membrane fully surrounding the limb but allowing the membrane and underlying tissue to enter the release openings. The membrane may contain electrodes, and it may constitute a roll-on liner that helps suspend the prosthesis. We introduce three socket designs: transradial, transfemoral, and transhumeral.

User and clinician perspectives on DEKA Arm: Results of VA study to optimize DEKA Arm

“…In gen 3, the LUI was replaced with an embedded wrist display (see Figure 3 in Resnik and Borgia in this issue [4]) that had light-emitting diode (LED) displays for grip, low battery, mode notification, and system faults, as well as indicators for Walk Detect and over-angle limit detect. DEKA designed inflatable bladders to be used inside transhumeral (TH) sockets to increase skeletal stabilization or for use inside X-frames to provide pressure relief [8]. During the gen 3 phase, DEKA introduced a dynamic socket controller (DSC) that could be used to regulate socket bladder inflation through independent pneumatic channels using the touch of one or more buttons.…”

User ratings of prosthetic usability and satisfaction in VA study to optimize DEKA Arm

“…DEKA designed inflatable socket bladders or actuators to be embedded inside TH sockets using a special design aimed at increasing skeletal stabilization [15] or to be used inside X-frame sockets to provide pressure relief and greater stability. During the gen 3 phase, DEKA introduced a dynamic socket controller that could regulate inflation of the socket bladders through independent pneumatic channels using the touch of one or more buttons.…”

Progress on stabilizing and controlling powered upper-limb prostheses

“…In this issue, Alley et al discuss a new approach to stabilizing sockets with respect to the underlying bone [16]. Socket stability is a key element in controlling the location of the TD.…”