Adjustable prosthetic limb socket

#A prosthetic device for an arm or leg is traditionally worn by inserting the residual limb into a rigid or semi-rigid socket. Traditional sockets are designed as a 360 degree container surrounding the entire residual limb. Sockets generally perform at least two broad functions. Firstly, the traditional socket is designed to allow comfortable weight bearing and prevent soft tissue damage as weight pressures are applied to the residual limb via the prosthetic socket. This is generally achieved with a combination of skeletal weight bearing and hydraulic lift created as the residual limb fluids are pressurized in the socket. Secondly, the traditional socket also functions to stabilize the skeletal components of the residual limb such that the user can move the prosthesis in space and minimize relative motion between the socket and the residual limb.

#A precise volumetric fit greatly aids both of these functions. Maintaining a proper amount of volumetric socket fit is challenging and often problematic due to the tendencies of the residual limb to change in volume and the soft tissue to displace under load. Residual limb volume change (RLVC) occurs due to many factors, including but not limited to: edema, muscle atrophy, weight gain/loss, renal dialysis, salt and water intake, alcohol consumption, menses, changes in wearing time and activity. Residual limbs also loose volume daily due to socket pressure and the pumping action of ambulation. Daily volume loss is generally replenished during non-wearing times i.e. sleep, and is cyclical and greatly affected by activity.

#As the residual limb loses volume the hydrostatic weight bearing and skeletal control characteristics of the socket are compromised. This leads to painful, limiting and/or injurious increases in socket pressure as well as energy wasting and destabilizing excessive motion between the socket and skeletal segments of the residual limb. As the user attempts to control the prosthesis in space by employing their proximal musculature, relative motion between the residual limb and prosthesis causes forces which accelerate and impact the residual limb. These forces can be compressive, or cause strain or shear, which in turn increase localized pressure and/or tension on the residual limb. This commonly results in pain and injury as well as increased energy use and premature fatigue. As a result, traditional sockets tend not to function well when changes in the residual limb's volume, shape or size occur. This is a common occurrence and has not been addressed effectively.

#The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

#FIG. 1 is a schematic drawing showing a perspective view of the rigid support (e.g., “J-socket”) of the “transfemoral posterior sail socket” of the present invention without the posterior flexible support (e.g., the posterior sail).

#FIG. 2A is a schematic drawing showing a perspective view of the rigid support of the transfemoral posterior sail socket of the present invention with the posterior flexible support and adjustment means.

#A description of preferred embodiments of the invention follows.

#The present invention relates to a new socket design that is stable, comfortable, and allows for volumetric changes in the residual limb. In particular, the present invention relates to a socket that has a rigid support that conforms to a portion of the residual limb, and a sail (also referred to herein as a “flexible support”) which is a strong, flexible and preferably non-elastic garment that covers the balance of the circumference of the residual limb. The socket system of the present invention also includes a means for securing the sail e.g. with a closure system, and an attachment at the base of the rigid support for attaching the prosthetic device.

#Unlike traditional sockets that include a rigid or semi-rigid socket that conforms to most or all of the outer circumference of the residual limb, the rigid support of the present invention is a partial support. More specifically, in an aspect, the rigid support of the present invention covers only about 50% or more of the surface area of the residual limb, or about 180° or more of the circumference of the residual limb. Having a rigid socket that covers only a portion of the residual limb is counter to traditional practices. Traditional prosthetic devices generally involve applications in which rigid or semi-rigid support covers most of the circumference of the residual limb. Accordingly, the present invention including only a partial rigid support in a socket that provides support, comfort and adjusts for volumetric changes is unprecedented, surprising and unexpected. As defined herein, the term “socket” or “socket system” refers to the combination of the rigid support and the sail (e.g., flexible support). Additionally, the term “J-socket” refers to the rigid support that is shaped as a “J” as further described herein.