A conditional braking knee includes an upper member configured to couple to a prosthetic socket. A braking member couples to the upper member. A lower member couples to the braking member and is configured to rotate with respect to the upper member. A flexion coupler couples to the braking member and is configured to couple to a prosthetic foot. The braking member is configured to prevent a rotation of the upper member relative to the lower member in response to a flexion of the prosthetic foot communicated to the braking member through the flexion coupler. In implementations the braking member is a clamping member rotatably coupled to the upper member with a first axle, the lower member is rotatably coupled to the clamping member with a second axle, and the clamping member prevents a rotation of the upper member relative to the lower member by clamping on the first axle.

A technology for a prosthetic above-knee device is provided. A socket may be used to attach the device to a residual limb, and may have a rigid body coupled to the socket. The device may include a first link with a first link end coupled through the rigid body to the socket and a second link end coupled to the rigid body. The second link of the device may have a third link end attached to the rigid body, and a fourth link end coupled to a housing. The device may include a hydraulic cylinder with a piston and a hydraulic cylinder link coupled between the rigid body and the piston of the hydraulic cylinder. The stability adjustment nut may adjust a travel distance of the hydraulic cylinder link with respect to the hydraulic cylinder to provide an adjustment of an instant center for stability modification.

A prosthesis system can have an advantageous use over conventional prostheses in certain activities, including, but not limited to certain sports activities: The system includes, elastic member(s) that can store and release energy. The storing and releasing of energy in the elastic members happens during the movements made by the user and with the application of the user's own body weight while performing an activity. Implementations can also include a variety of routing configurations for the elastic member(s), as well as a variety of mounting points to integrate the elastic member(s) into the system, and/or a variety of adjustable anti-hyperextension members, and/or a variety of interchangeable shoes used for applicable activities.

A prosthetic knee joint with buffering and braking effects has an upper connecting base, a linking assembly, a braking assembly, and a lower connecting base. The upper connecting base has two extending lugs and an accommodating recess. The linking assembly has two linking arms respectively and pivotally connected to the upper connecting base. The braking assembly has a braking arm protruding into the accommodating recess of the upper connecting base and pivotally connected to the two extending lugs. The lower connecting base is connected to the linking assembly and the braking assembly. The upper connecting base, the linking assembly, the braking assembly and the lower connecting base form a four-bar linkage. A cushion between an abutter and a main body provides a buffering effect during walking. Thus, the prosthetic knee joint has simplified structure and reduced cost and is convenient in assembly and use.