Stance Extension; Flexion Target Angle; Swing Extension; Terminal Swing (Ts) - Össur bionic RHEOLOGIC Technical Manual

Optimal stability: The level ground value is increased to match the stair/ramp value. Recommended when
stability is critical on all walking surfaces and stance flexion ambulation pattern is not being utilized. The user
will experience a high degree of stance resistance on all walking surfaces, including the first step of terrain
transition.
Variable stance resistance: When the level ground value is less than the stair/ramp value, easier stance flexion
walking is possible. A greater difference in resistance will be noticed during the first step of terrain transition.
Ensure alignment through knee center or 5mm posterior to knee center.
important: Foot alignment is critical. Posterior foot position may lead to difficulties in stance release. Anterior
foot position may lead to toe stubbing when walking in stance flexion.

Stance extension

Stance extension depicts the prosthetic limb in stance phase and moving in to extension. This adjustment
controls how rapidly the resistance increases with knee extension rate. The adjustment is required only when
the user is walking in a stance flexion ambulation pattern and assists in providing proper timing of stance
flexion/extension reciprocation and enhanced comfort. The default value is 30. Increasing the stance extension
resistance allows for more rapid increase in resistance to knee extension and slower knee extension rate when
load is placed on the prosthesis.

Flexion target angle

The flexion target angle depicts the prosthetic limb at its maximum knee flexion angle during the swing phase.
Adjustment of target angle varies from 45–80°. The default value is 60°.
Increasing the flexion target angle allows for increased heel rise and delays knee extension. Decreasing the
flexion target angle allows for decreased heel rise and promotes more rapid knee extension.
important: For most individuals, the flexion target angle should remain at the default setting, 60 degrees. When
manually adjusting the flexion target angle, make small changes one or two degrees at a time.

Swing extension

Swing extension (level ground) depicts the prosthetic knee moving into extension during the swing phase on
a level walking surface. Adjustment varies from 0–100. The default value is 20. Swing extension (ramps and
steps) depicts swing extension resistance for stair/ramp walking. Resistance activates after one step onto the
step/ramp.
This adjustment is minimized and set to zero so that rapid extension may occur on ramps and stairs for
increased security. Adjustment varies from 0 – 100. The default value is 0.
Increasing the extension resistance slows the extension rate towards the end of swing phase. Decreasing the
extension resistance increases the extension rate towards the end of swing phase.

Terminal swing (TS)

Terminal swing is the last phase of swing extension prior to full knee extension. The terminal swing adjustment
feature in RHEO KNEE is divided into two interlinked parameter settings:
Terminal swing resistance (TSR) controls the velocity of the terminal swing. Increasing the TSR values increases
the resistance. Decreasing the TSR values decreases the resistance. The default value is 20.
Terminal swing point (TSP) controls the rate of the terminal swing. Increasing the TSP values delays the
resistance onset. Decreasing the TSP values hastens the resistance onset. The default value is 20.
Note: The terminal swing parameter settings should only be utilized when the swing extension parameter has
been optimized to the user's gait.
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