Prosthetics Lower Extremities - Kinetech Medical

Modular Knee Joints
Modular Knee Joints
The function of a modular knee joint is vital to the overall performance of a prosthesis.
During stance phase knee stability is key, and the knee must not buckle
at heel strike. During swing phase, the motion of the prosthetic lower leg must
be controlled.
With mechanical knee components, stance phase stability can be achieved by
means of a lock (a common solution for geriatric fittings), weight-dependent friction
controls or polycentric constructions – and even with variable stance phase
flexion in knees like the 3R60. A hydraulic stance phase control is offered in knees
such as the 3R80.
With the electronic knee joints from the C-Leg® Product Line, the hydraulic unit
is microprocessor-controlled for stance phase stability.
The swing phase control is achieved with, for example, flexible extension assist
springs that function independently of walking speed. The pneumatic and hydraulic
elements resist motion depending on speed and adjust to the patient’s gait.
Based on real-time data, the C-Leg® Knee Joint System immediately adapts to
the patient’s current walking situation.
The selection of the appropriate mechanically or electronically controlled knee joint
is based on the the patient’s amputation level, the condition of the residual limb,
their activity level and health, their weight as well as his/her surrounding environment
and living conditions. Older prosthesis users with lower mobility require a
higher degree of knee stability. Easy handling and wearing comfort are more important
than dynamic function.
The knee joint and prosthetic foot are viewed as one functional unit; these components
must therefore work in harmony with each other and are tested to ensure the
best function possible (see “Component Combination: Knee-Foot” on page 48).
Knee Joints
Otto Bock HealthCare GmbH | Prosthetics – Lower Extremities | www.ottobock.com 141