Prosthetic legs bend at the knee through a combination of mechanical and, in more advanced models, computerized systems. Here's a breakdown:
The most basic mechanism involves a constant friction system designed to mimic natural knee movement. According to our reference:
- Constant Friction System: "There is a constant friction system in the knee, which means it will apply a braking force as the patient puts weight on the prosthesis, to prevent the knee from buckling."
- This system provides resistance when the user applies weight, preventing the knee from collapsing unexpectedly.
- When weight is not applied, the knee swings relatively freely, allowing for a more natural gait.
To summarize this information in a structured manner:
| Feature | Description | Function |
|---|---|---|
| Friction Mechanism | Constant friction is applied within the knee joint. | Provides braking force during weight-bearing to prevent buckling; allows free swing when no weight applied. |
| Weight-Activated | The braking force is activated by the weight of the user applied to the prosthesis. | Controls knee stability and movement during different phases of walking. |
| Free Swing Phase | When the user is not putting weight on the prosthetic leg, the knee joint swings relatively freely. | Facilitates forward movement of the leg during the swing phase of gait. |
In essence, the bending action relies on a balance between controlled resistance and free movement, coordinated with the user's weight-shifting during walking. More advanced prosthetic knees often incorporate microprocessors and sensors to dynamically adjust resistance based on terrain, walking speed, and other factors, but the fundamental principle of controlled movement around a pivot point (the knee joint) remains the same.
