What is a key characteristic of the single axis outside hinges?

The single axis outside hinges are primarily designed to provide a simple rotational movement around a single axis. This characteristic allows them to mimic the natural movement of a joint, such as the knee. While they enable flexion and extension, their design helps in managing knee length discrepancies effectively.

By having a fixed rotation mechanism, they do not allow for adjustments in angle, thereby enabling precise control over the knee's movement. This can be particularly useful for individuals who have specific needs related to joint function or alignment due to their anatomical structure or compensatory mechanics. Consequently, these hinges play a significant role in maintaining an appropriate alignment of the limb, which can be crucial for comfort and function in a prosthesis.

The other options, such as the provision of built-in stability control or immediate adjustability, are features that are generally associated with more complex hinge systems and do not apply to the simple and straightforward design of single axis outside hinges.