What type of ankle joint control is indicated for a patient with paralysis of the plantarflexors?

The correct answer is that a dorsiflexion (DF) stop is indicated for a patient with paralysis of the plantarflexors. In cases where the plantarflexors are weak or paralyzed, there is a significant risk that the foot may drop into excessive dorsiflexion during the stance phase of walking. This condition is known as foot drop, which can lead to a loss of control and stability during ambulation, increasing the likelihood of tripping or falling.

By implementing a DF stop in the ankle joint, the orthosis provides a mechanical restriction that prevents excessive dorsiflexion, ensuring the foot maintains a more neutral or slightly plantarflexed position. This helps to stabilize the foot during gait and allows for a more effective push-off with the contralateral leg, thereby improving overall gait mechanics and safety.

In addition, this design leverages the strength of the intact muscles around the ankle while compensating for the loss of function in the plantarflexors. This approach not only aids in achieving a more natural gait pattern but also protects the patient from secondary complications associated with poor foot positioning.