A patient reports that her knee locks sometimes and feels like it will give out. What condition is she most likely experiencing?

The patient's report of her knee locking and feeling as if it will give out is indicative of a meniscal tear. When a meniscus is torn, it can cause pieces of the cartilage to become lodged within the knee joint. This can result in the joint locking during movement or feeling unstable, as the torn tissue may hinder smooth motion or cause a sensation of giving way.

Symptoms associated with a meniscal tear often include pain, swelling, and difficulty moving the joint, which aligns with the patient’s experience of the knee feeling like it might give out. This condition is further characterized by mechanical symptoms, such as clicking or locking, which are particularly relevant in this scenario.

In contrast, while a ligament sprain, tendinitis, or patellar dislocation can cause pain or instability in the knee, they typically do not present with the locking phenomenon that is specifically associated with meniscal injuries.