What could cause sudden ankle pain without any injury or swelling?

Sudden ankle pain without any obvious injury or swelling can be puzzling. One possible cause is Bone Marrow Edema Syndrome, which affects the bones in the foot and ankle. This condition can cause pain due to fluid buildup in the bone marrow, even if there's no visible swelling.

Another potential cause could be problems with the ligaments around the ankle. For example, the deltoid ligament on the inside of the ankle can cause pain if it becomes irritated or inflamed, even without a clear injury.

There are also other less common reasons for ankle pain, such as stress reactions or small injuries that might not be immediately obvious. If you have sudden ankle pain, it might be helpful to consult with a healthcare professional to explore these possibilities and get the right treatment.