How can it be that my ankle keeps giving way?

Weak ligaments: If you have a history of sprains or even if you dont the ligaments may be weak. Important to evaluate the cause and consider bracing and a course of physical therapy. See your local foot and ankle specialist.

You have: Chronic lateral ankle instability. You can wear a brace to help prevent further sprains or have it corrected surgically. Therapy may help too.

Many causes: They range from stretched out or torn ankle ligaments (usually laterally) to nerve problems causing weakness of the muscle that prevent your ankle from twisting the tendon ruptures/problems. In addition bone structure problems such as tarsal coalitions or varus deformities of the hind foot. Sometimes just unrehabilitated muscle strength with loss of proprioception. Get evaluated to sort it out.