How do I know if my hinged brace fits correctly?

A properly fitted hinged brace should have its hinge axis aligned directly with your knee joint axis—you can verify this by bending your knee and confirming the hinge pivot point stays centered on the side of your knee. The frame arms should contact your thigh and calf evenly without gaps, and all straps should close securely without maxing out their adjustment range. You should be able to flex your knee to the brace's allowed range without pain, pinching, or the frame digging into your leg. If you feel pressure points after 15 minutes of wearing the brace while moving, the fit is likely wrong.