Sprain is an injury of a ligament.
Ligament is a structure which connecting and tightly anchoring two bones in the joint.
Ligament injury occurs when it is suddenly stretched or torn due to joint sprain.
When you sprained an ankle, knee, wrist or finger, immediate pain may occur due to
injury of the ligament in the joint. In worse cases, limping may ensue.

Important : In severe case, you need medical professional advice, you may need immobilization or surgery. In any case, complimentarily, Ligafix may be great and prompt(usually within 10 minutes) help for you.

note :
The information provided is of a general nature and should not be used as a substitute for professional medical advice. To diagnose clearly you should discuss with your family doctor.