Symptoms of a MCL, or medial collateral ligament, sprain include swelling, bruising, pain and tenderness in the knee, according to WebMD. Pain and difficulty with knee movement increase in the hours after the initial injury.
MCL injuries are classified by grade depending on the scope and severity of the injury, explains Sports Injury Clinic. Grade 1 symptoms are usually mild and include tenderness and pain, but no apparent swelling. Grade 2 symptoms include significant tenderness inside the knee, some swelling and pain, and reduced range of motion. Grade 3 injuries go beyond mere sprains and indicate a complete tear of the MCL.