DefinitionMedial collateral ligament (MCL) injury is an injury to the ligament on the inner part of the knee. This ligament keeps your shin bone (tibia) in place.It can be a stretch, partial tear, or complete tear of the ligament.Alternative NamesKnee injury – medial collateral ligament (MCL); MCL injuryConsiderationsThe medial collateral ligament (MCL) goes from the inside surface of the upper shin bone to the inner surface of the bottom thigh bone.The ligament helps keep the inside portion of the knee joint stable.CausesThe MCL is usually injured by pressure or stress on the outside part of the knee. A block to the outside part of the knee during football is a common way for this ligament to be injured.It is often injured at the same time as an anterior cruciate ligament (ACL) injury occurs.SymptomsSymptoms of a tear in the medial collateral ligament are:Knee swellingLocking or catching of the knee with movementPain and tenderness along the inside of the jointThe knee gives way or feels like it is going to give way when it is active or stressed in a certain wayFirst AidThe health care provider will examine your knee. An MCL test will be done to detect looseness of the ligament. This test involves bending the knee to 25 degrees and putting pressure on the outside surface of the knee.Other tests may include:Knee joint x-raysKnee MRITreatment includes:Applying ice to the areaNonsteroidal anti-inflammatory drugs (NSAIDS)Raising the knee above heart levelYou should limit physical activity until the pain and swelling go away.advertisementThe health care provider may put you on crutches and in a brace to protect the ligament. You may also be told not to put any weight on your knee when you walk.After a period of keeping the knee still, you will be taught exercises to strengthen and stretch the knee. Physical therapy may help you regain knee and leg strength.Surgery is often not needed when only the MCL has been torn. Most MCL injuries can heal with immobilization.If you need surgery, it will require an open incision where the ligament is repaired back to the bone.When to Contact a Medical ProfessionalCall your health care provider if:You have symptoms of MCL injuryYou are being treated for MCL injury and you notice increased instability in your knee, pain or swelling after they initially faded, or your injury does not get better with timeYou re-injure your kneePreventionUse proper techniques when playing sports or exercising. Many cases are not preventable.ReferencesDe Carlo M, Armstrong B. Rehabilitation of the knee following sports injury. Clin Sports Med. 2010; 29:81-106.Singhal M, Patel J, Johnson D. Medical ligament injuries: 1. Medical collateral ligament injuries in adults. In: DeLee JC, Drez D Jr., Miller MD, eds. DeLee and Drezs Orthopaedic Sports Medicine. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2009:chap 23;sect C.Silverstein JA, Moeller JL, Hutchinson MR. Common issues in orthopedics. In: Rakel RE, ed. Textbook of Family Medicine. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 30.Review Date:6/29/2012Reviewed By:Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington. C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.