what is an MCL sprain
Medial Knee Ligament Injury. A medial ligament sprain or MCL injury is a tear of the ligament on the inside of the knee, usually a result of twisting or direct impact.Medial ligament injuries are common in contact sports such as football and rugby, as well as martial arts.auses. Injury to the MCL often occurs after an impact to the outside of the knee when the knee is slightly bent. The ligament on the inside of the knee becomes stretched and if the force is great enough, some or even all of the fibres will tear.