medial collateral ligament (MCL) injury of knee

Last reviewed 01/2018

Medial collateral ligament (MCL) is the most commonly injured ligament in the knee (1)

MCL injuries can be seen in both contact and non contact sports. Examples include:   

• valgus stress caused by  lateral blows to the knee e.g. -  in contact sports such as football, ice hockey and rugby
• external rotation of the foot with a flexed knee e.g. - in skiing injuries
• frank knee dislocations (1)

The American Medical Association has classified had graded MCL accoerding to the amount of joint space opening with valgus stress at 300 of knee flexion.

• grade I - amount of medial joint line opening <5 mm
• grade II - amount of medial joint line opening 5-10 mm
• grade III - amount of medial joint line opening >10 mm

Most MCL injuries are isolated

• there is an increase risk of injury to associated structures of the knee with increasing severity e.g - anterior cruciate ligament (ACL), posterior cruciate ligament (PCL) etc
• a 78% rate of associated injury is seen in grade III sprains (1)

Reference:

• (1) Duffy PS, Miyamoto RG. Management of medial collateral ligament injuries in the knee: an update and review. Phys Sportsmed. 2010;38(2):48-54