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)
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