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MCL Injury

The medial collateral ligament (MCL) runs from the epicondyle of the femur to a more diffuse insertion on the upper tibia. It resists sideways (valgus) stresses to the knee. It is comprised of multiple parallel fibres. Strain of it can cause anything form a slight sprain without laxity, to fibres pulled and partially separated, through to complete rupture or detachment from bone.


‘Valgus’ strain

  • Tackle from outer aspect of knee

  • Studs caught & fell to same side

‘Felt knee open up’
‘Heard a pop’
Immediate swelling
Pain medially (inner side of knee)

Tender anywhere along MCL

  • Medial epicondyle

  • Several cm onto proximal tibia

Opens up on valgus stress at 30o knee flexion

  • Grade 1: Tender; <5 degrees opening; firm end point

  • Grade 2: 5 to 10 degrees opening; soft end point

  • Grade 3: > 10degrees opening; soft end point

Does not open up with knee extended; if it does the ACL is likely damaged also.

MCL exam.jpg

MCL assessment

Grade 1

  • Rest, Ice, NSAIDs

  • Tubigrip (Knee brace not usually needed)

  • Full weight bearing

  • Cycle, strengthening immediately as tolerated

  • Proprioceptive rehab

  • Aim for return to play at 4 - 6 weeks

Grade 2

  • Rest, Ice, NSAIDs

  • Knee brace full range 6 weeks

  • Weight bearing as tolerated

  • Strengthening immediately as tolerated

  • Avoid too much stress in terminal 20o 

  • Avoid fixed flexion due to tightening

  • Proprioceptive rehab

  • Aim for return to play at 8 - 10 weeks

Grade 3

  • Rest, Ice, NSAIDs

  • Knee brace 20o extension block for 6 weeks

  • PWB on crutches 4 weeks

  • Consider operative repair for distal avulsion

  • Avoid fixed flexion due to tightening

  • Proprioceptive rehab

  • Aim for return to play at 12 weeks

As with all knee injuries, the structural damage is often not as severe as the damage to balance and proprioception, so any rehab program must include neuromuscular retraining. Splints, supports and strapping have some short term benefit, but the majority actually work by increasing this proprioceptive feedback by skin pressure. They can be counterproductive in that they replace this feedback such that it may reset at a lower level leading to worse feelings of instability when removed.

Rarely in complete avulsion or chronic laxity MCL reconstruction is indicated. More commonly it is performed with ACL reconstruction in multi-ligament knee injuries.


MCL reconstruction using hamstring tendon reinforced by an artificial ligament

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