Medial collateral ligament injuries in the knee

This is one of the common injuries of the knee. Medial collateral ligament (MCL) locates inside the knee and connects medial epicondyle of the femur and the posteromedial crest of the tibia. MCL is a broad and strong band to stabilize the knee joint. MCL consists of superficial and deep medial collateral ligament.

Proximal insertion at medial epicondyle of superficial medial collateral ligament (sMCL) blends into the semimembranosus tendon. Distal attachment is at the posteromedial surface of the tibia.

The deep medial collateral ligament (dMCL) is composed of 2 ligaments which are meniscofemoral and meniscotibial. The proximal insertion of meniscofemoral is at the femur just distal to insertion of the sMCL and on medial meniscus. The meniscotibial ligament is thicker and shorter. It originates frim the medial meniscus to the distal edge of the articular cartilage of the medial tibial plateau.  *1

 MCL works as a knee joint stabilizer, the proximal sMCL resists valgus force at any degrees of knee flexion where knee goes inward while distal portion of sMCL helps stabilize external rotation of the flexed knee at 30 degrees. The dMCL works to stabilize internal rotation of the knee from 0-90 degrees of knee flexion.

MCL also guides knee ROM and absorbs loads until it cannot tolerate. It has a role to prevent knee from overextension and tibia from shifting posteriorly.

When MCL is over-stretched, it elicits neurological feedback which produces muscle contraction to protect ligament from tearing or injury.

The role of MCL

• Stabilizing the knee joint
• Helping stabilize internal rotation of the knee and external rotation of the knee flexed at 30 degrees  
• Absorbing tensile loads
• Evoking neurological feedback to contract muscle if it is overloaded or overstretched

Aetiology

 The role of medial collateral ligament of the knee is to stop knee from going medially too much which means to resist valgus force (pressure from outside to inside).

 The knee is forced to push inwards.

• Sudden trauma such as sports accident and car accident
• Weakness of the muscles can cause problems
• Young athletes who play soccer, ice hockey, skiing, lacrosse and football.

Sign and symptoms

• Swelling of the knee (Medial side)
• Stiffness of the knee joint
• Weakness and instability of the knee
• Pain with valgus force

Severity

1. Grade 1 LCL sprain (mild)

Grade 1 is involved in a few fibres overstretched and no stability although it is partial tear. Valgus opening 5mm

• Grade 2 LCL sprain (moderate)

In this grade, ligament is partly torn and disruption of more fibres. Swelling and tenderness are often seen over the knee area. You feel instability of the knee and pain with movement. Vulgus opening 5-9mm

• Grade 3 LCL sprain (Complete tear)

Grade 3 is the condition where ligament is completely torn, which causes swelling and sometimes bleeding underneath the skin. Therefore, you would feel instability of the knee joint and difficult to do weight-bearing movement. At this grade, other structures injuries such meniscus, ACL and other ligaments can occur with MCL injury as these other structures have to compensate MCL to stabilise the joint.

Special test for MCL Sprain

• Valgus stress test (Knee bend slightly and put pressure from lateral side of the knee towards medial side) https://www.youtube.com/watch?v=GSFbttpxCuQ

Treatment

• Ice
• Tape to help stabilise the joint
• Splint or supporter (about 4week of injury)
• Strengthening exercise and rehabilitation  
• Muscle Energy Techniques and Neuro Muscular Technique to strengthen and lengthen muscles

Cadavers were used to see what degree of knee flexion is prone to be injury when valgus and varus force were applied. The research shows that strain in the posterior and central portion of MCL gets less risky when increasing knee flexion angle while strain in anterior portion remains at any knee flexion angle. However, he most common strain location is near femoral insertion when knee is full extended.  *5

Goal setting for athletes with isolated MCL sprain*6

1. Ice the area 15-20mins every 3-4 hours for first 24-48 hoursUse braces and crutches if needed
2. Walking in the swimming pool, EMS (electrical muscle stimulation) or non-weight bearing exercises if pain level is 0-4
3. Walking without support: Isometric training to strengthen
4. 90 degrees of knee flexion: Start bicycle with high seat →low seat (more ROM), weight bearing concentric and eccentric exercises
5. Full knee flexion: Strat running, jumping and functional exercise for the sports
6. Complete entire running program in one session: Begin participating training sessions or games as much as they can   

References

1. Pallavi juneja and John B.hubbard Anatomy, Bony pelvis and lower limb, knee medial collateral ligament 2018 StatPearls
2. Phinnit Phisitkul, Stan l James, Brian R Wolf, Annunziato Amendola MCL Injuries of the knee: Current Concepts Review 2006 lowa Orthopeodic journal 26:77-90
3. Tadlock BA, Pierpoint LA, Covassin T, Caswell SV, Lincoln AE, Kerr ZY. Epidemiology of knee internal derangement injuries in United States high school girls’ lacrosse, 2008/09-2016/17 academic years. Res Sports Med. 2019 Oct-Dec;27(4):497-508
4. Ellsasser JC, Reynolds FC, Omohundro JR. The non-operative treatment of collateral ligament injuries of the knee in professional football players. An analysis of seventy-four injuries treated non-operatively and twenty-four injuries treated surgically. J Bone Joint Surg Am. 1974;56(6):1185–1190
5. Gardiner JC, Weiss JA, Rosenberg TD. Strain in the human medial collateral ligament during valgus loading of the knee. Clin Orthop. 2001. pp. 266–274
6. Reider B. Medial collateral ligament injuries in athletes. Sports Med. 1996;21(2):147–156