MCL/ LCL Injuries

What are MCL/LCL Injuries?

MCL (Medial Collateral Ligament) and LCL (Lateral Collateral Ligament) injuries involve damage to the ligaments that provide stability to the sides of your knee joint. The MCL runs along the inside of your knee and prevents excessive inward movement, whilst the LCL runs along the outside and prevents excessive outward movement of the knee.

These injuries are graded from 1-3 based on severity: Grade 1 (mild stretching), Grade 2 (partial tear), and Grade 3 (complete rupture). MCL injuries are far more common than LCL injuries, particularly in contact sports, due to the mechanism of injury and anatomical differences.

What Causes MCL/LCL Injuries?

MCL and LCL injuries typically occur through specific mechanisms:

MCL injury mechanisms:

  • Direct impact to the outside of the knee forcing it inward (valgus stress)

  • Contact injuries during rugby tackles or football collisions

  • Non-contact pivoting movements with excessive knee valgus

  • Landing awkwardly from jumps with inward knee collapse

  • Skiing accidents with outward ski movement

LCL injury mechanisms:

  • Direct impact to the inside of the knee forcing it outward (varus stress)

  • Less common than MCL injuries due to protective positioning

  • High-energy trauma or motor vehicle accidents

  • Contact sports with direct lateral impact

  • Hyperextension injuries with rotational component

Contributing factors:

  • Weak hip and glute muscles affecting knee control

  • Poor landing mechanics with excessive knee valgus

  • Previous knee injuries creating instability

  • Muscle imbalances around the knee and hip

  • Inadequate neuromuscular control during dynamic activities

  • Fatigue affecting protective muscle responses

High-risk activities:

  • Contact sports (rugby, football, hockey)

  • Skiing and snowboarding

  • Sports involving cutting and pivoting movements

  • Activities with potential for direct knee impact

What Are the Symptoms?

MCL and LCL injury symptoms vary based on location and severity:

MCL injury symptoms:

  • Pain along the inside of the knee

  • Tenderness when pressing on the inner knee joint line

  • Swelling on the medial aspect of the knee

  • Pain that worsens with valgus stress (knee pushed inward)

  • Feeling of instability when changing direction

LCL injury symptoms:

  • Pain along the outside of the knee

  • Tenderness over the lateral joint line

  • Swelling on the outer aspect of the knee

  • Pain with varus stress (knee pushed outward)

  • Less common but often more severe than MCL injuries

Grade-specific symptoms:

Grade 1 (Mild):

  • Mild pain and tenderness

  • Minimal swelling

  • No instability with stress testing

  • Able to continue activity with discomfort

Grade 2 (Moderate):

  • Moderate pain and swelling

  • Some looseness with stress testing

  • Difficulty continuing activity

  • Noticeable functional limitations

Grade 3 (Severe):

  • Severe initial pain that may diminish

  • Significant instability with stress testing

  • Complete inability to continue activity

  • Often associated with other knee injuries

Functional limitations:

  • Difficulty with cutting and pivoting movements

  • Pain when walking, particularly on uneven surfaces

  • Reduced confidence in knee stability

  • Compensatory movement patterns affecting hip and ankle

  • Impact on sporting activities requiring lateral movements

Associated symptoms:

  • Bruising around the knee joint

  • Stiffness after periods of rest

  • Muscle weakness from pain inhibition

  • Apprehension during activities involving knee stress

Suffered a knee injury from contact or twisting? Our specialist team has extensive experience treating knee ligament injuries in professional contact sport athletes, including rugby players and UFC fighters. We provide comprehensive assessment using advanced testing including our VALD Dynamo strength testing, targeted rehabilitation programmes focusing on stability and movement retraining, and sport-specific conditioning to ensure safe return to play and prevent future injuries.