Knee ligament injuries

Anterior cruciate ligament injury
- Typical sport injury
- Etiology
  - Sudden twisting of the leg
  - Osteoarthritis of knee (osteophytes can damage ligament)
- Clinical features
  - Swollen leg (haemarthrosis)
    - Due to bleeding from the ACL
  - Acute pain
  - Knee instability
- Diagnosis
  - Positive Lachman test
  - Positive anterior drawer test
  - MRI
    - Gold standard
  - Not visible on x-ray
- Treatment
  - Conservative
    - Stabilize the knee, by:
    - Strengthen muscles
    - Wear a brace
  - Surgery
    - Arthroscopic surgery
      - Not in the acute setting
      - Only if knee instability remains after a long time and after trying conservative therapy
    - An artificial ligament or a bone-tendon-bone (BTB) graft is used to replace the ACL
    - Patient can return to activity soon
Posterior cruciate ligament injury
- Less frequent than ACL injury
- Occurs due to posterior injury to a flexed knee
- Clinical features
  - Same symptoms as for ACL injury, but much less intense/significant
- Diagnosis
  - MRI
    - Gold standard
  - Positive posterior drawer test
- Treatment – Same as for ACL injury
Medial collateral ligament injury
- Most commonly injured knee ligament
- Caused by valgus stress to the knee
- Clinical features
  - Knee swelling
  - Pain
  - Knee instability
- Diagnosis
  - Positive valgus stress test
  - MRI not needed
- Treatment
  - Conservative – for isolated MCL injury
  - Surgery – if multi-ligament injury is present
Lateral collateral ligament injury
- Isolated LCL injury is rare
- Clinical features
  - Knee swelling
  - Pain
  - Knee instability
- Diagnosis
  - Positive varus stress test
  - MRI not needed
- Treatment
  - Needs surgery