Knee Ligament Examination

Inspect

• Wasting: Observe for muscle atrophy.
• Scars: Look for surgical or injury-related scars.
• Deformity: Assess for visible abnormalities.

Walk

• Check for ACL deficiency gait.

Lie Down

• Range of Motion (ROM): Assess joint movement.
• Screen for Sag: Look for posterior sag (PCL assessment).
• Posterior Draw Test: Evaluate posterior cruciate ligament (PCL) integrity.
• Quads Active Test: If PCL laxity is present, observe tibial movement during quadriceps contraction.
• Lachman Test: Assess anterior cruciate ligament (ACL) integrity.
• Collateral Ligaments:
  • Varus and valgus stress tests.
• Pivot Shift: Dynamic test for ACL laxity.
• Dial Test: Assess for posterolateral corner injuries.

Finishing

• Joint Lines and Menisci: Palpate for tenderness and check for meniscal involvement.
• Pulses and Neurology: Evaluate vascular and nerve function.
• Full History: Gather a complete patient history.
• Imaging: Order appropriate imaging for confirmation (e.g., MRI, X-ray).

Pivot Shift Quantification

• Grade 1: Glide.
• Grade 2: Clunk.
• Grade 3: Gross clunk with locking.
• In extension, the tibia starts anteriorly subluxated.
• Mechanism:
  • Valgus force tensions the MCL.
  • During flexion, the knee pivots around the MCL.
  • The ITB moves posterior to the knee's center of rotation (COR), working as a flexor, reducing the tibia with a clunk.

Lachman Test Quantification

• Position: Perform at 30° flexion when ACL is most lax.
• Grades:
  • Mild: 0–5 mm translation.
  • Moderate: 6–10 mm translation.
  • Severe: >10 mm translation.
• Comparison: Always compare with the contralateral knee to determine normal.
• End Point: Assess the quality of the end point.
• KT 1000 Testing:
  • Translation of 11 mm or a Lachman delta of 3 mm is diagnostic.
  • High-grade laxity may indicate associated MCL or posterior horn medial meniscus tears.

PCL Sag Sign

• Grades:
  • Grade 1: Tibia still in front of femoral condyles.
  • Grade 2: Tibia level with condyles.
  • Grade 3: Tibia sagged behind condyles.

Collaterals

• Varus Opening:
  • At 0°: Suggests LCL and PLC injury (high likelihood).
  • At 30°: May indicate isolated LCL injury (uncommon).