Meniscus and ligament knee injuries

Background

• Anterior Cruciate Ligament
  • Limits anterior translation of tibia
  • 75% of all hemarthroses are caused by disruption of ACL
• Posterior Cruciate Ligament
  • Limits posterior translation of tibia
  • Isolated injuries are rare
• Medial Collateral Ligament
  • Provide restraint against valgus (outward) stress
• Lateral Collateral Ligament
  • Provide restraint against varus (inward) stress

Diagnosis

ACL

1. Healing/feeling a "pop" during injury is pathognomonic
2. Anterior Drawer Sign
   1. Pt supine, knee flexed 90', attempt to displace tibia from femur in a forward direction
   2. Displacement of >6mm compared w/ opposite knee indicates injury
3. Lachman Test
   1. Pt supine, knee flexed 30', femur held w/ one hand, prox tibia pulled up w/ other hand
   2. Displacement >5mm or soft end-point indicates injury

PCL

1. Posterior Drawer Sign
   1. Pt supine, knee flexed 90', attempt to displace tibia from femur in backward direction

Meniscus

1. Symptoms
   1. "Locking" of joint or sensation of popping, clicking, or snapping
2. Signs
   1. Effusions that occur after activity
   2. Joint-line tenderness
3. Tests
   1. McMurray, grind test only 50% Sn

Treatment

• Knee immobilizer, ice, elevation, ambulation as soon as comfortable
• Ortho referral

Source

• Tintinalli