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

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

PCL

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

Meniscus

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

Differential Diagnosis

Knee diagnoses

Acute knee injury

• Knee dislocation
• Knee fractures
  • Patella fracture
  • Segond fracture
  • Tibial plateau fracture
• Meniscus and ligament knee injuries
• Patella dislocation
• Patellar tendonitis
• Patellar tendon rupture
• Quadriceps tendon rupture

Nontraumatic/Subacute

• Arthritis
• Gout and Pseudogout
• Osgood-Schlatter disease
• Patellofemoral syndrome (Runner's Knee)
• Patellar tendonitis (Jumper's knee)
• Pes anserine bursitis
• Popliteal cyst (Bakers cyst)
• Prepatellar bursitis (nonseptic)
• Septic bursitis
• Septic joint
• DVT

Treatment

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

Source

• Tintinalli

See Also

• Knee Diagnoses