Acute knee injury

Background

Knee ligaments

Knee anatomy. Right knee shown from anterio-lateral view.

• 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

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

Evaluation

Knee x-rays

• Anteroposterior and lateral views
  • Consider sunrise if pain over patella