Patellofemoral syndrome

Background

• Also known as "Runner's Knee"
• Major cause of anterior knee pain (especially in women)
  • Pain comes from contact of posterior surface of patella with the femur
• 3 major causes:
  • 1. Focal trauma (least common)
  • 2. Overuse
  • 3. Abnormal patellar tracking (due to quadriceps weakness)
• Term Chondromalacia patella typically used synonymously, however this term implies softening of the cartilage

Clinical Features

• Gradual onset of unilateral, anterior knee pain, nonradiating
• Pain worsened by prolonged knee flexion ("moviegoer syndrome") and stair climbing
• Patellar grind test
  • Press patella away from femoral condyles while patient contracts the quadriceps
    • Sudden patellar pain and relaxation of the muscle is positive test

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 XR series
  • Patella may not line up with groove of the femur on sunrise view
  • Decreased space posterior to patella
  • Bony erosions

Management

• Conservative therapy (with emphasis on physical therapy and strengthening)

Disposition

• Outpatient management

See Also

• Knee (Minor)