Patellofemoral syndrome

Background

Anatomy of anterolateral aspect of right knee.

• 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
• Term Chondromalacia patella typically used synonymously, however this term implies softening of the cartilage

Major Causes

1. Focal trauma (least common)
2. Overuse
3. Abnormal patellar tracking (due to quadriceps weakness)

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)