Extensor Mechanism Injury

Other Names

Knee Immobilizer

• Knee Extensor Injury

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Background

• Characterized by loss of ability to actively extend knee
• Can refer to
  • Quadriceps Tendon Rupture
  • Patellar Fracture
  • Patellar Tendon Rupture

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Differential Diagnosis

• Fractures
  • Distal Femur Fracture
  • Patellar Fracture
  • Tibial Plateau Fracture
  • Proximal Fibula Fracture
• Dislocations & Subluxations
  • Patellar Dislocation (and subluxation)
  • Knee Dislocation
  • Proximal Tibiofibular Joint Dislocation
• Muscle and Tendon Injuries
  • Quadriceps Contusion
  • Iliotibial Band Syndrome
  • Quadriceps Tendonitis
  • Quadriceps Muscle Strain
  • Patellar Tendonitis
  • Popliteus Tendinopathy
  • Extensor Mechanism Injury
    • Patellar Tendon Rupture
    • Quadriceps Tendon Rupture
    • Patellar Fracture
• Ligament Pathology
  • ACL Injury
  • PCL Injury
  • MCL Injury
  • LCL Injury
  • Meniscal Pathology
  • Posterolateral Corner Injury
  • Multiligament Injury
• Arthropathies
  • Knee Osteoarthritis
  • Septic Arthritis
  • Gout
  • Synovial Osteochondromatosis
• Bursopathies
  • Prepatellar Bursitis
  • Pes Anserine Bursitis
  • MCL Bursitis
  • Infrapatellar Bursitis
• Patellofemoral Pain Syndrome (PFPS)/ Anterior Knee Pain)
  • Chondromalacia Patellae
  • Patellofemoral Osteoarthritis
  • Osteochondral Defect Knee
  • Plica Syndrome
  • Infrapatellar Fat Pad Impingement
  • Patellar Instability
• Neuropathies
  • Saphenous Nerve Entrapment
• Other
  • Bakers Cyst (Popliteal Cyst)
  • Patellar Contusion
  • Pellegrini Stieda Syndrome
  • Parameniscal Cyst
• Pediatric Considerations
  • Patellar Apophysitis (Sinding-Larsen-Johnansson Disease)
  • Patellar Pole Avulsion Fracture
  • Tibial Tubercle Avulsion Fracture
  • Tibial Tuberosity Apophysitis (Osgood Schalatters Disease)
  • Proximal Tibial Metaphyseal Fracture
  • Proximal Tibial Physeal Injury

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See Also

• Internal
  • Knee Pain (Main)
  • Physical Exam Knee
  • Knee Anatomy (Main)
• External
  • Sports Medicine Review Knee Pain: https://www.sportsmedreview.com/by-joint/knee/

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