Knee

Patellar Tendon Rupture

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Patellar Tendon Rupture

  • See Also
  1. Patellar Tendinopathy
  • Risk Factors
  1. Patellar Tendinopathy
  2. Older age
  3. Abnormal vascular changes
    1. Obesity
    2. Systemic Lupus Erythematosus
    3. Chronic Kidney Disease
  4. Medications
    1. Fluoroquinolone use
    2. Prolonged Systemic Corticosteroid use
    3. Corticosteroid Injection
    4. Testosterone administration
  • Mechanism
  1. Forceful knee flexion against resistance
  2. High energy Trauma (fall from height, sports-related injury, Motor Vehicle Accident)
  • Symptoms
  1. Sudden, severe pain
  2. Popping or tearing Sensation
  3. Knee swelling
  • Signs
  1. Large Knee Effusion
  2. Palpable defect between tibial tubercle and inferior Patella margin
  3. Difficult active knee extension
    1. Some knee extension may be maintained if Patellar Retinacular fibers are intact
  • Differential Diagnosis
  1. Patellar Dislocation
  2. Quadriceps tendon rupture (elderly)
  3. Tibial tuberosity avulsion (adolescents)
  1. Insall-Salvati Ratio for Patella evaluation
    1. Distance ratio between
      1. Proximal tibial tubercle
      2. Inferior pole of the Patella
    2. Normal ratio: +1 or -0.2
  2. Interpretation: Severe Patella alta (high riding)
    1. Suggests Patellar ligament rupture
  3. Other findings
    1. Patella avulsion Fracture
  • Imaging
  • Advanced
  1. Knee Bedside Ultrasound
    1. Apply linear transducer over the Patellar tendon in the sagittal plane
    2. Ruptured tendon will appear hypoechogenic with a separation between tendon ends
    3. Dynamic views may better define the tendon ends
  2. Knee MRI
    1. Definitive study to identify extent of rupture and plan surgical repair
  • Management
  1. Surgery (preferred in all full thickness tears)
    1. Surgical Correction within 10 days of injury
      1. Complications include post-operative infection, Patellar baja (low riding Patella)
    2. Cast immobilization for 6 weeks following surgery
    3. Physical therapy
  2. Conservative Management
    1. Indications
      1. Partial Patellar tendon tear
      2. Serious comorbidity risk outweighs surgical benefit
    2. Approach
      1. Knee immobilization in full extension
      2. Non-weight bearing
      3. Intensive physical therapy
    3. Efficacy
      1. Functional limitations (knee extension)
      2. Typically worse outcomes than with surgery
  • Complications
  1. Persistent quadricep weakness in knee extension
  2. Knee Stiffness
  • Complications
  • Associated with delayed surgery
  1. Quadriceps contracture shortens extensor mechanism
  • References
  1. Benjamin (2023) Crit Dec Emerg Med 37(7): 20-1
  2. Hoppman and Shannon (2021) Crit Dec Emerg Med 35(11): 16-7