II. Epidemiology

  1. Males affected more often (6:1 ratio)
  2. Ages 25 to 40 most often affected
  3. Tendonitis without rupture occurs in teen boys
    1. Associated with jumping sport during growth spurt

III. Risk factors

  1. Athletes in jumping sports
    1. High jump
    2. Basketball
    3. Football
    4. Gymnastics
  2. Comorbid conditions
    1. Systemic Lupus Erythematosus
    2. Rheumatoid Arthritis
    3. Chronic Renal Failure
    4. Diabetes Mellitus
    5. Paget's Disease
  3. Other associated factors
    1. Knee Local Corticosteroid Injections
    2. Repetitive Trauma to knee extensor tendon

IV. Signs: Patellar Tendon Rupture

  1. Large Knee Effusion
  2. Defect between tibial tubercle and inferior Patella
  3. Difficult active knee extension

V. Differential Diagnosis

  1. Patellar Dislocation
  2. Quadriceps tendon rupture (elderly)
  3. Tibial tuberosity avulsion (adolescents)

VI. Imaging: Patellar tendon rpture

  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

VII. Management

  1. Surgical Correction within 10 days of injury
  2. Cast immobilization for 6 weeks following surgery
  3. Physical therapy

VIII. Management: Experimental techniques

  1. Autologous blood injection into the Patellar tendon

IX. Precautions

  1. Do not inject Corticosteroid (risk of Patellar Tendon Rupture)

X. Complications: Associated with delayed surgery

  1. Quadriceps contracture shortens extensor Mechanism

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Ontology: Patellar tendonitis (C0158317)

Concepts Disease or Syndrome (T047)
ICD9 726.64
ICD10 M76.5 , M76.50
SnomedCT 268089006, 156662006, 37785001
English Patellar tendinitis, patellar tendinitis (diagnosis), patellar tendonitis, patellar tendinitis, Patellar tendinitis, unspecified knee, Patellar ligament desmitis, Patellar tendonitis, Patellar tendonitis (disorder), patella; tendinitis, tendinitis; patella
Dutch tendinitis van patella, patella; tendinitis, tendinitis; patella, Tendinitis van patellapees
French Tendinite rotulienne
German Tendititis der Patella, Tendinitis der Patellarsehne
Italian Tendinite del rotuleo
Portuguese Tendinite rotuliana
Spanish Tendinitis rotuliana, tendinitis rotuliana (trastorno), tendinitis rotuliana, tendinitis patelar
Japanese 膝蓋腱炎, シツガイケンエン
Czech Patelární tendinitida
Korean 무릎뼈 힘줄염
Hungarian Patella tendinitis