Diagnosis of knee pain

A thorough and detailed history will aid the physician in diagnosing the cause of knee pain. Inquire about:

• any event resulting in trauma to the knee
  • a direct blow to the knee -
    • to the anterior aspect of the knee -
      • to the proximal tibia with the knee in flexion (e.g., during vehicle accident where the knee hits the dashboard) results posterior cruciate ligament injury
    • to the lateral aspect of the knee - medial collateral ligament injury
    • to the medial aspect of the knee - lateral collateral ligament injury (1) (one of the most commonly injured ligaments in the knee) (2)
      
      
  • noncontact forces
    • significant deceleration forces (sudden stops and sharp cuts or turns) can cause anterior cruciate ligament injury
    • hyperextension - injury to the anterior cruciate ligament or posterior cruciate ligament
    • sudden twisting or pivoting movements - can cause meniscal injury (1)
      
      
• characteristics of the pain e.g. - onset, location, duration, severity, quality (dull sharp achy) of pain
  • spontaneous onset of severe pain can be due to trauma, osteonecrosis, infection (3)
  • pain at rest, unchanged by activity or worse at night should prompt for an investigation of an underlying serious condition (3)
  • in an acute injury, ask whether the patient was able to continue activity or bear weight after the injury or was forced to cease activities immediately (1)
    
    
• aggravating and alleviating factors (1)
  • sporting activities (running, jumping) act as a precipitating factor in patellofemoral pain
  • pain aggravated by kneeling specially in older adults indicate prepatellar bursitis or patellofemoral osteoarthritis (3)
    
    
• symptoms such as locking, popping, or giving way of the knee at the time of injury
  
  • locking episodes suggests a meniscal tear
  • sensation of popping during the time of the injury suggests ligamentous injury (complete rupture of a ligament)
  • episodes of giving way may be due to patellar subluxation or ligamentous rupture
    
    
• swelling of the knee joint - the amount and speed of onset
  • rapid onset (within 2 hours) of a large and tense effusion - rupture of a ligament (anterior cruciate) or fracture of the tibial plateau hemarthrosis
  • slower onset (over 2-36 hours) of a mild to moderate effusion - meniscal injury or ligamentous sprain
  • recurrent knee effusion after activity - meniscal injury (1)
  • in patients without a history of trauma
    • acutely knee swelling with symptoms of less than 24 hours - septic arthritis, crystal arthritis, haemarthrosis, rheumatoid arthritis (3)
      
      
• of previous injuries, surgery, or medical conditions (gout, pseudogout, rheumatoid arthritis, or other degenerative joint disease) (1)

Reference:

• 1. Calmbach WL, Hutchens M. Evaluation of patients presenting with knee pain: Part II. Differential diagnosis. Am Fam Physician. 2003;68(5):917-22.
• 2. Malanga GA et al. Physical examination of the knee: a review of the original test description and scientific validity of common orthopedic tests. Arch Phys Med Rehabil. 2003;84(4):592-603.
• 3. Australian Acute Musculoskeletal Pain Guidelines Group 2003. Evidence-based management of acute musculoskeletal pain. Australian Government National Health and Medical Research Council