What are the key components of a thorough history and physical examination (HPI) for a patient presenting with knee pain?

Key Components of a Thorough History and Physical Examination for Knee Pain

A systematic approach to history and physical examination is essential for accurate diagnosis and management of knee pain, focusing on identifying the underlying cause to improve morbidity, mortality, and quality of life outcomes.

History Components

Pain Characteristics

• Location: Determine precise location (anterior, posterior, medial, lateral) as this helps localize the pathology 1
• Onset: Sudden (traumatic) vs. gradual (degenerative or overuse) 1
• Duration: Acute (<6 weeks) vs. chronic (>6 weeks) - chronic pain may warrant radiographic imaging 1
• Quality: Sharp, dull, aching, burning, or throbbing 1
• Severity: Use pain scale (0-10) and impact on daily activities 2
• Aggravating factors: Weight-bearing activities, squatting, stairs, prolonged sitting 3
• Alleviating factors: Rest, medications, ice/heat application 1

Associated Symptoms

• Mechanical symptoms: Locking, catching, clicking, popping, or giving way (suggests meniscal or ligamentous injury) 4
• Swelling: Timing (immediate vs. delayed), frequency, and severity 1
• Instability: Sensation of knee "giving out" (suggests ligamentous injury) 4
• Systemic symptoms: Fever, chills, weight loss (suggests infection or inflammatory condition) 1

Trauma History

• Mechanism of injury: Direct impact, twisting, hyperextension, or fall 1
• Activity at time of injury: Sports-related, occupational, or daily activities 3
• Ability to bear weight immediately after injury 1

Past Medical History

• Previous knee injuries or surgeries 1
• Degenerative joint conditions: Osteoarthritis, rheumatoid arthritis 2
• Systemic conditions: Gout, pseudogout, autoimmune disorders 1
• Previous treatments: Physical therapy, injections, medications 5

Physical Examination

Inspection

• Alignment: Standing alignment, genu varum/valgum (bow-legged/knock-kneed) 4
• Swelling: Location and severity of effusion 1
• Muscle atrophy: Particularly quadriceps and vastus medialis 5
• Skin changes: Erythema, warmth (suggests infection or inflammation) 1
• Gait analysis: Antalgic gait, limping, or other abnormalities 5

Palpation

• Joint line tenderness: Medial or lateral (suggests meniscal injury) 4
• Patellofemoral joint: Tenderness, crepitus 3
• Bony landmarks: Tibial tubercle, femoral condyles, patella 1
• Temperature: Warmth suggests inflammation or infection 1

Range of Motion Assessment

• Active and passive ROM: Compare with uninjured knee 4
• Pain with motion: Note at which degree of flexion/extension pain occurs 1
• Crepitus: Grinding sensation during movement 3

Strength Testing

• Quadriceps strength: Particularly vastus medialis 5
• Hamstring strength: Compare with contralateral side 1
• Hip musculature: Assess for weakness in hip abductors and external rotators 5

Special Tests

• Ligament stability tests:

  • Anterior cruciate ligament: Lachman test, anterior drawer test, pivot shift test 4
  • Posterior cruciate ligament: Posterior drawer test, posterior sag test 4
  • Medial collateral ligament: Valgus stress test 4
  • Lateral collateral ligament: Varus stress test 4

• Meniscal tests:

  • McMurray's test 4
  • Apley's compression/distraction test 4
  • Bounce home test 4

• Patellofemoral tests:

  • Patellar apprehension test 3
  • Patellar grind test 3
  • Q-angle measurement 3

Neurovascular Assessment

• Pulses: Dorsalis pedis and posterior tibial 1
• Sensation: Light touch in dermatomes 1
• Motor function: Toe flexion/extension, ankle dorsiflexion/plantar flexion 1

Red Flags Requiring Urgent Referral

• Severe pain with inability to bear weight after acute trauma 1
• Joint effusion with fever and erythema (suggests septic arthritis) 1
• Significant joint instability suggesting complete ligament tear 1
• Locked knee unable to fully extend (suggests displaced meniscal tear) 4

Diagnostic Approach Based on History and Physical

• Initial radiographs should be reserved for:

  • Chronic knee pain (>6 weeks) 1
  • Acute trauma meeting evidence-based criteria 1
  • Suspected fracture or degenerative changes 6

• MRI should be considered only when:

  • Surgery is being considered 6
  • Pain persists despite adequate conservative treatment 1
  • Initial radiographs are normal but symptoms persist 6

• Ultrasound is useful for:

  • Evaluating effusions and cysts (e.g., Baker's cyst) 1
  • Assessing superficial structures 1
  • Detecting synovial pathology 6