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 appropriate management of knee pain, focusing on identifying the underlying cause to improve morbidity, mortality, and quality of life outcomes.

History Taking Components

Pain Characteristics

• Location: Determine the precise location (anterior, posterior, medial, lateral) as this helps localize the anatomical structure involved 1
• Onset: Sudden (traumatic) versus gradual (degenerative or overuse) 1
• Duration: Acute (<6 weeks) versus chronic (>6 weeks) - this affects imaging decisions 1
• Quality: Sharp, dull, aching, burning, or throbbing 1
• Severity: Use pain scale (0-10) and impact on daily activities 2
• Aggravating factors: Activities that worsen pain (squatting, stairs, running, jumping) 3
• Alleviating factors: Rest, medications, ice/heat, positional changes 1

Associated Symptoms

• Mechanical symptoms: Locking, catching, giving way, or instability suggest internal derangement 1
• Swelling: Timing (immediate vs. delayed), frequency, and severity 1
• Stiffness: Morning stiffness or after prolonged sitting (suggests arthritis) 2
• Systemic symptoms: Fever, weight loss, fatigue (may indicate infection or inflammatory condition) 1

Trauma History

• Mechanism of injury: Direct impact, twisting, hyperextension 1
• Ability to bear weight immediately after injury: Inability suggests significant injury 1
• Audible sounds: Pop or snap at time of injury (suggests ligament tear) 4

Past Medical History

• Previous knee injuries or surgeries 1
• Chronic medical conditions: Arthritis, gout, diabetes 2
• Family history: Especially for arthritis or autoimmune conditions 2
• Current medications: Including supplements and over-the-counter drugs 1

Functional Assessment

• Impact on daily activities: Work, sports, recreation 3
• Changes in activity level: Recent increases in intensity or duration of exercise 5
• Footwear: Recent changes or inappropriate footwear for activities 3

Physical Examination Components

Inspection

• Gait analysis: Observe for limping, antalgic gait, or other abnormalities 4
• Alignment: Standing (varus/valgus), Q-angle, patellar tracking 5
• Swelling: Localized or diffuse 1
• Muscle atrophy: Particularly quadriceps (vastus medialis) 5
• Skin changes: Erythema, warmth, scars from previous surgeries 1

Palpation

• Joint line tenderness: Medial and lateral (suggests meniscal injury) 4
• Patellofemoral joint: Facets, tracking during flexion/extension 3
• Bony structures: Tibial tubercle, femoral condyles, patella 4
• Soft tissues: Ligaments, tendons, bursae 1
• Effusion: Ballottement test, bulge sign 1

Range of Motion

• Active and passive ROM: Extension (0°) to flexion (135°) 4
• Compare with uninjured knee: Always examine the contralateral knee first 4
• Pain with movement: Note at which degree of flexion/extension pain occurs 4

Strength Testing

• Quadriceps strength: Particularly vastus medialis 5
• Hamstring strength: Often overlooked but important for knee stability 5
• Hip muscle strength: Abductors, adductors, and rotators affect knee mechanics 5

Special Tests

• Ligament stability tests:

  • Anterior cruciate ligament: Lachman test, anterior drawer, pivot shift 4
  • Posterior cruciate ligament: Posterior drawer, tibial sag 4
  • Medial collateral ligament: Valgus stress at 0° and 30° 4
  • Lateral collateral ligament: Varus stress at 0° and 30° 4

• Meniscal tests:

  • McMurray's test: Rotation with valgus/varus stress during extension 4
  • Apley's compression test: Axial loading with rotation 4
  • Bounce test: Pain with quick extension from flexion 4

• Patellofemoral tests:

  • Patellar apprehension test: For instability 3
  • Patellar grind test: For chondromalacia 3
  • J-sign: Lateral deviation of patella during extension 3

Neurovascular Assessment

• Pulses: Dorsalis pedis and posterior tibial 1
• Sensation: Light touch in all dermatomes 1
• Motor function: Distal muscle groups 1

Common Pitfalls to Avoid

• Failing to examine the contralateral knee for comparison 4
• Overlooking referred pain from hip or lumbar spine pathology 6
• Neglecting to assess functional limitations beyond pain 3
• Rushing to imaging before completing a thorough clinical examination 6
• Missing muscle imbalances, particularly between vastus medialis and lateralis 5
• Not considering systemic conditions that can manifest as knee pain 1

When to Consider Urgent Referral

• Severe pain, swelling, and instability after acute trauma 1
• Inability to bear weight following injury 1
• Signs of infection: Fever, erythema, warmth, and limited range of motion 1
• Suspected fracture or dislocation 1
• Neurovascular compromise: Decreased pulses, sensation, or motor function 1