Knee Examination: History Taking and Clinical Examination

The clinical knee examination of the knee is one of the most important components of orthopedic assessment. A structured approach helps identify the underlying pathology, distinguish between traumatic and non-traumatic conditions, and determine whether the problem originates from the knee or is referred from another region such as the hip or lumbar spine.

A complete knee assessment consists of:

• History taking
• Inspection
• Palpation
• Assessment of range of motion
• Special orthopedic tests
• Neurovascular examination (when indicated)

History Taking

A detailed history often provides the diagnosis before physical examination begins.

Pain

Assess the characteristics of the patient’s pain carefully.

• Onset
  • Sudden (trauma, ligament injury, infection)
  • Gradual (osteoarthritis, inflammatory arthritis)
• Duration
  • Acute
  • Chronic
  • Recurrent
• Severity
  • Mild
  • Moderate
  • Severe
• Character
  • Aching pain → degenerative disorders, bone tumors
  • Throbbing pain → infection
• Progression
  • Insidious onset → degenerative or mechanical disorders
  • Acute onset → trauma or septic arthritis
• Diurnal variation
  • Morning stiffness → inflammatory arthritis
  • Evening pain → mechanical disorders or osteoarthritis
  • Night pain → inflammatory disease, infection, tuberculosis, or malignancy
• Activity-related pain
  • Pain that worsens with activity commonly suggests osteoarthritis or mechanical pathology.
• Radiation
  • Pain radiating to the calf may occur with degenerative or mechanical disorders.
  • Consider referred pain from the lumbar spine.
• Pain after prolonged sitting (“Theater Sign”)
  • Suggests patellofemoral disorders.
• Bar or vice-like anterior knee pain
  • May indicate patella baja (low-riding patella).
• Pain elsewhere
  • Hip pathology
  • Lumbar spine disorders
  • Inflammatory polyarthritis
• Previous episodes
  • Previous injuries
  • Prior surgery
  • Recurrent instability

Deformity

Ask whether the patient has noticed any deformity.

Common deformities include:

• Genu varum
  • Osteoarthritis
  • Rickets
  • Post-traumatic deformity
• Genu valgum
  • Rheumatoid arthritis
  • Rickets
• Genu recurvatum
  • Poliomyelitis
  • Generalized ligamentous laxity
• Flexion deformity
  • Infection
  • Joint effusion
  • Hemophilia
  • Scarring
• Triple deformity
  • Tuberculosis
• Broadening of the knee
  • Osteophytes
  • Hemophilic arthropathy

Patellar abnormalities include:

• Patella alta
• Patella baja
• Lateral patellar subluxation
• Bipartite patella
• Small or hypoplastic patella

Also enquire about deformities involving:

• Hip
• Foot
• Small joints of the hands

These may indicate systemic disease.

Swelling

Determine:

• Onset
• Duration
• Mechanism
  • Traumatic
  • Atraumatic
• Associated symptoms
  • Fever
  • Pain
  • Weight loss

Ask whether aspiration has been performed previously.

The appearance of aspirated fluid can provide important diagnostic clues.

Long-standing painless swellings may represent:

• Meniscal cyst
• Osteochondroma
• Benign soft tissue tumors

Painful swellings raise concern for:

• Infection
• Malignancy
• Hematoma

Instability (Laxity)

Ask specifically whether the knee:

• “Gives way”
• “Goes out”
• Buckles unexpectedly

These symptoms may suggest:

• ACL rupture
• Patellar instability
• Meniscal pathology
• Loose bodies
• Articular cartilage injury
• Quadriceps weakness
• Neuromuscular disease
• Generalized ligamentous laxity

Locking

Determine whether locking is:

True Locking

Characterized by inability to fully extend the knee.

Common causes include:

• Meniscal tear
• Loose bodies
• Torn ACL stump

False Locking (Catching)

Usually caused by:

• Patellofemoral disorders
• Hoffa’s fat pad impingement

Limitation of Movement or Stiffness

Determine whether restriction is:

Painful

Suggests:

• Arthritis
• Trauma
• Infection
• Tumor

Painless

Usually mechanical, including:

• Muscle contracture
• Tendon contracture
• Fascial tightness
• Malunited fracture
• Osteophytes
• Arthrodesis

Restriction may also be:

• Intra-articular
• Extra-articular

Other Important Symptoms

Ask about:

• Crepitus
• Clicking
• Clunking
• Snapping
• Catching sensations
• Previous surgery
• Previous injections
• Functional limitations
• Sports participation

Patient-reported outcome measures such as the International Knee Documentation Committee (IKDC) Score may also be useful during evaluation.

Inspection

Inspection should begin with the patient standing.

Standing Examination

Kneel in front of the patient to inspect the knees at eye level.

Attitude

Observe:

• Knee extension
• Hip extension
• Plantigrade feet
• Patellae facing forward

Alignment

Evaluate overall lower limb alignment.

Look for:

• Normal physiological alignment
• Genu valgum
• Genu varum
• Windswept deformity

Inspect the Knee from All Directions

Look for:

Swelling

Generalized or localized swelling may indicate:

• Bursitis
• Meniscal cyst
• Baker’s cyst
• Osteochondroma
• Osgood-Schlatter disease
• Sinding-Larsen-Johansson syndrome
• Patellar tendinopathy (Jumper’s knee)
• Hoffa’s disease

Joint Effusion

Observe for fullness around the patella.

Skin Changes

Inspect for:

• Erythema
• Sinuses
• Surgical scars
• Neurofibromatosis
• Psoriatic lesions

Patellar Abnormalities

Assess for:

• Bipartite patella
• Squinting patella
• Frog-eye patella
• Patella magna
• Patella breva

Muscle Wasting

Particularly examine:

• Vastus medialis obliquus (VMO)

Quadriceps wasting commonly accompanies chronic knee pathology.

Gait Examination

Observe walking from:

• Front
• Back
• Side

Frontal Plane

Look for:

• Valgus thrust
• Varus thrust
• Circumduction gait
• Varus recurvatum thrust
• Duck-footed gait

Lateral View

Observe for:

• Antalgic gait
• Stiff-knee gait
• Flexed-knee gait

Sitting Examination

Assess:

• Patella alta
• Patella baja
• J-sign
• Dynamic patellar tracking
• Patellar tilt

Supine Examination

Reassess findings noted during standing.

Pay particular attention to:

• Flexion deformity
• Joint effusion
• Alignment correction

Correction of deformity in the supine position often indicates an intra-articular cause.

Palpation

Always compare both knees.

Anterior Aspect

Temperature

A warm knee suggests:

• Infection
• Inflammatory arthritis
• Active synovitis

Joint Effusion

Assess using:

• Fluid shift test (≈15 mL)
• Cross-fluctuation test (≈30 mL)
• Patellar tap (ballottement)
• Transillumination (selected cases)

Palpate the synovium for thickening or bogginess.

Patella and Extensor Mechanism

Examine:

• Patellar facet tenderness
• Patellar tendon
• Quadriceps tendon
• Bipartite patella
• Tibial tubercle

Assess:

• Patellar glide
• Patellar tracking
• Patellar tilt
• Patellar grind test
• Fairbank apprehension test

Wilson Test

Wilson’s test helps detect osteochondritis dissecans of the medial femoral condyle.

Medial Aspect

Palpate:

• Medial joint line
• Pes anserinus
• Pes anserine bursa
• Meniscal cyst
• Medial collateral ligament (MCL)

Joint line tenderness is highly suggestive of a medial meniscal tear.

Lateral Aspect

Assess:

• Lateral joint line
• Lateral collateral ligament (LCL)
• Iliotibial band
• Gerdy’s tubercle

Perform:

• Ober’s test (iliotibial band tightness)
• Allis (Galeazzi) test when limb length discrepancy is suspected

Posterior Aspect

Examine the patient prone when appropriate.

Assess:

• Flexion deformity
• Baker’s cyst
• Popliteal masses
• Popliteal aneurysm
• Enlarged lymph nodes

Craig’s (Ryder) test may be used to assess femoral anteversion.

Clinical Pearls

• The patient’s history frequently provides the diagnosis before examination.
• Always compare the affected knee with the contralateral side.
• Observe gait before palpation to avoid altering the patient’s natural walking pattern.
• Inspect the patient both standing and supine, as subtle deformities or effusions may only become apparent in one position.
• A systematic examination reduces the likelihood of missing significant pathology.

References

1. Hoppenfeld S. Physical Examination of the Spine and Extremities.
2. Magee DJ. Orthopedic Physical Assessment.
3. Solomon L, Warwick D, Nayagam S. Apley’s System of Orthopaedics and Fractures.
4. American Academy of Orthopaedic Surgeons (AAOS). Clinical evaluation of the knee.
5. Norris R, et al. The clinical examination of the knee. BMJ. 2018.
6. Logerstedt DS, et al. Knee stability and movement coordination impairments. Journal of Orthopaedic & Sports Physical Therapy (JOSPT). 2017.
7. American College of Rheumatology recommendations for the evaluation of knee pain and arthritis.