Knee Examination
The knee examination is frequently tested and must be comprehensive yet efficient. Examiners expect systematic assessment of all four ligaments, both menisci, the patellofemoral joint, and recognition of effusion. The Lachman test is considered the gold standard for ACL assessment.
Quick Reference One-Pager
Look
- Gait and alignment (varus/valgus)
- Effusion (loss of dimples, swelling)
- Muscle wasting (VMO, quadriceps)
- Scars, skin changes
- Patellar position (alta, baja, lateral tilt)
Feel
- Temperature
- Effusion (patellar tap, sweep test)
- Joint line (medial/lateral)
- Patella facets, tendon
- Tibial tubercle, popliteal fossa
Move
- Flexion 0-135°
- Extension 0° (hyperextension 5-10°)
- Observe for crepitus, catching
Special Tests
- ACL: Lachman, anterior drawer, pivot shift
- PCL: posterior drawer, sag sign
- MCL/LCL: valgus/varus stress at 0° and 30°
- Meniscus: McMurray, Thessaly, joint line
- Patella: apprehension, grind, tracking
Introduction and Setup
Before You Start
Start with Gait: Observe walking for antalgic gait, thrust, locking
Patient Positioning:
- Supine for most tests
- Compare with contralateral knee throughout
- Sitting for patellar tracking
Exposure: Both legs exposed from mid-thigh to ankle
Consent Script: "I'm going to examine your knees. I'll look at both sides, feel the joints, and test the ligaments and movements. Some tests may be uncomfortable - please tell me if anything hurts."
Look (Inspection)
- Alignment: Varus (bow-legged), valgus (knock-kneed), recurvatum
- Muscle bulk: Quadriceps wasting (especially VMO)
- Swelling: Location (suprapatellar, infrapatellar)
- Scars: Arthroscopy portals, incisions
- Posture: Fixed flexion, hyperextension
Effusion Detection: The loss of the normal concave dimples on either side of the patella is the earliest sign of effusion. More significant effusions cause suprapatellar fullness.
Effusion Assessment
Testing for Effusion
Sweep Test (Small Effusion):
- Sweep fluid from medial side up into suprapatellar pouch
- Sweep down lateral side
- Observe for fluid refilling medial side
Patellar Tap (Moderate Effusion):
- Squeeze suprapatellar pouch to push fluid under patella
- Tap patella sharply downward
- Positive: Patella taps against femur (ballotable)
Cross-Fluctuation (Large Effusion):
- One hand over suprapatellar pouch
- Other hand over infrapatellar area
- Feel fluid transmission between hands
Feel (Palpation)
Systematic Palpation
Temperature: Use back of hand, compare sides
Bony Landmarks:
- Tibial tubercle: Prominence (Osgood-Schlatter's)
- Patella: Facets, inferior pole (patella tendinopathy)
- Femoral condyles: Medial and lateral
- Fibular head: Lateral, LCL attachment
Joint Lines:
- Medial joint line: Flex knee to 90°, palpate gap between tibia and femur medially (medial meniscus)
- Lateral joint line: Palpate laterally (lateral meniscus)
Soft Tissues:
- Patella tendon: Tenderness (tendinopathy)
- Quadriceps tendon: Integrity, tenderness
- Collateral ligaments: MCL, LCL
- Popliteal fossa: Baker's cyst, popliteal pulse
Move (Range of Motion)
- normalRange
- 0-135°
- technique
- Heel to buttock
- keyPoints
- Limited by effusion, OA, locked meniscus
- normalRange
- 0°
- technique
- Straighten knee fully
- keyPoints
- Loss = FFD, bucket-handle tear
- normalRange
- 5-10°
- technique
- Lift heel off bed
- keyPoints
- Increased = ligament laxity
During Movement Assess:
- Crepitus: OA, patellofemoral pathology
- Catching/locking: Meniscal tear, loose body
- Arc of pain: Position where pain occurs
Special Tests
ACL Assessment
Special test
Lachman Test
ACL integrity (gold standard)
Technique
- 1Patient supine, knee flexed 20-30°
- 2Stabilize distal femur with one hand
- 3Hold proximal tibia with other hand
- 4Apply anterior translation force to tibia
Positive Sign
Increased anterior translation with soft/absent endpoint
Indicates
ACL rupture
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Anterior Drawer Test
ACL integrity
Technique
- 1Patient supine, knee flexed 90°, foot flat on bed
- 2Sit on patient's foot to stabilize
- 3Hands around proximal tibia, thumbs on joint line
- 4Pull tibia forward
Positive Sign
Increased anterior translation (greater than 6mm or compared to opposite)
Indicates
ACL rupture (less sensitive than Lachman - hamstrings guard)
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Pivot Shift Test
Rotatory instability (ACL)
Technique
- 1Patient supine, leg extended and relaxed
- 2Apply valgus force and internal tibial rotation
- 3Slowly flex the knee from extension
Positive Sign
Clunk or jerk at 20-30° as tibia reduces from subluxed position
Indicates
ACL deficiency with anterolateral rotatory instability
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
PCL Assessment
Special test
Posterior Drawer Test
PCL integrity
Technique
- 1Patient supine, knee flexed 90°, foot flat
- 2Assess starting position (sag)
- 3Push tibia posteriorly
Positive Sign
Increased posterior translation (posterior sag already present)
Indicates
PCL rupture
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Posterior Sag Sign (Godfrey Test)
PCL integrity
Technique
- 1Patient supine, both hips and knees flexed to 90°
- 2Examiner supports both heels together
- 3Observe tibial plateau position from side
Positive Sign
Tibia sags posteriorly on affected side
Indicates
PCL rupture
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Collateral Ligament Assessment
Special test
Valgus Stress Test (MCL)
Medial collateral ligament integrity
Technique
- 1Support leg at ankle, other hand on lateral knee
- 2Apply valgus force (pushing knee medially)
- 3Test at 0° (full extension) and 30° flexion
Positive Sign
Increased medial opening compared to other side. Grading: I: 0-5mm, II: 5-10mm, III: greater than 10mm
Indicates
MCL injury. Opening at 30° only = isolated MCL; opening at 0° = MCL + cruciate
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Varus Stress Test (LCL)
Lateral collateral ligament integrity
Technique
- 1Support leg at ankle, other hand on medial knee
- 2Apply varus force (pushing knee laterally)
- 3Test at 0° and 30° flexion
Positive Sign
Increased lateral opening
Indicates
LCL injury, posterolateral corner injury
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Dial Test
Posterolateral corner injury
Technique
- 1Patient prone, both knees flexed to 30° then 90°
- 2Externally rotate both feet simultaneously
- 3Compare tibial external rotation side to side
Positive Sign
Greater than 10° increased external rotation. At 30° only = isolated PLC; at both angles = PLC + PCL
Indicates
Posterolateral corner injury
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Meniscal Assessment
Special test
McMurray Test
Meniscal tear
Technique
- 1Patient supine, knee flexed fully
- 2Hold heel and place other hand on joint line
- 3For medial meniscus: externally rotate tibia, extend knee while applying valgus
- 4For lateral meniscus: internally rotate tibia, extend knee while applying varus
Positive Sign
Palpable click or pop at joint line with pain
Indicates
Meniscal tear (location determined by rotation and stress direction)
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Thessaly Test
Meniscal tear
Technique
- 1Patient standing on affected leg with 20° knee flexion
- 2Support patient's extended hands for balance
- 3Patient rotates body and knee internally and externally three times
Positive Sign
Joint line pain or mechanical catching
Indicates
Meniscal tear
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Apley Grind Test
Meniscal vs ligament pathology
Technique
- 1Patient prone, knee flexed 90°
- 2Apply axial compression through tibia while rotating (grind)
- 3Then apply distraction while rotating (distraction)
Positive Sign
Pain on compression = meniscal; pain on distraction = ligamentous
Indicates
Differentiates meniscal from ligamentous injury
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Patellofemoral Assessment
Special test
Patellar Apprehension Test
Patellar instability
Technique
- 1Patient supine, knee extended and relaxed
- 2Apply gentle lateral pressure to patella
Positive Sign
Patient becomes apprehensive, guards, or grabs examiner's hand
Indicates
Patellar instability (previous dislocation)
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Patella Grind Test (Clarke's Test)
Patellofemoral pathology
Technique
- 1Patient supine, knee extended
- 2Press patella distally with web of hand
- 3Ask patient to contract quadriceps
Positive Sign
Pain behind patella, inability to complete contraction
Indicates
Chondromalacia, patellofemoral arthritis (low specificity)
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
J-Sign (Patellar Tracking)
Patellar maltracking
Technique
- 1Patient sitting, legs hanging
- 2Observe patella during active knee extension
Positive Sign
Patella moves laterally in terminal extension forming 'J' shape
Indicates
Lateral patellar maltracking, patella alta
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Neurovascular Assessment
Quick Neurovascular Check
Vascular:
- Popliteal pulse (posterior, deep in fossa)
- Dorsalis pedis, posterior tibial pulses
- Capillary refill
Neurological:
- Common peroneal nerve at fibular neck
- Sensation: Lateral leg (L5), dorsum foot (L5), sole (S1)
- Motor: Foot dorsiflexion (L4,5), plantarflexion (S1,2)
Complete the Examination
Always state to the examiner:
"To complete my examination, I would like to:
- Examine the hip as the joint above
- Examine the ankle and foot as the joint below
- Perform neurovascular assessment of the lower limb
- Examine the lumbar spine for referred pain
- Obtain X-rays (AP standing, lateral, skyline patella)"
Summary Presentation
“25-year-old male footballer with right knee injury after pivoting tackle. Felt pop, developed immediate swelling.”
Common Conditions Table
- look
- Effusion
- feel
- Joint line tender
- move
- May be full
- specialTests
- Lachman +, anterior drawer +, pivot shift +
- look
- May have effusion
- feel
- Joint line tenderness
- move
- Locking, catching
- specialTests
- McMurray +, Thessaly +
- look
- Medial swelling
- feel
- MCL tenderness
- move
- Full unless acute
- specialTests
- Valgus stress + at 30°
- look
- Varus/valgus deformity
- feel
- Bony enlargement, crepitus
- move
- Reduced flexion/extension
- specialTests
- Crepitus, bony tenderness
- look
- Effusion if acute
- feel
- Medial retinaculum tenderness
- move
- Full
- specialTests
- Apprehension +, J-sign +
Video Demonstration
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Comprehensive demonstration of systematic knee examination including inspection, palpation, range of motion, and all special tests.
Examiner Tips
Do
- Demonstrate Lachman confidently
- Test all four ligaments systematically
- Compare endpoints with other side
- Assess effusion before anything else
- Test at 0° AND 30° for collaterals
Don't
- Forget the posterior drawer
- Miss the posterior sag sign
- Rush the meniscal tests
- Ignore patellofemoral joint
- Forget dial test for PLC injury