Master the comprehensive knee examination including ligament stability testing (ACL, PCL, MCL, LCL), meniscal assessment, patellofemoral evaluation, and common pathology recognition.
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.
High-Yield Exam Summary
Start with Gait: Observe walking for antalgic gait, thrust, locking
Patient Positioning:
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."
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.
Sweep Test (Small Effusion):
Patellar Tap (Moderate Effusion):
Cross-Fluctuation (Large Effusion):
Temperature: Use back of hand, compare sides
Bony Landmarks:
Joint Lines:
Soft Tissues:
| movement | normalRange | technique | keyPoints |
|---|---|---|---|
| Flexion | 0-135° | Heel to buttock | Limited by effusion, OA, locked meniscus |
| Extension | 0° | Straighten knee fully | Loss = FFD, bucket-handle tear |
| Hyperextension | 5-10° | Lift heel off bed | Increased = ligament laxity |
During Movement Assess:
ACL integrity (gold standard)
Increased anterior translation with soft/absent endpoint
ACL rupture
Ability to detect true positives
Ability to exclude false positives
ACL integrity
Increased anterior translation (greater than 6mm or compared to opposite)
ACL rupture (less sensitive than Lachman - hamstrings guard)
Ability to detect true positives
Ability to exclude false positives
Rotatory instability (ACL)
Clunk or jerk at 20-30° as tibia reduces from subluxed position
ACL deficiency with anterolateral rotatory instability
Ability to detect true positives
Ability to exclude false positives
PCL integrity
Increased posterior translation (posterior sag already present)
PCL rupture
Ability to detect true positives
Ability to exclude false positives
PCL integrity
Tibia sags posteriorly on affected side
PCL rupture
Ability to detect true positives
Ability to exclude false positives
Medial collateral ligament integrity
Increased medial opening compared to other side. Grading: I: 0-5mm, II: 5-10mm, III: greater than 10mm
MCL injury. Opening at 30° only = isolated MCL; opening at 0° = MCL + cruciate
Ability to detect true positives
Ability to exclude false positives
Lateral collateral ligament integrity
Increased lateral opening
LCL injury, posterolateral corner injury
Ability to detect true positives
Ability to exclude false positives
Posterolateral corner injury
Greater than 10° increased external rotation. At 30° only = isolated PLC; at both angles = PLC + PCL
Posterolateral corner injury
Ability to detect true positives
Ability to exclude false positives
Meniscal tear
Palpable click or pop at joint line with pain
Meniscal tear (location determined by rotation and stress direction)
Ability to detect true positives
Ability to exclude false positives
Meniscal tear
Joint line pain or mechanical catching
Meniscal tear
Ability to detect true positives
Ability to exclude false positives
Meniscal vs ligament pathology
Pain on compression = meniscal; pain on distraction = ligamentous
Differentiates meniscal from ligamentous injury
Ability to detect true positives
Ability to exclude false positives
Patellar instability
Patient becomes apprehensive, guards, or grabs examiner's hand
Patellar instability (previous dislocation)
Ability to detect true positives
Ability to exclude false positives
Patellofemoral pathology
Pain behind patella, inability to complete contraction
Chondromalacia, patellofemoral arthritis (low specificity)
Ability to detect true positives
Ability to exclude false positives
Patellar maltracking
Patella moves laterally in terminal extension forming 'J' shape
Lateral patellar maltracking, patella alta
Ability to detect true positives
Ability to exclude false positives
Vascular:
Neurological:
Always state to the examiner:
"To complete my examination, I would like to:
"25-year-old male footballer with right knee injury after pivoting tackle. Felt pop, developed immediate swelling."
| condition | look | feel | move | specialTests |
|---|---|---|---|---|
| ACL Rupture | Effusion | Joint line tender | May be full | Lachman +, anterior drawer +, pivot shift + |
| Meniscal Tear | May have effusion | Joint line tenderness | Locking, catching | McMurray +, Thessaly + |
| MCL Injury | Medial swelling | MCL tenderness | Full unless acute | Valgus stress + at 30° |
| OA | Varus/valgus deformity | Bony enlargement, crepitus | Reduced flexion/extension | Crepitus, bony tenderness |
| Patellar Instability | Effusion if acute | Medial retinaculum tenderness | Full | Apprehension +, J-sign + |
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Comprehensive demonstration of systematic knee examination including inspection, palpation, range of motion, and all special tests.
High-Yield Exam Summary