The Knee: Clinical Evaluation

Nick Iannuzzi, MDNovember 28th - 2011

Outline

• Anatomy• History• Differential Diagnoses

– Structured Evaluation

• Practice Physical Exam

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The Knee

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The Knee

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Exam Maneuvers

• Anterior drawer test• Lachman test• Pivot shift test• Posterior sag sign• Posterior drawer test• Quadriceps active test• Valgus stress test• Varus stress test• Patellofemoral grind test• Apprehension test• Joint line tenderness • McMurray Test• Apley grind test• Bounce home test

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WHAT?

WHY?

WHEN?

History

Timing? Mechanism? Pain description? Swelling? Mechanical Symptoms? Instability?

Baker et al 1983; Hughston et al 1985, Laprade et al 1997

Differential Diagnoses

• Anterior Knee pain

• Extensor mechanism rupture/failure

• Patellofemoral pain• Patellofemoral

instability• Plica• Arthritis

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Differential Diagnoses

• Lateral knee pain • Lateral meniscal tear• IT band friction

syndrome• Segond fracture• LCL/PLC tear• Gastrocnemius

strain/tear• Arthritis

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Differential Diagnoses

• Medial Knee Pain • Medial meniscus tear

• MCL strain/tear• Hamstring strain/tear• Pes anserine bursitis• MPFL disruption• Arthritis

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Differential Diagnoses

• Posterior knee pain

• Popliteal/Baker’s cyst (meniscal tear)

• Tumors• Claudication• Radiculopathy

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Differential Diagnosis

• Locked knee • Meniscal tear• OCD lesion

(femur/patella)• Tibial spine

avulsion• Osteochondroma

(tendons incarcerated)

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Rule #1

Always compare to the other Knee!!

INTERNAL CONTROL

EXAM-Getting Started

Inspection/Palpation-Effusion?-Tender?-Skin Breaks?

Alignment-Varus/Valgus?-Dislocated?

Range of Motion (0-130+) -Mechanical Block-Contractures-Crepitus

“Seek Out Disease, Don’t Hope For Health”-anonymous

WHAT DO YOU SEE??

EXAM-Overview

Inspection/PalpationAlignmentRange of Motion (0-130+)

Tracking

Extensor Mechanism

Stability-Provocative Tests

GAIT Analysis

ACL – Anterior Drawer

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Knee at 90 degrees

Anteriorly translate the tibia with thumbs palpating relationship between femoral condyles and tibia

Sensitivity 22-41% (acute injuries); 50-95% (chronic injuries)

ACL - Lachman Exam

Position: -Supine -Knee flexed 0-15 deg

Force Applied: Anterior

Grading Scale:Grade I: 1-5mmGrade II: 6-10mmGrade III: >10mm

Sens 80-99%, Spec 95%

Gross Anterior Displacement: ACL+PLC

Hamstrings RelaxedFeel for Endpoint

ACL - Pivot Shift

Position: -Supine -Knee ExtensionFlexion

Force: Valgus, IR Pathomechanics:

-SUBLUXEDReduced -ITT reduces tibia @ 20-30 flexion

Pathoanatomy: -Positive: Glide, Shift, Gross

Sens 35-99%, Spec 98%

*Key Testable Exam Finding

PCL – Posterior Sag Sign

• Position supine– Hip flexed 45 degrees– Knee flexed 90

degrees

• Normally, tib plateau extends 1cm beyond femoral condyles

• Sens 79%, Spec 100%

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PCL - Posterior Drawer

Position: -Supine -Knee flexed 90 deg

Force Applied: Posterior Pathomechanics:

-Post translation tibial plateau-Tibial Plat comp to Femoral Condyle

Pathoanatomy:

-G I/IIPCL injury -G IIIPCL + PLC injury

Sens 50-100%, Spec 99%

Negative in all normal knees, Cooper 1991

Gollehon et al 1987, Grood et al 1988, Noyes 1996

Varus/Valgus Stress Position:

-Supine-Knee 0/30 deg flexion

VALGUS:-0 degMCL + ACL/PCL-30 degMCL

VARUS:-0 degLCL

+Cruciate/IT/Bicep-30 degPop/PFL/Lat cap

Negative in all normal knees, Cooper 1991

PLC/PCL - ER stress (Dial) Position:

-Prone -Hip Neutral (0 deg flexion)-Knee Flexed 30/90

Force: ER Pathomechanics:

-Tibial ER on Femur

Pathoanatomy: >10 deg of Asymmetry 30 degPLC Injury90 degPLC + PCL Injury

TMA-Transmalleolar AxisNegative in all normal knees, Cooper 1991

PLC/PCL - External Rotation Recurvatum

Position:-Supine-Hip neutral (0 deg flexion)-Knee extended

Force: Lift FF anterior Pathomechanics:

-Knee hyperextends-External rotation-Varus

Pathoanatomy:-PLC injury- ±PCL/ACL tear

Negative in all normal knees, Cooper 1991

Meniscus – Joint Line Tenderness

• Can palpate medial and lateral joint lines of tibia at ~90 degrees flexion

• Medial meniscus more prominent with IR

• Lateral meniscus more prominent with ER

• Sens 55-85%, Spec 30-67%

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Meniscus – McMurray’s

• Hyperflex knee– Hold heel in one hand– Hold knee with other– Internally rotate knee while

extending to 90 degrees– Externally rotate knee while

extending to 90 degrees– Can apply varus/valgus

stress

• Sens 16-58%, Spec 77-98%

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Patellofemoral Instability – Q angle

• Angle formed by – Line drawn from

ASIS to center of patella

– Line drawn from center of patella to tibial tubercle

– Normal is 10-15 deg

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Patellofemoral Instability – Apprehension Sign

• Leg hanging off table, supported by thigh

• Knee flexed 30 degrees• Attempt lateral

translation of patella • Positive sign results

when patient flexes quad to resist translation

• Sens 39%

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Vascular Exam

Pulses-Popliteal

-Dorsalis Pedis

-Posterior Tibial Capillary Refill/Warmth

Ankle/Brachial Index:

≥0.9 NPV 100%

<0.9 PPV 90%,

Miranda: 35 knee dislocations

Exam :100% NPV ->Popliteal injury

-Serial Exams over 24hrs

POSITIVE: Angiography or OR!!

KNEE Emergencies?

INFECTION

DISLOCATION

VASCULAR INJURY

-Dislocations

-Distal femur/Prox Tibia

Most knee complaints are NOT emergencies!!

Surgical Problems

Pathology Finding

ACL Lachmans

Meniscus McMurray’s

Arthritis Hx/Xray

Infection Pain/Effusion/Labs

Vascular ABI/Hard Signs

CONCLUSIONS

HISTORY

EXAMINE NL KNEE

R/O EMERGENCY

REPETITION IS KEY

PHONE A FRIEND

30IT IS ONLY A VIRTUE IF YOU’RE NOT A SCREWUP!