Daniel Mantuani MD/MPHAssistant Director Emergency Ultrasound

Alameda Health SystemHighland General Hospital

The Hot Joint

Disclosures

None

Anatomy

Ultrasound-guided Arthrocentesis Summary

Rationale

OutlineRationale

20% had more the ONE Joint Involved

Increasing incidence (10-40 per 100,000) = aging population and

more Ortho interventions

Risk Factors Signs and Symptoms

WBC >10K : LR 1.3

ESR > 30 : LR 1.4

CRP > 100 : LR 1.6

Arthrocentesis is the BEST test to determine the presence of a septic joint

Laboratory Blood TestsNot Sensitive/Specific

32 primary studies

“Because H&P and serum markers are not helpful to significantly adjust postest probability of septic arthritis,

synovial fluid analysis is essential”

Septic Arthritis

• Cant miss Diagnosis: Meningitis of the Joint? • Suspicion should be high• Threshold to tap should be low

Arthrocentesis

Before We StartDoes your patient even have an effusion?

PhysicalExam

XRY CT MRI

Ultrasound?

Ultrasound?

US prevented 27/39 planned arthrocentesis

US changed management 35/54 patients

Soft Tissue Joint CapsuleVS

Knee

Femur

Quadriceps Tendon

Effusion

Patella

Soft Tissue VS Joint Capsule

Knee

Quadriceps Tendon Patella

Femur

Abscess

Joint CapsuleVSSoft Tissue

Abscess

Knee

Joint CapsuleVSSoft Tissue

Shoulder

Humerus

Effusion

Humerus

Glenoid

Joint CapsuleVSSoft Tissue

ShoulderLeft Right

Glenoid GlenoidHumerus Humerus

???

Joint CapsuleVSSoft Tissue

Shoulder

Joint CapsuleVSSoft Tissue

Septic Bursitis

Million Dollar QuestionCan you have a Septic Joint if there is

no JOINT CAPSULE effusion on Ultrasound??

REVELATION Joint Capsule!!

ArthrocentesisOptions

Vs Ultrasound-Guided

Dry Tap?

Ultrasound Basics

Linear Probe

3-4cm

Increased ResolutionDecreased Depth

ElbowAnkleSmall JointsEasiest Needle VisualizationPediatric

Curvilinear Probe

> 9cm

Increased DepthDecreased Resolution

HipShoulder

Difficult Needle Visualization

• 1st: Examine the unaffected extremity first• 2nd: Identify classic bony landmarks• 3rd: Look for the distended JOINT CAPSULE

Landmark Based UltrasoundIn-plane technique

Out-of plane technique

ANKLE

KNEE

SHOULDER

HIP

Identify Classic Landmarks Aim at the Umbilicus

Identify Ultrasound Landmarks Compare Hips>5mm or asymmetry >2mm

In-plane with clear view of screen Gentle Aspiration

In-Plane Hip Arthrocentesis ED Hip Clinic

Steroid Injections Hip Arthritis

ANKLE

KNEE

SHOULDER

HIP

Identify Classic Landmarks Identify Ultrasound Landmarks

Compare Ankles Compare Ankles

Tibia

TalusEffusion

Locate the Tendon Locate Tendon Aspirate Medially Out-of-Plane

Out-of-plane Aspiration Out-of-plane Aspiration

Talus

Tibia

Talus

Tibia

Path of Needle

Out-of-plane Aspiration

ANKLE

KNEE

SHOULDER

HIP

Identify Classical Landmarks

someone

show coralso can slooking at

Identify Ultrasound Landmarks

glenoidfossa

humeralhead

HHG

Identify Ultrasound Landmarks

GlenoidHumeral

Head

Open the GH Joint

Compare Shoulders

glenoidhumeral

head

Effusion

Identify the Effusion

Anterior Posterior

In-plane Medial Aspiration In-plane Lateral Aspiration

Out-of-plane Aspiration

ANKLE

KNEE

SHOULDER

HIP

Identify Classic Landmarks

Quadriceps FemorisTendon

PatellaPatella

Femur

Quadriceps FemorisTendon

Suprapatella Fat Pad

Identify Ultrasound Landmarks

Identify Ultrasound Landmarks

Patella

Femur

Quadriceps FemorisTendon

Effusion

Locate Effusion

Rotate probe above Effusion In-plane Aspiration

In-plane Aspiration In-plane Aspiration

Summary**Fluid Analysis

>10 mmol/L : essentially RULES IN a septic joint

Summary

1.Find ultrasound bony landmarks2.Look at unaffected extremity FIRST3.Look for distended Joint Capsule