Arthrocentesis

Indications

• Suspicion of septic arthritis
• Suspicion of crystal induced arthritis
• Evaluation of therapeutic response for septic arthritis
• Unexplained arthritis with synovial effusion

Relative Indications

• Therapeutic (decrease intra-articular pressure, injection of anesthetics/steroids)

Contraindications

1. No absolute contraindications for diagnostic arthrocentesis
2. Do not inject steroids into a joint that you suspect is already infected
3. Relative Contraindications:
   1. Overlying cellulitis
   2. Coagulopathy
   3. Joint prosthesis (refer to ortho)

Equipment Needed

1. Betadine or Chlorhexadine
2. Sterile gloves/drape
3. Sterile gauze
4. Lidocaine
5. Syringes
   1. Small syringe (6-12cc) for injection of local anesthetic
   2. Large syringe (one 60cc or two 30cc) for aspiration
6. Needles
   1. 18 gauge: knee
   2. 20 guage: most other joints
   3. 25 guage: MTP joints
   4. 27 gauge for anesthetic injection
7. Collection tubes (red top)
8. Culture bottles

Procedure

1. Prep area w/ betadine or chlorhexadine using circular motion moving away from joint x 3
2. Drape joint in sterile fashion
3. Inject lidocaine w/ 25-30ga needle superficially and then into deeper tissues
4. Insert 18ga needle (for larger joints) into joint space while pulling back on syringe
5. Stop once you aspirate fluid; aspirate as much fluid as possible
   1. Send: cell count, culture, Gram Stain, crystal analysis

Approach

Shoulder

1. Anterior approach
   1. Sit pt upright facing you
   2. Insert needle just lateral to coracoid process (between coracoid process and humeral head)
   3. Direct needle posteriorly
2. Posterior Approach
   1. Sit pt upright w/ back facing you
   2. Palpate scapular spine to its lateral limit (the acromion)
   3. Identify the posterolateral corner of the acromion
   4. Insert 1.5-in needle 1 cm inferior and 1 cm medial to this corner
   5. Direct needle anterior and medial toward presumed position of coracoid process
   6. Glenohumeral joint is located at a depth of approximately 1-1.5in

Elbow

1. Place elbow in 90^o flexion, resting on a table, w/ hand prone
2. Locate radial head, lateral epicondyle , and lateral aspect of olecranon tip
   1. These landmarks form the anconeus triangle
3. Palpate a sulcus just proximal to the radial head (in the middle of the triangle)
4. Insert needle into sulcus directed medial and perpendicular to radius toward distal end of antecubital fossa

Wrist

1. Palpate landmarks w/ wrist in neutral position:
   1. Radial tubercle of distal radius
   2. Anatomic snuffbox
   3. Extensor pollicis longus tendon
   4. Common extensor tendon of index finger
2. Insert needle perpendicular to skin, ulnar to radial tubercle and anatomic snuffbox, between extensor pollicis longus and common extensor tendons

Knee

1. Can be entered medially or laterally to the patella, superior or inferior to patella
2. Fully extend knee and ensure quadriceps muscle is relaxed
3. Identify midpoint of patella; insert needle either lateral or medial
4. Direct needle posterior to patella and horizontally toward the joint space
5. Compression or "milking" applied to both sides of joint space may facilitate aspiration

Ankle

1. Lateral approach (subtalar)
   1. Keep foot perpendicular to leg
   2. Enter subtalar joint just below tip of lateral malleolus
   3. Direct needle medially toward joint space
2. Medial approach (tibiotalar)
   1. Have pt supine w/ foot perpendicular to leg
   2. Palpate sulcus lateral to medial malleolus and medial to TA and EHL tendons
   3. Then plantarflex foot w/ needle entering skin overlying the sulcus
   4. Angle needle slightly cephalad as it passes between medial malleolus and TA tendon

Metacarpophalangeal

1. have palm facing down and apply gentle traction to the affected digit
2. insert needle dorsally just medial or lateral to midline and proximal to the base of the proximal phalanx

Interphalangeal

1. have palm facing down and apply gentle traction to the affected digit
2. insert needle dorsally medial or lateral to midline and proximal to base of middle or distal phalanx

Metatarsophalangeal

1. patient supine with flexion of the MTP joint 15-20 degrees and apply gentle traction
2. insert needle dorsally just medial or lateral to midline between the metatarsal head and base of proximal phalanx

Interphalangeal

1. patient supine with joint flexed 15-20 degrees with gentle traction
2. insert needle dorsally, medial or lateral to midline between head of proximal phalanx and base of more distal phalanx

Complications

1. pain
2. infection
3. reaccumulation of effusion
4. damage to tendons, nerves, or blood vessels

See Also

• Septic Arthritis (General)
• Arthritis
• Monoarticular Arthritis
• Septic Arthritis (Hip)
• Septic Arthritis (Peds)

Source

• Tintinalli
• http://emprocedures.com/arthrocentesis/introduction.htm