Arthrocentesis

Question 1

Why would you want to arthrocentesis?

Answer 1

• Diagnostic –> local anesthesia for lameness test, clin path on synovial fluid, contrast studies, wound involvement, joint communication
• Therapeutic –> medications, lavage (septic arthritis)

Question 2

What joints/ synovial structures do you perform arthocentesis on the forelimb? Hindlimb?

Answer 2

• Forelimb –> DIP, MCP, DFTS, Carpal joint
• Hindlimb –> Metatarsal, digital flexor tendon, stifle, tmt/ dit

use a 20 G 1” needle

Question 3

Is physical or chemical restraint preferred for performing arthocentesis?

Answer 3

Physical!

Question 4

What is a possible complication of joint taps?

Answer 4

• Increased risk of hair contamination from large gauge needles
• Need to clip hair and try to only use needle once!

Question 5

How can you minimize joint contamination?

Answer 5

• Use 1 needle
• No spinal needles
• Use smallest possible gauge needle

Question 6

How can you reduce risk of joint infection?

Answer 6

• Use 125mg Amikacin with other meds

will use Naxcel (ceftiofur) in lab, use 2ml (100mg)

Question 7

What are your landmarks for radiocarpal joint arthrocentesis?

Answer 7

• Distal medial ridge of the radius and proximal edge of the radiocarpal bone
• Insert needle between ossous landmark parallel to the ground
• *use a dorsal approach**

Question 8

What are your landmarks for mid-carpal joint arthrocentesis?

Answer 8

• Distal ride of radiocarpal bone and proximal edge of 3rd carpal bone
• *use a dorsal approach**

Question 9

What joints of the tibiotarsal joint communicate?

Answer 9

Tibiotarsal and proximal intertarsal joints

Question 10

What are the landmarks of the tibiotarsal joint?

Answer 10

• Medial malleolus of the tibia

- INsert needle medial or lateral to saphenous v. as it crosses tarsus

Question 11

What are the landmarks/ location of injection for tarsometatarsal joint tap?

Answer 11

• Proximal to head of 4th metatarsal (lateral splint) dorsomedially and slightly distal angle

Question 12

What drug do you want to give post-op athrocentesis?

Answer 12

Phenylbutazone 2.2mg/kg

Question 13

What different directions can you do a joint tap on the distal interphalangeal (coffin) joint?

Answer 13

• Dorsal parallel just proximal to coronary band
• Dorsal perpendicular
• Lateral
• Can take 5-7 ml

Question 14

What are the landmarks and what is the approach for metacarpophalangeal joint?

Answer 14

• Landmark is palmar MC3, dorsal border of supsensory ligament, and distal border of MC4/ splint bone/ button