Arthrocentesis

Question 1

Why would you do an arthrocentesis ?

Answer 1

Lameness evaluation

Clinopathological evaluation

Contrast studies

Wound involvement

Joint communications

Theraputic — medication or lavage

Question 2

Routinely treated synovial structures of the forelimb?

Answer 2

Distal interphalangeal (DIP)
Metacarpal phalangeal (MCP)
DFTS 
Carpal joints

Question 3

Routinely treated synovial structures of the hindlimb?

Answer 3

Metatarsal phalangeal (MTP)
DFTS
TMT/DIT
Stifle

Question 4

T/F: you should always clip for the area for IA injections

Answer 4

False

Site is sterile clipped or non clipped

Clipping can actually increase little hair debris

Question 5

What needle size is used for most IA injections?

Answer 5

20g 1”

Larger gauge needles increases risk of contamination

Question 6

How can you minimize joint contamination ?

Answer 6

Use needles ONCE
Limit use of spinal needles or remove hair prior to use of spinal needles

Removal of hair might be contraindicated with hypodermic needles

> 18G needles increase risk of hair contamination

Allow fluid to drip out of hub or aspirate prior to injection to clear tissue and hair debris

IA antibiotics

Question 7

500mg of __________ provides 72hrs concentration >MIC for most common pathogens

Answer 7

Amikacin

Question 8

What IA antibiotic are we administering to our donkeys and how much?

Answer 8

Ceftiofur (50mg/ml)

Giving 2mls (100mg)

Question 9

What are the landmarks for radiocarpal arthrocentesis ?

Answer 9

Palate distal medial ridge of the radius and proximal edge of the radiocarpal bone

Insert needle midway between these, and between the ECR and CDE tendons

Question 10

What are the landmarks for an intercarpal arthrocentesis ?

Answer 10

Between distal ridge of radiocarpal bone and proximal edge of 3rd carpal bone

Question 11

What synovial structures communicate at the carpus?

Answer 11

Inter-carpal joint and carpometacarpal joint (CMC)

Question 12

What are the landmarks for tibiotarsal joint arthrocentesis ?

Answer 12

Palate medial malleolus of tibial

Insert needle medial or lateral to saphenous vein as it crosses the tarsus (1-1.5” distal to medial malleolus in horses)

Question 13

Landmarks for the tarsometatarsal joint?

Answer 13

Insert needle just proximal to the head of the 4th metatarsal (lateral splint) dorsomedially and at a slightly distal angle

Question 14

What needle size do you use for arthrocentesis of distal interphalangeal (coffin) joint?

Answer 14

20g 1 1/2”

Question 15

What are sites for a distal interphalangeal joint arthrocentesis ?

Answer 15

Dorsal parallel just proximal to coronary band

Dorsal perpendicular

Lateral

Question 16

What are the landmarks for a metacarpophalangeal joint arthrocentesis ?

Answer 16

Collateral seasmoidean ligament approach
- joint is flexed

OR
Proximal palmar/plantar pouch approach
Cranial border: Palate palmar MC3

Plantar border: Dorsal border of suspensory lig

Proximal border: Distal border of MC4 (splint bone)

Lateral border: Proximal lateral seasmoid bone

Question 17

What needle size is used to do an arthrocentesis on the stifle?

Answer 17

20G 1.5” needle

Question 18

What two approaches are used for the stifle?

Answer 18

FP— lateral approch
-lateral to patellar lig and 2” dorsal to lateral meniscus insert until you feel bone

MFT
—proximal to tibia between medial patellar ligament and medial femorotibial ligament

Question 19

T/F: it is best to inject all compartments when treating the stifle

Answer 19

True

Question 20

The femoropatellar joint communicates with what compartments?

Answer 20

MFT (medial femorotibial )
And LFT (lateral femorotibial)

Question 21

What are the landmarks for the cranial approach to the femorotibial compartments? And what size needle do you use?

Answer 21

Between medial and lateral patellar ligaments
Directed proximally into the trochlear groove

3” spinal needle

Question 22

What landmarks do you use for a lateral approach to the femorotibial joint spaces and what needle do you use?

Answer 22

Caudal to the lateral patellar ligament and 6cm proximal to the lateral tibial condyle

1.5” 20g needle

(Performed with limb unloaded)