Arthrocentesis General Info

Question 1

risk factors for joint contamination during arthrocentesis (2)

Answer 1

-larger needles/spinal needles (that’s why you should only use a 20 G 1” if possible) -reuse of needles (only use one needle/attempt!)

Question 2

when doing arthrocentesis in equines you should almost always use a 20 G 1” needle. what are the three exceptions?

Answer 2

-lavaging: need larger!! -bursa: use spinal needle -femoropatellar joint: -cranial approach use 3” spinal needle -lateral approach use 20 G 1.5” needle

Question 3

reasons for doing arthrocentesis

Answer 3

-diagnostic (lameness evaluation, clin path of joint fluid, contrast studies, to check if joint is involved in wound) -therapeutic (lavage and medications)

Question 4

Answer 4

Question 5

Answer 5

Question 6

tips for arthrocentesis (10)

Answer 6

-remove needle and syringe as one unit -physical restraint is preferred over sedation for diagnostic arthrocentesis -MUST be aseptic -must remove all scrub from skin (can scald) -place needle rapidly WITHOUT syringe -if not fluid initially, try spinning needle -use new needle for every attempt -clipping does NOT affect asepsis; only clip for spinal needles -aspirate or allow some fluid to drip out prior to injection (decreases contamination) -inject local anesthetics (lidocaine) or amikacin following every tap (antimicrobial effects)

Question 7

where to do a arthrocentesis of the lateral femorotibial joint

Answer 7

proximal to tibia between lateral patellar ligament and lateral femorotibial ligament

Question 8

what equipment do you need for arthrocentesis (5)

Answer 8

-scrub -clippers (only for spinal needles) -20 G 1” needle or spinal needle (usually only for bursa) -3 cc syringe -lidocaine or amikacin for inside joint afterwards

Question 9

Answer 9

Question 10

landmarks for tarsometatarsal joint arthrocentesis

Answer 10

-proximal to head of 4th metatarsal/lateral splint bone: inject dorsomedial at slightly distal angle

Question 11

landmarks for intercarpal joint arthrocentesis

Answer 11

• radiocarpal bone
• third carpal bone

Question 12

landmarks for tibiotarsal joint arthrocentesis

Answer 12

• craniodistal to medial malleolus of tibia
• medial or lateral to medial saphenous v.

Question 13

approaches to arthrocentesis of the medial femorotibial joint

Answer 13

-proximal to tibia between medial patellar ligament and medial femorotibial ligament -using sartorius m. as landmark: insert needle cranial -> caudal parallel to ground between medial patellar ligament + sartorius m.

Question 14

should you clip prior to arthrocentesis?

Answer 14

ONLY when using spinal needles; does not affect asepsis for regular needles

Question 15

methods for arthrocentesis of distal interphalangeal/coffin joint

Answer 15

**done while weight bearing -dorsal parallel approach -dorsal incline approach -dorsal perpendicular

Question 16

does the femoropatellar joint communicate with the other stilfe joints in the equine?

Answer 16

communicates with medial femorotibial joint in 60-65% communicates with lateral femorotibial joint in 1-25% must block all three to block entire stifle in horse!!

Question 17

largest compartment of the equine stifle

Answer 17

femoropatellar joint

Question 18

approaches used for arthrocentesis of the metacarpo/metatarsophalangeal joints

Answer 18

• proximal palmar/plantar pouch (back side of joint)
• through collateral sesmoidean ligament

Question 19

Answer 19

Question 20

what landmarks do you use when doing an arthrocentesis of the metacarpo/metatarsophalangeal joints using the collateral sesmoidean ligament approach (3)

Answer 20

• dorsal border of M4
• dorsal border of suspensory ligament
• proximal lateral border of sesamoid bone

Question 21

landmarks for radiocarpal joint arthrocentesis

Answer 21

• distal MEDIAL edge of radius
• radiocarpal bone

Question 22

Answer 22

Question 23

dorsal incline approach is used for arthrocentesis of which joint? and how is it done?

Answer 23

distal interphalangeal/coffin joint insert on midline of dorsal foot just proximal to coronary band at an angle perpendicular to the skin

Question 24

approaches to arthrocentesis of the femoropatellar joint

Answer 24

• cranial using a 3” spinal needle
• lateral using a 20 G 1.5” needle

Question 25

weight should be rocked forward onto toe/limb unloaded for which arthrocentesis?

Answer 25

lateral approach to arthrocentesis of the femoropatellar joint

Question 26

Answer 26

Question 27

how to do arthrocentesis of the metacarpo/metatarsophalangeal joints using the collateral sesmoidean ligament approach

Answer 27

1. support joint in flexed position (this pulls the bones up and away from the joint space)
2. palpate palmar M3 on lateral side
3. inject where the following meet:
   - dorsal border of M4
   - dorsal border of suspensory ligament
   - proximal lateral border of sesamoid bone

Question 28

Answer 28

Question 29

landmarks for the cranial approach to arthrocentesis of the femoropatellar joint

Answer 29

between medial and middle patellar ligaments or lateral and middle patellar ligaments into the trochlear groove at a proximally directed angle

Question 30

landmarks for lateral approach to arthrocentesis of the femoropatellar joint

Answer 30

caudal to lateral patellar ligament + 6 cm proximal to lateral tibial condyle weight should be rocked forward onto toe/limb unloaded

Question 31

what’s unique about arthrocentesis of stifle?

Answer 31

there are three joint spaces. all must be blocked if you want to block entire stifle