Joints and Lameness: Arthrocentesis, Septic arthritis, Lameness, OA Flashcards
What type of needle (gauge and length) is typically used for arthrocentesis?
20G 1”
Why is physical restraint preferred to chemical restraint for arthocentesis?
Drugs renduce inhibition so horse can react more rapidly and exagerated when needle goes in
Left forelimb: What structure(s) are indicated by #13? #14?
13: Extensor brnach of interosseus
14: Flexor tendons
What limb is this (fore or hind)? What is indicated by #1, #2, #3, and #6?
Forelimb (lateral view)
1: Large metacarpal bone (MC III)
2: Proximal sesamoid bones
3: Proximal phalanx
6: Navicular bone
What are the landmarks for performing a radiocarpal joint arthrocentesis?
Distal medial ridge of the radius
Proximal edge of the radiocarpal bone
With which joint does the carpometacarpal joint communicate?
Middle/Inter carpal joint
With which joint does the tibiotarsal joint communicate?
Proximal intertarsal joint
What landmark do you palpate for a tibiotarsal joint arthrocentesis?
Medial malleolus of tibia
You know the drill
Blue: Common digital extensor muscle
Pink: Superficial digital flexor tendon
Aqua: Deep digital flexor tendon
Green: Common digital extensor tendon
This bone is one landmark used to ID the radiocarpal joint. Identify the bone indicated.
a. Third carpal bone
b. Ulnar carpal bone
c. Metacarpal IV
d. Radial carpal bone
d. Radial carpal bone
What is the preferred approach to the metacarpophalangeal joint?
Collateral sesamoidean ligament approach
How many compartments does the stifle joint have? What are they? Which should you inject when treating the stifle?
3
Femoropatellar joint
Medial femorotibial joint
Lateral femorotibial joint
Inject all compartments
Which which compartment does the femoropatellar joint communicate with more often?
MFT
Describe the pathogenesis of septic arthritis.
Decreased HA synthesis
Loss of PG
Joint effusion
Pain
Compromise synovial blood flow
What are the types of septic arthritis is foals? What is involved in each type?
S, E, and P
S: Synvoial structures (membrane, fluid)
E: Epiphysis
P: Physis of long bones +/- joint
Which type of septic arthritis in a foal is highly effusive and typically affects multiple larger joints?
S-type
Which type of septic arthritis in foals occurs at a few weeks of age usually following another disease such as pneumonia or diarrhea? How does the lameness present?
E-Type
Mild lameness followed by acute exacerbation (“Lame on and off and then suddenly super lame”)
Which type of septic arthritis in foals presents with swelling but no effusion? How many sites are usually affected?
P-type
One site (e.g. distal physis of MCIII/MTIII, radius, tibia)
What should you evaluate and how in addition to the joints in a foal with septic arthritis?
Umbilicus
Ultrasound
Which bacterium is usually associated with iatrogenic septic arthritis in adult horses? Traumatic septic arthritis?
Staphylococcus
Enterobacteriaceae
T/F: An open joint is only considered infected if there is effusion.
False, an open joint is always an infected joint
What is involved in foal septic arthritis that is usually not involved in adults?
Bone
What is the gold standard for diagnosing sepsis?
Microbiology
What is the normal TP in synovial fluid?
<2.0 g/dL
>3.5 g/dL is abnormal
What are the 2 requirements for successful treatment of septic arthritis?
Rapid recognition of disease
Immediate aggressive treatment
What is the mainstay of treatment for septic arthritis?
Lavage
Early and often with large volumes (5-10L) and large G needle (16-18)
How should antibiotics be administered for septic arthritis?
Local is vital
How long should you leave the tourniquet when performing regional limb perfusion? What dosage is usually used?
30 min
1/3 of systemic dose
What is usually the cause of lameness?
Pain