Joint disease part 1

Question 1

What is the makeup of cartilage

Answer 1

5% chondrocytes
95% Extra cellular matrix
no blood vessels or nerves

Question 2

What makes up extra cellular matrix

Answer 2

Water, proteoglycans, collagen network

Question 3

What are the four qualities of cartilage and what are they for

Answer 3

Smooth surface: for gliding
Sufficient elasticity: shock absorbing
Sufficient stiffness: to transfer loads
Sufficient strength: to prevent damage

Question 4

Why does cartilage have poor regenerative ability

Answer 4

-Avascular nature
-Adult chondrocytes do not replicate or migrate

Question 5

What are clinical signs and radiographic findings of osteoarthritis

Answer 5

-Clin signs: lameness, pain, stiffening, joint effusion, soft tissue swelling, reduced range of motion, positive flexion test
-Radiographic findings: osteophytes, increased bone formation, osteolysis, cysts, bone sclerosis, reduced joint space

Question 6

Why is there pain if there is no nerve supply to cartilage

Answer 6

-Pain due to: Inflammation of synovial membrane/joint capsule, increased intra-articular pressure, bone irritation

Question 7

What is the general principle of the treatment of osteoarthritis

Answer 7

-If present, eliminate primary cause, break through vicious circle and reduce inflammatory part and stop ongoing damage

Question 8

What are 4 nonsurgical treatments of osteoarthritis

Answer 8

1) exercise regime
2) hoofcare/orthopedic shoeing
3) physical techniques
4) medications

Question 9

What are some options under exercise regime for treating OA

Answer 9

-Box rest
-Uncontrolled exercise
-Controlled exercise
-Specific training/ rehab
-Physiotherapy

Question 10

What are some options for hoofcare/ortho shoeing for treating OA

Answer 10

-Foot axis/ hoof balance
-Shock absorbing (hoof pads)
-Pressure distribution/loading
-Ortho shoeing

Question 11

What are some physical therapies for treating OA

Answer 11

-Hydrotherapy
-Thermotherapy
-Extracorporeal shockwave therapy
-Magnetic field therapy

Question 12

What are some options for medication for treating OA

Answer 12

-NSAIDs
-Corticosteroids (locally at level of joint)
-Disease modifying OA drugs(chondromodulating/ chondprorotectives)
-Cell based therapies
-Others like Tildren DMSO Orthokin)

Question 13

What is the pathogenesis of septic arthritis

Answer 13

-Bacteria easily colonize joint if able to enter due to very little defense (few WBCs, synovium rich in blood)
-Causes potent inflammatory response, release of toxins/cytokines, macrophages attracted, lysosomal enzymes released
-Further tissue damage leads to destruction of cartilage, capsule, bone damage

Question 14

What are the most common etiologies of septic arthritis

Answer 14

-Traumatic wounds most common
-Joint infections followed by joint surgery and idiopathic causes
-In foals, usually hematogenous spread

Question 15

What are the most common bacterial agents in septic arthritis

Answer 15

-91% aerobic or facultative anaerobes
-28% Enterobacteriaceae
-13% strep 11.8% staph
-mixed infections common with traumatic wounds
-staph and strep common with post injection or post surgical infections
-foals: enterbacteriaceae most common typically from umbilicus

Question 16

What are the three types of septic arthritis in foals

Answer 16

-S type infections: synovial membrane and fluid only involved, usually < 1 week
-E type infections: bone adjacent to articular cartilage involved, older foals (weeks old)
-P type infections: primary infection of long bone physics, +/- joint involvement, extension into joint usually at level of joint capsule, foals weeks to months old

Question 17

What clinical signs are seen with septic arthritis and what are diagnostic options

Answer 17

-Joint effusion and heat, fever (rare in adults), lameness
-Diagnostics: history, clin signs, arthrocentesis (synovial fluid interpretation), rads/US, wound evaluation

Question 18

What does normal synovial fluid look like

Answer 18

-Translucent, pale yellow
-Viscous
-Sterile
-10-20g total protein/L
-WBCs: total .2-2x10^9/L, mainly lymphocytes and large mononuclear cells

Question 19

What changes in synovial fluid would be expected with diseased joints

Answer 19

-Increased volume (joint effusion)
-decreased viscosity
-Appearance: cloudy/turbid/amber if septic, hemorrhagic if traumatic
-Total protein: >40 g/L in septic arthritis
-WBCs: >20x10^9/L, >90% PMNs (mostly neutrophils) in septic arthritis, toxic neutrophils indicative of infection

Question 20

How quickly will you see radiographic changes in a foal and adult horse with arthritis

Answer 20

-Foals: less than 1 week
-Adults: 10-12 days

Question 21

What are treatment options of septic arthritis

Answer 21

-Drainage and lavage
-Antibiotics: selection/delivery methods important
-Antiinflammatories and analgesics

Question 22

How to perform needle lavage of a septic arthritic joint

Answer 22

-Sterile balanced electrolyte solution (LRS)
-Sedated or anesthetized
-18G or 16 G needles
-2-3 L on a pressure bag

Question 23

What are the benefits of arthroscopic lavage

Answer 23

-Allows rapid delivery of fluids
-Facilitates removal of fibrin clots
-Debridement of any unstable cartilage or bone
-Direct evaluation of the condition of the joint surfaces

Question 24

What types of antibiotics should be used to treat septic arthritis

Answer 24

-Broad spectrum until sensitivity results
-Penicillin an aminoglycosides (gentamicin and amikacin, good penetration)
-combine systemic and local administration

Question 25

What types of antibiotics should be used in IV regional perfusion

Answer 25

-Non irritant: amikacin, gentamicin, crystalline penicillin, (ceftiofur and cefquinome only if Cand S recommends them)
-Dose at 1/3 systemic dose

Question 26

When should you mostly consider intra-osseous antibiotics in foals

Answer 26

If bone involvement such as type E infection

Question 27

Why are corticosteroids contra-indicated in treating septic arthritis

Answer 27

Can prolong infection if actively infected, dampens immune response

Question 28

Why does the contra lateral limb sometimes get laminitis with arthritis

Answer 28

-Opposite (not arthritic) leg is overloaded and foot is overworked
-Excessive weight bearing leads to ischemia
-Little to no perfusionof foot when loaded, needs to be partially unloaded to allow perfusion to dorsal laminae

Question 29

What are some options for anti-inflammatories and analgesics to treat joint disease

Answer 29

-NSAIDs: toxicity effects possible
-Multimodal analgesia: opioids, local anesthetics, ketamine CRI, alpha 2s, lidocaine
-Consider delivery routes: CRI, epidural catheters