Lecture 37 4/25/25

Question 1

What are the steps to osteoarthritis development?

Answer 1

-joint inflammation/synovitis leads to cartilage breakdown
-cartilage breakdown leads to joint inflammation

Question 2

What are the goals of osteoarthritis treatment/management?

Answer 2

-mitigate pain and inflammation
-prevent progression of cartilage loss
-perform as much low impact exercise as animal will tolerate
-recognize that there is NO cure

Question 3

What are the treatment options for osteoarthritis?

Answer 3

-medical management; multiple options
-surgical management: facilitated ankylosis or arthrodesis

Question 4

How does the location of osteoarthritis impact the treatment choice?

Answer 4

-TMT/DIT joints: usually ankylose themselves, but can be facilitated
-PIP: facilitated ankylosis or arthrodesis; usually does not fuse itself
-MCP/MTP: arthrodesis is salvage procedure; will create gait abnormality

Question 5

What leads to subchondral bone disease?

Answer 5

-cyclic microtrauma builds up over time
-bones are not able to complete the remodeling process

Question 6

What are the charactersitics of the incomplete bone remodeling process that occurs in subchondral bone dz?

Answer 6

-osteoclasts remove damaged bone while osteoblasts replace bone
-inappropriate bone modeling occurs to accommodate applied stresses
-heterogenous mineralization leads to sclerosis of some areas and osteonecrosis in others
-focal areas of stress are experienced by cartilage, leading to damage

Question 7

What are the most common locations for subchondral bone dz?

Answer 7

-distal aspect of MC3/MT3
-proximal aspect of P1
can occur in any subchondral bone

Question 8

What is the presentation of a horse with subchondral bone dz?

Answer 8

-often remain sound until there is irreversible damage
-mild lameness/asymmetry that localizes with low 4-point block
-possible concurrent MCP/MTP joint synovitis
-no significant worsening or improvement with exercise

Question 9

What are the diagnostics done in subchondral bone dz cases?

Answer 9

*lameness exam to localize
*radiographs
-can see lysis, sclerosis, and fragmentation in severe cases
*CT/MRI
-necessary for diagnosis in mild to moderate cases

Question 10

What are the treatment steps for subchondral bone dz?

Answer 10

*treat concurrent joint dz
*exercise program management
-consistent but low intensity
*promote remodeling of subchondral bone
-transcondylar screw placement
-drilling
-pulsed electromagnetic therapy

Question 11

What is the prognosis for subchondral bone dz?

Answer 11

-depends on profession and concurrent joint dz
-excellent for life
-fair to guarded for athletics

Question 12

What are the characteristics of osteochondral chip fractures?

Answer 12

-due to direct trauma
-occur during stance phase when limb is in hyperextension
-commonly due to dorsal aspect of P1 hitting the cannon bone

Question 13

What are the most common sites for osteochondral chip fractures?

Answer 13

-dorsal medial/lateral proximal P1
-proximal/distal radial carpal bone
-proximal/distal intermediate carpal bone

Question 14

What is the presentation of osteochondral chip fractures?

Answer 14

-mild to moderate lameness
-joint effusion
-positive flexion test

Question 15

How are osteochondral chip fractures diagnosed?

Answer 15

traditional oblique rads

Question 16

What are the treatment options for osteochondral chip fractures?

Answer 16

-rest/retirement; chip may heal back to parent bone
-arthroscopic removal

Question 17

What is the prognosis for osteochondral chip fractures?

Answer 17

-depends on degree of cartilage erosion due to chip fragment; loose fragments cause more damage
-excellent prognosis for life
-conservative management has a good prognosis for low intensity athletics
-conservative management has a poor prognosis for high intensity athletics
-surgical management has an excellent prognosis for all athletics with early removal

Question 18

What are the characteristics of “splints”?

Answer 18

-medial and lateral “splint” bones are the 2nd and 4th metacarpal/tarsal bones
-MC2 splint bone contributes the most to carpometacarpal/tarsometatarsal joint stability, while MT4 contributes the least
-pathogenesis of disease is usually via direct trauma

Question 19

What are the three possible outcomes of direct trauma to the splint bones?

Answer 19

-fracture
-exostosis/hemorrhage under periosteum
-interosseous ligament desmitis

Question 20

What is the presentation of a horse with splint bone pathology?

Answer 20

-grade 3-4/5 lameness
-swelling
-reactive to palpation
-possible to have a wound

Question 21

What does splint bone fracture treatment depend on?

Answer 21

-which splint fractured
-whether the fracture, is proximal, mid-body, or distal on the bone

Question 22

What are the characteristics of surgical repair of splint bone fractures?

Answer 22

-done for almost all proximal fractures; MT4 may simply be removed
-want to prevent callus impingement or damage to suspensory ligament origin
-open fractures and infection will delay surgery; must control infection first

Question 23

What are the treatment options for splint bone exostosis or interosseous ligament desmopathy?

Answer 23

-anti-inflammatories
-ice
-compressive bandages
-shockwave therapy
-possible local corticosteroid injections
-boots or wraps to prevent further trauma during work

Question 24

What is the prognosis for splint bone pathology?

Answer 24

*fracture:
-highly dependent on fracture
-typically excellent for life
-typically good for athletics

*non-fracture:
-excellent for life
-excellent for athletics if no concurrent suspensory damage/impingement

Question 25

What are the characteristics of the suspensory ligament?

Answer 25

-primary support structure for fetlock -originates at proximal MC3/MT3 -splits at distal third of MC/MT to insert on abaxial margin of proximal sesamoids -normal structure has muscle fiber bundles embedded into origin

Question 26

What is the presentation of a horse with suspensory desmitis?

Answer 26

-grade 3/5 lameness -"works" into a lameness -typically worse on soft footing -localized with blocks to lateral palmar/deep branch of lateral plantar nerve -can have focal swelling -may be painful to deep palpation of origin -can have focal welling, enlargement, and pain on palpation of branches/insertions

Question 27

What are the treatment options in the acute phase of suspensory desmitis?

Answer 27

-NSAIDs -ice -compression bandage -laser treatment

Question 28

What are the treatment options in the repair phase of suspensory desmitis?

Answer 28

-biologics -shockwave

Question 29

Why is it important to do rest and controlled return to work in suspensory desmitis?

Answer 29

high risk of reinjury without adequate time off

Question 30

What are the surgical options for suspensory desmitis?

Answer 30

*hindlimb only* -deep branch of lateral plantar nerve neurectomy -plantar fasciotomy

Question 31

What is the prognosis for suspensory desmitis?

Answer 31

-depends on degree of injury, location, and conformation -generally excellent for life -generally good for athletics

Question 32

What are the two mechanisms for injury in flexor tendonopathy?

Answer 32

-normal load on abnormal tendon -excessive load on a normal tendon

Question 33

What is the presentation of a horse with flexor tendonopathy?

Answer 33

-acute onset with grade 3-4/5 lameness -swelling, heat, and/or pain of palmar metacarpus/plantar metatarsus

Question 34

What are the treatment options in the acute phase of flexor tendonopathy?

Answer 34

-ice -bandage -handwalking -therapeutic laser

Question 35

What are the treatment options in the repair phase of flexor tendonopathy?

Answer 35

-biologics -therapeutic ultrasound -restricted exercise w/ gradual return to work -shockwave

Question 36

What is the prognosis for flexor tendonopathy?

Answer 36

-depends on degree of injury -excellent for life -poor for athletics with compete disruption -guarded for athletics with large core lesion -good for athletics with small core lession

Question 37

What are the characteristic of the accessory ligament of the DDFT?

Answer 37

-aka inferior check lig. or distal check lig. -originates at palmar aspect of carpus/palmar ligament -merges with DDFT at mid-metacarpus

Question 38

What is the presentation of a horse with flexor tendonopathy of the accessory ligament of the DDFT?

Answer 38

-focal swelling, heat, and/or pain on palpation proximal to mid-metacarpus -0-3/5 lameness; sound or mildly lame

Question 39

What is the treatment for flexor tendonopathy of the accessory ligament of the DDFT?

Answer 39

-ice -NSAIDs -compressive bandage -rest -biologics

Question 40

Why is it important that the accessory ligament of the DDFT is considered a "spare part"?

Answer 40

-can treat conservatively; prone to reinjury if exercised too soon -can surgically transect for chronic or repeat injuries

Question 41

What is the prognosis for flexor tendonopathy of the accessory ligament of the DDFT?

Answer 41

-excellent for life -good to excellent for athletics -frustrating for owners and vet team because horse needs ample time for recovery despite appearing sound

Question 42

What is the purpose of the annular ligaments?

Answer 42

present on the palmar/plantar fetlock to help flexor tendons stay in place during motion

Question 43

What is the presentation of a horse with annular ligament desmitis?

Answer 43

-distal limb swelling and edema -grade 3/5 lameness -positive distal limb flexion test

Question 44

How is annular limb desmitis diagnosed?

Answer 44

*ultrasound -thickening of annular ligament -possible discrete tears or fiber disruption

Question 45

What is the treatment for annular ligament desmitis?

Answer 45

-biologics -rest -ice -compression bandage -surgical desmotomy

Question 46

What is the prognosis for annular ligament desmitis?

Answer 46

-excellent for life -good to excellent for athletics

Question 47

What is the flexor tendon sheath?

Answer 47

synovial sheath surrounding flexor tendons from distal third MC/MT to mid-pastern

Question 48

What is the presentation of a horse with flexor tendon sheath tenosynovitis?

Answer 48

-thickening, inflammation, and effusion of the sheath -often sound if lesion is primary -sympathetic effusion if issues elsewhere; cellulitis, sepsis, flexor tendonopathy, arthritis, etc.

Question 49

How is flexor tendon sheath tenosynovitis diagnosed?

Answer 49

-lameness exam to determine primary vs secondary -diagnostic analgesia to localize to the tendon sheath -ultrasound to assess concurrent dz

Question 50

What is the treatment for flexor tendon sheath tenosynovitis?

Answer 50

*if lameness blocks to sheath: -tenoscopy -anti-inflammatories *if sound: -benign neglect

Question 51

What is the prognosis for flexor tendon sheath tenosynovitis?

Answer 51

-excellent for life and athletics if primary and sound -good to excellent for life and athletics if primary and mildly lame -dependent on primary issue if tenosynovitis is secondary