Lecture 37 4/25/25 Flashcards
What are the steps to osteoarthritis development?
-joint inflammation/synovitis leads to cartilage breakdown
-cartilage breakdown leads to joint inflammation
What are the goals of osteoarthritis treatment/management?
-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
What are the treatment options for osteoarthritis?
-medical management; multiple options
-surgical management: facilitated ankylosis or arthrodesis
How does the location of osteoarthritis impact the treatment choice?
-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
What leads to subchondral bone disease?
-cyclic microtrauma builds up over time
-bones are not able to complete the remodeling process
What are the charactersitics of the incomplete bone remodeling process that occurs in subchondral bone dz?
-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
What are the most common locations for subchondral bone dz?
-distal aspect of MC3/MT3
-proximal aspect of P1
can occur in any subchondral bone
What is the presentation of a horse with subchondral bone dz?
-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
What are the diagnostics done in subchondral bone dz cases?
*lameness exam to localize
*radiographs
-can see lysis, sclerosis, and fragmentation in severe cases
*CT/MRI
-necessary for diagnosis in mild to moderate cases
What are the treatment steps for subchondral bone dz?
*treat concurrent joint dz
*exercise program management
-consistent but low intensity
*promote remodeling of subchondral bone
-transcondylar screw placement
-drilling
-pulsed electromagnetic therapy
What is the prognosis for subchondral bone dz?
-depends on profession and concurrent joint dz
-excellent for life
-fair to guarded for athletics
What are the characteristics of osteochondral chip fractures?
-due to direct trauma
-occur during stance phase when limb is in hyperextension
-commonly due to dorsal aspect of P1 hitting the cannon bone
What are the most common sites for osteochondral chip fractures?
-dorsal medial/lateral proximal P1
-proximal/distal radial carpal bone
-proximal/distal intermediate carpal bone
What is the presentation of osteochondral chip fractures?
-mild to moderate lameness
-joint effusion
-positive flexion test
How are osteochondral chip fractures diagnosed?
traditional oblique rads
What are the treatment options for osteochondral chip fractures?
-rest/retirement; chip may heal back to parent bone
-arthroscopic removal
What is the prognosis for osteochondral chip fractures?
-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
What are the characteristics of “splints”?
-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
What are the three possible outcomes of direct trauma to the splint bones?
-fracture
-exostosis/hemorrhage under periosteum
-interosseous ligament desmitis
What is the presentation of a horse with splint bone pathology?
-grade 3-4/5 lameness
-swelling
-reactive to palpation
-possible to have a wound
What does splint bone fracture treatment depend on?
-which splint fractured
-whether the fracture, is proximal, mid-body, or distal on the bone
What are the characteristics of surgical repair of splint bone fractures?
-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
What are the treatment options for splint bone exostosis or interosseous ligament desmopathy?
-anti-inflammatories
-ice
-compressive bandages
-shockwave therapy
-possible local corticosteroid injections
-boots or wraps to prevent further trauma during work
What is the prognosis for splint bone pathology?
*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
What are the characteristics of the suspensory ligament?
-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
What is the presentation of a horse with suspensory desmitis?
-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
What are the treatment options in the acute phase of suspensory desmitis?
-NSAIDs
-ice
-compression bandage
-laser treatment
What are the treatment options in the repair phase of suspensory desmitis?
-biologics
-shockwave
Why is it important to do rest and controlled return to work in suspensory desmitis?
high risk of reinjury without adequate time off
What are the surgical options for suspensory desmitis?
hindlimb only
-deep branch of lateral plantar nerve neurectomy
-plantar fasciotomy
What is the prognosis for suspensory desmitis?
-depends on degree of injury, location, and conformation
-generally excellent for life
-generally good for athletics
What are the two mechanisms for injury in flexor tendonopathy?
-normal load on abnormal tendon
-excessive load on a normal tendon
What is the presentation of a horse with flexor tendonopathy?
-acute onset with grade 3-4/5 lameness
-swelling, heat, and/or pain of palmar metacarpus/plantar metatarsus
What are the treatment options in the acute phase of flexor tendonopathy?
-ice
-bandage
-handwalking
-therapeutic laser
What are the treatment options in the repair phase of flexor tendonopathy?
-biologics
-therapeutic ultrasound
-restricted exercise w/ gradual return to work
-shockwave
What is the prognosis for flexor tendonopathy?
-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
What are the characteristic of the accessory ligament of the DDFT?
-aka inferior check lig. or distal check lig.
-originates at palmar aspect of carpus/palmar ligament
-merges with DDFT at mid-metacarpus
What is the presentation of a horse with flexor tendonopathy of the accessory ligament of the DDFT?
-focal swelling, heat, and/or pain on palpation proximal to mid-metacarpus
-0-3/5 lameness; sound or mildly lame
What is the treatment for flexor tendonopathy of the accessory ligament of the DDFT?
-ice
-NSAIDs
-compressive bandage
-rest
-biologics
Why is it important that the accessory ligament of the DDFT is considered a “spare part”?
-can treat conservatively; prone to reinjury if exercised too soon
-can surgically transect for chronic or repeat injuries
What is the prognosis for flexor tendonopathy of the accessory ligament of the DDFT?
-excellent for life
-good to excellent for athletics
-frustrating for owners and vet team because horse needs ample time for recovery despite appearing sound
What is the purpose of the annular ligaments?
present on the palmar/plantar fetlock to help flexor tendons stay in place during motion
What is the presentation of a horse with annular ligament desmitis?
-distal limb swelling and edema
-grade 3/5 lameness
-positive distal limb flexion test
How is annular limb desmitis diagnosed?
*ultrasound
-thickening of annular ligament
-possible discrete tears or fiber disruption
What is the treatment for annular ligament desmitis?
-biologics
-rest
-ice
-compression bandage
-surgical desmotomy
What is the prognosis for annular ligament desmitis?
-excellent for life
-good to excellent for athletics
What is the flexor tendon sheath?
synovial sheath surrounding flexor tendons from distal third MC/MT to mid-pastern
What is the presentation of a horse with flexor tendon sheath tenosynovitis?
-thickening, inflammation, and effusion of the sheath
-often sound if lesion is primary
-sympathetic effusion if issues elsewhere; cellulitis, sepsis, flexor tendonopathy, arthritis, etc.
How is flexor tendon sheath tenosynovitis diagnosed?
-lameness exam to determine primary vs secondary
-diagnostic analgesia to localize to the tendon sheath
-ultrasound to assess concurrent dz
What is the treatment for flexor tendon sheath tenosynovitis?
*if lameness blocks to sheath:
-tenoscopy
-anti-inflammatories
*if sound:
-benign neglect
What is the prognosis for flexor tendon sheath tenosynovitis?
-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
