Large Animal Sx- Pathophysiology of Joint Dz 1

wilsbach's version from 2015-11-04 18:55

basic joint stuff

Question Answer
normal color of synovial fluid?light yellow
normal clarity of synovial fluid?clear
normal viscosity of synovial fluid?strings 1-3 inches
normal protein content of synovial fluid<20 gm/L
normal WBC/μL content of synovial fluid?<200 (0.2 X 10^9/L) [[PMN= <10%, mononuclear=>90%]]
what is the normal/is there a mucin clot in normal synovial fluid?mucin clot should be tight and ropy
what is a mucin clot?look at hyluronic acid in joint fluid
what is the "floor" that the "carpet" of joint cartilage sits on?the subchondral bone
why do we care about the subchondral bone so much?Important to health of overlying cartilage- if this bone is irregular, the cartilage that sits on it will be irregular too.
do you want stiff or do you want flexible subchondral bone?subchondral bone has to flex too. gottta have some ablity to deform under pressure (so doesnt crush cartilage) so then if it gets sclerotic from trying to remodel, will get brittle and can crack and wont protect cartilage
3 Mechanisms for cartilage damage?(1) Abnormal cartilage (Insufficient biomechanical strength) (2) Normal cartilage under abnormal stress (trauma, severe inflammation, infection) (3) Abnormal subchondral bone
(pic) how is the collage in the cartilage (type of cartilage?) arranged in joints?hyaline cartilage. arranged like little croquet wickets (uh...or you could just say arches)
(pic) basic components of the cartilage?
5 tissues which can feel pain/be painful in the joint? which CAN'T?PAIN: synovial membrane, joint capsule, ligaments, subchondral bone, mensecii. NO PAIN: cartilage (very very little blood supply/nerves and stuff)
how well does cartilage heal? how does it heal?the nearly absent blood supply means cartilage doesnt heal very well, and heals slowly. And what DOES heal is no longer hyaline cartilage- it is fibrocartilage. Which is ok but not great for strenuous activity
Articular Cartilage Repair--> what is intrinsic repair like?Chondrocyte mitosis is limited
Articular Cartilage Repair--> what is extrinsic repair like? how can we help this process?Mesenchymal cells from subchondral bone, Can be enhanced by osteostixis or subchondral bone micropick. (Implantation of chondrocytes stimulated by growth factors current hot area of research)
Articular cartilage repair--> what is matrix flow?Cartilage flows from perimeter of lesion
what is "micropick" and why do we like this?puncture tiny holes in the subchondral bone in the area of the damaged cartilage. This allows mesenchymal cells to come to surface and try to fill in joint
which cartilage injuries heal better- partial or full thickness?Partial thickness lesions heal very poorly- Full thickness lesions heal by extrinsic repair with modified fibrocartilage
which size of injury on the cartilage might still have good healing?Less than 5 mm excellent healing (little holes heal well)
do weight bearing or non-weight bearing heal better?Non-weight bearing surface lesions heal faster and more completely
which cartilage heals better- young horse cart or old horse cartYounger animals have better healing capacities

specific diseases of the joints- intro, synovitis, osteoarthritis

Question Answer
5 major joint dzs or horses?Synovitis, Traumatic Arthritis, Osteoarthritis, Osteochondrosis, Septic Arthritis
SYNOVITIS can be caused by what things?trauma, synovitis, OCD
why is the term "Idiopathic synovitis" a misnomer?used to be called... but we know why it happens. almost always OCD lesion (can be super tiny but cause synovitiis)
how significant is the lameness caused by synovitis?rarely causes sig lameness
what's bog spavin?Bog spavin is a swelling of the tibiotarsal joint of the horse's hock (swelling near tarsocrural joint) <--can be caused by synovitis [his terminology def is: A puffy swelling or distention of the capsular ligament on the inside, and slightly to the front, of the hock joint.]
what's a "DIRT" lesion?lesion on the distal intermediate ridge of the tibia
Traaumatic joint dz can lead to what kind of problems?synovitis, capsulitis, ligament damage, cartilage damage, subchondral bone damage
All traumatic injuries to the joint can lead to ___ if untreated or not amenable to treatment!osteoarthritis
(said in class) sagital fractures are common to get in what kinda horses?racehorses
osteophytes form with which dz?osteoarthritis
what's an enthesophyte?a reaction at the attachment of any ligament/tendon (new bone production at the site of an attachment of a dense collagen structure - tendon, ligament or joint)
what's a "kissing lesion"?a secondary lesion directly opposite of the primary lesion (like a fragment) where the wearing from the primary lesion causes the secondary one
****what is osteoarthritis?Disease of synovial joints with progressive and functional deterioration of cartilage accompanied by changes in bone and soft tissues of the joint.
***osteoarthritis is a disease of..articular cartilage!!! (if you say horse has osteoarthritis, that is like a permanent marker on that horse, because it will never really heal well)
major causes of osteoarthritis?(1) USE TRAUMA (2) SECONDARY TO OTHER DISEASE OR INJURY (Osteochondral fractures, Sepsis, dislocation, OCD, wounds)
osteoarthritis (OA) can be secondary to what 5 dzs/probs?Osteochondral fractures, Sepsis, dislocation, OCD, wounds
**explain how osteoarthritis (OA) can be a total vicious cycleThere is an initial injury--> this can cause cartilage damage AND can cause soft tissue damage. As cartilage is damaged, it releases stuff/shrapnel that irritate the soft tissues. Soft tissues, in response to damage and irritation, release chemical inflammatory mediators like interleukins...which then damage the cartilage which causes the whole cycle to start again
what's bone spavin?[his terminology definition is: A bony growth inside and just below the hock joint] it's a response of osteoarth of distal hock joint
why must you be VERY careful of steroid injections in the joints?steriods can cause breakdown of cartilage via destruction of collagen
what is ringbone?Bony formation in the pastern region.
what is sidebone, how often does it cause problems?Ossification of either lateral cartilage of the foot. Rarely causes problems or lameness
**Radiographic signs of osteoarthritis?? (8)Soft tissue swelling, Narrowing of the joint space, Subchondral bone irregularity (-->uneven joint space), Subchondral bone sclerosis, Subchondral bone lysis, Osteophytes, Remodeling of the joint, Periarticular bone formation
what's a match race? bet another guy that your horse runs better-- no regulation by some company- between two people
*how long should you rest a horse with osteoarthritis?REST DOESN'T HELP OA
***Which 3 joints can you fuse?Pastern joint, Distal intertarsal joint (centrotarsal), tarsal-metatarsal joint
how can you use/ surgically perform arthrodesis?can surgically drill it out, or you can inject alcohol in which will chemically fuse it
what are some things you can do to help manage osteoarthritis?REST DOESNT HELP!!!! Bute, corrective shoes, sx, fuse (if a joint you can fuse), steroids, platelet rich plasma
What will you recommend if horse with osteoarthritis becomes consistently lame when placed back into work?steroid injections