Exam 2 Flashcards

Question

Transporting Horse w/ Fracture

Answer 1

o hay net may be best for keeping horse calm o Space minimized to support the animal on all sides o Forelimbs should be transported backwards o Hindlimbs transported forward o Head and neck should be left free or loosely tied for balance

Answer 2

Pathophysiology * Piece of dead bone that has become separated during the process of necrosis from the sound bone * Most secondary to trauma and are infected * Or develop secondary to vascular compromise of the cortex (periosteum) Clinical Signs * +/-lameness * Localized heat and swelling * Persistent drainage with tract Diagnosis * Radiographs at 12 days usually demonstrate separated bone * Bone usually is not completely separated until 3 weeks Treatment * Surgical removal * May be done standing in selected cases * Fragment should be removed and the granulation bed débrided to healthy tissue * +/- Antibiotics

Answer 3

Risk Factors * More common in foals w/ bacteremia/septicemia * Standardbred * Intra-articular injections * Failure of passive transfer * Systemic sepsis Clinical Signs * Lameness * Transient fever * Joint effusion Diagnosis * Arthrocentesis * Usually >30,000 WBCs w/ 80% degenerative * TP > 3 * gram stain slides * culture * rads for rule out & determine prognosis

Answer 4

Common Bacteria * E. coli * Strep * Staph (post injection or sx) * Anaerobes Treatment * Broad spectrum antibiotics 2-3 wks post infection * Joint lavage * Hyaluronana IV or IA to reduce inflammation & DJD Prognosis * Better in adults than foals

Answer 5

o Indicated in ALL cases of septic arthritis o Use needle, arthroscopy, or arthrotomy o Sterile balanced electrolyte solution

Answer 6

o chronic sepsis or cases that do not respond to joint lavage o 3-5 cm arthrotomy incisions  -> o Drain into sterile bandage which is changed 1-2x daily o When upper joints are involved cross tie to prevent contamination

Answer 7

o Maximize tissue penetration of antibiotic around joint o Use 1g Gentamicin diluted to 30-60ml o Place tourniquet above & maybe below target site -> o Inject antibiotics into vein distal to site or into medullary cavity

Answer 8

o Used to impregnate Antibiotic into tissue o Antibiotic release is based on diffusion concentration gradients

Answer 9

o Part of the polyarthritis or polyosteomyelitis syndrome in young foals o Usually <2mo old Pathophysiology * Pooling of blood in the venous sinusoid at the junction of the epiphyseal bone and cartilage -> * Sluggish blood flow encourages bacteria to lodge and establish at this site Diagnosis * Septic arthritis of adjacent joint * Arthrocentesis & culture * Radiographs now and in 7 days * CT shows early changes * MRIs best

Answer 10

o Time it takes for bacteria to multiply 10^6 bacteria per gram of tissue

Answer 11

o Contamination with feces (10^11 bacteria per gram) o Contamination with soil (as little as 100 microorganisms per gram) o Virulence of offending bacteria o Reduced local defense mechanisms due to damaged blood supply, foreign body presence, or necrotic tissue

Answer 12

What to use * balance between antimicrobial action and tissue cytotoxicity. * 10ml Betadine 10% per liter of irrigation fluid = 0.1% * 25ml Chlorahexidine 2% per 975 mL of irrigation fluid = 0.05% * homemade saline = 8tsp salt/1gallon H2O or 10ml/L * may use antibiotics but should use before closure Is the joint involved? * Do arthrocentesis * Don’t go through contaminated wound

Answer 13

o Wounds at or below carpus & tarsus o Normal process due to lack of skin, motion, infection o Must eliminate underlying issues Pathophysiology * Fibroblasts & endothelial cells + no nerves -> * Needed as scaffold for epithelial migration -> * Resistant to infection Treatment * Trim * Topical corticosteroids

Answer 14

* Stop bleeding * Assess the ENTIRE horse * Clean wound * Local anesthesia * Assess for synovial envolvement * Bandage or cast

Answer 15

Clinical Signs * Knuckiling * Quickly learn to place correctly Treatment * Debride aggressively * May need splint/cast/shoe if horse is knuckling * Rarely suture extensor tendon

Answer 16

o must have 6 cortices proximal and distal to fracture   o must have 180 degrees of cortices to carry weight   o P1 fractures must have an intact strut of bone spanning the fetlock and pastern joints for internal fixation

Answer 17

o Drill glide hole (outside diameter of the screw) near cortex -> o Drill thread hole (core diameter of the screw) -> o Counter sink -> o Measure -> o Tap (create threads in far cortex) -> o Place and tighten screw

Answer 18

o Every screw = 1mm fracture compression (up to 4)

Answer 19

o Reduce survival by 50%

Answer 20

o Callus formation due to unstable mechanical environment caused by motion

Answer 21

o Strain = ratio of change in gap width over total width of gap o More change in gap -> less good healing Mechanisms for reduction * Fragment end resorption increases width of gap -> decreases ratio of change -> decreases strain * Number of fracture lines decreases strain on any individual fracture line * Sequential formation of stiffer tissues in the fracture gap

Answer 22

Displaced, comminuted fractures of the * femur, * humerus, * proximal tibia * proximal radius in adult horse

Answer 23

o Controlled Exercise (wind swept foals) o Corrective Shoeing (lateral or medial bending) o Cast Application o Growth Acceleration o Growth Retardation o Deformity of bones

Answer 24

o ^ valgus o v verus

Answer 25

Fetlock  Medical – 4wks  Surgical – 2mo Distal tibia  Medical – 4mo  Surgical – 4-6mo Distal radius  Medical – 4-6mo  Surgical – 6mo

Answer 26

o Inverted T-shape in periosteum above physis o Done on side hoping to accelerate growth o Controversial

Answer 27

o Both must be CAREFULLY monitored Bridge  Screws above and below physis parallel to joint surface  Retards growth across physis on that side  Wire must get tight before change Transphyseal  Screw bridging physis  Quicker than bridge

Answer 28

o Hyperextension of fetlock o Laxity at flexors Treatment  Exercise  Shoes  Cautious w/ bandaging (do not use rigid)

Answer 29

* Analgesics * Oxytetracycline IV (once hydrated!) * Toe extension * Splints/casts * Surgery for flexor carpi ulnaris & ulnaris lateralis tendons

Answer 30

* Most common acquired Flexural Deformity * Coloqually called club foot Cause * Contracture of the deep digital flexor tendon Treatment * Transection of the inferior check ligament (desmotomy) * + concurrent & repeated trimming of hoof to lower the heel

Answer 31

Medial * Cosmetic Lateral * Easier * Less wrap around of check ligament * Can result in entrapment of medial palmer artery (bad)

Answer 32

Signalment * 5-25% of horses affected * Warmbloods, thoroughbreds, QHs Most Common Joints * Tarsocural * Femoral patellar * Metacarpalphalangeal Pathogenesis * Genetic predisposition + * Too much dietary energy, high phosphorous, high zinc + * Biomechanical overload -> * Vascular compromise to nourishing vessels of epiphyseal cartilage -> * Failure of ossification & retained growth cartilage -> * Retained cartilage plugs die Histilogic Lesions * Persistent chondrocytes in mid-late hypertrophic zone * Failure of vascular invasion * Osteogenesis

Answer 33

OCD * Flap develops in areas of shear forces Cysts * Develop in areas of weight bearing

Answer 34

Signalment * All ages but mostly <3yo Location * Distal intermediate ridge of tibia > lateral trochlear ridge > medial malleolus Symptoms * Often present w/ synovial effusion * Lameness rare Diagnosis * Rads of dorsomedial plantarolateral oblique (DMPLO) Treatment * Surgical removal if clinical * May recover on own

Answer 35

Clinical Signs * Lesions stabilize by 8mo old & show signs at 3yr old * Often occur bilaterally * Joint effusion * Variable lameness Common locations * Lateral trochlear ridge * Maybe medial trochlear & patella Prognosis * Dependent on extent of damage in trochlear groove

Answer 36

Locations * Usually medial femoral condyle * Maybe lateral condyle or proximal tibia * Usually bilateral Clinical Signs * Detected once in training * Can result from trauma Treatment * Sx debridement * Injection of cyst w/ steroids * Rest * Transcondylar Screw across cyst (best)

Answer 37

Area  Between sensitive & insensitive laminae Clinical Signs  Warm  Increased digital pulses  Sensitive to hoof testers  Severe lameness  Acute onset Causes  Sole bruising  Penetrating injury of foot  “hot nail” nail from shoe in wrong place  Migration of infection from white line Diagnosis  May use nerve blocks  ID of abscess tract

Answer 38

 Create small hole to drain & follow tract to completion  DO NOT expose too much solar corium If abscess won’t open yet * Soak in warm water & Mg Sulfate * Poultice of Epsom salt or Mg Sulfate * Extensive sole resection & hospital plate Once Open * Flush tract w/ iodine -> * Pack w/ small amount iodine soaked gauze -> * Soak 1-2x/day for 2d * Check tetanus status * NSAIDs

Answer 39

Pathophysiology  Similar to hoof abscess  Ascending infection from white line  Usually associated w/ previous pathology of white line Clinical Signs  Swelling at coronary band  Lameness  Heat  Pain  Swelling  Drainage at coronary band Diagnosis  Rads Treatment  Debridement of hoof wall  Radical hoof wall resection

Answer 40

Pathophysiology  Inflammation or edema of sensitive lamellae ->  Breakdown & degeneration of union btwn horny & sensitive laminae ->  Rotation or sinking of P3  Often affects front > rear Signalment  15% of adult horses affected at some point  Most result in euthanasia Causes  Biomechanical  Ingestion of excess grain  Grazing of lush pasture  Excessive exercise/concussion in unfit horse  Endotoxemia  Systemic Dz Clinical Signs  Increased digital pulses  Warm/cold feet  Stance: weight on hind w/ front extended Treatment  Stall rest  NSAIDs, Opioids  Foam support p[ads  Ice boots  Corrective trimming/shoeing  May do DDF tenotomy but only helps some

Answer 41

 Surface areas = 1sq meter Epidermal lamellae * Avascular & aneural Dermal Lamellae * Very vascular & neural Basement Membrane * Tough sheet of connective tissue at the interface of the lamellar * Receptor site for growth factors, cytokines, and adhesion molecules

Answer 42

Developmental * 24-48hrs * You may be able to intervene but rarely seen now Acute * First signs of hoof pain Chronic * Rotation or sinking of P3

Answer 43

o Mostly water o Other part is type II collagen > proteoglycan > minerals > chondrocytes/lipids o Avascular, aneural, alymphatic o Matrix maintenance and turnover regulated by chondrocytes (VERY slow)

Answer 44

 Disruption of balance between degradation and synthesis of extracellular matrix ->  Breakdown of the collagen framework ->  Reduction in proteoglycan content and alteration of proteoglycan structure ->  Increased water content ->  Increased degradative enzyme activity ->  Articular cartilage becomes softer in compression and weaker in tension ->  DJD  Cartilage has very limited ability to heal

Answer 45

 Partial thickness defects -> rarely completely heal, may not compromise joint function  Full thickness defects -> repair by in growth of subchondral fibrous tissue -> not affective for normal use  Non weight bearing heals fast than weight bearing  Repair tissue is usually Type I collagen

Answer 46

Clinical Signs o Heat o Pain o Lameness o Effusion o Crepitus o Decreased range of motion OA Rads o Periarticular osteophyte formation o Subchondral bone sclerosis o Subchondral bone lysis o Narrowing of the joint space o Ankylosis Treatment o CANNOT REDUCE DAMAGE o Surgery for prevention o Adequan o Hyaluronan o Corticosteroids

Answer 47

 PSGAG  May alter progression of DJD  Used when extensive cartilage loss  Chondroprotective  Can prolong bleeding times & potentiate infection  Give IM or IA w/ Amikacin

Answer 48

 Hyaluronic acid  Linear polysaccharide  May decrease lameness  Anti-inflammatory  May induce production of endogenous hyaluronic acid

Answer 49

Use * Used to treat various arthopathies * Onset of action is immediate Drugs * Methylprednisolone Acetate (Depo) * Triamcinolone Acetonide (causes laminitis?) Adverse Effects * High doses can damage cartilage matrix metabolism * Steroid arthropathy * Post injection flare * Potentiation of infection

Answer 50

Signalment o Small feet o Underrun heels o Long toes o Often QHs Clinical Signs o Blocks out w/ palmer digital nerve block o Bilateral o Chronic o Progressive forelimb lameness Areas that can be affected o Navicular bone o Navicular bursa o Coffin joint o P2, P3 o Impar ligament o Deep digital flexor tendon Diagnosis o Ultrasound o CT (best value) o MRI (best image)

Answer 51

Medical  Correct hoof imbalances w/ trimming and/or shoeing  Allow hoof expansion  Short-term raise angle of hoof w/ heel wedge  Phenylbutazone  Steroid injection in coffin joint or navicular bursa Surgical  Palmer digital neurectomy (careful they may hurt themselves)  Navicular suspensory ligament desmotomy (out of favor)  Navicular bursoscopy

Exam 2 Flashcards

(75 cards)