Large Animal Surgery 2

Front 1

What is thought to be the cause of fractures of the body of P1?

Back 1

torsion applied to the sagittal groove

Front 2

Where do fractures of the body of P1 mostly occur?

Back 2

forelimbs of racing animals

Front 3

What is the one c/s you may see with fractures of the body of P1?

Back 3

from slightly lame to leg carrying lameness

Front 4

Why is a fracture of the body of P1 the one time you may want to do radiographs before doing a lameness exam/nerve blocks?

Back 4

performing a routine lameness exam w/nerve blocks can cause a compelte breakdown of bone

Front 5

What should be done differently if the lameness if more chronic and fracture of the body of P1 is suspected?

Back 5

a thorough lameness exam to locate the area of lameness should be done PRIOR to radiographs

Front 6

When would you most likely suspect a fracture of the body of P1?

Back 6

with a lameness following a race when palpation and torsion of the pastern cause increased pain

Front 7

How do you manage a sagittal nondisplaced fracture of the body of P1?

Back 7

percutaneous placement of lag screw to compress the fragments

best to apply a cast for anesthetic recovery

Front 8

What is the prognosis for a single fracture of the body of P1?

Back 8

good

Front 9

What is the prognosis for >1 fracture of the body of P1?

Back 9

fair to poor

Front 10

How do you manage a frontal nondisplaced fracture of the body of P1?

Back 10

repaired as a sagittal nondisplaced fx EXCEPT if there is disruption of the attachment of the distal sesamoid ligaments sometimes there is subsequent subluxation of the pastern, therefore arthrodesis of the pastern should be considered to prevent this complication

Front 11

how do you manage moderately displaced fracture of the body of P1?

Back 11

repair w/lag screw is one solid piece of bone extends from fetlock to pastern joint

open reduction w/ percutaneous screw better to be sure fx is aligned correctly ("I" shaped skin incision)

cast application for 6 weeks

Front 12

How do you manage a severely comminuted fracture of the body of P1?

Back 12

euthanasia should be considered bc these animals will NOT be sound

transfixation pins is breeding potential or emotional value

Front 13

With a comminuted fracture of the body of P1, how will the transfixation pins be applied?

Back 13

pins incorporated in a half-limb cast (up to just distal to the carpus/tarsus)

pins attached to a Nunamaker external fixator w/acrylic

foot wired to foot plate and apparatus extended and positioned to align fx

Front 14

What is the problem with using the transfixation pins?

Back 14

they will loosen over time

Front 15

What is a dorsal proximal osteochondral border fracture of P1?

Back 15

small chip fx off the prox dorsal margin of P1

Front 16

dorsal proximal osteochondral border fracture of P1: Which part of the bone is most commonly involved?

Back 16

medial eminence

Front 17

Where is a dorsal proximal osteochondral border fracture of P1 common and in which horses?

Back 17

metacarpal phalangeal joint of race horses

Front 18

What is a dorsal proximal osteochondral border fracture of P1 caused by?

Back 18

trauma as a result of marked extension of the fetlock joint

Front 19

What are the c/s of a dorsal proximal osteochondral border fracture of P1?

Back 19

-slight lameness, joint effusion
-if small fragment, lameness regresses rapidly

Front 20

dorsal proximal osteochondral border fracture of P1 is aka?

Back 20

cranial proximal P1 fx

Front 21

A dorsal proximal osteochondral border fracture of P1 is common in which breed?

Back 21

thoroughbreds on hard tracks

Front 22

How do you dx a dorsal proximal osteochondral border fracture of P1?

Back 22

pain w/joint flexion
radiographs

Front 23

How do you manage a dorsal proximal osteochondral border fracture of P1?

Back 23

small fx- covered by synovial membranes rapidly and many heal w/o intervention
sx removal w/arthroscope

Front 24

What is the prognosis for a dorsal proximal osteochondral border fracture of P1?

Back 24

usually able to return to previous level of performance

Front 25

In which limbs do proximal pal/plant border fx of P1 primarily occur?

Back 25

primarily in rear limbs

Front 26

What are the two different types of a proximal pal/plant border fx of P1 and how should they be managed?

Back 26

Type I- involve the axial pal/plant rim- removed w/arthroscopic sx
Type II- involve the abaxial pal/plant rim- don't commonly cause a problem bc usually larger and non articular

Front 27

Type I proximal pal/plant border fx of P1 are most common in what breed?

Back 27

standardbreds

Front 28

What are the c/s of proximal pal/plant border fx of P1?

Back 28

slight effusion of the involved joint and some lameness at high speeds

Front 29

How can you find a TYPE I proximal pal/plant border fx of P1 on a radiograph?

Back 29

move the tube head proximal and dorsal so that the beam si aligned approx 20 degrees from horizontal and 20 degrees from a transverse projection

Front 30

how do you manage type I proximal pal/plant border fx of P1 in yearlings?

Back 30

remove fragment to prevent problems when they go into race training, though most are not lame

Front 31

How do you surgically remove a proximal pal/plant border fx of P1?

Back 31

scope is placed through the plan/pal pouch of the fetlock w/the instrument portal at the base of the proximal sesamoid bone

Front 32

What are the option for managing a Type II proximal pal/plant border fx of P1?

Back 32

do nothing
sx removal
stabilize w/bone screw

Front 33

What is another name for osteoarthritis of the fetlock joint?

Back 33

osslets

Front 34

What is osslets?

Back 34

swelling of the anterior aspect of the fetlock caused by traumatic capsulitis w/periosteal proliferation at the attachment of the joint capsule

Front 35

How is osslets caused?

Back 35

-wear and tear lameness assoc w/deterioration of cartilage
-starts as synovitis and capsulitis
-some assoc w/osteochondrosis and subchondral cystic lesions

Front 36

Which of the causes of osslets is common in racing animals?

Back 36

starting as synovitis and capsulitis

Front 37

What are the c/s of osslets?

Back 37

initially- heat, effusion, pain w/flexion (horse warms out of the lameness w/exercise)
distended fetlock joints
marked reduction in range of motion

Front 38

How do you dx osslets?

Back 38

PE
radiographs- loss of joint space, periosteal proliferation

Front 39

W/radiographs of osslets, Which is more common when you see loss of joint space: collapse of the medial side of the join or the lateral side?

Back 39

collapse of the medial side

Front 40

How do you manage early cases of synovitis and capsulitis?

Back 40

NSAIDS
intra-articular steroid injections
intra-articular hyaluronan (possibly IV)
+/- IM adequan (glycosaminoglycans)
+/- oral glucosamine & chondroitin
steroid injections if cartilage continues to break down

Front 41

T/F: Many horses race w/osslets after standing in hot water before and after a race?

Back 41

false: they stand in COLD water

Front 42

What has been done to try and get a few more races out of horses w/osslets?

Back 42

intra-articular silicon oil inj
intra-articular cobra venom to desensitize

Front 43

What is the result of this problem?

Back 43

-some horses undergo arthrodesis but are pasture sound at best afterwards
-many horses are retired or euthanized

Front 44

What is OCD of the fetlock joint? What are the two types?

Back 44

osteochondrosis dessicans (aka osteochondrosis and subchondral cysts of the fetlock joint)- cartilaginous flap and subchondral cysts

Front 45

OCD involves what feet and is most common in which animals?

Back 45

both front and rear fetlocks

young racing animals

Front 46

What part of the fetlock is commonly involved in OCD with a cartilaginous flap?

Back 46

dorsal sagittal ridge

lesions on the palmar sagittal ridge are more severe and usually cause osteoarthritis

Front 47

What is sometimes involved in OCD with subchondral cysts?

Back 47

P1

Front 48

What causes OCD?

Back 48

the osteochondritis syndrome- poor quality underlying bone causing breakdown of cartilage

Front 49

What are the c/s of OCD and which lesions usually show more lameness?

Back 49

varying lameness
joint distention

palmar lesions usually show more lameness

Front 50

How do you dx OCD?

Back 50

+ flexion tests
radiographs for extend of problem
nerve blocks usually not needed for dx

Front 51

How do you manage palmar or plantar OCD?

Back 51

-usually surgically inaccessible so permanent lameness is common
-debride the lesions (arthroscopic sx)- dorsal sagittal ridge and parasagittal, lesions or cystic lesions
-tx w/hyaluron inj (very effective w/cystic lesions

Front 52

chronic proliferative synovitis is aka?

Back 52

villonodular synovitis

Front 53

What is chronic proliferative synovitis?

Back 53

proliferation of the synovial membrane of the MC-phalangeal joint

Front 54

What causes chronic proliferative synovitis? (1 & 2)

Back 54

Primary- repeated hyperextension of the fetlock and trauma to the synovial membrane
Secondary- dorsal phalangeal fx that are not removed cause irritation and proliferation of the synovial membrane

Front 55

c/s of chronic proliferative synovitis

Back 55

firm enlargement on the dorsal aspect of the MC-phalangeal joint
moderate --> severe lameness

Front 56

Who is more commonly affected by chronic proliferative synovitis? (age and breed)

Back 56

young horses in training

standardbreds

Front 57

How do you dx chronic proliferative synovitis radiographically?

Back 57

bone lysis on the dorsal aspect of the distal MC adjacent to the synovial mass
contrast material- show a filling defect
U/S shows a synovial mass

Front 58

how do you manage primary chronic proliferative synovitis?

Back 58

arthroscope to remove synovial mass
large masses might require arthrotomy
joint inj w/corticosteroid and hyaluron allow use but NOT cure

Front 59

How do you manage chronic proliferative synovitis secondary to chip fx?

Back 59

correction of primary problem plus remove mass

Front 60

Prognosis of both primary and secondary chronic proliferative synovitis

Back 60

Primary: ~80%
Secondary: depends on primary problem

Front 61

:uxation of the fetlock occurs secondary to what?

Back 61

rupture of the medial or lateral collateral ligament

Front 62

How is is caused? and what is it commonly associated with?

Back 62

trauma

commonly assoc w/being caught in a cattle guard or stepping in a hole

Front 63

c/s of luxation of the fetlock

Back 63

extreme lateral or medial deviation of the limb

Front 64

What are radiographs used for with luxation of the fetlock?

Back 64

to determine the extent of the injury

Front 65

How do you manage a closed luxation of the fetlock?

Back 65

manipulation to correct the luxation
casting for 6-8 weeks

Front 66

How do you manage an open luxation of the fetlock?

Back 66

qdequate wound management (incl antibiotic impregnanted beads)
correct luxation and cast for 6 to 8 weeks

Front 67

What is the prognosis for animals with luxation of the fetlock?

Back 67

some with CLOSED luxation may return to use
open luxation response depends on the extent of involvement and the degree of infection

Front 68

Proximal sesamoid bone fx are considered what? What happens?

Back 68

breakdown injuries

fx of the medial and lateral sesamoid bones with complete disruption of the fetlock joint

Front 69

With a high degree of involvement, a proximal sesamoid bone fx can cause disruption of what?

Back 69

the suspensory apparatus

Front 70

What causes a proximal sesamoid bone fx?

Back 70

trauma as a result of exercise

but it is SELDOM assoc w/EXTERNAL trauma

Front 71

What are the c/s of proximal sesamoid bone fx?

Back 71

joitn effusion in all but abaxial nonarticular fx
moderate to severe lameness

Front 72

How do you manage apical fx that involve < 1/3 of the proximal sesamoid bone?

Back 72

remove by arthroscopy or arthrotomy

Front 73

When removed w/arthroscope, where is the portal of entry for the arthroscope and the instrument?

Back 73

arthroscope- dorsal caudal pouch of the fetlock
instrument- level of the fx

Front 74

How do you manage mid body fx of the prox sesamoid bone?

Back 74

repair with lag screw or circlage wire

Front 75

Describe how you use a lag screw to repair midbody fx of the prox sesamoid bone

Back 75

a glide hole drilled from base or apex (depends on fx) --> guide placed in hole and screw hole is drilled opposite the fragment --> screw hole is tapped and a compression screw is inserted and tightened to reduce fx

Front 76

Describe how you use cerclage wire to repair midbody fx of the prox sesamoid bone

Back 76

incisions made to see the axial and abaxial aspects of bone (2 long or 1 "C"-shaped) --> tendon sheath opened to get to axial side of sesamoid bone --> hole drilled abaxial to axial side of bone --> wire is tightened to compress fx

Front 77

How do you manage basal fx of the prox sesamoid bone?

Back 77

-if small and not extending tto caudal aspect of bone- fragment removed
-if extend complete width of bone- all attachments to distal sesamoidean ligaments are involved = poor prognosis
**- only recommended tx = encircling wire (not very successful)

Front 78

Why can't you use a lag screw to manage basal fx?

Back 78

bc the bone usually fragments

Front 79

How do you manage abaxial fx of the prox sesamoid bone?

Back 79

involves the joint- remove with arthroscope
no joint involvement- conservative- rest

Front 80

how do you manage sagittal fx of the prox sesamoid bone?

Back 80

encircling wire is suggested

usually occur in assoc w/other injuries such as condylar fx

Front 81

What is the prognosis for apical fx that involve 1/3 of the prox sesamoid bone?

Back 81

can return to previous level of performance following fx removal

Front 82

What is the prognosis of abaxial fx of the prox sesamoid bone that do NOT involve the joint?

Back 82

respond fairly well to conservative management

Front 83

What is the prognosis of all other fx types of the prox sesamoid bone?

Back 83

limited success

Front 84

What is arthrodesis of the fetlock joint?

Back 84

-breakdown injury where the suspensory apparatus has been destroyed (both sesamoid bones are usually fx)
-chronic painful condition that has not and probably will not respond to therapy

Front 85

How is the horse positioned for sx for arthrodesis of the fetlock joint?

Back 85

lateral recumbency with the involved leg up

Front 86

Describe the sx performed for correcting arthrodesis of the fetlock joint

Back 86

long. incision on anterior aspect of limb (coronary band to mid-MC) --> split common/long digital extensor tendon --> remove periosteum from anterior MC and P1 --> divide lateral collateral lig of fetlock and the lateral sesamoidean lig --> remove all joint cartilage --> bone plate to anterior surface of MC/MTIII and P1 --> bone screw in each prox sesamoid bone --> half cast

Front 87

What do you do (sx) if the suspensory apparatue is not intact?

Back 87

lateral to medial hole drilled 6cm prox to fetlock in MC/MT III and 6cm distal in P1 --> stainless steel suture to run through holes and form tension band

Front 88

Prognosis for arthrodesis of fetlock joint

Back 88

not sound following this procedure

most that can hope for is pasture soundness

Front 89

What is the most frequent site for OCD in the fetlock?

Back 89

dorsal sagittal ridge

Front 90

What is osteochondrosis?

Back 90

failure of endochondral ossification

Front 91

What are the c/s of osteochondrosis in the dorsal sagittal ridge of MC/MT III?

Back 91

mild effusion and lameness

sometimes asymptomatic

Front 92

What radiographic views are used to dx osteochondrosis in the dorsal sagittal ridge of MC/MT III?

Back 92

dorsopalmar view or slightly underexposed flexed lateral-medial view

Front 93

how do you manage osteochondrosis in the dorsal sagittal ridge of MC/MT III in younger animals?

Back 93

conservative (rest)

Front 94

How do you manage osteochondrosis in the dorsal sagittal ridge of MC/MT III in yearlings or older animals?

Back 94

currete w/aid of arthroscope

Front 95

Angular limb deformities occur where?

Back 95

fetlock, carpus, and tarsus

Front 96

What is a valgus deformity?

Back 96

lateral deviation of the limb distal to the location of the deformity

"knock-knead" and "splay foot"

Front 97

What is a varus deformity?

Back 97

medial deviation of the limb distal to the location of the deformity

"bow-legged" and "pidgeon toed"

Front 98

List of the sites of deviation for angular limb deformities

Back 98

prox P1
dist MC/MT
dist radius
dist tibia
carpus
tarsus
diaphysis of MC/MT III

Front 99

in reference to angular limb deformities, the carpus (and less commonly the tarsus) is deformed as a result of what? (3 possibilities)

Back 99

-hypoplasia of the carpal/tarsal bones
-weakness of the collateral ligaments
-abnormal development of the epiphysis

Front 100

T/F: many of these deformities are present at birth and correct without intervention in time

Back 100

true

Front 101

T/F: there is generally some rotational deformity to go along with the angular limb deformity

Back 101

true: pigeon toe, splayed foot

Front 102

What can cause angular limb deformities?

Back 102

weakness of supporting structures
hypoplasia of carpal/tarsal bones
metaphyseal, epiphyseal, or diaphyseal dysplasia
trauma to physis

Front 103

Which is the msot common cause of angular limb deformities?

Back 103

metaphyseal dysplasia

Front 104

Deviation of ___ degree is assumed to be normal?

Back 104

<4 degrees

Front 105

How can you diagnose an angular limb deformities caused by a weakness of supporting structures?

Back 105

deviation switched between varus and valgus with pressure
limb can be easily manipulated into correct position
radiographs show normal osseous structure

Front 106

How can you dx an angular limb deformity caused by hypoplasia or poor ossification of the cuboidal bones?

Back 106

deviation switched between varus and valgus w/pressure
radiographs show incomplete ossification

Front 107

How can you dx angular limb deformities caused by metaphyseal dysplasia?

Back 107

deviation does NOT change w/pressure
radiographs show deviation in the metaphysis (lines should be drawn thru the long axis of the bones prox and distal to deviation --> where they cross = deviation site)

Front 108

How can you dx angular limb deformities caused by epiphyseal dysplasia?

Back 108

as with metaphyseal dysplasia except the lines drawn through the long axis of the bones cross at the epiphysis

Front 109

How can you dx angular limb deformities caused by diaphyseal dysplasia

Back 109

curving of the diaphysis

(uncommon)

Front 110

How can you dx angular limb deformities caused by trauma to the physis?

Back 110

hx of trauma
radiographic evidence of closed physis

Front 111

How do you manage angular limb deformities caused by weakness of supporting structures?

Back 111

stall rest w/hand walking daily
swimming is best
casts/splints NOT indicated bc some degree of tension is necessary to strengthen structures

Front 112

How do you manage angular limb deformities caused by hypoplasia of the carpal bones?

Back 112

stall rest along if deviation not severe (~1mo)
tub casts or splints to support the limb until there is evidence of normal ossification (foot shouldn't be in cast)
exercise w/o support will cause problems

Front 113

How do you manage angular limb deformities caused by metaphyseal dysplasia?

Back 113

-allow time for natural correction (~4-6 wks stall rest, though reduced time for distal MC/MT physis bc closes early)
-splints for minor problems or custom made braces (both labor intensive)
-trim feel to keep balanced
-surgery

Front 114

What surgical techniques can be used to manage angular limb deformities caused by metaphyseal dysplasia?

Back 114

stimulation of growth to the concave part of the bone
retarding growth on the convex part of the bone
combination of both

Front 115

What are the age limitation for stimulation growth on each of these parts of bones:
1. distal radius
2. distal tibia
3. distal MC/MT
4. Proximal P1

Back 115

1. 6 months
2. 4 months
3. 2 months
4. 2 months

Front 116

What are the two ways to stimulate growth?

Back 116

periosteal transection (stripping) to stim growth on concave side of the limb
irritation of physis

Front 117

With periosteal stripping, how long does the affect on bone growth last? Can it be repeated?

Back 117

two months (check out 3-22 for procedures)

can be repeated if age limits have not been reached

Front 118

What are the age limitation for retardation of growth on each of these parts of bones:
1. distal radius
2. distal tibia
3. distal MC/MT
4. Proximal P1

Back 118

1. 12 months
2. 8 months
3. 4 months
4. 4 months

Front 119

What is the most important thing to talk to the client about when explaining the procedure for retarding bone growth?

Back 119

emphasize that the hardware MUST be removed when the limb is straight to prevent overcorrection

Front 120

Why, when using staples instead of cerclage wire, is the correction of the bone slower?

Back 120

bc initially there is not as much tension with staples

Front 121

what are the four pieces of equiment that could be used/placed when retarding growth by temporarily stabilizing the convex side of the limb?

Back 121

screws and wire
staples
small bone plates attached with screws
a single transphyseal screw

pg 3-22/23 for procedures

Front 122

Which is the latest procedure and where can it not be used? Where is ti most commonly used?

Back 122

single transphyseal screw (inserted perpendicular to the physis)

can be used in all areas EXCEPT the prox physis of P1

most commonly used in the distal MC/MT

Front 123

T/F: both retardation and stimulation can be used on opposite sides of the bones at the same time

Back 123

true

Front 124

T/F: epiphyseal dysplasia responds well to stimulation and retardation of physeal growth

Back 124

false: it responds well to neither - the limb can be made to look better but the biomechanics are flawed and the animal won't perform well

Front 125

How do you manage diaphyseal dysplasia?

Back 125

at less than 2 months of age, it is effective to incise the periosteum over the length of the diaphysis, elevate the periosteum along the entire length, and make perpendicular incision thru the periosteum at each of end of the long incision

Front 126

how does trauma to the physis cause an angular limb deformity?

Back 126

iy only one side of the physis is involved, traums will usually cause the physis to mature (close) and an angular limb deformity develops

Front 127

T/F: stabilize the deformity caused by trauma to the physis will not correct but will stop the development of the deformity

Back 127

true: growth of the limb will stop and the involved limb will be shorter than the contralateral limb

Front 128

congenital flexural deformities are a much greater problem in which limbs?

Back 128

forelimbs

Front 129

What are some possible causes of congenital flexural deformities? (4)

Back 129

abnormal uterine position
genetic
ingestion of toxins during pregnancy (loco weed, sudan grass)
influenza (during pregnancy)

Front 130

what are the 3 varying degrees of flexion of the fetlock, pastern, and coffin joint with congenital flexural deformities

Back 130

upright w/no angle to the fetlock
walking on the front of the fetlock
walking on the toe w/the heel off the ground

Front 131

Regression

Back 131

Guarding against anxiety by retreating to behavior of an earlier, less demanding, and safer stage of development.

Front 132

T/F: if one can get the foal to bear weight on the toe, then continued weight bearing will stretch the tendon and result in a less deformed conformation, though not quite normal

Back 132

false: it will result in normal conformation

Front 133

T/F: pressure sores on the anterior of the fetlock are a problem

Back 133

true

Front 134

What does placing the limb in a cast for a period of time do for congenital flexural deformities?

Back 134

causes relaxation of the flexor tendons

Front 135

What else can be done to manage congenital flexural deformities?

Back 135

acrylic toe extensions
interior check ligament desmotomy (seldom necessary)

Front 136

What is an acquired flexural deformity?

Back 136

foal is normal at birth and develops either a Club foot or hyperextension of the hock

Front 137

What is Club foot? What are the two types?

Back 137

coffin and pastern joint flexion

Type I- anterior hoof wall angle w/the sole surface of the hoof is <90 degrees
TypeII- anterior hoof wall w/the sole surface of the hoof is >90 degrees