LA MS #3

britt611's version from 2017-02-05 19:35

Section 1

Question Answer
Distal tarsal osteoarthrosis is very common in which animal?horse- called a bone spavin, low motion joints and often bilateral and bilaterally symmetrc
which joints affected by OA have a more guarded prognosisproximal intertarsal and tarsocrucural joints (high motion joints)
what are the radiographic signs of OAperiarticular osteophytes, joint space narrowing, variable ankyloses (joint fusion), loss of coritcomedullar definition (medullary sclerosis)
Treatment of OApalliate pain, +/- join injections and corrective shoeing or chemical arthrodesis (iatrogenic joint fusion)
Define OC/OCDdevelopmental disorders, usually monosotoic but can be multifocal, centered on articular surfaces/subchondral bone
define OAacquired degenerative disease, almost always polyostotoic, centered on joint (periarticular margin)
define osteomyelitis aggressive, can be monostotic or polyostotic, can be centered anywhere (joint = septic arthritis with osteomyelitis; physis = septic physitis; Diaphysis = osetomyelitis secondary to penetrating wound

Section 2

Question Answer
What are 3 fracture typesactue/traumatic, chronic, pathologic
acute vs pathologic fracturesacute = abnormal force placed on normal bone, pathologic = normal forces on an abnormal bones
what is a chronic fracturehealing and or remodeling
what are some acute fractureslong bone fractures, edge of bone fractures, salter harris fractures
what is an example of pathologic fractureinfection (osteomyelitis), metabolic bone disease, neoplasia
what are the radiographic featrues of an acute fracturesharp, well defined fracture margins, normal cortical and trabecular bone
what are the radiographic features for a chronic fracture rounded but well defined fracture margins, callus fformation
what are the radiographic features for pathoglogic fracturepoorly defined fracture margins, signs of aggressive lesions (periosteal reaction, lysis), thin cortical osteopenia
what is a common location for long bone fractrues in horsesdigits (proximal, middle and distal pahlanges), third metatarsal/metacarpal bones, tibia
what are 3 edge of bone fractures1. avulsion (pull from a ligament or tendon attachment), 2. chip ( one articular surface), 3. slab: two articular surfaces
what are physeal fracturesSH , young animals
what are the main horse fracturesproximal sesamoid bone fractures, distal phalanx fractures
What is the most common fracture on the distal phalanx (P3)type 6 SH- solar margin fracture and often secdonary to laminitis
why is it challengins to diagnose a distal P3 fractureusualy minimally displaced
what is healing difficult to diagnosis in distal P3 fractures?limited periosteum- can take 3-19 mo
what can you use nuclear scintigraphy to monitor?assesses bone activity
what is a type 6 fracture?small fragments along the solar margin- most common in the distal phalanx and often secondary to laminitis,
what do you need to be careful with when evaluating the solar margintype 6 fracture- dont OVEREXPOSE - can miss it

Section 3

Question Answer
what causes proximal sesamoid bone fractures?extreme forces (high motion fetlock joints)
why type of fractures is commonly associated iwth proximal sesamoid bone fractruesavulsion fracture- insertion of the suspendory ligament branches - often abaxial
what is the insertion and origin of the proximal sesamoid bonesinsertion of the suspensory ligament branches and orgiin of distal sesamoidean ligaments
What is the most common proximal sesamoid bone fracturesapical, mid body and basilar (apical can remove fragment -> good prognosis, mid-body + basilar: recommend surgical fixation -> guarded pronosis
what are some other differential diagnosis for small fragments adjacent to proximal sesamoid bonesosteochondral fragments, avulsion of palmar annular ligament, chip fractures, if very small, arthroscopic removal recommended
what are chip fractures common in?race horses: carpus, fetlock
describe a chip fracture in the carpusdorsodital articular surface of the radius, dosrsoproximal margins of the radial and intermediate carpal bones
describe chip fractures in the fetlockproximodorsal rim of the proximal phalanx, most are considered OCD fragments, may also be separate centers of ossification
what can all chip fractures lead to?OA

Section 4

Question Answer
What are slab fracturesfracture line courses between two articular surfaces - usually refers to cuboidal bones
what is the most common slab fractures in the carpus3rd carpal bone***, other: intermediate and 4th
which views are best when looking at slab fracturesskyline and flexed views
where are slab fractures seen in the tarsus3rd and central tarsal bone
what is needed in order to detect a fracture line radiographically?the xray beam must penetrate the fracture to expose the film
when should you recheck radiographs if you dont see a fracture but a horse is fracture lame?7-10 days- fracture gaps are wider
what structures allow tarsal slab fractures minimal fracture displacementintertarsal and collateral ligament
what does nuclear scintigraphy providefunctional information regarding bone turn over, has poor spatial resolution,
high vs low activity of nuclear scintigraphyhigh: osteomyelitis, acute fracture, low: OA, OCD, chronic/healing fractures
what are condylar (metacarpal/metatarsal) fractures common in?young, racing thoroughbreds - almost exclusively secondary to strenuous exercise
is it more common to get condylar fractures in the throacic or pelvic limbsThoracic > pelvic
how many types of condylar fractures are there4; based on complete vs incomplete and extent--- ALL are articulare
medial condylar fracture tend to extend more ____ then ____proximal then lateral

Section 5

Question Answer
what are complications of bone trauma?secondary to large soft tissue wounds that extend to the bone, fracture complication, secondaryt o osteomyeltiis
define sequestrumavacular portion of bone - acts as a reservoir for infection - not penetrated by antibiotics, surrounded by necrotic material/ pus
what does a sequestrium almost always requiresurgical removal/debridement
what is an involucrumsclerotic zone of surrounding endosteal/periosteal reaction
what is a cloacadraining tract
what are sequestration common in?bone with little soft tissue (3rd metacarpal + metatarsal bones, radius)
is a sequestration an example ofan aggressive bone lesion
what are radiographic signs of sequestration? computed tomographysmoother periosteal prolifateration, heterogenous bone opacity, mild soft tissue swelling focally worst medially

Section 6

Question Answer
what are some examples of LA developmental disorders?osteochrondrosis, incomplete ossificaiton of cuboidal bones, angular limb deformity, metabolic disorders, others: aspetic physitis, tendon contracture
define cuboidal bone hypoplasia?failure in appropriate ossification
what are 2 causes of cuboidal bone hypoplasiapre-mature foal: born early and suboidal bones have insufficeint time to develop, OR dysmature foals: born at the appropriate time but small/immature for the age
what are radiographic signs of cuboidal bone hypoplasia?small, rounded cubodial bones, increase width of joint space
what are sequellae to cuboidal bone hypoplasiajoint collapse/fractures, angular limb deformity
what are 2 types of angular limb deformity?valgus and varus
valgus vs varus deformityvalgus: lateral deviation of the limb distal to the problem (splay foot-> more common), Varus: medial deviation (pigeon toed)
what are the underlying etiolgies of angular limb deformity?MANY! abnormal cuboidal bones, SH fractures, fractures, wedge shapped epiephysis
what are the radiographic signs of angular limb deformitymedial or lateral deviation of the limb, intersecting lines bisectin the long axis of the long bones help idenity the level of the problem
what are treatments of angular limb deformitycats, splits, surgerys

Section 7

Question Answer
bone is a ____ metabolic tissues highly
what minerals/vitamins are associted with boneca, p vit D, vit A
what are uncommon causes of metabolic bone diseasecommercial diets, congential
what are causes of metabolic bone disease in LAprimary and secondary hyperparathyroidsim (renal/nutritional), inadequate Ca, hypertrophic osteopathy
what are key interpretation prinicpals of metabolic bone diseasediffuse osteopenia, often worse with high bone turnover, considered polyostotic non aggressive bone lesions
what are radiographic signs of hypovitaminosid D - Rickettsdiffuse osteopenia: thin corticies, coarse trabecular bone, wide physis , pathologic fractures
what is the main underlying bone pathoogy oc patholgoic fracturesosteomyeltisis- can also be from: metabolic bone disease or neoplasia (uncommon in LA)