IMSK Exam 3

Label 1-7

1) sulcus 2) Tibial Tuberosity 3) Fibular head 4) Cranial cruciate ligament 5) caudal cruciate ligament 6) Lateral meniscus 7) Medial Meniscus
4 and 5 cruciate ligaments are named by their tibial INS

Lateral view (label 1-6)

1) fabella (lateral) 2) Lat collateral 3) long digital extensor tendon 4) femoropatellar ligamnet 5) lateral meniscus 6) infrapatellar fat pad

Medial view 1-4

1) fabella (medial) 2) medial collateral ligament 3) medial meniscus 4) intrapatellar fat pad

Femoropatellar ligamnets

continuation of the femoral fascia or at the sides of the patella
lateral - better defined

CrCL vs CdCL

cranail cruciate ligament
Caudal cruciate ligament

CrCL prevents

hyperextension, excessive internal rotation, cranial tibial translation

Screw home mechanism

some internal tibial rotation natrually occurs as you flex your knee

Meniscus - anatomy

fibrocartilage “wedges” between the femoral condyles and the tibial plateau (mostly type I collagen, they alleviate incogruity between a rounded strucutre and a flat surface)

Meniscus - funciton in stiffle

stabilization, load bearing, shock absorption, joint lubrication, mechanoreceptor

CrCL disease - etiology

biomechanical - trauma, hyperextension <10%
Biological - spontaneous degeneration >90%

CrCL etiology and presentation - traumatic

may be associated with other damage to the stiffle (collateral ligament, caudal cruciate ligament, menisci)
typically unilateral injuries
predominantly complete tears
in puppies - is likely associated with an avulsion vs midsubstance tear in the adult

CrCL disease - etiology and presentation - degenerative

spontaneous, commonly bilateral (~10% bilateral on presentation but up to50% will rupture the other side within 1 year and 60% will rupture the other side in their lifetime)
tears can be partial or complete - partials progress to full tears over time

CrCL disease - risk factors - degenerative

Breed - lab, golden, rottweiler
sex - femlae >male
neutred>male
larger>smaller
obesity implicated but not proven
Anatomy (increased tibial slope has been implicated)
other disesae (endocrinopathies)
Age - unknown if true risk facort (peak at 7-10 years) (smaller are later in life, larger are earlier)

CrCL disease - meniscal injury (medial vs lateral)

medial meniscus - #1 side injured (caudal horn)
lateral Meniscus - injuries here are much less common (Must check during sx)

CrCL disease - Hx and s/s

Hx - non-weight bearing lameness
muscle atrophy of quadriceps
medial buttress
reluctant to have the stiffle joint maximally flexed or exteneded

CrCL disease - Pe findings

gait - short stride/obvious lamenees, look for atrophy and symmertry
sit test - sit with the most painful stiffle extended out laterally and roll onto the opposite (good) limb
standing plapaiton - look for symmetry
recumbent palpation - CREPI, cranial drawer and cranial tibial thrust

CrCL disease - stiffle exam - 2 tests

Cranial drawer test (passive)
Tibial compression test (dynamic test) - mimics weight bearing

CrCL - stiffle exam - testing for cranial-caudal instability (full vs partial tears)

Full tears - cranial drawer is typically easy to palpate
partial tears - may only have mild or subtle cranial drawer so you must test in flexion and extension, test for pain on stifffle hyperextension, base a presumptive dx off of x-ray findings (secondary OA)
if still unsure - rest, NSAID, nad recheck in 2-4 weeks (repeat full exam)

CrCL band (cualda laterla nad cranial medial) reaction to flexion and extension

only loose when caudal lateral is in flexion

CrCL disease - x-rays signs of secondayr OA

Scerlosis
Osteophytes - proximal and distal patella, trochlear ridges, fabella
Efussion - cranila displacment of the infrapatellar fat pad, caudal displacment of gastrocnemius fascial plane

NO

NO

CrCL disease - sx options - Lateral sutures - objectives of sx

placing a prosthetic sutreu to mimic the CrCL
goal is to neutralize the effects of cranial tibial thrust and cranial drawer by replacing the damaged CrCL with lateral suture

CrCL disease - sx lateral suture - stability

provides static and dynamic stabilization
craniocaudal instability is neutralized by extra-capsular support
short term stability - suture material
long term stability - periarticular fibrosis
after sx, the cranial cruciate ligament is not neccessary to stiffle stabilization
tfibrosis replaces the suture and creates the stability

CrCL - sx options - lateral suture - clinical concerns/benefits

recent evidence is less supportive - instability presensent in many dogs
suture will break over time and relies on soft tissue healing
if P has cushing they don’t have fibrious laying down and it won’t work

CrCL - disease - TTA - objective of this sx

to neutralize the effects of crnail tibial thrust
the tibial tuberosity is osteotmized and advanced forward
the stiffule is redesigned and cranial tibial thrust is neutralized by placement of the patellar tendon perpendicular to the tibial plateau

during CrCL disease sx and you cut the bone that means it is what kind of sx and provides what kind of stabilization

it is a dynamic surgery and provides dynamic stabilization

CrCL - TTA sx - stabilization

dynamic
when weight bearing - stiffle is stable
when not weight bearing - cranial drawer may be palpable
Since it is dynamic the cranial cruciate ligament is not necessary for stiffle stabilizaiton and active wieght bearing

CrCL - TTA - clinical conerns/benefits

less evidence for efficacy - results appear similar to lateral suture
removal of any inected impalnts can be challenging

CrCL disease - TPLO sx - objectives

to neutralize the effects of cranial tibial thrust
the stiffle is redesigned and the cranial tibial thrust is neutralized by roating the tibial plateau to be “level”

CrCL disease - TPLO - stabilization

dynamic stabilization
when weight bearing - stable stiffle
when not weight bearing - cranial drawer may be palpable
after sx the CrCL is not necessary for stifle stabiliatoin under active weight beairng “dynamic stabilization”

TPLO - clinical concerns/Benefits

best evidence for efficacy - dogs use limb quickly after surgery
dogs indistringusihable from normal 6-12 months after sx

Caudal crucitae function

primary stabilizer agaisnt caudal drawe (caudal tibial subluxation) function with cranial crucitate ligament to - prevent internal rotation and prevent hyperextension

Caudal cruciate injury - prevalence, breeds, etiology, concurent injuries

Prevalence - rare in isolation
Breeds - any dogs
etiology - trauma (tibia expeirences blow to the cranial cortext forcing it caudally)
concurrent injuries - often combined with medial collateral/ crnail crucitate ligmaent injury

LA x-rays, marker is always placed

lateral or dorsal (the one depends on what x-rays you are doing)
if doing a side angle should always be lateral (lateral trumps dorsal)

Typical x-rays for fetlock in LA and what to lock for

LM, DP
proximal sesamiod bones (camera is angled down a little to evalute)
condyles, sagital ridge, condyles, sagitatal goove
also flexed LM (common for OCD)

4 common abnormalities in fetlock LA

OA, trauma/repetitive stress injuries, OCD, sesamodiitis

LA fetlock OA - s/s

fetlock joint effusion (variable)
lameness localized to the fetlock region (or joint)
degree of lameness variable

LA fetlock OA - readiographic signs

osteophytes, supracondylar lysis, soft tissue swelling, narrowed joint space (marked)

LA fetock OA - ostephophyte formation location

Dorsomedial and dorsolateral aspect of proximal P1
proximal and distal aspects of sesamoid bones
palmar processes of P1

What is wrong with these horses

Fetlock OA due to osteophyte formation

Feltock LA oA supracondylar lysis

bone resorption due to chronic effusion/synovitits
Normal A=B
abnormal A>B

LA fetlock - repetitive stress injuries etiology

sclerosis of carpal bone
- cyclic loading (additional bone laid down = sclerosis, bone beocmes less elastic and compromised bow flow, microfracutres = stress riser, predisposed to gross fracture)
- wolff’s law

LA fetlock subchondral bone cysts - etiology, x-ray, tx

etiology - likely traumatic (sit leison in cartilage, hydraulic theory)
x-rays - may need to take steeper DP to see in MC/MTIII, will be surrounded by sclerosis
Tx - surgical stabilizaiton (subchondral screw)

LA fetlock POD - x-rays s/s

sclerosis and flattening between P2 and P1
occurs in racehorses, maladaptive remodeling

LA fetlock POD - tx

rest, injection of the joint
if severe, significantly reduced athletic use

Dorsal P1 chip fractures - etiology and location

etiology - in TB racehores, trauma, hyperextension of fetlock, clinical significance variable
locaiton - most commonly dorsomedially in forelimbs

LA Dorsal P1 chip fracture - tx

arthroscopic removal

Palmar/Plantar P1 chip fracutres - etiology, location, tx

etiology - more common in hindlimbs of SB racehorese may be developmental or avulsion fracture
may need special x-ray to see
tx - arthroscopic removal

LA Metacarpal(tarsal) III condylar fractures - etilogy, x-rays, tx

etilogy - common in racehores
x-ray - medial tend to spiral and may ned special view
tx - surgical stabilization

LA - proximal sesamoid bone fractures - etiology, types, dx, tx

etiology - common race horse injruy
types - apical (proximal 1/3), midbody, basilar (distal 1/3)
dx - U/S to evalutate suspensory ligament
tx - surgical stabilization if large, treat the suspensory

LA fetlock OCD location

saggital ridge

LA fetlock sesamoiditis - dx

x-rays but also u/s suspensory branches

Metacarpus/tarsus - routine views and what can you see

LM, DP
MTII anda IV (split bone)
McIII/MTIII (canon bone)

no

no

Periostitis (bucked shins) - etiology, location

racehorses, stress remodeling in response to training, microfractures and subperiosteal hemorrhage leads to subperiosteal callus
can lead to stress fractures/saucer fractures
generally occurs in forelimbs

Metacarpus/tarsus LA stress fractures - etiology, location, x-rays, tx

racehorses in training (2-3), middle or distal 1/3rd of dorsal cortex, acute on chronic,
may need DMPLOS at various angles
may need bone scan to diagnose
tx - rest

Don’t confuses stress fractures with

nutritent formane
is in the proximal third of the bone and has uniform width and tube like apperance

Sequestrum LA metacarplas - locatoin, causes, x-rays

common in metacarpus/tarsus beucase of lack of soft tissue coverage
loss of periosteal blood supply, death of outer 1/3 cortex
takes 10-14 days to show up on rds
compotnets - squestrum (piece of bone), involucrum (lucent zone around bone), cloaca (may not have if early)S

Sequestrum tx

surgical removal of sequestrum

LA metacarpus/tarsus - split exostosis - s/s, location, tx

s/s - lamness when first occur, often indicdental ulness impinging on suspensory ligament
location - most common in medial splint bone in FLs
tx - non if not imping on suspensory, if they are shockwave, loca steroids helpful

Suspensory ligament - OR and INS

or - proximal third metacarpal/tarsal bone
INS - proximal sesamoid bones

lA Splint bone fractures - locaiton,etiology, dx, tx

common
proximal ½ - blunt trauma
distal - supensory injruy
dx - U/S suspensory
tx - rest, surgical removal/stabilziation

LA Carpal Pathology exam findings (4)

decreased ROM, pain during passive range of motion, effusion present on palpation, positive flexion exam

during a flexion test the carpus shoudl touch the

metacarpus

LA Osteoarthritis in carpus - begins as and progresses to, s/s on r-xray

beings as capsulitis, synoviits and when marked leads to medial collapse of joint with risk of fracture or lage osteophytes
s/s - osteophytes

LA Carpal Chip fractures - etiology, s/s, locaiton

Racehorses, secondary to hyperextension of carpus
s/S - acute lamness, occ crepitus, same as OA
location - raidal carpla bone, plamar translation (proximal row)

LA Carpal chip fractures are commonly found in what bone

radial carpal

lA Carpal slab fractures - etiology, location, S/s

racehores
locaiton - 3rd carpla bone, radial carpal bone, intermediate carpla bone
s/s - same as OA, occ crepitus, likely very reactive to flexion, x-ray BEFORE blocking

LA Carpal fractures - tx and prognosis

sx - remove the fragment, stabilize the fracture
sequela if you do nothing (OA)
prognoisis for athelets - good for small, chips, nondisplaced slap fractures if caught acutely, dependent on degree of cartilage damage

LA Carpal - catastrophic fractures - origin, tx

traumatic in origin
acute tx = stabilization - lateral/palmar splint
longer term stabilization - carpal arthrodeiss, performed for preservation of life

LA carpal hygromas - what is it, origin, s/s

isolated dorsal, fluctuant swelling over the carpus
synovial fistula = communicaiton between adjacent synovial strucutres (may appear as two separate areas of swelling)
traumatic in origin
horses may not be lame if no other pathology present

Carpal hygromas LA - dx, tx, prognosis

dx - u/s, contrast x-rays, arthroscopy
tx - antiinflammatories/bandaging early, surgical resection of hygroma, none
prognosis ofr athletic use - excellent, cosmetic issue

LA Carpal extensor tenosynovitis - what is it, location, origin, lameness?

acute or chronic flutuant swelling dorsal carpus
often at distal aspect of carpus/proximal metacarpus
traumatic in origin
horses usually sound

LA carpal extensor tenosynovitis - dx, tx, prognosis

dx - u/s, synoviocentesis if hx of wound
tx - local anti-inflammatories, sx (if septic), none
prognosis for atheltic use - excellent (cosmetic)

LA diseases of proximal forelimb (3)

ulnar/olecranon fractures, radial fractures, elbow/shoulder OA

LA ulnar/olecranon fractures - origin, s/s, dx

trauamtic in origin
acute, makred lameness, may have dropped elbow apperacne (due to lack of tricepts function w/ dispalced fractures), swelling/pain on palpation of the area
dx - radiographs, nuclear scintigraphy

LA Ulnar/olecranon fractures - tx, prognosis

tx - surgical repiar, strict stal rest (for non-displaced, non-articular fractures)
prognosis for athletic use - closed fracture (good if non articular), open fracutre (guarded due to high risk of infection)

LA radial fractures - origin, s/s, dx

traumatic in origin
S/S

Subsolar Abscess etiology

defect in sole/wall (microcrack, white line)
trauam (puncture, bruise)
environment (moisture, wet-dry condition)
trasnlocation of bacteria

Subsolar abscess - s/s

Acute severe lameness - lame at walk → non-weight bearing
single leg

What is the most common cause of severe lamness in equine

subsolar abscess

DDx for severe acute lameness in equine

Fractures/dislocation
sepsis (intrasynovial, celluitits)
severe soft tissue injury
laminitis

Subsolar abscess - dx

PE - increase digital pulse and hoof capsule temp, coronary band/heel bulb (swelling, painful, purulent discharge), hoof tester response
Visual exam, explore suspect area
± peri-neural ax (treatmetn), x-rays

Subsolar abscess - tx

main goal = drainage
facilitate ventral drainage (can rupture at coronary band)
foot bandage - hyperosmotic
tetanus prophylaxis can happen due to open foot wound - check vx status
± pain management and antibotics

Subsolar abscess - prognosis

Uncomplicated - good
involvement of other structures - depnds on what structures

Thrush -what is it, etiology, locaiton, environment

degerative keratolytic condition of the frog with specific etiologic agent is unknon (anaerobic)
sulci of frog (superficial tissues)
enviroment - poor foot care, stable hygiene

Thrush - s/s, ddx

none to minimal lameness, foul odor and discharge, 1 to multiple limbs
ddx - canker

Thrush - tx, prognosis

tx - routine cleaning/picking out hoof, topical tx - disinfectant, hardener, enviromental managment is key
prognosis - good recurrence

Canker - what is it, etiology,

Proliferative pododermatitis (epidermis and dermis) - frog central or collateral sulci (heel bulbs, sole, hoof wall, coronary band)
etiology - exact unknown, anaerobic bacteria, spirochete, bovine papillomavirus

Canker - predisposing factors, s/s

predisposing - poor hygeiene, enviromnet (warm/moist), breed
s/s - lameness (depends on severity), 1 to multi limbs, painful

Canker -ddx and dx

ddx - thrush, proud flesh
dx - presumptive, biopsy/histopath

Canker - tx

surgical debridemetn
topical therapy - antiseptic/antimicrobial, desiccating agents
hoof bandage
pain managemetn
environmental management

Canker - prognosis

inital - guarded with complete recovery possible
recurrence - enviromental factors

While line disease - what is it, etiology, can lead to

crumpling/decomposition of white line (separation of hoof wall)
etiology - unknown, anaerobic bacteria, fungi
1 or multible limbs
distal phalanx displacment possible

White line disease - s/s, ddx

incidental finding
lameness - debris->pressure, distal phalanx displacmetn (hoof wall pulls away)
ddx - abscess, laminits

White line disease - dx/tx

dx - soft/chalky horn, x-rays
tx - hoof wall resection, topical rx, hoof wall stabilization

White line disease - prognosis

fair to good - depends on extent of disease, distal phlanx displacmetn, hoof wall regrowth
recurrence

Hoof crakcs are classififed by

vertical or horizontal fissures, orientation, location, depth, length

Hoof cracks - predisposing factors, s/s

predisposing factors - hoof wall imbalance, trauma (coronary band), hoof quality, infrequent/poor trimming
s/s - visual exam, ± lameness

Hoof cracks - tx and prognosis

tx - id and treat underlying cause, stabilize crack, unload wall under crack
prognosis - depend on locaiton/depth/cause