MSK 2 Flashcards
aggressive bone lesions are typcially the result of
neoplasia or osteomyelitis
list a few examples of nonaggressive bone lesions
osteoma, cartilaginous exostoses, enthesophytosis
what are some ways to differentiate between nonaggressive and aggresive bone lesions?
- bone lysis
- periosteal reaction
- cortical integrity
- zone of transition
if there is bone lysis present, what does this tell you about the type of bone lesion?
bone lysis usually happens with aggressive processes and suggests there is more bone destruction and prouction, HOWEVER, lysis does not always associated with an aggressive lesions
characterize the following into aggressive or nonaggressive bone lesions:
- cortical destruction
- periosteal reaction
- zone of transition
aggressive: cortical destruction, periosteal reaction is not smooth, zone of transition is not distinct
nonaggressive: no cortical destruction, no periosteal reaction, zone of transition is sharp
what 3 things classify an aggressive bone lesion?
- cortical destruction
- periosteal reaction
- non distinct/long zone of transition
what 3 things classify a non aggressive bone lesion?
- no cortical destruction
- no periosteal reaction
- sharp zone of transition
what are the 3 types of bone lysis?
- geographic
- moth eaten
- permiative
what is the most aggressive type of lysis, and what is the least aggressive?
geographic<moth eaten<permiative
what does geographic bone lysis look like?
- margins are well defined with clear demarcation of the adjacent normal bone
what kind of bone lysis is this and why? is this an aggressive or non aggressive bone lesion?
geographic: can see the well defined margins and you can easily tell the lytic bone from the adjacent normal bone. this is a subchondral bone cyst
a non aggressive bone lesion
what is the pathology seen here?
a sunchondral bone cyst, can see a little circle of radiolucency in the subchondral bone on the medial chondyle
subchondral cysts are seen in horses of what age? what joint are they most common in? What is their classic location?
- seen in horses of any age
- usually the stifle but can be any joint
- seen most commonly in the weight bearing area of the medial femoral chondyle
what pathology is seen here?
a subchondral bone cyst. can see a round area of radiolucency on the medial chondyle
when would you see an INCREASE in the OPACITY of subchodnral bone?
with benign joint disease such as:
- degenerative joint disease
- sunchondral sclerosis seconday to chronic stress remodelling (like elbow dysplasia)
what type of bone lysis is seen here?
moth eaten lysis, can see multiple small geographic areas of lysis
what are some characteristic of permeative bone lysis?
- it is not well defined
- a long zone of transition to normal bone
what kind of bone lysis is this?
permeative. can see it is poorly defined and has a long zone of transition
a long zone of transition is associated with…
more aggressive bone diseases
what is a “periosteal reaction?”
- when the periosteum is proliferating and mineralizing in response to normal bone injury and healing
- the type of periosteal reaction you see happening can help you differentiate between aggressive vs non aggressive lesions
if the rate of bone destruction outweighs the rate of periosteal proliferation then…
you’ll see varying amounts of an abnormal periosteal bone response
in general, the more solid and smoothly marginated the periosteal reaction…
the less aggressive the bone lesion
why is it important to lassify the most aggressive periosteal response seen on a bone lesion?
because over time, a once aggressive lesion can look more normal and could appear non aggressive
what are the 5 kinds of periosteal reaction in order from least aggressive to most aggressive?
- solid
- lamellated/onion skin
- columnar/palisading
- star burst
- amorphus
mneumonic: some lions can swin anywhere
true or false: with a solid periosteal reaction, periosteal proliferation and mineralization far outweighs osteoclastic/resorptive activity
true
what kind of periosteal reaction is happening here?
solid
what is codmans triangle?
the mineralization of fibers underneath the periosteam where the periosteam cannot keep up with the level of bone destruction happening underneath of it
what type of periosteal reaction is this?
palisading. there is a strong periosteal response but no cortical destruction, and the perisoteum is not projecting outwards from the bone either. this is hypertrophic osteopathy.
what is hypertrophic osteopathy? what is it associated with?
generalized overproduction of the periosteum affecting the long bones of the extremities. it is associated with pulmonary neoplasia as well as non neoplastic lesions in the thorax and abdomen. HOWEVER it is not a neoplastic disease of the bone, aka, it is NOT metastatic disease!
what kind of periosteal reaction is this?
sunburst (he also said some palisading in here too but….honestly idk)
what kind of periosteal reaction is this?
amorphus: not defined, no structure, cortical destruction, bad news!!!
which is normal and which is abormal. what do you see here?
the one on the left is normal with a nice fat pad in the joint which appears more radiolucent than soft tissue orfluid. in the one on the right, there is joint effusion as seen by the increase in opacity where the fat pad should normally be, and the fat pad is displaced cranially.
it can be difficult to identify cruciate ligament injuy sometimes. What is sometimes the only radiographic finding?
joint fluid/effusion
other than joint effusion, what are some other radiographic signs of cruciate lig injury?
osteophyte formation and cranial displacement of the tibia
true or false: you can diagnose cruciate ligament injury based on radiographs.
false! you need to correlate findings with the physical exam of the patient, it is usually not a radiographic diagnosis
what are two general categories that can cause a decreased subchondral bone opacity?
osteochondrosis, inflammatory joint disease
briefly describe what osteochondrosis is
derrangement in endochondral ossification, leading to focal necrosis and ischemia, leading to chondromalacia. this soft bone can’t support the cartilage. This forms flaps and even joint mice
if you suspect osteochondrosis and when you take a radiograph you don’t see any areas of lucency in the sunchondal bone, can you exclude this disease?
no! just because there’s not a lucency doesn’t mean they don’t have it! remember, cartilage is mostly water, so the only way you’ll see this disease on rads is if the bone is moving WITH the cartilage!
osteochondrosis is common in
young growing large breed dogs and horses
what disease process is this?
osteochondrosis
septic arthritis often happens after…
a traumatic injury, or with vascular emboli via hematogenous spread
septic arthritis, if culture and sensitivity/arthrocentesis fails, you should…
take radiographs!!
what radiographic things will you see with septic arthritis?
- early on it will look normal
- narrowing of the joint space–>loss of bone and cartilage integrity
- soft tissue thickening and effusion OR effusion in the joint
- subchondral bone lysis
- gas may be present but this is rare
what pathology is seen here?
little gas bubbles near the joints–>septic arthritis!
what pathology is seen here? what periosteal response is this? if this were a horse, what would I be concerned about?
- sepatic arthritis in a cow
- cows have a very aggressive osseous response to DJD as well as septic arthritis, as seen in this case
- strong destructive/lytic and productive response seen in the distal interphalangeal joint
- this is a palisading periosteal reaction
- if this were a horse I would be worried about degernative joint disease
what is navicular disease?
a chronic progressive syndroe involving the navicular bone as well as many other structures in the foot. the precise souce of pain in navicular lameness is not known, and we think it is a biomechanical cause, not a vascular problem.
accoding to the textbook what are the 3 types of bone lysis?
Geographic: well defined
Moth eaten: smaller foci of bone lysis
Permeative: pinpoint lytic foci
true or false: rather than focusing on geographic, moth eaten, or permeative bone lysis, it’s better to focus on cortical integrity and the periosteal reaction to identify an aggressive bone lesion
true, the textbook says this
_______is the clue that the periosteal reaction is active
The presence of an irregular margin of the periosteum
the transition zone is evaluated where?
The transition zone is typically evaluated in the MEDULLARY CAVITY of the bone
true or false: a codmans triangle is usually associated with non aggressive lesions
false! it is associated with aggressive lesions
