Week 4 - Pathology of Joints Flashcards
Articulations or joints are formed when ____ or ____ bones are united by _____, _____ or ______ tissues or by a combination of these tissues.
two, more, fibrous, elastic, cartilaginous
Fibrous joints (_________): Bones are united by _____ tissue.
synarthroses, fibrous
Examples of fibrous joints include?
joints between cranial bones; joints between the teeth and alveolar bone
In addition to sutures on top of head
Cartilaginous joints (________): Bones are united by _____ cartilage (e.g., _______ joints) or _____ (____ and ______ symphyses, intervertebral joints).
Amphiarthroses, hyaline, costochondral, fibrocartilage, pelvic, mandibular
Synovial Joints (____ joints or ______): Unite ____ bone ends covered by ______ articular cartilage. An ________ capsule surrounds a cavity filled with _____ fluid.
True, Diarthroses, two, hyaline, articular, synovial
Label the diagram accordingly
Bone ends covered by articular cartilage. Cavity is filled with synovial fluid produced by synovial membrane. Orange = synovial membrane with synovites that produce this material; also acts as nutrients to provide nutrition to articular cartilage. Synovial joints are enclosed by CT capsule. The joint is also fixed with ligaments containing fibrocartilage, etc.
Old or young animal? Older b/c we do not see the physis, growth plate b/c already closed.
Most common joint lesions in domestic animals involve ?
synovial (diarthrodial) joints
Injury to articular cartilage results in _______ (fraying), _____ or “Joint ___” formation
fibrillation, eburnation, mice
Subchondral bone and on top is the articular cartilage made of hyaline cartilage. Regenerative capability is very low b/c no true perichondral? in there. dots = Chondrocytes in lacunae surrounded by matrix.
Fibrillation = color of articular cartilage that is usually bluish-white under normal circumstances in young animals. But in the case of fibri –> erosion of articular cartilage -> fibrillar gross appearance due to proteolycan, glycans and exposure of cartilage. No longer shiny, but rather yellowish in color and is more granular or fibrular. This is indicative that there is some damage of articular cartilage.
Eburnation: Eventually, if the lesion is more severe, end up with ulceration of articular cartilage. Color appears to be more intense due to increased density of the subchondral bone in an area of ulceration in the cartilage. Subchondral gets thicker because there is no nerve endings in articular cartilage aka no pain and even in cases of fibrillation when there is erosion, however, when eburnation happens, bone and bone starts touching each other and bone contains a lot of nerve terminals so chronic osteoarthritis is associated with that.
Left to Right
Articular cartilage is normal
Ridges = fibrillation of articular cartilage due to some degree of erosion
Clean = Focal eburnation of joint.
________ formation may be a sequel of chronic joint injury. _______ doesn’t matter whether traumatic or developmental defect that lead to increased _______ of joint, these changes you will see are _________ of the cause.
Cartilage is abnormal; more _________ and not very ______ and _____.
Increased _______ –> stimulation of _________ margin = boundary between _____ cartilage and _______ of the bone. In this area, increased mobility produces stimulated ________ and produces bone -> ______ formation -> _______ proliferation of bone covered by a little bit of _______. _________ of joint capsule, which is usually more ________, but in this image it is very ____ due to chronic ________ due to deposition of collagen, etc.
Osteophyte, Etiology, mobility, independent, granular, smooth, shiny, mobility, chondroosteose, articular, periosteum, periosteum, osteophyte, nodular, cartilage, Thickening, membranous, thick, inflammation
E.g. hip joint of a dog.
Villous hypertrophy/ hyperplasia of the synovial membrane is other manifestation of chronic joint injury.
Finger proliferations of the synovial membrane in a case of severe chronic joint injury.
Synovial membrane is usually very thin and translucent, but in cases of chronic damage you can appreciate villous hypertrophy due to chronic inflammation and proliferation of inflammatory cells.
Loss of articular cartilage on head of femur here.
Evidence of ebrunation in joint.
______ formation – another possible sequel to chronic joint injury
Pannus
Pannus is a ______ (granulation) and ______ tissue that develops within the ______ membrane at its junction with the ______ and
cartilage margins (_______ zone) and can spread over the articular surfaces as a ______ membrane.
fibrovascular, histiocytic, synovial, periosteum, transitional, velvety
Develops at margins of synovial membrane.
May have severe joint injury, traumatic, infectious, leading to damage to cartilage and expose subchondral bone -> fibrobascular tissue proliferation and tries to almost repair areas of injury. Mmeb raneous tissue inside the joint represents pannus formation.
Anchylosis can result due ot proliferation of pannus formation?
Inflammatory cells within the pannus along with _______ from synovial fibroblasts may further damage the articular cartilage and lead to _______
(?) of the joint.
collagenases, ankylosis, fixation
New vascularization
Presence of inflammatory cells producing proteases and other enzymes that will increase damage already present in affected joint.
“End-stage Joint” is a generic term to describe a ?
joint with severe chronic injury.
In cases of End-stage joint, affected joints exhibit ______ degrees of damage to the articular cartilage, _______, _____ and _____ formation, capsular _____, synovial villous _____/ ______ and occasional ______ (fixation, immobility).
variable, deformation, osteophyte, pannus, fibrosis, hypertrophy, hyperplasia, ankylosis
Osteochondrosis (Dyschondroplasia) is characterized by ?
abnormal growth and maturation of the articular cartilage
Relatively common condition in young domestic animals, especially common in swine, young horses, poultry, and large breed dogs
What is a common sequel of Osteochondrosis (Dyschondroplasia)?
Severe degenerative joint disease is a common sequel
Osteochondrosis (Dyschondroplasia) is the most common cause of _______ in domestic animals, especially ?
lameness, swine, horses, poultry and large breed dogs
Animals growing rapidly
Osteochondrosis (Dyschondroplasia)
Pathogenesis is ?
multifactorial but poorly understood
nutrient deficiency plays a role; main change is ischemic damage to the cartilage and the subchondral bone in many cases.
Osteochondrosis (Dyschondroplasia)
Whatever the underlying cause is, ______ damage to the _______ cartilage seems to play a significant role
ischemic, growing
Osteochondrosis (Dyschondroplasia)
In rapidly growing pigs the incidence may reach close to ____% in the herd. Maybe only ____% are presenting clinical signs.
100, 30
Several animals in herd present lameness, must think that this is a possibility.
Osteochondrosis/ Osteochondritis Dissecans (OCD) [sub condition of Osteochondrosis]
Specific form of osteochondrosis characterized by the _______ of a piece (____) of articular cartilage from the ______ bone.
separation, flap, subchondral
May see some degenrative changes in cartilage, but classicaly there is a separation from subchondral bone.
Osteochondrosis/ Osteochondritis Dissecans (OCD)
In dogs lesions are more common in ______ ___-growing males of ____ and ____ breeds and affect primarily the ______ and _____ joints.
young, fast, large, giant, shoulder, elbow
OCD is an important disease of horses and common cause of lameness in young animals. In horses, OCD lesions can be widespread but the stifle, hock, fetlock joints (hindlimb) are commonly affected sites.
Osteochondrosis/ Osteochondritis Dissecans (OCD)
Lesions in the ____ joint form part of the “_____ _____ syndrome” which also includes ______ _____ process and fragmented (or ____) _____ ________ process of the ___; important orthopedic conditions in young dogs.
elbow, elbow dysplasia, ununited anconeal, ununited, medial coronoid, ulna
OCD is an important disease of _____ and a common cause of ______ in ____ animals.
horses, lameness, young
In horses OCD lesions can be widespread but the ____, ____ and ____ joints are commonly affected sites.
stifle, hock, fetlock
OCD lesions in dogs. Humeral head
Focal area of ulceration of cartilage/ebrunation eventually.
Osteochondris and ostrochondrosis dissecans
OCD lesions in dogs. Humeral head
This flap of cartilage broke off and got into synovial cavity. They become what is called joint mice that you can see in US or you can do radiographs and see pieces of cartilage that remain in synovial cavity and increase in size because of synovial fluid contains neutrons? so cartilage can survive in there.
Dogs = shoulder joint is one that is affected.
Distal femur - horse
Femular trochlea with the ridges, blue in the enter.
Focal areas of ulceration, loss of cartilage in trochlea. Changes in color of articular cartilage around tere beause early stages of formation in one of these flaps.
When we talk about osteochondrosis and OCD, change is not only affecting articular catilage but alos subchondral bone; multifactoral but probably ischemic damage ot subchondral bone.
Shape of bone can change as well.
________ bet articular cartilage and subchondral bone that will eventually form the ____ (arrows) -> formation of typical ____ of _______ _____.
Thickness of articular cartilage should be ______.
Cavitations, flap, flap, osteochondritis dissecans, uniform
OCD lesion, distal femur, lateral ridge, horse, UCVM – 2009
Trochlea looks a bit abnormal; lesion of OCD, flap broke off due to joint mice. A bit of cartilage may be present in areas of cartilage ulceration. noduler areas of cartilage that tend of regenerate these areas but are unsuccessful.
OCD lesion, distal femur, lateral ridge, horse, UCVM – 2009
Note abnormal growth of the articular cartilage and subchondral bone
resulting in deformation of the trocheal groove and ridges, OI.
Collapse of the articular surface in a pig with osteochondrosis,
Pig, femoral head
Folds are articular cartilage into the bone underneath.
Right: normal femoral head, pig
Roung ligament fo femoral head seen through perforation.
Osteochondrosis, pigs, UCVM, OI. The many small Cartilage nodules (top image) represent regenerative attempts at repair.
Fingerlike projections of ? membrane.
Cartilage nodules representing not very successful regenerative attempts of articular cartilage.
Osteochondrosis in pigs
Articular cartilage is unhealthy; looks raphint, not very smooth due to fibrillation.
See flap on left
CT capsule of joint is thickened.
normally femoral head is rounder; in this case it is flat, suggesting a lack of conformity.
Erosion of articular cartilage and eventually leads to areas of ulceration where you can underlying subchondral bone.
Osteosclerosis or thickening of subchondral bone.
Very few areas where cartilage is normal here.
Yellowish discoloration
Surface looks rafant due to fibrillation
Typcal appearance of an area of ebrunation.
Ulcertaion of articular cartilage -> eentually have subchondral bone that aquires very shiny, smooth, ivory like appearance.
synovial membrane is very prominent.
DJD –Hip Joint, Aged German Shepherd
Atlantic veterinary College (AVC)
What can be seen here?
Hansen’s type I (B) and type II (A) IDD
Gray = nucleus proposis
Two form of IDD =
B = more severe one; extrusion of nucleus proposis into the intervertebral canal. More seen in chondrodystophic breeds, such as daschund’s. Can be playing around and all of a sudden develop acute signs. Rupture of anulous fibrosis and extrusion of material into the spinal canal. Sometimes it can hit the spinal chord and produce more severe ischemic lesions in the spinal chord.
A = degeneration of anulous fibrosis –> progressive protrusion of IDD into the spinal canal. Protrusion is also called Hansen’s Type 2. Common in dogs aging –> degenerative change in IDD –> lesions.
Type 1 is More common in chondrodystrophic breeds.
1 - extrusion
2 - protrusion
IDD - Dog
Take out vertebral column and pass saw down the middle to examine IDD.
Examine fibrocartilage
Upward curve = protrusion –> compression of spinal chord.
Can be relatively slow and progressive -> ataxia, paresis
Radiograhically can make diagnossi of IDD. Measure space between vertebral bodies. If those spaces are uneven, aka area of degeneration, space may have collapsed -> indication of IDD. In many cases, when you see this lesion, mineralization has occurred.
Spinal chord may be soft due to malacia.
Clinical signs will vary between animals.
Spondylosis deformans, 20 year-old donkey, TAMU
Wider line –> space between IDD is more narrow, lesions of spondylosis/spondylosis deformans on the bottom (bone proliferation –> fixation).
Fusion of dorssalspinus processes on top. Can result in neuro problems –> compression of spinal nerves when exiting from formaina.
Osteosclerosis of vertebral body; normally cancellous bone in vertebrae but sometimes?
Ankylosing spondylosis – aged bull, Cornell Show and Tell, Dr. King
Macerated and bleached bone specimen.
- Bone has been bleached
- vertebra bodies on right are fused together which isn characteristic of spondylosis.
- lateral area = osteophyte formation and fixation.
- very common in bulls, especially those use for artificial insemination.
- if there is no mobility in vertebra —> pathological fracture?
Age related osteoarthropathy
In last few years, noticed change in the vertebral column in the lumbar region -> Lordosis
Ventral deviation of vertebral column
Losing weight b/c complete attrition of the teeth, chronic diarrhea, became lame
Eventually euthanized
Lumbar segment of vertebral column, Intervertebral disk disease (IDD)
Leading to sub-luxation of L3-L4 and spondylosis deformans
- IDD to the left is normal, but the other three are not. Lead to increased instability and mobility.
- circle = osteophyte proliferation in ventral surface trying to compensate for increased mobility in the area.
Periosteum in these areas –> ? - neuro exam on horse = horse was ataxic
Ringbone
Ring bone, horse – Vet Path Museum, University of Liverpool
Common in horses used in rodeo events (barrel racing) or Polo –> chronic trauma: the result of abrupt stops, turns and twists
Degenerative disease in horses affecting the inter-phalangeal joints (2ry DJD)
injury to interphalangeal oints –> formation of ostephytes in the joints of third and ssecond phalynx aka the coffin joint and the first and the second phalynx too
sometimes osteophytes wrpa around tendons, tensors and flexors, of legs.
Horses are predisposed to chronic degenerative joint disease.
PAstern joint bet p1 and p 2 is hwere you can develop osteophytes and ring bone.
Changes between p2 and p3= osteophyte in coffin joint.
Inflammatory Joint Disease
Route of Infection
joint taps –> not careful in cleaning needles –> carry infection into a joint
5 = lcoal damage = produce area of septic arthertiis (more common in farm animals in calves, lambs, foals, pigs) nd very often associated in cases of neonatal sepsis. young arm animals are susceptible to developing abcteremia and speticimea and can loocaloize in synovial mebrane –> septic artehrtiis. Can arrive in bone and prpduce osteomyelitis.
- Hematogenous spreading
- Bacteria cirucolating in blood –> osteomyleitis
- oriign of infection in metaphysis but eventually suppurativ e exudate and proteolytic enzymes that lyse the tissue, inflammatory process spreads into synovial cavity and produce aseptic artheritis. - Inflammatory process around a joint can also extend into the joint and produce artheritis.
Arthertisi? more common in dogs and cats
When we help in the birth of these animals, we eed to properly disinfect instruments so is not source of bacteremia.
Several joints can be swollen becuase filled wit suppurative exudate. Lesions are called polyarthertiis because not just one joint is affected.
Horse legs on right = hock joint is very swollen in comparison to the left leg.
Usually in foals see septic arthertis between birth and they are around 7 months of age. can be very painful for these animals, have problems such as lameness, pain, etc.
Common bacteria isolated from septic arthritis
e. rhusiopathiae –> associated with diamond skin
