Lecture 2-3 1/24-27/25 Flashcards
What are the layers within a normal joint?
-articular cartilage
-subchondral plate
-cancellous bone
Why is it important that the chondrocytes change orientation within the articular cartilage?
-parallel chondrocytes on the surface help to resist shearing
-more vertical chondrocytes deeper in the cartilage allow for compression
What is the tide mark?
line differentiating more superficial non-calcified cartilage from deeper calcified cartilage
What are the components of a normal hip joint?
-joint capsule
-synovial lining layer
-acetabular fossa
-ligament of the head of the femur
What are the layers of the cartilage?
-non-calcified:
–articular surface
–zone 1
–zone 2
–zone 3
-tide mark
-calcified:
–zone 4
–osteochondral junction
-subchondral bone plate
What is released when proteoglycan breaks down?
chondroitin sulfate
What is cartilage loading?
when weight/pressure is applied to the cartilage, water is “squeezed” to the surface and the matrix is compressed
What absorbs water during cartilage unloading?
glycosaminoglycans
Which molecule is unique to articular cartilage?
type 2 collagen fibrils
What is the overall function of articular cartilage?
to provide a low friction system that helps resist abnormal wear
What is arthritis?
inflammation of the joint(s)
What are the common clinical presentations for arthritis?
-lameness
-difficulty ambulating
-decreased activity
What are the common clinical findings in arthritis?
-lameness
-joint effusion
-stiffness
-decreased activity
-decreased joint range of motion
-muscle atrophy
What are the clinical findings associated with inflammatory or septic arthritis?
-fever
-lethargy
-inappetence
-other systemic signs
Which conditions are considered non-inflammatory joint disorders?
-osteoarthritis/degenerative joint disease
-traumatic injury
-neoplasia
Which conditions are considered inflammatory joint disorders?
-non-infectious, immune mediated disorders
–erosive
–non-erosive
-infectious arthritis
What is the general diagnostic approach for arthritic patients?
-history
-physical and orthopedic examinations
-radiographs (before more invasive procedures)
-arthrocentesis
-CBC/serum chem/UA
-serologic testing for tick-borne disease
What is the technique for an arthrocentesis?
-clip and prep the area
-insert a 21g needle into the joint
-allow fluid to drip into a purple top/EDTA tube
-use syringe if necessary to aspirate fluid; increases red cell contamination
What are the characteristics of a normal arthrocentesis fluid?
-transparent
-very high viscosity
-low WBC count
-low PMNs/neutrophils
-high mononuclear cells
-healthy cells
What are the characteristics of an OA arthrocentesis fluid?
-transparent
-high viscosity
-lower WBC count
-low PMNs/neutrophils
-high mononuclear cells
-healthy cells
What are the characteristics of an erosive immune-mediated arthrocentesis fluid?
-clear or opaque
-low viscosity
-moderate WBC count
-moderate to high PMNs/neutrophils
-moderate to high mononuclear cells
-mainly healthy cells
What are the characteristics of a non-erosive immune-mediated arthrocentesis fluid?
-clear or opaque
-very low viscosity
-moderate to high WBC count
-moderate to high PMNs/neutrophils
-low to high mononuclear cells
-mainly healthy cells
What are the characteristics of a bacterial arthrocentesis fluid?
-opaque
-very low viscosity
-high WBC count
-high PMNs/neutrophils
-low mononuclear cells
-degenerate cells
What are the characteristics of osteoarthritis?
-changes that occur in all aspects of the “joint organ”
-synovitis leads to pain and sensitized nociceptors
-progressive degenerative changes lead to decreased structure and function of the cartilage and atrophy of articular tissues