Orthopaedics synovial joints Flashcards
What are three key components of the extracellular matrix in articular cartilage
Hyaluronan
Type II collagen
Fibronectin
What is synovial fluid made of
Plasma dialysate + supplementation of hyaluran from synovial fibroblasts + lubricin from chondrocytes
What inflammatory mediators are released from synovial macrophages/other inflammatory cells
IL-1beta
IL-6
TNF
PGE2
What are the 4 types of non-inflammatory joint disease
Degenerative joint disease
Neoplasia
Trauma
DOD (developmental orthopaedic disease)
How can we subclassify immunological joint diseases
Whether erosive or non-erosive
What are some immunological erosive joint disaeses
Rheumatoid arthritis
Periosteal proliferative polyarthritis
Mycoplasma
Feltys
What are some immunological non-erosive joint diseases
Idiopathic joint disease
Systemic lupus erythematosus
Polyarthritis-polymyositis
Is erosive or non-erosive immunological joint disease more common
Non-erosive
- Especially idiopathic
When is joint disease painful
When there is erosion of superficial cells down to subchondral bone which contains nociceptors
How can we classify joint defects by thickeness
Chondral/ partial thickness
= commonly get chondral injury secondary to ligament destruction
Osteochondral/full thickness
= commonly due to fracture
Why might we convert a partial thickness chondral defect to full thickness
To engage the bone marrow for fibrocartilagenous repair
Is primary or secondary degenerative joint disease more common in small animals
Secondary
Examples of secondary degenerative joint disease
Congenital e.g achondroplasia
Developmental e.g osteochondrosis, hip/elbow dyspasia
Acquired e.g traumatic, CCL rupture
What are some acquired causes of degenerative joint disease
Trauma
Cranial cruciate or other ligament rupture
Non-immunological causes of non-infectious inflammatory joint disease
Crystal induced
Haemarthrosis where blood enters joint and has negative effects on the cartilage
Where are we more likely to see haematogenous spread of bacteria to joints
Large breed dogs with established DJD
Or dogs with joint replacements
Septic joint presentation
Sudden onset severe lameness
Painful, hot, swollen joint
Generally just a single joint affected
Early and chronic radiographic changes with septic joint
Soft tissue swelling, joint effusion
–> Chronic changes = cartilage loss, periosteal bone formation, osteolysis that may cross joint
What does osteolysis that crosses the joint surface suggest about the cause
Much more likely to be an infection rather than tumour
What is the best way to do bacterial isolation from synovial fluid
Synovial fluid inoculated into blood culture is best
Then synovial membrane
Then worst is direct culture
Changes in synovial fluid with septic joint
Increased volume
Turbid fluid
Decreased viscosity
High cell count with ~80% neutrophils (degenerate)
Changes in synovial fluid with DJD
Normal looking fluid (clear/straw)
May be slightly increased in volume
Slightly raised cell counts; monocytes
Synovial fluid characteristics in idiopathic joint disease or SLE
Clear/straw
Increased volume
Decreased viscosity
Increased cell counts with high proportion neutrophils (degenerate)
Synovial fluid characteristics with rheumatoid arthritis
Yellow/cloudy fluid
Increased volume
Decreased viscosity
Increased cell counts, 85% neutrophils
Synovial fluid characteristics with trauma to the joint
Haemorrhagic or xanthochromic colour fluid
Increased volume
Normal or reduced viscotiy
Variable cell counts with high % red blood cells
Normal synovial fluid volume in a joint + characteristics
0.1 - 0.5ml
Clear/straw colour
Normal viscosity
1-3 x10^9/L monocytes mostly
How to treat a joint infection
Flush and give antibiotics
May need debridment and lavage, especially with post-surgical septic joints to remove implants
Can do local antibiotics with depot preparation
What is the signalment for rheumatoid arthritis
Small and toy breed dogs
Typically affects lower joints i.e carpus, tarsus, digits
Presentation of RA
Collapse or joint deformity
May have secondary CCL rupture
Can have systemic signs e.g fever
Diagnostic criteria for rheumatoid arthritis
2 out of:
> Destructive lesions on radiograph
> Serological evidence of rheumatoid factor
> Characteristic synovial membrane histology
> Other radiography characteristics (subchondral erosions, soft tissue swelling, osteopaenia in chronic disuse, joint deformity or laxity)
Rheumatoid factor serology characteristics
Not specific since there is cross reactivity with other chronic inflammatory disease
Strong positive titre of >1:40 is suggestive of RA but a negative titre doesn’t rule it out
Treatment of rheumatoid arthritis
NSAIDs, steroids, immunosuppression
May not always need drugs since the disease waxes and wanes
+ may need surgical stabilisation if there is subluxation of cranial cruciate disease
What is systemic lupud erythematosus and what is the signalment
Inflammatory immune-mediated non-erosive disease
Associated with multi-organ disease
More common in females
More common in GSDs, afghans, irish setter, old english sheepdog
CLinical signs of SLE
Most cases have shifting arthritis so appear stiff
+ disease often phasic
Associated with multi-organ disease e.g skin, GI, UG, AIHA, ITP
Diagnostic criteria for SLE
Must meet all:
- Strong titre >1:64 of serum anti-nuclear antigen
- Involvement of more than 1 organ system
- Demonstrable immunopathology e.g anti-platelet Ab or positive Coombs test
What might we see on the bloods of a dog with SLE
Anaemia
Leukopenia
Thrombocytopaenia
Treatment of SLE
Corticosteroids
+ can add in immunosuppressants e.g azathioprine, cyclophosphamide, cyclosporine
What is the most common inflammatory joint disease
Immune-mediated polyarthritis
What are the 4 types of immune-complex polyarthritis hypersensitivities
1 = uncomplicated
2 = associated with a remote infection e.g pyo
3 = associated with GI tract disease
4 = associated with neoplasia
Signalment for immune mediated polyarthritis
Young adults especially spaniels and shelties
History and clinical signs of immune mediated polyarthritis
Waxing and waning lameness, stiff animal
Distal small joints are swollen and painful
Diagnostic tests for immune mediated polyarthritis
On X ray see effusion/soft tissue thickening but no joint degeneration
Image thorax and abdomen to rule out GI (type 3) and neoplasia (4)
On arthrocentesis see increased cellularity esp of neutrophils
Treatment of immune mediated polyarthritis
Treat underlying cause if present
Immunosuppression; tapening prednisolone over 2-6 months; tapening azathioprine/cyclophosphamide
50% achieve remission
What breeds can sulphonamides cause non-erosive arthritis
Dobermans
Weimeraners
What vaccine can cause arthritis as a reaction
Feline calicivirus vaccine
Which species have age-related wear and tear in DJD
Humans and cats
How does rupture of CCL affect joint lubrication
Doubles the coefficient of friction so get increased heat and damage to cells causing further cartilage degeneration
Radiographical features of degenerative joint disease
Joint space narrowing
Osteophyte formation
Enthesophyte formation
Subchondral sclerosis
Summary of medical/conservative management of DJD
- Weight loss
- Rehab
- Neutraceuticals e.g omega-3 fatty acis, glucosamne, chondroitin, green-lipped mussel
- Chondroprotectants
- NSAIDs
- Anti-NGF
What chondroprotectants might we use when managing DJD
- Hyaluronic acid; for viscosupplementation in synovitis and early DJD
PSGAGs to reduce PG degradation and MMP synthesis
What are the surgical mangement options for DJD
Consider for severe non-medically responsive disease
- Osteotomy
- Arthrodesis
- Joint replacement
What is platelet rich plasma and how is it useful in DJD
Autologous concentrated platelets
REleases reparative products e.g PDGF, VEGF, FGF-2, TGF-beta
What are the risks with NSAID use
GI disease
REnal disease
What are librela and solensia
Monoclonal antibodies to nerve growth factor
WHat things can make a dog non weight bearing lame
Neoplasia
Infection
Fracture
Ligament rupture
