osteoarthritis (Steve Darby) Flashcards
What is osteoarthritis?
degenerative disease
characterised by the progressive degeneration, destruction and erosion of articular cartilage
bone ends rub together
difference between OA and RA
OA is a degenerative disease -> RA is an autoimmune disease OA inflammation is minimal -> RA has imflammed synovial membrane OA is erosion of cartilage -> RA erosion of bone OA bone ends rub together -> RA they don't OA asymmetrical -> RA symmetrical
When is stiffness with OA?
morning stiffness lasting less than 30mins
joints most affected
knee
hip
hand/wrist
risk factors for OA
occupation (coal miners, golfers, footballers, rugby) bending of the knee kneeling squatting standing for long hrs (>2 per day) walking >3km per day regular stair climbing heavy lifting vibration
What chromosome is important for genetic linkage of OA?
chromosome 2q13-32
- includes the IL-1 gene cluster
- frizzles related protein (FRZB)
- cartilage structural protein matrilin-3 (MATN3)
What happens in early stages of OA?
cartilage develops irregularities at the surface where it becomes fibrillated
What happens as OA progresses?
- deep clefts form in cartilage
- loss aggrecan and type II collagen within the cartilage extracellular matrix (structural proteins)
- chondrocytes clump within cartilage surrounded by regions of intense staining material indicating increased proteoglycan
- ongoing cartilage damage, articular joint surface damaged, loss of joint fxn
MMPs
matrix metallo proteases
What leads to MMP production?
- increased mechanical insult (yrs of damage)
- chondrocytes release cytokines (IL1, TNF alpha)
- increases MMP production
What do MMPs do?
degrading enzymes
- breakdown extracellular matrix in tissues
- collagen destruction
- synovial cell irritation
Where do cartilage breakdown products go?
into synovial fluid
synovial cells ingest the breakdown products
What do synovial cells release?
proteinases and proinflammatory cytokines
these upregulate catabolic processes in synovial membrane and cartilage
What structural proteins are broken down in the cartilage?
collagen
proteoglycan
What are osteophytes?
bony spurs formed in OA
can limit space in the joint
pinch nerves
Where can osteophytes occur?
neck shoulder knee lower back fingers big toe foot/heel
OA symptoms
- clicking/cracking sounds in joints
- slow onset of symptoms
- mild swelling
- asymmetry
- stiffness
- pain in a joint (hip/knee/hands most common)
- bone spurs
- reduced flexibility (bending/stairs)
OA diagnosis
medical Hx
physical examination
x-ray/MRI
fluid aspiration (oculd be joint infection, crystals-gout)
primary OA
- no known cause (onset over time)
- idiopathic OA
- elderly
- most common
secondary OA
- linked to an existing disease (gout, haemochronatosis)
- congenital abnormality
- hormonal/inflammatory disorder (Acromegaly/Paget’s)
- joint injuries (not repaired correctly)
- younger patients
- less common
What approach is used for management of OA?
combined approach of
- non-pharmacological
- pharmacological
non-pharmacological management
exercise and manual therapy joint aids/supports TENS surgical joint replacement and arthroscopic lavage nutraceuticals
pharmacological management
- paracetamol
- NSAIDs
- capsaicin
- corticosteroids
- DMOADs (not on market)
main non-pharmacological management
weight loss - aerobic exercise - low impact - swimming/yoga muscle strengthening - joints - ligaments/tendons - stretching/physiotherapy
joint supports and examples
balance/shift load from affected joint/lessen impact knee braces shoe wedges insoles walking aids - frames, crutches, stick
What does TENS stand for?
transcutaneous electrical nerve stimulation
How do TENS work?
pads placed around the joint
pain signals can be blocked by electrical impulses from a TENS machine
non-invasive, fast acting and drug free
When would surgery be done?
- treatments are ineffective
- constant/high pain levels
- lack of joint movement
- joint destruction
- impacting QoL
3 types of surgery options
- joint fusing - make a joint fixed
- osteotomy - addition/removal of small bones
- whole joint replacement - prosthesis (hip/knee)
What are nutraceuticals?
dietary supplements
- glucosamine
- chondroitin
- S-adenosylmethionine
possible MOA of nutraceuticals
possibly stimulate chondrocytes
may inhibit cartilage enzyme activity (glucosamine sulfate)
What do chondrocytes do in healthy cartilage?
- produce structural components of cartilage
- > like collagen, proteoglycans, glycosaminoglycans
- structural component lossed in OA
What does NICE say about glucosamine or chondroitin products?
don’t offer them for OA management
hyaluronic acid for OA
injection
not recommended
-> thought to support elasticity of joints and help synovial fluid
1st line analgesics
paracetamol
ahead of NSAIDs
What to give if pain relief not sufficient with paracetamol?
combination with opiods
- co-codamol (codeine and paracetamol)
problems with giving opioids
additction potential
-> withdrawal strategies in place
2nd line drug therapy
NSAIDs
- topical considered over oral (ibuprofen or naproxen)
What to give if paracetamol/topical NSAIDs ineffective?
oral NSAID/COX-2 inhibitors
oral NSAID at lowest possible dose for shortedt period of time
considerations before starting on oral NSAIDs
CV risk
GI risk
renal risk
if thye’re on low dose aspirin (CV)
Treatment for gastric problems with NSAIDs
co-prescribe PPI
- omeprazole
- lansoprazole
- pantoprazole
- esomeprazole
What NSAID has lowest vascular risk?
naproxen
1st/2nd/3rd/4th line management of OA
1st - paracetamol
2nd - paracetamol with opioids
3rd - topical NSAIDs
4th - oral NSAIDs (PPI if GI problems)
What treatment can be given adjunct to NSAIDs esp for knee/hand OA?
capsaicin
What is capsaicin from?
chili peppers (analgesic properties)
How deos capsaicin work?
- repeated administration produces a desensitisation and an inactivation of sensory neurons
- binds to TRPV1 - transient receptor potential vanilloid 1
- NTs released when body feels heat
- use capsaicin, will feel burning/stinging sensation
- gives relief from pain of OA
What is TRPV1?
transient receptor potential vanilloid 1
ligand gates cation channel
selectively expressed in nerve fibres
When are intra-articular injections of corticosteroids given?
moderate to severe pain
examples of steroid used for intra-articular injections
hydrocortisone (most used)
dexamethasone
prednisolone
How often are intra-articular steroids given?
every 3 months
What injection is not recommended in UK?
hyaluronic acid
