Osteoarthritis Flashcards
Definition
Wear and tear condition in the joint
Chronic joint disorder in which there is progressive softening and disintegration of articular cartilage accompanied by new growth of cartilage and bone (osteophytes)
Cause
Cartilage ageing does occur, resulting in splitting and flaking of the surface, but these changes are not progressive and they do not cause symptomatic arthritis
Epidemiology
Age
May take many years to develop
Risk factors
Obesity
Age
Occupation
Family history
Trauma
Clinical presentation
Might have a history of injury to the joint
Pain starts insidiously and increases slowly over months or years
Aggravated by exertion and relieved by rest, although with time relief is less and less complete
Pain, swelling and stiffness of joint affected
Joint may become unstable
Unrelated to systemic manifestations like RA
Stiffness worse after periods of rest
Morning stiffness for up to 30 mins
Crepitus may be present
Pathology
OA result of active, sometimes inflammatory but potentially reparative processes
Not necessarily result of trauma or ageing
Progressive destruction and loss of cartilage
Exposed subchondral bone becomes sclerotic
With increased vascularity and cyst formation
Body attempts to repair with cartilaginous growths which later become calcified (known as osteophytes)
Epidemiology
Worldwide disease, uncommon in the black population
2:1 woman to man ration of getting disease
Familial tendency
Increases in age, esp over 50
Hand involvement
DIP’s affected (look for herberdens nodes)
PIP’s affected (look for bouchards nodes)
Squaring at the base of the thumb at the carbo-metacarpal joint
Weak grip
Reduced range of motion
Examination
Deformity of bone and enlargement of joints may be obvious
PROM crepitus
Hard end feel and restricted ROM
Muscle wasting
Differential diagnosis
RA
Psoriatic arthritis
Gout
Reactive arthritis
Septic arthritis
Investigations
X-rays:
– L- loss of joint space
– O- osteophyte formation
– S- Subchondral sclerosis (increased density of the bone along the joint line)
– S- subchondral cysts (fluid-filled holes in the bone, aka geodes)
MRI:
– early cartilage changes
Arthroscopy:
– surface erosion of the cartilage
Treatment
No cure for OA, over time it is just going to get worse, however there are ways off managing it better.
Pain relief medicines:
– paracetamol
– NSAIDS
– Opioids (codeine), help relieve severe pain, stronger than paracetamol
– Capsaicin cream (block nerves that send pain messages in the treated area).
– steroid injections (can ease pain for several weeks or months)
– manual therapy:
– to increase mobility
Education:
– education on loosing weight
– exercise, making sure they are doing the right kind, and when to rest
– what drugs to and to not take
– hot and cold therapy
Surgery:
– if destruction of the knee is very bad, arthroscopy can be done to replace joint with an artificial one
– osteotomy (if joint is not suitable for surgery), adding bone either above or below the joint
– joint fusion (arthrodesis), if joint is not suitable for replacement, joint will be much stronger and less painful but you will no longer be able to move it.
Pathophysiology
Within the synovium, there are tissue macrophages
Tissue macrophages can become stimulated, for a variety of reasons:
– trauma, joint abnormalities, degeneration of tissues, all the risk factors of OA
Macrophages will release cytokines:
– TNF-alpha
– IL-1B
– IL-6
– will also cause VEGF (which will cause new blood vessels to form), important factor in angiogenesis
– E-selectin is caused- where other immune cells can be recruited to the area, because of receptors being formed within the blood vessel
—- this promotes the inflammatory response
All the cytokines produced, T-cells and macrophages as well- stimulate FLS to create proteases:
– proteases, can cause cartilage destruction within the joint
The cytokines also stimulate osteocytes, which in turn creates more osteoblasts to build new bone:
– this is sort of a repair mechanism from the body, to repair the bone that is getting damaged
—- this causes subchondral sclerosis (the hardening of the joint line bone)
– long term depositing, causes the formation of osteophytes within the joint
Age pathophysiology:
– thinning of cartilage due to:
—- decreased hydration of the cartilage
– brittle bones caused
– chondrocalcinosis caused
