Osteoarthritis Flashcards
What is it ?
A degenerative joint disorder in which there is progressive loss of articular hyaline cartilage, new bone formation and capsular fibrosis
What happens to the cartilage when damaged?
- Initially- cartilage becomes swollen and there is increased proteoglycan and chondrocyte content to try repair the damage (several years)
As disease progresses:
- Proteoglycan and chondrocyte content reduced
- Loss of elasticity with a reduced tensile strength (cartilage softens)
Over time cartilage becomes so eroded to the subchondral bone resulting in loss of joint space
Primary OA risk factors ?
- increased age (in >65s- 80% have OA)
- Female sex- Women are more symptomatic than men
- Ethnicity (increased risk in African-American, American Indian or Hispanic)
- Family history- strong heritability for knee and
hand OA
What is Secondary OA?
When there is a precipitating cause to the OA
Secondary OA risk factors ?
- Occupation
- Obesity- increased incidence and progression of hand knee OA
- Trauma
- joint malalignment through trauma or
muscle weakness - Infection- septic arthritis or TB
- Inflammatory arthritis - RA, AS
- Metabolic disorders eg. gout
Aetiology and causes of OA
- Damage to normal cartilage due to excessive loading for long periods
- Damaged or defective cartilage failing under
normal conditions of loading - Cartilage damage due to defective stiffened
subchondral bone causing excessive load
Where can pain come from in the joint?
- microfractures of subchondral bone
- low grade synovitis
- capsular distension
- muscle spasm
All innervated except from cartilage
Differentials ?
- Gout
- pseudogout
- RA
- Bursitis
Symptoms
- Non-inflammatory Joint pain and stiffness
-deformity - instability
- reduced ROM
- Crepitus
Type of pain in OA? when? better? morning stiffness?
- Intermittent at first then constant
- Worse on movement and weight-bearing
- Better with rest
- Morning stiffness <30 mins
If there’s knee inactivity what can occur in morning?
Gelling- feeling of stiffness- called Gel phenomenon due to caused by a temporary thickening of natural fluids inside the joint
What other symptoms do pt with knee OA have?
Knee giving way
Where is OA most common in body?
Hip
Knee
Cervical spine
Lumbar spine
Small joints in hands- DIPJs and 1st CMCJ
Less common:
Sacro-iliac
Wrist
1st MTPJ- hallux rigidus
Ankle
What are signs of OA on examination? and on hands
- Crepitus
- reduced range of motion
- tenderness
On hands:
-Heberden’s nodes(in the DIP joints) and Bouchard’s nodes(in the PIP joints)
- Squaring at the base of the thumb at the carpo-metacarpal joint
- Weak grip
- Reduced range of motion
how to diagnose ?
Usually clinical diagnosis-
If pt over 45 with good clinical picture this is enough
If not clear investigations will be further done
