Osteoarthritis

Question 1

What is osteoarthritis?

Answer 1

Characterised by thinning of the cartilage at articular surfaces, loss of joint space and formation of bony spurs (osteophytes)
Degenerative disorder- most common form of arthritis

Question 2

Pathogenesis of osteoarthritis

Answer 2

Normally- the matrix of the cartilage is formed by chondrocytes which are embedded within it.

In disease- loss of matrix causes cytokine release. This causes IL-1, TNF, prostaglandins etc to be released by the chondrocytes within the matrix.
Fibrillation of the cartilage surface occurs and attempted repair causes osteophyte formation and loss of joint space.

Question 3

Symptoms of osteoarthritis

Answer 3

Mechanical pain- pain on movement- relieved at rest
Crepitus- creaking, cracking noise
Stiffness
Bony swellings and deformity of the joint
Effusions and soft tissue thickening
Loss of function

Question 4

Which joints are most often affected by osteoarthritis?

Answer 4

Neck, lower back, hips, base of thumb, end of fingers, base of big toe, knee

Question 5

Risk factors for osteoarthritis

Answer 5

Age
Gender- more common in women
Occupation
Previous injury
Obesity
Other underlying conditions e.g. rheumatoid.

Question 6

Investigations into osteoarthritis

Answer 6

Blood tests- inflammatory markers usually normal
X-ray- shows LOSS
L-loss of joint space
O- osteophytes
S- sclerosis
S- subchondral cysts.

Question 7

Describe some differences between osteoarthritis and rheumatoid arthritis

Answer 7

proximal joints involved-
RA tends to involve metacarpophalangeal and proximal interphalangeal whereas OA involves distal interphalangeal and carpometacarpal.

Heberdens nodes present in OA but not in RA

Joints feel soft, warm and tender in RA but hard and bony in OA.

Stiffness in RA is worse after resting, whereas in OA gets worse after movement.

Question 8

Difference between lab findings in RA vs OA

Answer 8

RA-
anti CCP antibody positive
Positive rheumatic factor
Elevated ESR and C reactive protein

OA-
Anti-CCP negative
Negative RF
Normal C reactive protein and ESR.

Question 9

Treatment/management of OA

Answer 9

Analgesia- e.g. paracetamol
NSAIDS- may offer additional symptomatic relief.
Pain modulators- tricyclics-amitriptyline
-Anti-convulsants gabapentin.
Intraarticular steroids

Non-pharmacological-
Physiotherapy to strengthen muscles
Education
Weight loss
Footwear. 

Dependent on extent of joint involvement- joint replacement surgery.