Osteoarthritis

Question 1

What is the pathophysiology of OA? (Brief overview)

Answer 1

Long term chronic condition characterised by the deterioration of cartilage in joints which results in bones rubbing together and creating stiffness, pain and impaired movement

Degenerative disease of chi deal cartilage

Inflammation occurs late in disease

Inflammatory mediators include: matrix metalloproteinases (MMPs), and aggrecanases, inflammatory cytokines including IL-1 and TNF-a

These enhance the synthesis of proteins des and other catabolic factors to degrade the articular cartilage membrane

Question 2

What deformities may be brought about by OA?

Answer 2

Valgus (knees in)

Varus (knees out)

Question 3

What is the structure of the articular cartilage?

Answer 3

Bottom layer (closest to bone) : calcified cartilage

Deep zone: cells (chodrocytes) arranged in columns

Middle zone: a lot fewer cells, much more of the other components of cartilage (ECM and collagen…). This is the part than gets worn away in OA

Superficial zone: chondrocytes arranged in a flat layer at the edge. (Also gets worn away)

Question 4

What are the risk factors of Osteoarthritis?

Answer 4

Age

Weight/obesity

Mechanical constraints (sport, profession)

Heredity

Female gender (menopause)

Osteonecrosis

Leg bone malalignemet

Oestrogen deficiency

Metabolic syndrome

Advanced hip osteoarthritis caused by soo dull arthritis or rheumatoid arthritis

Other:

Injury (crucial ligament rupture, meniscectomy (removal of meniscus))

Infectious disease such as TB

Rheumatoid arthritis sequallae

Question 5

What is the vicious cycle of obesity related to OA?

Answer 5

Obesity ->

Increased pressure won knee joints ->

Joint pain ->

Limited mobility ->

Lack of physical activity ->

Obesity ->

Plus in addition to obesity there may be other disorders such as depression, type 2 diabetes and heart disease

Question 6

What is the distribution of primary osteoarthritis?

Answer 6

Knees

Hips

Spine

Fingers

There may be exceptions but these should trigger consideration of secondary causes of osteoarthritis

Question 7

What are the symptoms and signs of osteoarthritis?

Answer 7

Pain

Pain gets worse during the day

Minimal morning stiffness (<20 mins) (gelling). This is unlike rheumatoid arthritis which has prolonged morning stiffness

Range of motion decreases

Jointninstability

Bony enlargement (osteophytes)

Crepitus

Variable swelling

Question 8

How is osteoarthritis assessed in clinical practice?

Answer 8

Look (could there be another cause? Operation?)

Feel

Move (range of movement…)

Special tests (anterior drawer test, Lachman test)

Question 9

What are the laboratory tests involved in OA?

Answer 9

There are no specific ones

No associated abnormalities

But there are investigational ones to rule out other diseases (cartilage degradation products, serum and joint fluid…)

Question 10

What are some radiographic changes in osteoarthritis?

Answer 10

Loss of joint space

Sclerosis (whiter bits)

Subchondral cysts

Osteophytes

Question 11

What is the management of osteoarthritis?

Answer 11

Conservative:

Weight loss

Analgesics (oral/topical NSAIDS)

Physiotherapy

Walking aids

Avoid exacerbating activity

Injection (steroid/viscosupplementation)

Injection:

Steroids

Lubrication gel

Platelet rich plasma

Stem cells?

Operative:

Replace

Realign

Excise

Fuse

Arthroscopy?

Deenervate (to reduce pain)