Osteoarthritis

Question 1

What is it?

Answer 1

A non-inflammatory disorder of movable joints characterised by deterioration or articular cartilage and the formation of new bone at the joint surfaces and margins.

New definition:
Age-related, dynamic reaction pattern of a joint in response to insult or injury. All tissues of the joint are involved. Articular cartilage is the most damaged but there is also damage to the underlying bone.

Question 2

Is the condition inflammatory or non-inflammatory?

Answer 2

Non-inflammatory

Question 3

What is another name for osteoarthritis?

Answer 3

‘wear and tear arthritis’

degenerative joint disease

Question 4

Prevalence?

Answer 4

Most common disease affecting synovial joint
Prevalence increases with age
By 40, 90% have OA in weight bearing joints

Question 5

What is the relationship to sex?

Answer 5

<45 yrs more common in males

>55 yrs more common in females

Question 6

What cytokines are involved?

Answer 6

IL-1
TNF-a
NO
(Little inflammation, driven by mechanical forces)

Question 7

What are the main pathological features?

Answer 7

Loss of cartilage and disordered bone repair

Question 8

Define primary and secondary OA?

Answer 8

Primary/idiopathic - No identifiable predisposing cause

Secondary - underlying cause is implicated

Question 9

Risk factors for OA?

Answer 9

Increased age
Family history - genetic component
Female post-menopausal
Caucasian
Obesity
Occupation - manual labour, sports
Local trauma
Inflammatory arthritis
Neuropathic conditions
Deformities - e.g. congenital, SUFE.
Increased bone density

Question 10

Symptoms and signs of OA?

Answer 10

Pain - worse on exertion
Stiffness - worst after rest
Swelling - bony and soft tissue (effusion/intermittent or continuous from capsular thickening)
Functional impairment
(typically after middle age)
Morning stiffness

Alteration in gait
Bony enlargement
Synovitis
Limited ROM
Crepitus
Tenderness
Deformity
Muscle wasting
Joint instability - late onset

Question 11

Key radiological features of OA? (5)

Answer 11

Joint space narrowing
Osteophyte formation
Subchondral scleosis
Subchondral cysts
Abnormalities of bone contour

Question 12

What is the pathogenesis?

Answer 12

Articular cartilage failure
Chondrocytes are the most important cells responsible for osteoarthritis

Some involvement of proteases, cytokines, anabolic cytokines and inflammation.

Question 13

What is one key difference between OA and inflammatory joint disease?

Answer 13

Not associated with systemic manifestations.

Question 14

What joints are most commonly affected?

Answer 14

Knee
Hip
DIPJ + PIPJ (two end joints)
1st CMC
Spine
1st MTPJ

Question 15

Describe the nature of the pain experienced in OA?

Answer 15

Insidious onset - months to years
Aggravated by activity
Relieved by rest
May be referred pain

Question 16

What is the origin of the pain experienced in OA?

Answer 16

Articular cartilage and synovium has no nerve supply. Pain due to capsular stretching and vascular congestion of bone.

Question 17

What is the name of the stigmata present in the hands which are the palpable osteophytes in the joints?

Answer 17

Heberden’s nodes - DIPJ

Bouchard’s nodes - PIPJ

Question 18

What are the differential diagnosis of OA?

Answer 18

Rheumatoid arthritis
Gout
Osteonecrosis
Neuropathic joint

Question 19

What signs are characteristic?

Answer 19

Pain worse at night/ on use
Morning stiffness <30 mins, degenerative. >1hr, inflammatory
Herberden’s and Bouchard’s nodes

Question 20

What investigations would you do in OA?

Answer 20

X-ray (Asymmetric loss of joint space, sclerosis, cysts, osteophytes)
Majority of cases
Rheumatoid factor and anti-CCP negative

CT (for joints not clearly visible on x-ray)
MRI (rarely used)
Isotope bone scan (‘hot’ due to increased vascularity and new bone formation)
Laboratory tests (blood and synovial fluid - would expect to be normal)
Diagnostic injection
Arthroscopy (can help to isolate affected joint)

Question 21

What is the management option selected dependent on?

Answer 21

Joint involved
Stage of disorder
Severity of symptoms
Age of patient
Functional needs

Question 22

What are the management options for OA?

Answer 22

Conservative / Non-surgical
Injection
Surgical

Question 23

What might conservative management of OA include?

Answer 23

Decrease load on joint (weight loss and exercise)
Analgesia (topical products, capsaicin or NSAIDS, paracetamol, NSAIDs, Cox-2 inhibitors (w/o GI side effects of NSAIDS)
Promote movement (physiotherapy)
Mobility aids (waking sticks, heel raises)

Question 24

Do any exercises increase the risk of OA?

Answer 24

Neuroanatomically normal (NAN) joints are at increased risk of developing OA in the absence of adequate exercise.

NAN joints are not at increased risk upon exposure to repetitive, low-impact, exercise.

NA abnormal joints are at increased risk upon exposure to repetitive, low impact, exercise.

NAN joints are at increased risk upon exposure to repetitive, high-impact exercise.

So basically, running would be risky as high impact and could affect normal joint.
Something low impact like walking would only be bad if neuroanatomically abnormal joint.

Question 25

What substance might be injected as management of OA?

Answer 25

Steroid injections (definite short-term benefit)
Hyaluronic acid

Question 26

What surgical management options are there for OA?

What are the goals?

Answer 26

Remove pain
Improve function
Correct deformity

Debridement of joint
Realignment of osteotomies
Joint excision
Joint fusion
Joint replacement (arhroplasty) - metal joint

Question 27

What are some of the indications for arthroplasty?

Answer 27

Uncontrolled pain (esp. night)
Significant limitation of function
Fitness for surgery
(Note, age is a consideration due to limited lifespan of prosthetic joints (10-15 years))