MKSAP 4: Osteoarthritis

Question 1

What is osteoarthritis characterized by?

Answer 1

Loss of cartilage accompanied by reactive bony changes including osteophyte formation, subchondral bony sclerosis and subchondral cysts

Question 2

OA is usually present in younger populations due to what?

Answer 2

Occupational injury and genetic predisposition

Question 3

Describe the pathophysiology of OA?

Answer 3

Matrix metalloproteinases (MMPs) such as collagenase, stromelysin, gelatinase are secreted by chondrocytes and degrade cartilage collagen

Question 4

What are risk factors for OA including what surgical procedure?

Answer 4

Advanced age, female, obesity, joint injury caused by repetitive use, trauma or certain occupations.
Joint malaignment, ligamentous laxity, meniscal injury or surgical meniscectomy can accelerate the onset of OA.

Question 5

Name the classifications of osteoarthritis:

Answer 5

Primary OA
-Erosive OA
Secondary OA
Diffuse Idiopathic Skeletal Hyperostosis (DISH)

Question 6

Describe primary osteoarthritis

Answer 6

most cases of OA, no specific antecedent event or predisposing disease is present. Does not exclude impact of routine factors such as obesity, aging or chronic history of significant joint use. Typically affects knees, hips, hands, spine and feet (single or a few joints) or generalized (multiple joints). Apparent around age 55

Question 7

Describe erosive OA

Answer 7

Subset of primary OA. Radiographic erosions are seen. IP joints of the fingers, intermittent flares of swelling of these joints.
Erosive OA: central erosions on radiographs with collapse of subchondral bone
RA/psoriatic: marginal erosions
More likely to have pain and disability than those without erosive features.
Common in DIP joints, does not affect wrists or elbows, not associated with RF, anti-CCP or elevated ESR or CRP like RA

Question 8

Describe secondary OA

Answer 8

Joint degeneration in the setting of preexisting joint abnormality. Trauma or congenital abnormalities.

Question 9

Male with OA symptoms of 2nd and 3rd MCP joints, what is the associated cause and diagnostic test to order?

Answer 9

Finally, secondary OA may occur in the setting of metabolic or systemic diseases such as hemochromatosis (iron overload, which is associated with a characteristic OA pattern involving the second and third metacarpophalangeal joints and is diagnosed with the aid of transferrin saturation measurement

Question 10

Describe DISH and how is it diagnosed?

Answer 10

Diffuse idiopathic skeletal hyperostosis - lack of systemic inflammation, characteristic bony remodeling changes and frequent co-expression with OA. Diagnosed on plain radiograph by presence of flowing osteophytes involving anterolateral aspect of four or more contiguous vertebrae most easily detected in the thoracic spine.

Question 11

What are the radiographic hallmarks of OA?

Answer 11

oint-space narrowing (articular cartilage loss), subchondral sclerosis, and marginal osteophyte formation are the radiographic hallmarks of OA

Question 12

What are the radiographic hallmarks of RA?

Answer 12

periarticular osteopenia and marginal erosions (as seen in rheumatoid arthritis)

Question 13

What is subchondral sclerosis and what does it represent pathologically in OA?

Answer 13

Subchondral sclerosis is seen on plain radiographs as increased bone density subjacent to joint-space narrowing. Both subchondral sclerosis and osteophytes reflect reaction of bone to growth factors stimulated by the mechanical changes driving OA.

Question 14

What does the ACR recommend in regards to NSAID use for OA in patients over age 75?

Answer 14

Furthermore, the American College of Rheumatology currently recommends topical NSAIDs rather than oral NSAIDs for patients aged 75 years or older. However, they are associated with more skin reactions and are significantly more expensive than oral NSAIDs.

Question 15

What do treatment guidelines say about course of treatment for OA?

Answer 15

Treatment guidelines suggest using the lowest effective NSAID dose for the shortest time period in order to reduce risk of side effects

Question 16

What NSAID is recommended for knee and hip OA?

Answer 16

The recent meta-analysis suggests that out of the seven NSAIDs in the meta-analysis studies, diclofenac was the most effective for knee and hip OA. .

Question 17

What is the initial treatment recommendation for OA?

Answer 17

Acetaminophen is the initial choice for osteoarthritis pain control in most instances; if acetaminophen provides inadequate relief, NSAIDs should usually be tried.
(Recent meta analysis states NSAIDs are more effective - unsure if this will change guidelines.)

Question 18

What is the best surgical treatment for OA?

Answer 18

The most effective surgical intervention for knee or hip osteoarthritis is total joint arthroplasty, which can reduce pain, improve function, and enhance quality of life.