Osteoarthritis

Question 1

osteoarthritis - defined

Answer 1

*mechanical degenerative disorder of joint cartilage caused by wear and tear
*occurs as joint cartilage thins, most often gradually over time
*pathogenesis: imbalance of destruction & repair of cartilage

Question 2

osteoarthritis - epidemiology

Answer 2

*27 million Americans
*9.5% of adults > 60
*slightly more common in women
*most common in patients 65+
*most common form of arthritis

Question 3

osteoarthritis - pathogenesis

Answer 3

*complex and not fully understood
*imbalance of destruction & repair of cartilage:
-chondrocytes produce cartilage matrix
-most of the effector molecules target chondrocytes
*genetic, physical, and lifestyle factors may contribute

Question 4

osteoarthritis - risk factors

Answer 4

*increasing age
*female sex
*genetics
*obesity
*joint injury
*anatomic factors

Question 5

osteoarthritis - clinical presentation

Answer 5

*non-inflammatory arthritis (<30 minutes of morning stiffness, worsens with use, improves with rest)
*pain = key feature
*loss of function and instability
*GELLING phenomenon (sitting for a long time, then get up, then pain goes away after 10-15 steps)
*affects larger weight bearing joints plus DIPs, PIPs, CMC joint, first MTP and mid-foot

Question 6

classic joints in the hands that are affected by osteoarthritis

Answer 6

*disease affects:
1. DIPs (distal interphalangeal joints)
2. PIPs (proximal interphalangeal joints
3. CMC joint (at base of thumb)
4. also affects feet: first MTP, mid-foot

*disease SPARES: MCPs (contrast to RA)

Question 7

osteoarthritis - physical exam findings

Answer 7

*may have some swelling
*bony overgrowth:
-Heberden nodules (bony enlargments of DIPs)
-Bouchard nodules (bony enlargement of PIPs)
-squaring of the CMC

Question 8

osteoarthritis - diagnosis

Answer 8

*clinical findings
*labs typically are not abnormal (recall: ESR can rise with age, as can RF)
*non-inflammatory synovial fluid (synovial fluid WBC < 200)

Question 9

radiology findings of osteoarthritis

Answer 9

*osteophytes
*ASYMMETRIC joint space loss/narrowing
*subchondral cysts
*subchondral sclerosis

contrast to RA, which has symmetric joint space loss

Question 10

radiology findings of the hand in later osteoarthritis

Answer 10

*CENTRAL erosions
*“Gull Winging” pattern or sawtooth pattern
*only in DIPs and PIPs (spares MCPs)

Question 11

osteoarthritis management - overview

Answer 11

*management, not treatment
*current treatment goals focused on:
-reducing pain and inflammation
-maintaining or improving joint mobility
-limiting functional impairment
-improving quality of life

Question 12

non-pharmacologic osteoarthritis management

Answer 12

*exercise
*weight loss
*good footwear
*bracing or assist devices
*physical therapy
*patient education

Question 13

pharmacologic management of osteoarthritis

Answer 13

*acetaminophen first
*NSAIDs second
*if acetaminophen and NSAIDs fail, consider:
-steroid injections
-intraarticular hyaluronic acid
-topical therapy

Question 14

non-pharmacologic osteoarthritis management: EXERCISE

Answer 14

*strongly recommended by ACR
*high quality evidence
*low risk (esp. compared to medication)
1. land-based exercise
2. physical therapy (QUAD STRENGTHENING)
3. aquatic-based exercise (water aerobics, PT)
4. weight loss if patient is overweight

Question 15

non-pharmacologic osteoarthritis management: other modalities

Answer 15

*conditional recommendation: assist devices, splints for CMC joints, medial wedge insoles for lateral compartment OA, Tai Chi, acupuncture

*NOT recommended: patellar taping, knee braces, lateral wedge insoles

Question 16

pharmacologic osteoarthritis management: acetaminophen

Answer 16

*1000 mg TID
*advise to avoid more than 3000 mg
*first-line treatment for osteoarthritis

Question 17

pharmacologic osteoarthritis management: NSAIDs

Answer 17

*used for those who fail acetaminophen
*COX-1 and COX-2 inhibitors that prevent arachidonic acid conversion, preventing formation of thromboxane A2, prostacyclins, etc
*ADEs: decreased renal blood flow, increased gastric acid production (increased risk of ulcerations and bleeding), increase BP

Question 18

pharmacologic osteoarthritis management: topical NSAIDs

Answer 18

*topical diclofenac gel: indicated for pain of OA of hand and knee

Question 19

pharmacologic osteoarthritis management: intra-articular steroids

Answer 19

*inject to decrease pain so that they can go to physical therapy and/or exercise

Question 20

pharmacologic osteoarthritis management: intra-auricular hyaluronic acid

Answer 20

*subjective improvement (not proven by studies)
*works best (?) in patients with mild disease who still have cartilage present (does not work for bone-on-bone)

Question 21

pharmacologic osteoarthritis management: opioids

Answer 21

*for knee, hip, or lower back pain
*not safer than giving NSAIDs; only given as last-resort
*no difference in pain score or functionality
*falls/fractures increased in OA patients on narcotics

Question 22

surgery for osteoarthritis

Answer 22

*osteotomy
*joint replacement

Question 23

general ADEs of NSAIDs

Answer 23

1. decreased renal blood flow (renal toxicity)
2. increased BP (slightly)
3. increased risk of GI ulcers or bleeding (due to increased gastric acid production)

Question 24

GI ADEs of NSAIDs

Answer 24

*GI toxicity is mediated mostly by COX-1 inhibition
*increased gastric acid production → increased risk of ulcerations, bleeding
*worse with: history of ulcers; concurrent use of aspirin, warfarin, other NSAIDs; age > 60; use of steroids
*can add a PPI if pt has risk

Question 25

renal ADEs of NSAIDs

Answer 25

*increased BP (slightly)
*can interfere with anti-hypertensive effects of beta blockers, ACE inhibitors, ARBs, diuretics, etc
*can lead to renal insufficiency with chronic use
*caution if pt is already renally compromised