Avascular necrosis / Osteonecrosis

Question 1

Risk factors for avascular necrosis

Answer 1

steroid use

ETOH

SLE

antiphospholipid,

sickle cell,

infections (osteomyelitis, HIV),

renal transplant

decompression sickness

Question 2

Clinical manifestations of avascular necrosis

Answer 2

groin pain with weight bearing,

pain on hip abduction, internal rotation,

no erythema, swelling or point tenderness

Question 3

Laboratory findings

Answer 3

normal WBC normal ESR and CRP

Question 4

Radiographic imaging

Answer 4

Cresent sign on advanced stage

order MRI if XR shows no findings

Question 5

Avascular necrosis

Answer 5

progressive dx that involves bone and bone marrow cell destruction and caused by compromised bone blood supply and if left untreated can cause joint destruction.

Question 6

Most common site of joint involved with avascular necrosis

Answer 6

femoral head

Question 7

GOLD standard imaging for avascular necrosis

Answer 7

MRI

Question 8

treatment options of avascular necrosis of femoral head

Answer 8

core decompression

vascularized bone graft

non vascularized bone graft

osteotomy

decompression

joint replacement

Question 9

treatment option of avascular necrosis of femoral head for an older sedentary pt

Answer 9

need a total hip replacement with significant symptoms related to AVN

Question 10

treatment option for younger pt with avascular necrosis of the femoral head

Answer 10

core decompression or non vascularized bone grafting

they may be troubled by the mobility limitation of total hip replacement.

Question 11

Osteonecrosis is AKA

Answer 11

avascular necrosis of hip

Question 12

Risk factors for osteonecrosis

Answer 12

prior fracture, radiation exposure, excessive alcohol use, sickle cell anemia, chronic steroid use

Question 13

Which bones are commonly affected in osteonecrosis?

Answer 13

long bones, (femoral head, humeral head, distal femur)

Question 14

What happens in osteonecrosis or avascular necrosis?

Answer 14

involved area of one collapses leading to rapidly progressive osteoarthritis

Question 15

Presentation of osteonecrosis

Answer 15

groin pain (true hip pain) radiation to buttock, worsens with ambulation (same way osteoarthritis may present)

Question 16

Physical exam findings related to osteonecrosis (avascular necrosis of hip)

Answer 16

reduced ROM of hip, altered gait, pain with weight bearing.

Question 17

XR changes of osteonecrosis include:

Answer 17

bone density changes, sclrosis, cyst formation, subchondral radiolucency and “crescent sign” indicates subchondral collapse End stage dx is with femoral head collapse, joint space narrowing and degenerative changes

Question 18

Are RA patients more at risk for osteoporosis?

Answer 18

yes. osteoporosis in high risk women can happen <65 yrs old and can repeat DEXA every 2 years if risk factors continue

Question 19

if concerned about osteonecrosis or vascular necrosis of hip what is 1st imaging study to order?

Answer 19

plain radiography If XR normal, order MRI