SR4-AVN & Related Conditions Flashcards
Which of the following names does not belong? Avascular necrosis Ischemic necrosis Aseptic necrosis Hemochromatosis Osteonecrosis Bone infarct
Hemochromatosis
Bone infarct is the same pathophysiologically, but it occurs in the metaphysis or diaphysis
List the two AVNs of the hip:
Legg-Calve-Perthe’s
Adult AVN
AVN in the wrist? Two names
- Keinbock’s
2. Preiser’s
AVN in the shoulder? (1)
- Hass’ disease
Osteochondritis dissecans, SONK, and Blount’s disease are AVN of the ____
Knee
Freiberg’s and Kohler’s are AVN of the ____
Foot
AVN in the spine? (1)
Scheuermann’s
Name the AVN:
- Affects the capital epiphysis (femoral head) of children between 2 and 12
- 3:1 Male predominance
- Can be bilateral
- Pain is presenting complaint, can refer to knee
- Alteration of gait
LCP
The measured distance between the inside of the acetabulum and the femoral epiphysis is called?
Tear-drop distance
The line drawn on an x-ray along the medial femoral neck/shaft, that should line up nicely with the upper obturator foramen is called?
Shenton’s line
AVN of the lunate?
Keinbock’s disease
AVN of the scaphoid?
Preiser’s disease
The “feeder” vessel of the Scaphoid bone enters the middle (waist) of the bone and feeds proximal/distal?
Proximal (kind of backwards)
AVN of the humeral head?
Haas’ Disease
___ affects the LATERAL portion (slope) of the medial femoral condyle, while ___ affects the MEDIAL portion (weight bearing) of the medial femoral condyle
Osteochondritis dissecans (OCD), Spontaneous Osteonecrosis of the Knee (SONK)
Tibial vara. Affects the medial growth plate, epiphysis, and metaphysis. Unknown cause
Blount’s Disease
An “infarction”. Causes flattening and fragmentation of the head of the metatarsal (usually 2nd)
Freiberg’s Disease
AVN of the navicular bone.
Kohler’s Disease
Wavy, serpiginous calcifications, most common in the knee with the same risk factors as AVN. These occur in the metaphysis or diaphysis.
Medullary bone infarct
A common DDX of medullary bone infarcts?
Enchondroma w/popcorn calcification
A common type of soft tissue cancer, NOT common in bone. BUT pre-existing bone infarcts can give rise to this in bone.
Malignant Fibrous Histiocytoma (MFH)
The “T and 6 S’s” for the risk factors of AVN are?
- Trauma
- Sickle cell anemia
- SLE
- Steroids
- Scuba divers
- Sterno abusers (alcoholics)
- Storage disease (Gaucher’s disease)
The teardrop distance should be no more than __-__mm side-to-side
1-2
Most common route of bone contamination?
Blood-borne (hematogenous) (infections spread!
Mandibular osteomyelitis from tooth infection is an example of what route of bone contamination?
Direct spread from contiguous source
A compound fracture is an example of ______, a route of bone contamination.
Direct implantation
Post-operative infection is an example of a ____ route of bone contamination.
Iatrogenic
90% of all bone and joint infections are caused by _____
Staphylococcus aureus (bacteria)
Osteomyelitis in children can look like what two bone tumors/conditions?
Ewing’s sarcoma, osteosarcoma
The radiographic features of acute osteomyelitis are similar to what?
Primary bone malignancy
- permeative/moth eaten bone destruction
- periosteal response
- cortical destruction
A way to potentially differentiate osteomyelitis from a primary bone malignancy on x-ray is ___ of the fat/muscle interface (in osteomyelitis)
Blurring
A dead fragment of bone that is the source of re-infection unless removed
Sequestrum
Heavy periosteal new bone surrounding infection
Involucrum
A channel that develops due to pressure so that pus can escape
Cloaca
Subacute osteomyelitis: a smoldering infection that doesn’t get better or worse. Due to low virulence of the organism and/or good immunity of the host. What is this called?
Brodie’s Abscess
DDX for Brodie’s Abscess?
Osteoid Osteoma
This can happen secondary to chronic osteomyelitis with a draining sinus (smells). Skin cancer tracks down the sinus into the bone
Epidermoid Carcinoma (poor prognosis)
An organism deposits in vertebral endplate and quickly spreads to the disc causing “discitis”
Spinal osteomyelitis
Radiographic signs:
- loss of disc height
- ill-defined endplates w/erosions
- soft tissue swelling (where applicable)
Spinal Osteomyelitis
T/F: The “Vacuum Phenomenon” which sometimes shows up in the discs of patient’s w/DDD will also occasionally show up in patients w/spinal osteomyelitis
FALSE
Are osteophytes and subchondral sclerosis seen in both DDD and spinal osteomyelitis?
No, just DDD
There is a classification system in endplate changes due to infection called?
Modic Changes
There are 3 types of Modic changes. Initially water/liquid shows up on T1 as LOW signal, and T2 as HIGH signal. Which type of Modic change?
Type 1
Modic type 2 shows up HIGH T1 and HIGH T2 and is due to ____
Fat
Modic 3 shows up as LOW T1 and LOW T2, and is due to _____
Bone (marble)
Which phase of Modic changes can be captured on plain film?
3 (bone)