#77 - MSK radiology Flashcards
List the 4 diagnostic features of osteoarthritis on radiographs.
- non-uniform joint space narrowing
- osteophyte formation (bumps of bone)
- subchondral sclerosis
- subchondral cysts
T/F: Osteoarthritis can usually be diagnosed by history and physical exam.
False. You need x-ray.
T/F Osteoarthritis usually affects joints aymmetrically, while RA affects them symmetrically.
True!
two most common joints for osteoarthritis
hip and knee. also interphalangeal joints in hand..
characteristics separating RA from OA.
RA: symmetric, uniform narrowing, joint subluxation/ dislocation.
OA: asymmetric, non-uniform narrowing.
3 rules for imaging MSK trauma
- cover the joint above and below
- get two perpendicular views.
- get additional views more sophistocated studies (CT) when needed.
what does comminuted mean?
fractured into more than 2 pieces.
pathologic fracture =
result of a tumor
what does a torus/buckle fracture mean?
there is a bump on the surface of the bone.
T/F : If you see a fracture in a non-walking child, it’s probably non-accidental.
True
Explain the Salter- Harris Pediatric Fracture Scale
Rates pediatric fractures 1 to 5, on how bad they disrupt the growth plate. 4 and 5 are devastating as they impair physeal growth, leading to shortened limb..
what is the most suspicious sign for non-accidental fractures in a child?
multiple fractures of different ages.
-bucket handle also is associated with abuse.
List the unique pediatric fractures.
- Greenstick (doesn’t go all the way through the bone)
- Torus / Buckle (bump on bone)
- bucket handle (wisps on edge of a bone)
What is the most sensitive and specific imaging for osteomyelitis?
MRI
What is the least sensitive and specific imaging for osteomyelitis?
X ray
List the radiographic signs of osteomyelitis. (4)
1-Destruction of bone - most important.
2-Periosteal reaction
3 - Soft Tissue swelling.
4- presence of subcutaneous air (If present, means an aggressive fulminant infection.)
T/F. Negative X ray rules out osteomyelitis.
FALSE. Get an MRI if you are very suspicious.
2 criteria in a 40+ year old patient that is 99% specific for metastasis or multiple myelitis.
1- radiograph showing a lytic bone tumor (looks like a tumor not an abscess or other lytic/dark/lucent area where bone is being destroyed.
2- lytic area is proximal to elbows or knees.
49 yo woman, knee pain (probably early onset osteo arthritis), since you know you need x ray to diagnose osteoarthritis, you get an x ray. Instead the xray shows a destructive lytic bone lesion, in the distal femur. Now she has a 99% chance of osteomyelitis or metastasis. In a busy practice you’ll see this once every 3 months!\
next, what do you do?
most common source in 49yo F = breast. Take a chest X ray looking for abnormalities in chest (should be present). Also , do breast exam and a mammogram. Now you have a stage and you can get started on treatment or palliative care
Patient comes in with pain in the joints with walking. Radiograph shows hair like structures coming out of the bone, along with some triangular structures protruding from bone. What is it?
Osteosarcoma. Hair coming out of bone = classic.
Also, you will see areas of lysis.
