MSK Rotation Notes
-Work from the musculoskeletal Xray and musculoskeletal CT/MRI worklists.
-Copy the “bone” templates into personal macros (see accompanying handout)
-We communicate with the ED via the Ibox feature of PACS. This should only be done after review with
an upper level radiologist.
-Check for STAT CT C-spines from the ED. You should be paged for level I traumas. Level I trauma Cspine
results are called to 66622 after review by an upper level radiologist.
-Intraoperative template is used when imaging (e.g. C-arm) is provided by the department but we are
not asked to provide an interpretation. This is ususally for orthopedic fracture fixation or spine fusion.
-The PMR physicians (Arthur Smith and Dr. Gibert) do spinal injections with imaging. For these exams,
just change the study status to approved. We do not put any dictation on these exams.
-The orthopedists (Dr. Merrill) also sometimes do spine injections (ESI or foraminal nerve root injection).
These should be dictated as intra-operative.
-Cardiac caths are often inappropriately on the worklist. Don’t dictate, just change status to approved.
-ERCP and GI studies are sometimes on the list. The body resident should be taking care of the barium
exams, but we should let the body people know about the ERCP exams, because they usually dictate a
report for them. We do not.
-For studies stuck in temporary status that cannot be dictated after allowing a reasonable amount of
time (1hr?), try to reach the performing radiography area. This is sometimes found under the “study
highlights” box. When you can’t reach anyone else, try 27450 for the main tech area.
There are a number of issues that relate to us being the only radiologists in Rutledge Tower:
-We cover all contrast reactions. CT and MRI start at 730am and run until at least 5pm
-The MRI and CT techs place a stack of contrast forms to be signed at the front workstation every
afternoon. These need to be signed by a physician to indicate that contrast was administered. This is
the residents’ responsibility. You are not attesting to anything other than the fact that the patient did
receive contrast.
-You will need to sign for heparin orders (100U/mL) for accessed ports
-You will need to write PO Valium orders for MR patients with claustrophobia. 5mg is the standard
dose, ask if you have a question
First year goals
Accurately localize and describe bone fractures of the extremities, pelvis, and spine
Accurately describe orthopedic fixation and complications
Accurately describe arthroplasty hardware and complications
Accurately characterize arthritis
Recognize features of:
- Avascular necrosis
- Paget’s disease
- Skeletal infection
- Scoliosis, hip impingement, and foot deformities
- Recognize the classic appearance of the more common focal bone lesions: non-ossifying fibroma,
fibrous dysplasia, enchondroma, solitary bone cyst, giant cell tumor, osteosarcoma and metastases
Texts:
Language of Fractures
Arthritis in Black and White
Greenspan text chapter for cervical spine injuries
Chapters 1-16 of the Requisites
Fracture Description
What bone is it?
What is the location in the bone? (Proximal or distal, metaphyseal or diaphyseal)
What is the fracture orientation? (Transverse, oblique, spiral, or comminuted)
Is there displacement, angulation, or apposition/distraction? Describe the angulation or displacement of
the distal fracture fragment relative to the proximal portion of the bone.
Is there involvement of a growth plate or articular surface? If so, use the Salter Harris scheme and
describe stepoff at the articular margin (2mm is a reasonable number for significant stepoff).
If you see that it’s an open fracture, say so.
Fracture Examples:
-There is a (fracture orientation) (comminuted or open as necessary) fracture of the (location in bone) of
the (name the bone) with (anterior, posterior, medial, lateral) displacement and (anterior, posterior,
medial, lateral) angulation of the distal fracture fragment(s). There is (intra-articular extension with
approximately 2 mm stepoff at the articular margin) and/or (distraction/apposition).
-There is an oblique comminuted fracture of the distal tibial diaphysis with anterior and medial
displacement and posterior angulation of the distal tibia.
-There is an oblique mid shaft fracture of the fibula with medial displacement of the distal fibula and 2
cm of bayonette apposition.
-There is a comminuted fracture of the distal radius with dorsal displacement and angulation of the
distal fracture fragments. There is intra articular extension with 3mm stepoff at the distal articular
surface of the radius. There is an ulnar styloid fracture with widening of the distal radial-ulnar joint.
Approach to the Cervical Spine (7 item checklist)
Visualize all 7 vertebral bodies
Prevertebral soft tissues
Atlanto-occipital and Atlanto-axial alignment on the lateral view
Dens and lateral masses of C1-C2 on the open mouth view
Anterior and posterior cortex of the vertebral bodies, and spinolaminar line
Facet alignment
Compression and chip fractures of the vertebral bodies
C-spine Injuries:
Craniocervical (atanto-occipital) dislocation
Type 1,2, and 3 dens fractures
Jefferson burst fracture of C1
Hangmans fracture of C2 (traumatic spondylolysis)
Flexion Teardrop
Extension sprain (+/- fracture)
UID
BID
Compression fracture
Clay shovelers fracture of the spinous process
On CT, look for laminar fractures, fractures of the transverse processes and fractures extending into the
transverse foramina
Hardware
Hip arthroplasty is the characteristic joint replacement and is more commonly a total hip
arthroplasty (replace femoral and acetabular surfaces) than a hemiarthroplasty (replace femoral head
without acetabular replacement). The acetabular and femoral components of a total hip arthroplasty
may be cemented to the bone or press fit without cement. A bipolar arthroplasty, although classified as
a hemi, is a bit of a hybrid with an acetabular component that rotates within the acetabular fossa and a
femoral component that rotates within that (it rotates around 2 “poles”). The bipolar has a
characteristic large acetabular cup overhanging the femoral neck and the cortex of the acetabulum will
be preserved. The most helpful feature in evaluating for complication is change from prior appearance
of the hardware.
The complications we assess for are periprosthetic fracture and loosening (aseptic or septic).
Loosening and infection are frequently indistinguishable radiographically. Lucency around the
prosthesis > 2mm suggests loosening. We also look for evidence of asymmetric wear of the
polyethylene cup, which is radiolucent. With polyethylene wear, we may also see secondary bone
erosion secondary to macrophage recruitment to the joint, which is best termed particle disease and
may also be seen with metal on metal implants of the hip, which do not have a poly liner.
Knee arthroplasty almost always involves replacement of the medial and lateral tibiofemoral
articular surfaces as well as the patellofemoral articulation. Revision knee arthroplasties have long
medullary stems and often a central post which may be large or small, making them fully or semiconstrained, respectively.
Shoulder arthroplasty is more frequently a hemiarthroplasty and the metallic hemisphere is
often subluxed superior to the glenoid by design contacting the coracoacromial arch in the cuff deficient
shoulder. Total shoulder arthroplasty requires an intact rotator cuff. The reverse total shoulder
arthroplasty has the metallic hemisphere mounted on the scapula and is performed in cuff deficient
patients as well.
Other frequently seen hardware:
Anterior plate and screw cervical spine fixation
Pedicle screw fixation of the posterior L-spine
Cement in the vertebral body for vertebral or kyphoplasty
Plate and screw fixation for long bone and pelvic fracture
Cortical screws usually have a high pitch (close spacing of threads)
Cancellous screws have widely spaced threads
Scaphoid screws (aka Herbert screws) are cancellous and cannulated
Dynamic compression hip screw with lateral plate used for femoral neck fractures
Bone anchors at the greater tuberosity and wrist
Lesser phalanges of the feet may be fused for hammertoe correction
Rotationally osteotomy is frequently performed for correction of bunion (metatarsus primus varus and
hallux valgus) deformity
Tibial and femoral tunnel screws are characteristically seen for ACL reconstruction
Arthritis characterization
Joints involved and whether the arthritis is erosive, productive, or mixed is the key
In erosive arthritides, the earliest radiographic findings may be those secondary to synovitis i.e. soft
tissue swelling and periarticular osteopenia
Use the ABCDEs of arthritis:
Alignment
Bone Density
Cartilage Space
Distribution
Erosive or Productive
Soft Tissues
Soft tissues – Is there soft tissue swelling? Distal tapering is seen with systemic sclerosis.
Bone Density – Classically looking for periarticular decreased density secondary to synovitis
Cartilage Space – Is there joint space narrowing? Is it uniform (RA) or non-uniform(OA)?
Erosions – Central (erosive OA), marginal (classically RA), or juxta-articular (gout)
Productive changes – osteophytes and subchondral sclerosis
Alignment – Subluxations without erosion classic in SLE. Ulnar deviation and flexion deformities in RA
Seronegative spondyloarthritides are so named because they are usually rheumatoid factor negative
and involve the spine. They are:
-ankylosing spondylitis
-psoriatic arthritis
-chronic reactive arthritis (Reiter’s)
-enteropathic arthritis (usually IBD related )
Know the characteristics of pyrophosphate arthropathy, erosive OA, and gout