Untitled Quiz

Bone Density

• Assesses general bone density and contrast between bone and soft tissues.
• Sufficient contrast implies healthy bone and soft tissue. Denser cortical shell appears brighter than less dense cancerous bone.
• Osteomalacia: Hypocalcification disorder that produces bone but cannot calcify it. Results in wide, porous bone and a looser zone in radiographic findings.
• Textural abnormalities are observed by looking for trabecular changes in bone appearance. These changes are a radiologic hallmark for diagnosing diseases.
  • Trabecular descriptors include: thin, delicate, smudge, fluffy.
• Hyperparathyroidism causes decalcification of bones, erosion of the cortex, and a squiggly, translucent appearance in the tibia.
• Coley's anemia is an inherited blood disorder that destroys red blood cells. It leads to cortical thickening, osteopenia, and marrow proliferation in metacarpals and phalanges.
• Local density changes can be observed in areas of weight-bearing.
  • Sclerosis is an increase in bone density in areas subjected to increased stress; a sign of repair.
  • Excessive sclerosis can be normal during bone healing or can be degenerative.
    • Can be a reaction to tumors or cancer.
• Osteomyelitis is a reactive sclerosis process where the body attempts to contain an infected area.

Cartilage Spaces

• Joint spaces are assessed for width and preservation of cartilage/disc/tissue. Decreased space usually signifies degenerative changes.
• Subchondral bone is assessed for density and irregularities.
  • Osteoarthritis (OA) is a destructive joint disease with pain, stiffness, loss of range of motion, and loss of activity tolerance. X-rays show narrowed joint space, sclerosis, osteophyte formation and subchondral lucency.
  • Rheumatoid arthritis (RA) and gout have little reactive sclerosis. Instead, they show erosions of the subchondral bone with radiolucencies at the joint margins.
• Epiphyseal plates are assessed for position, size, smooth borders, and disruptions. Disruptions in the growth plates are indicative of trauma or metabolic disease. They require comparative lateral films for diagnosis.

Soft Tissues

• Muscles are assessed for girth and changes due to muscle wasting or swelling. Gross muscle wasting can be caused by primary muscle disease, paralysis, severe illness, or disuse atrophy. Gross swelling can indicate inflammation, edema, hemorrhage, or tumors.
• Fat pads are assessed for position. Changes in position usually indicate swelling and injury to an adjacent structure.
• Joint capsule is generally not visible, but can be seen when swelling is present. Swelling can be caused by exacerbation of arthritic conditions, infection, hemophilia, acute joint trauma, or effusion from trauma/intra-articular fracture.
  • Lipohemoarthrosis: A mixture of fat and blood that enters the joint space through an osteochondral defect. The fat is less dense than blood and floats to the surface, visible as a fat fluid level or fat blood interface (FBI) on radiographs. Indicates a possible intra-articular fracture.
• Periosteum should be assessed for reactive processes which can be solid, laminated, sunburst, or Codman’s triangle.
  • Solid indicates indolent or slow-rolling processes like fracture healing or chronic osteomyelitis.
  • Laminated/onion skin indicates repetitive injury.
  • Sunburst can indicate malignant bone lesions, metastatic squamous cell tumors, or Battered Child Syndrome.
  • Codman’s triangle is an elevated piece of periosteum that ossifies into a triangular shape. Caused by tumors, subperiosteal hemorrhage, or Battered Child Syndrome.

Types of Fractures

• Imaging of musculoskeletal trauma typically involves X-rays.
• Primary trauma survey examples include:
  • Cross-table lateral view of the cervical spine to assess instability, fractures, or dislocations.
  • AP view of the chest to assess for hemothorax, pneumothorax or pulmonary contusion.
  • AP view of the pelvis to assess fractures or hemorrhage.
• Primary trauma survey aims to:
  • Avoid multiple radiographic exams.
  • Quickly screen for life-threatening injuries.
  • A CT scan is often utilized to reduce assessment time and decrease the chance of missing a fracture.
• Fractures with serious complications include:
  • Pelvis or femur fractures, which can cause hemorrhage.
  • Multiple crushing injuries, which can cause fat embolism.
  • Spine, elbow, or proximal humerus fractures, which can cause neurovascular damage.
• Definition of a fracture:
  • A fracture is a break in the structural continuity of bone or cartilage.
  • Fractures are described using anatomical and standardized terms in radiology.
  • Eponyms (e.g., Colles fracture or Boxer's fracture) are avoided in radiologic descriptions due to their lack of precision.
• Closed vs Open Fracture:
  • A closed fracture involves an intact skin and tissue overlying the fracture.
  • An open fracture involves a perforated or broken skin, regardless of wound size.
  • The distinction is based on exposure to the external environment.
  • The terms "simple" and "compound" are no longer used; replaced by "closed" and "open" in diagnostic terminology.

Elements of a Fracture

• 7 Elements of a Fracture*

• Anatomic site and extent of the fracture.

• Type of fracture: complete or incomplete.

• Alignment of the fracture fragments.

• Direction of fracture line.

• Special features of the fracture, such as impaction or avulsion.

• Associated abnormalities, such as joint dislocation.

• Special types of fractures resulting from abnormal stress or pathological processes in the bone, such as stress fracture or pathological fracture.

• #1 Anatomic Site and Extent of the Fracture*

• Distal femur fracture can be intra-articular or extra-articular.

• Intra-articular surface is located inside the joint.

• #2 Type of Fracture*

• Complete fracture: One bone becomes two fragments.

• Comminuted fracture: There are more than two fragments.

• Incomplete fracture: One cortical margin remains intact, with only one bone fragment because only one portion of the cortex is disrupted.

  • Relatively stable.
  • May remain in position if stresses are minimized.
  • Normally occurs in short bones, irregular bones, and flat bones.

• #3 Alignment of Fracture Fragments*

• Based on the position of the distal fragment in relation to the proximal fragment.

• Non-displaced: Some contact between fragments.

• Displaced: No contact between fragments.

• #4 Direction of Fracture Lines*

• Described in reference to the longitudinal axis of the long bone.

• Transverse: Bending force at a right angle to the longitudinal axis.

• Longitudinal: Force is parallel to the shaft of the bone.

• Oblique: Compression and bending rotation, diagonal orientation.

• Spiral: Spirals around the long axis, rotational force, vertical segment with sharp jagged edges, heal faster than oblique fractures because they fit better and are more stable.

• #5 Special Features*

• Impaction: Compression forces, commonly found in vertebrae.

• Avulsion: Tensile loading of bone at the attachment site, commonly occurs in the tibia or femur and can cause tibial plateau impaction fracture.

• #6 Associated Abnormalities*

• Swelling is an abnormality often associated with fractures.

• Stress Fractures*

• Regular localized areas of more radiodense bone.

  • Represents ongoing attempts at repairing the bone.

• Initial imaging may appear normal.

  • Diagnosis can be difficult and may take up to 6 weeks.

• Pathological Fractures*

• Occurs in weakened bone due to a pathological process.

  • Can be caused by Osteoporosis, Paget's disease, osteogenesis imperfecta, tumor infection, or disuse.

• Periprosthetic fractures can happen intra-operatively or around prosthetic components years after surgery.

  • Can also occur in bone graft fractures, spontaneously 2-3 years after implantation, not related to trauma.
    • Occurrence is 40% and higher for people with plate hardware or those undergoing chemotherapy.

• Sporadic Bone*

• White due to active turnover.

• Pathological fracture in osteogenesis imperfecta: Abnormal collagen maturation affecting both intramembranous and endochondral bone formation.

  • Common locations: Distal third of the olecranon.
  • Appearance: Diffuse decrease in bone density, thin cortices and flared metaphyses, cystic appearance of the proximal ends of the radius and ulna, mushroom appearance.

• Metastases*

• A bone scan showing a metastatic lesion caused by breast cancer.

  • Increased uptake at the injection site and bladder.

• A fracture at the proximal femur due to a tumor weakening the bone.

• Periprosthetic Fractures*

• Fracture around prostheses.

Fractures in Children - Salter-Harris Classification

• Fractures in children are complicated by features resembling fractures, such as growth plates, secondary centers of ossification, and large nutrient foramina.

• Comparison films of the uninvolved side are useful for diagnosis, as symmetry can aid in identification.

• Immature bone only shows ossified portions on imaging, preformed cartilage is not visible.

• Additional Elements of Fracture Description in Children:*

• Incomplete shaft fractures

• Fractures of the epiphysis and epiphyseal plate

• Incomplete Fractures in Children*

• Greenstick fracture: Incomplete fracture; the shaft is fractured on the tension side, the cortex and periosteum remain intact on the compression side.

• Torus fracture: Impaction fracture resulting in cortical buckling, often at metaphyseal regions; occasionally seen in adults with underlying pathology.

• Plastic bowing: Longitudinal compression forces on curved growing bone exceed elastic capacity, resulting in permanent bowing; a type of incomplete fracture with microscopic fatigue lines.

• Fractures of the Epiphysis and Epiphyseal Plate*

• Salter-Harris Classification:

  • Type I (S): Straight across (5% of fractures).
  • Type II (A): Above (75% of fractures).
  • Type III (L): Lower or below (10% of fractures).
  • Type IV (T): Two or through (10% of fractures).
  • Type V (ER): Erasure or crush of growth plate (5% or less of fractures).
  • Higher classification indicates greater risk of complications and worse prognosis.

• Example: Salter-Harris type II fracture of the distal tibia; fracture extends through the growth plate and exits through the metaphysis.

• Healing of Fractures in Children:*

• Divided into three phases: inflammatory (acute), reparative ( subacute ), and remodeling (chronic).

• Remodeling in children depends on:

  • Skeletal age
  • Distance of fracture from the growth plate.
  • Severity of fragment displacement.

• Children's fractures may not always remodel with optimal results depending on the fracture type and growth plate impact.

Fracture Reduction and Fixation

• Reduction: Restoration of displaced bone fragments to normal anatomical position.

  • Occurs via closed or open reduction.

• Closed Reduction:

  • No incisions made.
  • Manipulation, traction, or both are used to guide fragments into place.
  • Often involves a soft tissue pin between bone ends.

• Open Reduction:

  • Surgical incision to expose the fracture site.
  • Fracture fragments are kept in position through fixation after reduction.

• Fixation:

  • Method of maintaining fracture fragments in position after reduction to achieve healing.
  • Benefits:
    • Immediate pain relief.
    • Promote healing over time.

• Types of Fixation:

  • External Fixation:
    • Plaster cast
    • Splint
  • Internal Fixation:
    • Pins
    • Wires
    • Plates
    • Screws
    • Rods
    • Other hardware
  • Open Reduction Internal Fixation (ORIF):
    • Combination of open reduction and internal fixation.

• Examples of Fixation:

  • Plaster cast immobilizing a distal radius fracture.
  • Internal fixation with plate and hardware for wrist arthrodesis (fusion technique to relieve pain and provide stability in advanced arthritis).
  • Combination of internal and external fixation with a uniplanar external fixator for a comminuted distal radius fracture and ulnar styloid fracture.
  • ORIF of the right radius after a fall from a ladder.

Fracture Healing

• Types of Bone Healing:

  • Cortical Bone Healing:
    • Formation of new bone or callus bridging the fracture gap.
    • Hematoma fills the fracture site after the periosteum and endosteum rupture.
    • Bone deposition and creeping substitution.
    • Collar of callus surrounds the fracture site, replaced by secondary callus.
    • Callus organized by mechanical stresses (Wolff's Law).

• Cancellous Bone Healing:

  • Unite with little or no callus formation.
  • Direct osteoblastic activity at the fracture site.
  • Inter-trabecular bone formation (e.g., drill hole in the tibia).
  • Occurs in vertebral compression fractures, distal radius fractures, and tibial condyle fractures.
  • Membranous bone formation:
    • Requires close contact of fracture fragments.
    • If approximation is not achieved, hematoma fills the gap, and healing proceeds by callus formation.
    • Spatially restricted, slow, or incomplete if the gap is greater than a few millimeters.

• Surgically compressed and fixated bone healing:

  • Direct osteoblastic and osteoclastic activity.
  • Bone deposition and resorption occur simultaneously.

• Example of Fracture Healing in a Patient:

  • A 17 year-old girl with tibia and fibula fractures:

    • Image A: Fracture fragments displaced laterally.
    • Image B: Callus formation.
    • Image C: No fracture lines, residual callus.

  • Emergency Room films after a sledding accident:

    • Fracture at the junction of the distal and middle thirds of the tibia and fibula.
    • Fracture fragments overriding and displaced laterally, good alignment.
    • Follow-up after three weeks: Callus bridging the fracture gap.
    • Follow-up after one year: Good remodeling, no fracture lines.