Ch.22 - Recognizing Fractures and Dislocations Flashcards
Complete fractures:
- Involve the entire cortex.
- They are more common.
- Typically occur in adults.
Incomplete fractures:
Involve only a part of the cortex and typically occur in bones that are softer - Such as those of children.
Torus and greenstick fractures are … .
Incomplete fractures.
Fracture lines tend to be:
Blacker, more sharply angled, and more jagged than other lucencies in bones such as nutrient canals or epiphyseal plates.
Sesamoids, accessory ossicles, and unhealed fractures may mimic acute fractures BUT …
ALL will have smooth and corticated margins.
Dislocation is present when:
2 bones that originally formed a joint are no longer in contact with each other.
Subluxation is present when:
2 bones that originally formed a joint are in partial contact with each other.
Fractures are described in many ways, including:
- The number of fracture fragments.
- Direction of the fracture line.
- Relationship of the fragments to each other.
- Whether or not they communicate with the outside atmosphere.
Simple fractures have:
2 fragments.
Comminuted fractures have:
More than 2 fragments.
Segmental + Butterfly fractures describe …
2 types of comminuted fracture.
The direction of fracture lines is described as:
- Transverse.
- Diagonal.
- Spiral.
The relationships of the fragments of a fracture are described by 4 parameters:
- Displacement.
- Angulation.
- Shortening.
- Rotation.
Closed or open fractures are more common?
Closed are much more common.
Avulsion fractures are produced by …
The forceful contraction of a tendon or ligament.
Avulsion fractures can occur at any age, but …
are particularly common in younger, athletic individuals.
The Salter-Harris classification:
Categorizes fractures through the epiphyseal plate that are graded by severity + prognosis.
Child abuse should be suspected when there are:
- Multiple fractures in various stages of healing.
- Metaphyseal corner fractures.
- Rib fractures.
- Skull fractures.
esp. if multiple.
Stress fractures:
(eg. march fractures in the metatarsals) occur as a result of numerous microfractures and frequently are NOT visible on conventional radiographs taken when the pain first begins.
After some time, bony callous formation or a dense zone of sclerosis becomes visible.
Colles’ fractures:
Of the radius.
Smith’s fracture:
Of the radius.
Jones fracture:
of the base of the 5th metatarsal.
Boxer’s fracture:
Of the head of the 5th metacarpal.
March fracture:
In the foot.
Some fractures are more difficult to detect than others:
The easily missed fractures (and how common they are) include:
- Scaphoid fractures (common).
- Buckle fractures of the radius/ulna (common).
- Radial head fractures (common).
- Supracondylar fractures (common).
- Posterior dislocations of the shoulder (uncommon).
- Hip fractures (common).
What should alert you to the possibility of an underlying fracture:
- Soft tissue swelling.
- Disappearance of normal fat stripes and fascial planes.
- Joint effusions.
- Periosteal reaction.
Fractures heal with a :
Combination of ENDOSTEAL callus, recognized by a progressive indistinctness of the fracture line +
EXTERNAL callus that bridges the fracture site.
Definition of fracture:
A disruption in the continuity of all or part of the cortex of a bone.
Incomplete fractures tend to occur in bones that are …?
“Softer” than normal such as those in children, or in adults with bone-softening diseases such as:
- Paget.
- Osteomalacia.
Examples of incomplete fractures in children are …?
- Greenstick fracture –> Involves only one part of, but NOT the entire cortex.
- Torus fracture (buckle fractures) –> Compression of the cortex.
Sesamoids…?
Are bones that form in a tendon as it passes over a joint.
What is the largest and most famous sesamoid?
The patella.
Accessory ossicles…?
Are accessory epiphyseal or apophyseal ossification centers that do NOT fuse with the parent bone.
What can sometimes mimic acute fracture?
An old, unhealed fracture.
There almost always sesamoids present in the …?
- Thumb.
- Posterolateral aspect of the knee (Fabella).
- The great toe.
Accessory ossicles are most common in the …?
Foot.
Dislocation vs Subluxation:
Dislocation –> The bones that originally formed the two components of a joint are no longer in apposition to each other.
Subluxation –> Bones that originally formed the two components of a joint are in partial contact with each other.
BOTH occur only at joints.
Fractures are usually described using 4 major parameters:
- Number of fragments.
- Direction of the fracture line.
- Relationship of the fragments to each other.
- Communication of the fracture with the outside atmosphere.
How the fractures are described by the NUMBER of their FRAGMENTS?
Simple fracture –> If the fracture produces 2 fragments.
Comminuted fracture –> If it’s more than 2 fragments.
Some comminuted fractures have special names…?
- Segmental fracture –> A portion of the shaft exists as an isolated fragment.
- Butterfly fracture –> The central fragment has a triangular shape.
How fractures are described by the direction of the fracture line?
- Transverse fracture –> Force perpendicular to the shaft.
- Diagonal or oblique fracture –> Force is same direction as the long axis of the affected bone.
- Spiral fracture –> Twisting force or torque produces a fracture like those that might be caused by planting the foot in a hole while running.
By convention, abnormalities of the position of bone fragments secondary to fractures describe the …?
Relationship of the DISTAL fracture fragment relative to the PROXIMAL fragment.
The 4 parameters that are used to describe the relationship of fracture fragments:
- Displacement.
- Angulation.
- Shortening.
- Rotation.
Dislocation of the shoulder and hip - MC?
Shoulder –> Anterior, subcoracoid.
Hip –> Posterior + Superior more common.
Dislocations of the shoulder and hip - Caused?
Shoulder –> By a combination of abduction + external rotation + extension.
Hip –> Knee striking dashboard transmitting force to hip.
Dislocation of the shoulder and hip - Associated?
Shoulder –> With fractures of humeral head (Hill-Sachs lesions) + glenoid (Bankkart lesion).
Hip –> With fractures of posterior rim of the acetabulum.
Displacement describes …?
The amount by which the distal fragment is offset, front to back, and side to side, from the proximal fragment.
How fractures are described by the relationship of the fracture to the atmosphere?
- Closed fracture –> More common.
2. Open or compound fracture.
Avulsion fracture?
Avulsion is a common mechanism of fracture production in which the fracture fragment (avulsed fragment) is pulled from its parent bone by contraction of a tendon or ligament.
Although avulsion fractures can and do occur at any age, they are particularly common in …?
Younger individuals engaging in athletic endeavors.
In fact, they derive many of their names from the type of athletic activity that produces them, eg dancer’s fracture, skier’s fracture, sprinter’s fracture.
Avulsion fractures sometimes heal with such exuberant callous formation that they can be mistaken for a …?
Bone tumor.
Epiphyseal plate fractures are common and account for as many as …% of childhood fractures.
30%.
What classification is commonly used in order to describe epiphyseal plate injuries?
The Salter-Harris classification.
Avulsion fractures around the pelvis - Avulsed fragment = Anterior, superior iliac spine –> Muscle that inserts on that fragment?
Sartorius muscle.
Avulsion fractures around the pelvis - Avulsed fragment = Anterior inferior iliac spine –> Muscle that inserts on that fragment?
Rectus femoris muscle.
Avulsion fractures around the pelvis - Avulsed fragment = Ischial tuberosity –> Muscle that inserts on that fragment?
Hamstring muscles.
Avulsion fractures around the pelvis - Avulsed fragment = Lesser trochanter of femur –> Muscle that inserts on that fragment?
Iliopsoas muscle.
How many types does the Salter-Harris classification involve?
5 types.
Type I and II …?
Heal well.
Type III fractures …?
Can develop arthritic changes or asymmetric growth plate fusion.
Types IV, V are more likely to develop …?
Early fusion of the growth plate with ANGULAR deformities and SHORTENING of the bone.
Type I are fractures of the …?
Epiphyseal plate ALONE.
Type I fractures are … to detect.
DIFFICULT to detect without the OTHER SIDE FOR COMPARISON.
What is a manifestation of type I injury?
Slipped capital femoral epiphysis (SCFE).
Slipped capital femoral epiphysis (SCFE) occurs most often in …?
Taller + Heavier teenage boys.
What does SCFE involve?
Involves the inferior + medial + posterior slippage of the proximal (capital) femoral epiphysis relative to the neck of the femur.
SCFE is bilateral in …?
About 25% of cases.
SCFE may result in …?
Avascular necrosis of the slipped femoral head because of interruption of the blood supply in up to 15% of cases.
Type II is …?
Fracture of the epiphyseal plate and fracture of the metaphysis.
What is the MC type of Salter-Harris fracture?
Type II (75%).
Type II fracture is seen especially in …?
DISTAL RADIUS.
Which sign does type II fracture produce?
Corner sign.
Type III is …?
Fracture of the epiphyseal plate and the epiphysis.
Type III complications:
- Fractures the articular cartilage.
- Long-term implications for the development of osteoarthritis.
- Asymmetric + premature fusion of the growth plate –> Subsequent deformity of the bone.
Type IV is …?
Fracture of the epiphyseal plate, metaphysis, and epiphysis.
Type V is …?
Crush fracture of epiphyseal plate.
Skeletal trauma suspicious for child abuse - Distal femur/distal humerus/wrist/ankle?
Metaphyseal corner fractures.
Skeletal trauma suspicious for child abuse - Multiple?
Fractures in different stages of healing.
Skeletal trauma suspicious for child abuse - Femur, humerus, tibia?
Spiral fractures
Skeletal trauma suspicious for child abuse - Posterior ribs, avulsed spinous processes?
Unusual “naturally occurring” fractures
Skeletal trauma suspicious for child abuse - Multiple skull fractures:
Multiple fractures of occipital bone should suggest child abuse.
Skeletal trauma suspicious for child abuse - Fractures with abundant callous formation?
Implies repeated trauma and no immobilization.
Skeletal trauma suspicious for child abuse - Metacarpal and metatarsal fractures?
Unusual “naturally occurring” fractures
What is the MCC of death in child abuse under age 2 years.?
Head injuries.
- -> SAH, subdural hemorrhages, and cerebral contusions.
- -> Skull fractures tend to be comminuted, bilateral, and may cross suture lines.
Stress fractures - Conventional radiographs?
Although these are the first studies usually obtained, they may initially appear normal in as many as 85% of cases.
–> Patient complains about pain, yet the radiograph is normal.
A stress fracture may NOT be diagnosable until …?
After periosteal new bone formation occurs OR, in the case of a healing stress fracture of cancellous bone –> The appearance of a thin dense zone of sclerosis across the medullary cavity.
In a patient with a stress fracture, what will be positive very early?
Radionuclide bone scans - within 6-72h after the injury.
Common locations for stress fractures are …?
The shafts of long bones such as the proximal femur or proximal tibia, as well as the calcaneous and the 2nd and 3rd metatarsals (march fractures).
Scaphoid fractures are clinically suspected if there is a …?
Tenderness in the anatomic snuff box, after a fall on an outstretched hand.
