Bone Fractures Flashcards

1
Q

mechanical functions of bone

A

*skeleton plays a critical structural role in bearing functional loads
*weight-bearing and muscle loads
*bones act as levers (rigid bodies) to help our musculoskeletal system perform a task

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

types of mechanical loading

A

*compression/tension
*bending
*shear
*torsion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

bone remodeling & turnover

A
  1. osteoBlasts = BUILD bone; derived from mesenchymal stem cell line
  2. osteoClasts = CRUSH bone; derived from hematopoietic stem cell line
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

strength of bone

A

*strength = load bone can bear before breaking
*dependent on: 1) total bone mass; 2) geometric distribution; 3) material properties / tissue composition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

simple fracture patterns, correlated to loading mode

A
  1. tension → transverse fracture
  2. compression → oblique fracture
  3. bending → butterfly fracture
  4. torsion → spiral fracture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

common adult fracture morphologies

A

*transverse
*oblique (nondisplaced or displaced)
*spiral
*comminuted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

common pediatric fracture morphologies

A

*greenstick (one side broken but other side is not)
*torus
*SALTER classification describes pediatric fractures that occur near a growth plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

pediatric non-accidental trauma

A
  1. spiral fracture patterns in non-ambulatory children
  2. corner fractures

*these 2 fracture patterns raise red flags for non-accidental trauma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

common causes of fractures

A
  1. trauma
  2. fatigue
  3. pathologic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

common causes of fractures: TRAUMA

A

*injury can be one of two mechanisms:
1. direct force - bone breaks at the point of impact; soft tissues also damaged
2. indirect force - bone breaks at a distance from where the force is applied
*typically acute, high energy, and happen when the load exceeds the strength of the bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

most commonly fractured bone

A

CLAVICLE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

clavicle fractures

A

*mechanism: compression → oblique pattern
*initial tx: sling for comfort
*caution: neurovascular exam
*definitive treatment:
-non operative normally
-surgery if 100% displaced or open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

FOOSH - acronym and fractures that result from this mechanism

A

*FOOSH = fall on outstretched hand
*several fractures can result from this mechanism:
-distal radius
-monteggia
-galeazzi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

distal radius fractures

A

*common mechanism: falling on an outstretched hand
*compression mechanism
*initial tx: reduction, splint
*caution: acute carpal tunnel syndrome
*definitive tx: surgery if unstable or alignment not acceptable after reduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

monteggia fractures

A

*ulna fracture with dislocation of the radial head
*bones affected proximally
*can occur from FOOSH
*initial tx: splint
*caution: compartment syndrome risk
*definitive tx: operative

MUgger acronym:
-M = Monteggia
-U = ulnar fracture (w/ dislocation of radial head)
-A (monteggia ends in A): A is proximal in the alphabet, so bones affected proximally (close to the elbow)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

galeazzi fracture

A

*radius fracture with dislocation of the distal radioulnar joint
*bones affected distally
*can occur from FOOSH
*initial tx: splint
*caution: compartment syndrome risk
*definitive tx: operative

mugGeR acronym:
-G = galeazzi
-R = radius fracture (w/ dislocation of distal radioulnar joint)
-Z (galeezZi has a Z at the end): Z is distal in the alphabet, so bones are affected distally (near the wrist)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

scaphoid fractures

A

*evaluation: X-rays can be negative; repeat X-ray in 2 weeks or MRI to detect fracture
*presents with tenderness, swelling, pain in snuffbox region
*initial tx: thumb spica cast
*definitive tx: surgery if displaced or not healing
*caution: risk of AVN (avascular necrosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

common causes of fractures: FATIGUE / STRESS FRACTURES

A

*occur in normal bone, subject to repeated heavy loading, typically in athletes, dancers, or military personnel
*drugs like steroids and methotrexate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

stress fractures

A

*evaluation: X-ray first; repeat X-ray in 2 weeks or MRI to detect occult fracture
*initial tx: immobilization, weight-bearing restriction
*surgery if displaced or not healing
*consider endocrinology evaluation if no other cause

20
Q

common causes of fractures: PATHOLOGIC

A

*caused by condition/disease that led to weak bone
*low energy
*most common cause = osteoporosis
*other conditions: hyperparathyroidism, cancer, infection, bone disorders, bone cysts

21
Q

how aging can contribute to fracture risk

A

*normal physiologic aging → decreased bone mass, decreased bone strength, increased brittle bones → increased fracture risk
*bone remodeling = mechanical compensation: shifting effective bone to periphery
-increased moment of inertia as the cortex thins
-increased resistance to bending and torsion

22
Q

osteoporosis & fragility fractures

A

*osteoporosis: disease characterized by low bone mass + structural deterioration
*increased bone fragility and fracture risk
*most common fragility fractures = spine, hip, wrist

23
Q

factors increasing risk of fragility fractures

A

*increased age (routine screening at age 50)
*gender - more common in WOMEN
*physical inactivity (weight-bearing exercise is good!)
*nutritional problems, including lack of calcium and vitamin D
*chronic medical conditions - endocrine & intestinal disorders
*glucocorticoids
*tobacco & alcohol use
*previous fractures
*family history of osteoporosis

24
Q

evaluation of a patient with skeletal trauma: general signs

A
  1. follow ABCs (airway, breathing, circulatory problems, C-spine injuries)
  2. secondary survey - examine the main injury, ascertain type of fracture, classify
  3. brief history, including history of trauma (ascertaining the mechanism of injury is important)
25
evaluation of a patient with skeletal trauma: SYMPTOMS
*pain *bruising *swelling *numbness or loss of movement *deformity - more suggestive of a fracture
26
evaluation of a patient with skeletal trauma: physical exam
1. LOOK: -swelling, bruising, deformity -examine whether the skin is intact -note the posture of extremity and color of skin 2. FEEL: -gently palpate injured part -test vascular and peripheral nerve abnormalities 3. MOVE: -crepitus & abnormal movement may be present -more important to ascertain if the patient can move the joints distal to the injury
27
fracture description: closed vs. open
*closed = skin intact *open = open wound in skin communicates with fracture site (requires prompt administration of antibiotics to reduce risk of infection) -usually a 1st generation cephalosporin
28
X-ray investigation of fractures
*X-ray examination is MANDATORY for any trauma, injury, or bony to palpation *rules of twos: 1. 2 VIEWS - lateral and AP 2. 2 LIMBS - especially in children 3. 2 JOINTS - should be able to see joint above and below the fracture 4. 2 INJURIES - severe force often causes injuries at more than one level 5. 2 OCCASIONS - if you don't see a fracture but suspect it, repeat X-ray 2 weeks later
29
final description of fractures
1. open vs. closed 2. which bone is broken? where? 3. has it involved a joint surface? 4. what is the shape of the break? 5. is it stable or unstable? 6. is it a high-energy or low-energy injury?
30
indications for advanced imaging in fractures: CT SCAN
*peri-articular fractures: -tibial plateau -pilon fractures -pelvic ring/acetabular fractures -foot fractures *pathologic lesions - bony *tumor/oncologic processes
31
indications for advanced imaging in fractures: MRI
*suspected ligamentous or other intra-articular injury: -spine -shoulder (rotator cuff) -knee (ACL, PCL, etc) *stress fractures *tumors/oncologic processes
32
advanced imaging in fractures - overview
*should only follow a plain film for the purposes of: -further clarifying the injury/disease process to aid in the development of a treatment plan OR -when needed in the setting of otherwise normal x-rays to help diagnose or better delineate anticipated pathology that cannot be seen on plain x-ray
33
primary bone healing
***INTRAMEMBRANOUS OSSIFICATION: woven bone formed directly, without cartilage** 1. cutter cones re-establish Haversian structure of cortex 2. osteoclasts at tip of capillary bud cuts tunnel into cortical bone 3. behind this a cuff of osteoblasts lay down new concentric lamellae *in order to have primary bone healing, need absolute stability; rigid fixation *strain < 2%
34
secondary bone healing
***ENDOCHONDRAL OSSIFICATION (cartilage precursor before healing with bone)**: 1. stage 1 = tissue destruction and hematoma formation (7 days) 2. stage 2 = inflammation and cellular proliferation/granulation tissue (2-3 weeks) 3. stage 3 = callus/woven bone formation (4-12 weeks) 4. stage 4 = remodeling into compact bone (1-4 years) *occurs with non-rigid stabilization *strain 2-10%
35
mechanisms of bone fractures: tension
*when the bone is **pulled apart from top to bottom**
36
mechanisms of bone fractures: compression
*when forces are applied to the bone from both the top and bottom of bone ***"squishes" the bone**
37
mechanisms of bone fractures: bending
*when force on the bone causes it to distort into a curved shape *ex: greenstick fracture in pediatrics
38
mechanisms of bone fractures: shearing
*when nontwisting pushing or pulling forces are applied to the top and bottom of a bone in opposite directions
39
mechanisms of bone fractures: torsion
*when TWISTING forces are applied to the top and bottom of a bone in opposite directions *like wringing out a towel
40
mechanisms of bone fractures: avulsion
*when part of the bone is forcefully torn away from the rest of the bone
41
Salter-Harris classification of growth plate injuries: type 1
*fracture runs **straight across** the growth plate *the epiphysis is separated from the metaphysis
42
Salter-Harris classification of growth plate injuries: type 2
*involves a fracture **above the growth plate,** through the bony metaphysis *most common type of growth plate injury
43
Salter-Harris classification of growth plate injuries: type 3
*fracture is **lower than / below the growth plate** *involves a horizontal fracture through the growth plate and a vertical fracture of the epiphysis, creating a right angle
44
Salter-Harris classification of growth plate injuries: type 4
*fracture **through the metaphysis + growth plate + epiphysis** vertically at an angle
45
Salter-Harris classification of growth plate injuries: type 5
*fracture is due to a **compressive force that crushes (erases) the growth plate** by pushing the epiphysis into the metaphysis