1
Q
osteoblasts
A
secrete and mineralize ECM and develop into osteocytes
2
Q
osteocyte
A
start out as osteoblasts and switch from a matrix forming role to a load sensing and adaptation role; are contained with lacunae
3
Q
osteoclast function
A
break down/ resorb bone
4
Q
what forms the balance between bone forming and bone breakdown?
A
osteoblasts and osteoclasts
5
Q
what is the process that creates bone?
A
endochondral ossification which creates cartilage then replaces it with bone
6
Q
intramembranous ossification
A
no cartilage precursor stage and is the process where flat bones are formed; the bone is formed between two sheets of periosteum
7
Q
example of 2 bones formed by intramembranous ossification
A
flat bones like skull and scapula
8
Q
endochondral ossification
A
is the replacement of cartilage with bone and is the primary bone creation template
9
Q
what does remaining cartilage in bone form?
A
the articular surfaces
10
Q
diaphysis
A
the shaft of the bone
11
Q
epiphysis
A
the ends of the bone
12
Q
bone covering name
A
periosteum
13
Q
what is contained within the endosteum?
A
stem cells that can facilitate repair
14
Q
what is our bone marrow at birth?
A
all red marrow, so a lot of RBCs are contained here
15
Q
in adults, where is red bone marrow found?
A
mainly in the flat bone and at the proximal ends of the femur and humerus
16
Q
where is yellow bone marrow found?
A
the hollow interior of the middle portion of long bones
17
Q
risk of yellow bone marrow with fractures
A
fat embolism: can escape into the bloodstream and the fat contained in here can cause dangerous clots
18
Q
vascular supply of bone
A
10-20% of CO
19
Q
other names for compact bone
A
dense or cortical
20
Q
other names for spongy bone
A
trabecular or cancellous bone
21
Q
what is the main structure forming cortical bone?
A
haversian canals
22
Q
what lines haversian canals?
A
osteoblasts and osteoclasts
23
Q
what do haversian canals contain?
A
nerve and blood supply
24
Q
4 steps of bone making
A
resorbition, reversal, formation, and resting
25
reversal phase
transitional period between bone formation and breakdown where bone is being cleaned up
26
resorption phase
bone breakdown by osteoblasts
27
formation phase
creation of new bone by osteoblasts
28
resting phase
is when the remodeling site is inactive and has been filed
29
what is it called when a tumor makes a bone break?
metastatic fracture
30
lacunae
holds osteocytes that are surrounded by collagen, sending messages to other cells via canaliculi
31
canaliculi
are collagen extensions of the lacunae, allowing osteocytes to send messages to each other regarding load bearing
32
significance of haversian canal
blood and nerve supply for bone
33
bone multicellular unit
refers to the balance between osteoblasts and osteocytes for bone formation and breakdown
34
accessory/supernumerary bone
means more than one bone; this can occur via a secondary ossification centre that doesn't fuse
35
most common accessory/supernumerary bone
when the posterior aspect of the talus doesn't fuse with the tibia
36
what is the structure for bone mechanical responsiveness?
canaliculi
37
tethering filaments
respond to stretching during mechanical loading and is part of the lacunae/canaliculi structure
38
what happens when bone is compressed
fluid flows through canaliculi and produces a mechanical stimuli that sends a cellular signal telling osteoclast activity to decrease and for osteoblasts to increase in activity
39
net result of increased mechanical loading on bone
increased cortical cross sectional area, increased density of trabeculae, and alignment of bone along lines of stress, resulting is overall more strong and dense bone
40
cell activity as a result of unloading on bone
decreased osteocyte signaling and osteoblast activity and increased osteoclast activity
41
results of unloading on bone
osteoporosis, increased size of medullary cavity, reduced cortical thickness and trabecular density, and weakened bone, causing a higher risk for fractures
42
normal rate of bone loss with aging
1% per year
43
normal rate of bone loss with bed rest
1% per month
44
bone development in adolescence between genders
about a quarter of adult bone is formed between 12-13 in girls and 14-15 in males
45
other name for comminuted fracture
crush fracture
46
greenstick fracture
occurs in younger bones, causing one side of the bone to be concave and for the other side to be stretched
47
salter-harris fracture
is when the fracture goes through the growth plate in children
48
types I and II salter-harris fractures
don't interfere with growth because it is right below the growth plate
49
most common salter-harris fracture
type II, makes up about 75% of these fractures
50
types III to V salter-harris fractures
can affect growth due to going through growth plate, causing growth abnormalities
51
pathologic fractures
are due to pathological conditions weakening bone and making it more susceptible to fractures, ex. tumor
52
falls and those aged 65+
10% of falls results in fractures
53
risk of fractures between the genders
women are more prone to fractures, especially hip fractures (2x more than men)
54
colles fracture
fracture of the distal radius due to falling on the hand
55
mortality rate of fractures in aged 65+
6%
56
risk factors for fractures
age, low bone mineral density, underlying bone conditions, and an increased risk of falling (like dizziness)
57
what pathological response is there after a fracture?
necrosis of bone fragments, clot reaction, and inflammatory response
58
complications of fractures
shock (loss of BP), fat embolism, deep vascular thrombosis, compartment syndrome, avascular necrosis, infection, and early OA development
59
deep vascular thrombosis
a blood clot formed in veins, usually in the leg
60
avascular necrosis
is death of bone tissue due to a lack of blood supply
61
high risk fractures for avascular necrosis
proximal femur, base of 5th metatarsal, proximal humerus, scaphoid, and neck of talus
62
why do some fractures have a high risk for avascular necrosis?
due to their proximity to blood supply
63
primary bone healing
occurs if bony ends are in exact contact, this is a slower process but is cleaner with less inflammation
64
secondary bone healing
occurs when there is a gap between bones and there is a bigger inflammatory response, forming a larger callous
65
is primary or secondary bone healing faster?
secondary
66
how does a callous form?
bleeding causes a hematoma to form, followed by a fibrin mesh and granulation tissue which later forms a fibrocartilage procallus. It then forms a bony callus, followed by regeneration and a healed bone
67
is their scar tissue with bone healing?
no, the scar tissue is new bone
68
complications of fractures
joint contractures/adhesions, muscle weakness, infection, and union problems
69
malunion meaning
is when bones don't align well
70
cross-union meaning
occurs when bone aligns with the wrong bone
71
hypertrophic non-union
the bone has attempted to join together but there is a mini joint formed due to so much movement, preventing it from stabilizing well
72
atrophic non-union
when bone has not finished joining, common in those with diabetes
73
what is used to diagnose stress fractures?
bone scans
74
what is used to diagnose fractures of irregular bones?
CT scans
75
ottawa ankle fracture rules
tenderness at posterior lateral or medial malleolus, base of 5th metatarsal, and navicular
76
when does fracture rehab begin?
once the fracture is healed, when there is absence of pain when weight bearing, and when there is no tenderness on palpation
77
osteomyelitis
occurs with open fractures when inflammation of bone occurs due to invasion by a pathogen
78
common pathogen for osteomyelitis
S. aureus
79
risk factors for osteomyelitis
open fractures, diabetes, use of steroids, tobacco, cancer, and poor nutrition
80
pathophysiology of osteomyelitis
local accumulation of pus during inflammatory response, causing new bone to form in response to cytokines which forms a sinus tract through soft tissues and often to the joints
81
signs of osteomyelitis
cardinal signs of inflammation and systemic signs like fever
82
treatment of osteomyelitis
intravenous antibiotics which are more powerful, followed by oral antibiotics and then PT treatment
83
what is the classification of osteoporosis?
below 2.5 standard deviations below the young adult reference mean
84
what is the classification of osteopenia?
below 1-2.5 standard deviations below the young adult reference mean
85
risk of fractures with osteoporosis
is x10
86
fragility fracture
is a pathological fracture in someone who fell from standing height or less, reflects very fragile bones compared to normal bones
87
common sites for fragility fractures
neck of femur, vertebrae, or distal radius
88
severe osteoporosis
is below 2.5 standards deviations of young adult population and a history of one or more fragility fracture; these individuals are at 25x risk
89
primary osteoporosis
includes senile, post-menopausal, and idiopathic forms
90
secondary osteoporosis
related to another pathology like cushing's due to chronic corticosteroid use or parathyroidism
91
body build relationship to osteoporosis
lighter individuals are more prone to this due to less loads on bones, thus less adaptation from mechanical loading
92
risk factors for osteoporosis
age, women, menopause, light frame, poor diet, low PA, and hereditary factors
93
predisposed bones to osteoporosis
vertebrae and femoral neck
94
how is osteoporosis diagnosed?
bone mineral density test
95
first symptom of osteoporosis
may be a fracture, kyphosis, or loss of height
96
medical care for osteoporosis
calcium, vitamin D, calcitonin, bisphosphonates, and raloxifene (also more)
97
PT treatment for osteoporosis
exercise prescription, muscle strength, balance, posture (for kyphosis), and osteofit class
98
osteofit
is developed by UBC and uses jumping and balance control for osteoporosis
99
stress fracture
is a fatigue fracture which develops due to excessive stress/strain in the bones
100
who are at high risk for stress fractures?
runners and ballet dancers
101
most common sites for stress fractures
tibia (most common), metatarsals, and femur
102
intrinsic risk factors for stress fractures
pronation of foot, leg length, excessive weight, and vitamin D and calcium intake
103
extrinsic risk factors for stress fractures
overuse, footwear, and training surfaces
104
pathophysiology of stress fractures
normal cracks in bone outpace the renewal activity by osteoblasts, leading to larger cracks
105
signs and symptoms of stress fracture
a gradual onset of bone pain with a history of overloading
106
is there a callus with a stress fracture?
no, unless very large
107
diagnostic test for stress fracture
MRI (allows you to see the edema) or bone scan
108
PT treatment is no stress fracture on X-ray
gradually decrease the loading for a few weeks then return to sport, treated more like an overuse injury
109
what stress fractures require more treatment?
navicular, base of 5th metatarsal, base of 2nd metatarsal, femoral neck, and anterior tibial cortex
110
navicular stress fracture treatment
8 weeks in a non-weight bearing cast and can be a career stopping injury
111
femoral neck stress fracture signs
chronic hip pain in a runner
112
femoral neck stress fracture treatment
bed rest for a week followed by gradual reloading
113
compression vs tension side femoral neck stress fracture
tension side is more serious (this is the inferior side of the femur neck)
114
anterior tibial cortex stress fracture
6-8 weeks on crutches, in aircast boot, or intramedullary screw fixation
115
2nd metatarsal stress fracture treatment
non-weight bearing for 2 weeks
116
jone's position meaning
stress fracture of the 5th metatarsal
117
stress fracture of 5th metatarsal treatment
6 weeks cast immobilization
118
risk of stress fracture of 5th metatarsal
bone can become necrotic
119
medial tibial stress syndrome
interchangeable term for shin splints
