Bone Flashcards
Bone fx and Bone Histology
Define fracture
A break in the structural continuity of bone or cartilage
List the causes of a fracture
External Forces - Trauma
Internal Forces
Pathologies
List the signs of fractures
Deformity of the bone Edema Ecchymosis Loss of general function WB pain
Risk factors for a fracture
Bone demineralization
Trauma
List the forces that can cause fractures
Tension
Compression
Bending
Torsional
List the symptoms of fractures
pain
point tenderness
increased w/vibration or tapping
What are Greenspan’s 7 elements for complete description of fractures
- site and extent
- type (complete or incomplete)
- alignment
- direction of lines
- special features
- associated abnormalities
- special types
What is a comminuted fracture
More than two pieces of bone caused by higher load or trauma
segmental (across) or butterfly (down and across)
How do you describe fracture alignment
Distal segment relative to proximal
What is a displaced fracture
loss of contact b/t the two fragments
What is angulation?
Displacement of the distal fracture fragment, named by the direction of the apex formed
Describe Displacement:
Shifted
Fx surfaces not in contact w/one another & apposition is present
Describe Displacement:
Distracted
Ends are separated and pull apart from each other
Describe Displacement:
Overriding
Mm spasms w/injury causing bones to be pulled past each other and shortening it
Describe Displacement:
Distracted and rotated
Looks straight but is actually rotated about its longitudinal axis
Transverse Fracture
Perp to long axis of bone, caused by a bending force and usually retains its alignment
Longitudinal fracture
Parallel to long axis of bone, caused by a repetitive stress or extension of oblique fx
Risk: tibial in runners jumpers and old women
Oblique fx
across the bone, caused by combined forces of axial compression, bending and torsion, requiring moderate energy
Spiral fx
jagged points across bone, caused by a low energy torsion force and heals better due to pieces fitting together, but edges can damage soft tissue
Avulsion fx
at end of tendon or ligament caused by tensile loading of the bone from a forceful mm contraction
Butterfly fx
A comminuted fx from compression and bending forces, w/fx on side of concavity
impaction fx
Bone is driven into itself, shortening the bone from a axial compression force
What are the two types of impaction fractures
Depression: stronger bone into weaker bone
Compression: axial loading which compresses one side and puts traction on the other
List the special types of fractures
stress
pathological
periprosthetic
bone graft
What is a stress fracture
High frequency, low level loading fx from repetitive fatigue
what is a pathological fracture
systemic or local fx from a disease process
what is a periprosthetic fx
occur in association w/prosthetic joint replacement, years after operation
what is a bone graft fracture
2-3 years after a reconstruction surgery from defects in the screw holes
What are some fx in children
Greenstick - fx on tension side but cortex and periosteum still intact on compression side Plastic bowing Torus fracture (buckle) - of cortex
What is the SALTER-harris classification for
epiphyseal fractures in children
What does SALTER stand for?
S - straight across A - above L - lower / beLow T - through ER - Erase growth plate
What is the Tscherne Classification for?
Soft tissue injury in closed fx
BONUS CARD!
YOU’RE DOING GREAT!!! KEEP GOING :)
What is the Gustilo Classification for
Open fractures, and is based on the size of the wound
What are the fracture complicatoins
Nonunion - failure to unite
malunion - healing, but a deformity results angular or rotary
delayed union - slow
posttraumatic OA
pseudoarthrosis - false joint associated w/non-union ends
What are the 5 Ps of compartment syndrome?
Pain Pallor Paresthesia Paralysis Pulselessness
What are open fx complications
Nerve injury arterial injury infection complex regional pain syndrome limb length discrepancy
T or F: Fx can cause life threatening complications
True - fat embolisms, pulmonary embolism, gas gangrene, and hemorrhages can occur 2nd to fx
What are some of the fx healing considerations
Aging (adults slow, kids 2x)
Nutritional challenges (Vit D and Ca+ def)
Co-morbidities (bowel diseases)
Blood supply (poor circulation, smoking, vascular disease)
site and type of fx
What heals faster, cancellous or cortical bone
Cancellous (trabecular/spongy) bone since it has an abundant blood supply
What heals faster, spiral or transverse fx
spiral
What heals faster, UE or LE fx
UE
Cortical Bone Healing: Inflammatory stage
0-3 days after fx, w/mesenchymal cells to envelop fx w/a fibrin clot formed b/t the two ends
What happens if fx gap is….
< 10 micrometers
> 10 micrometers
< 10 - no bone death and Haversian remodeling occurs
> 10 - bone heals w/secondary bone
Cortical Bone Healing: Proliferative stage
Fibrin clot (osteogenic and condrogenic cells, osteoclasts) –> soft callus (fibroblasts, blood vessels, cartilage and new bone)
Cortical Bone Healing: Reparative stage - ossification phase
Callus absorbed and replaced by woven bone
What is a clinical union and what stage is it found in
Callus has united at fx site –> during proliferative site
what is an early union and what stage is it found in
trabecular fx pattern identifiable and crosses fx lines –> in ossification phase of reparative stage
Cortical Bone Healing: Reparative stage - consolidation phase
14-40 days after fx w/osteoclasts and osteoblasts filling in the gaps b/t the fragments w/new bone
what is an established union and what stage is it found in
Appearance of cortical structure and remodeling occurs along the lines of stress –> during consolidation phase of the reparative stage
In what stage of cortical bone healing can you be FWB
Consolidation phase of reparative phase
what is a fibrous union
clinically stable, pain-free fx w/o radiological evidence of fracture line repair remaining
When is the repair of a fx complete
when the bone density is normal
How does cancellous bone heal
little to no callus formation, intramembranous ossification
Timeline of fx healing:
UE vs LE
Callus visible by x-ray: 2-3 weeks BOTH Ossification: 4-6 weeks UE, 8-12 weeks LE Consolidation: 6-8 weeks UE, 12-16 weeks LE
What is reduction and when should you do it
It is the realignment of a fx site, done w/in 24 hours before swelling makes it difficult
what is a closed reduction
Nonsurgical reduction for minimal displaced fx
1 - distal part pulled in line
2 - reposition
3 - adjust align in each plane
4 - checked w/radiography after the reduction
what is an open reduction
requires surgery & done when closed reduction fails. Soft tissue in b/t fx ends
What are the ways to splint a fracture
Continuous traction - gravity alone, skin traction, skeletal
Cast
Functional bracing
What is involved with internal fixation
Rods/Nails for stability
compression plate to shield fx site from stress
buttress plates - to absorb some of the stress
What are some common complications of internal fixation
infection
non-union
implant failure
re-fracture
what are indications for external fixation
- fx w/severe soft tissue damage
- nerve or blood vessel damage
- severely comminuted/unstable
- pelvic
- infected
What are the benefits to external fixation
- more mobile,
- maintain alignment and length
- stress sharing
What are the complications of external fixation
infections
delayed union
What are the 4 major functions of bone
Provide: - structural support - protection of vital organs - environment for marrow To act as mineral reservoir for Ca+ homeostasis in the body
What are osteogenic cells
(from mesenchymal layer) Precursor to osteoblasts located in the endosteum and periosteum of bone
what are osteoblasts
sticky bone forming cells found near the surface of the bone layer that function in synthesis in secretion of osteoid.
(Can’t divide. Mobilized by thyroid)
what are osteoids
organic, un-mineralized component of cell matrix secreted by osteoblasts to provide the foundation for the minerals (like Ca+) to be deposited into
what is the bone matrix
formed from osteoid and inorganic mineral salt deposited within the osteoid
what are osteocytes
osteoblasts that have become trapped within the bone matrix and now function to maintain it
what are osteoclasts
derived from macrophage-monocyte system, multi-nucleated bone absorbing cells found on the bone surface to secrete hydrolytic enzymes to dissolve bone
what are osteonss
bone cylinders that contain the osteocytes and the bone matrix –> consists of lamellae and haversian canals
how can you differentiate osteoclasts from osteoblasts
osteoclasts have a ruffled border to increase SA and are multinucleated
What are the three types of bone
Woven
Lamellar, primary
lamellar, secondary
Which bone type is the weakest
woven bone
Where do you find wonven bone
adult tooth sockets, sutures of the skull
What type of bone is the first formed following a fracture
woven bone
what is woven bone
It consists of collagen fibers irregularly woven, osteocytes in lacunae irregularly dispersed to serve as a model from which primary and secondary bone can develop
What is a haversian system
a structural unit w/long cylinder parallel to long axis of bone for blood flow
What is lamellar primary bone
Compact/cortical bone (dense w/o marrow spaces) composed of haversian, circumferential, and interstitial systems
What is primary cancellous bone
Trabecular/Spongy bone that is oriented according to the stress placed on the bone (wolff’s law)
what is secondary bone
It is present during bone healing
What is the difference between secondary and primary osteons
Secondary are larger, have larger haversian canals, and are surrounded by a cement line b/t the osteon and the bone matrix
what is the periosteum
Dense fibrous connective tissue and inner cellular layers that acts as the external lining of all bone except at joints
what is the endosteum
a single layer of osteoprogenitor cells, osteoblasts, osteoclasts nad a small amount of CT that acts as the inner lining of thing specialized CT
What 3 events occur during bone remodeling?
ARF
Activation
Resorption
Formation
What is remodeling
The resorption and replacement of existing bone
What are the triggers for start of bone remodeling
Low serum Ca+ High blood Ca+ Skeletal microdamage Mechanical stimulus Mass needs of skeleton
What happens if there is low blood calcium
Parathyroid gland sense low blood Ca+ –> secrete PTH –> stimulates osetoclast activity –> reabsorb Ca+ from broken down bone –> blood Ca+ rises to normal
What happens if high blood calcium
thyroid gland senses high blood Ca+ –> secretion of calcitonin–>hormone stim osteoblast activity –> form of bone to remove Ca+ –> blood Ca+ falls to normal
What is the norm for Ca+ blood levels
- 10s for teens and YA
9s in adult hood
What is resorption
osteoclastic torpedo shape front line that secretes acid phosphatase, and other proteolytic enzymes to cut through bone
What is formation
osteoblasts follow osteoclastic front and deposit new bone (slower than osteoclast) that will calcify 8-10 days after matrix deposited
Timeline for bone healing
2.5 weeks usually
1 week after start of osteoclast –> formation –> 8-10 days later it calcifies
at what age is there an accelerated decline of bone
55 +
how much bone density is lost per year
approx 1% w/women more than men
what happens to bone as you age
Decreased minerals, water, and proteoglycans in the bone, causing it to be more likely to break.
Overall loss of bone tissue due to balance in abs and formation changing, leading to osteoporosis development.
What are the 4 main categories of Bone diseases/disorders
Bone death
Infection
Disruption of deposition/resorption
Bone tumors
What is the pathology behind osteonecrosis
Loss of blood supply causing death of bone and bone marrow (NO INFECTION), can be caused by trauma, stress, fluid buildup or genetic factors
What areas are commonly affected by osteonecrosis
Hip and shoulder!
knee, talus, jaw, carpals
Risk factors for oseonecrosis
- Corticosteroid use
- Men
- Alcohol abuse
- Secondary to sickle-cell anemia, gaucher, lupus, cassion’s disase, etc
What are the clinical manifestations of osteonecrosis
Insidious onset of localized bone pain w/WB in LE and swelling
What is trademark of osteonecrosis on imaging
Snowcap sign = dense sclerosing over the joint surface head
Stages of osteonecrosis
- abnormal scan - intense pain inc w/ WB
- radio show sclerosing (MRI best)
- bone begins to decay and collapse
- bone collapses, joint space narrows, bone cells die
Osteonecrosis in children
Interruption of blood supply to the bone (particularly the epiphysis)
AKA: aseptic necrosis (newborns), osteochondritis, legg calve perthes
What is Potts disease
tuberculosis that has progressed to the spine (mainly thoracic) causing an inflammatory process where granulation tissue erodes the cartilage and cancellous bone, causing demineralization and fractures
What are the s/s of tb
pain localized/referred, fever, chills, weight loss, fatigue, pain
Dx w/PA chest x-ray, TB tests, tissue cultures and tissue biopsy
What’s the onset of TB
insidious w/2-3 years after primary TB infection
what is osteomyelitis
Infection of bone marrow introduced into body through some sort of trauma, including iatrogenic sources (more commonly in spongy bone)
what is the pathology of osteomyelitis
Leukocytes enter infected area releasing an enzyme to lyse bone causing bus to enter blood stream and impair blood flow, leading to necrosing bone
S/S Osteomyelitis
fever fatigue edema erythema tenderness LOF
What is the treatment for osteomyelitis? PT?
Antibiotics w/PT low key until infection under control as they are at risk for fractures w/WB activities
What are two types of disruption of deposition/resorption of bones
Osteomalacia (RICKETS)
Osteoporosis
What is osteomalacia
A metabolic bone disease from a lack of vitamin D either due to reduced absorption or increased loss of renal phosphates that can develop at the epiphyseal plate in kids (Rickets) leading to decreased bone strength
What are the risk factors of osteomalacia
- little exposure of sunlight
- inadequate diet, increase in antacid
- housebound
- GI disorders
Clinical Manifestations
off Osteomalacia
Chronic Fatigue Generalized bone pain Muscle weakness Hypocalcemia Psuedofractures Postural deformities Late stages: waddling gait, difficulty climbing stairs or getting up from a seated position
What medical tests do you do for osetomalacia
Lab tests Urine analysis (Ca+ and phosphate) Bone scan - bone metabolic activity Radiograph - looser's zones Bone biopsy
Define osteoporosis
decrease in bone mass and increase in susceptibility to fracture bone in the absence of bone loss
(increased haversian canals, incomplete refilling)
What are risk factors to osteoporosis
Females after menopause
S/S Osteoposrosis
- Bone pain w/fx
- Kypotic deformity after fx (compression fx)
- 30-50% bone loss to show on x-ray
- Nuclear bone scan > radiography
Treatment for Osteoporosis
- CANT GET BACK TO NORMAL
Rx: preventative, med, bracing, general conditioning w/WB, Vit D and Ca+ - Sx: if progressive and isntabilty of spine
List the types of bone tumors
- Benign Bone Tumors
- Osteoid Osteoma
- Osteosarcoma
- Osteoblastoma
- Ewings Sarcoma
What is a neoplasm
An abnormal growth of cells that can be malignant or benign
What are benign bone tumors
Like a bone island that is round/oval in shape and small in size (<1cm)
What is an osteoid osteoma
A rare benign vascular osteoblastic tumor found in the cortex of long bones, more common in males < 25 yo.
What is an osteoblastoma
A benign reactive lesion that is more aggressive and will expand, typically found in the sacrum, spine, and flat bones in men < 30 yo.
Symptoms of osteoid osteoma vs osteoblastoma
Osteoid osteoma has a local gradual increase in pain that can be relieved by aspirin whereas an osteoblastoma is pain not relieved with aspirin.
What is an osteosarcoma
A malignant, destructive tumor that destorys bone cortex, mostly in the long bones and spine in males <30 yo
What are the s/s of osteosarcoma
Severe pain for > 1 month, edema, decreased ROM, and tenderness
What is ewings sarcoma
A cancerous tumor of bone or soft tissue more commonly in the pelvis or LE in those <20 yo
What are the risk factors of ewings sarcoma
Caucasian
Family exposure to pesticides, fertilizers (farmers)
Second hand smoke (parental smoking)
What are the sx of ewings sarcoma
Local bone pain edema
Difference b/t:
- osteoid osteoma
- osteoblastoma
- osteogenic sarcoma
- small benign tumor in cortex –> slightly larger in cortex into trabecula –> malignant and covering whole bone
What is multiple myeloma
A primary cancerous caner that involves bone marrow w/s/s of osteopenia, holes, sclerosing of bone, deep bone pain
