Fractures Flashcards
Bone Function
- Stability
- Mobility
- Hematopoiesis
- Protection of vital organs
Bone Layers
Cortex
- Hard, outer layer
- Covered by the periosteum
> Thick
> Contains vessels, nerve endings, & cells
> Repairs fractures
Cancellous bone
- Soft, inner layer
- Covered by the endosteum
Physis
Regions of long bone growth
- Highly vascular
- Prone to infections & fractures
Metaphysis
- Largely consists of spongy, cancellous bone
- Most susceptible region to compression fractures
Diaphysis
- Thick cortical bone
- Provides most of the structural support
Fracture
A disruption in the continuity or structural integrity of bone
- Occurs when stress applied to the bone is greater than the bone’s intrinsic strength
- Bone withstands high compressive force (BUT, susceptible to breaks from tension/torsion)
- Fractures involve the bone & surrounding soft tissue (e.g. periosteum, muscles, & vessels)
- open fractures = skin involvement*
Fracture Classifications
- Location
- Orientation
- Extent of fracture lines
- Amount of displacement
- Skin integrity
Clinical Sxs of Fractures
- Pain
` Worsened by movement
` May limit weight-bearing capacity - Swelling
- Decreased function
- Visible deformity w/ displaced fractures
- Numbness/tingling w/ injury to nerves or vessels
Open vs. Closed Fracture
Closed
- Skin over & near fx is intact
Open
- Skin over & near fx is lacerated or abraded by the injury
Types of Fracture Displacement
Non-displaced
*Fragments in anatomic alignment
Displaced
*Fragments NOT in usual alignment
Angulated
*Fragments are malaligned
*Displaced from midline
Bayonetted ("shortened")
*Distal fragment overlaps proximal fragment
Distracted
*Gap b/t distal & proximal fragmentsOrientation of Fracture Lines
- Transverse
- Comminuted
- Oblique
- Segmental
- Spiral
- Intra-articular
- Torus
- Greenstick
Transverse Fx
A fracture that is perpendicular to the shaft of the bone
Comminuted Fx
A fracture in which there are more than 2 fracture fragments
Oblique Fx
An angulated fx line
Segmental Fx
A type of comminuted fx in which a completely separate segment of bone is bordered by fx lines
Spiral Fx
A multiplanar & complex fx line
Intra-articular Fx
The fx line crosses the articular cartilage & enters the joint
Torus Fx
An incomplete buckle fx of one cortex, often seen in children
Greenstick Fx
An incomplete fx w/ angular deformity, often seen in children
Types of Fractures
- Impaction
- Compression
- Depression
- Stress (Fatigue)
- Stress (Insufficiency)
- Pathologic
Impaction Fx
A fracture that occurs when 1 bone hits or impacts an adjacent bone
Compression Fx
A type of impaction fx that occurs in the vertebrae, resulting in depression of the end plates
Depression Fx
A type of impaction fx that occurs in the knee when the femoral condyle strikes the softer tibial plateau
Stress (Fatigue) Fx
A fracture in normal bone that has been subjected to repeated or cyclical loads that alone are not sufficient to cause a fx
Stress (Insufficiency) Fx
A fx in weakened bone that has been subjected to a load insufficient to fx normal bone
Pathologic Fx
A fx through bone weakened by tumor, metabolic bone disease, or osteoporosis
Physical Exam Findings: Fracture
- Swelling
` extreme may –> compartment syndrome - Ecchymosis
- Deformity
- Skin lacerations/abrasions
- Palpation (+/- tenderness, crepitus, or compartment tightness)
Diagnostic Testing: Fracture
X-Ray
- initial test for suspected fx
- minimun, AP & lateral projections
- always includes joints above/below injury
CT
- indicated for evaluation of bony anatomy
- suspected joint involvement or bone loss
- MC used w/ spine, scapula, foot & hand
MRI
- indicated w/ soft tissue injury
- necessary for non-displaced or stress fx
Complications of Fractures
- Delayed union, non-union, or malunion (fx that heals w/ poor alignment -> poor functioning)
- Joint fx -> stiffness or contractures
- Osteonecrosis d/t compromised blood supply (MC in bones w/ tenuous blood supply, e.g. talus, scaphoid, & femoral head)
- Open fx -> soft tissue loss, infection, or osteomyelitis
- Compartment syndrome (pain w/ passive stretching of involved muscle & significant swelling)
Fracture Treatment
- 1st: manipulation, reduction, & urgent stabilization
- Immobilization
Cast, splint, or sling (extremities)Bed rest (axial fx-hip, pelvis, spine) - Surgery (displaced/unstable fx)
- Open Fx: copious irrigation & dressing, splinting, IV antibiotics, tetanus prophylaxis, & urgen surgery
- Following healing –> rehabilitation d/t muscle atrophy & joint stiffness
Factors that Improve Stability or Prognosis of Fractures
- Skeletal immaturity: thick periosteum, potential for remodeling, faster healing
- Non-displaced fx
- Single bone fx of forearm (radius/ulna) or lower leg (tibia/fibula)
- Thoracic spine fractures (support of rib cage provides added stability)
Factors that Worsen Stability or Prognosis of Fractures
- Skeletal maturity: little remodeling ability, thin periosteum, slower healing
- Marked displacement or segmental (indicates soft-tissue stripping)
- Intra-articular fractures
- Nerve or vascular injury
- Compartment syndrome
- Osteonecrosis
- Oblique fracture pattern
Fracture Healing
Structural regeneration
- Complex biologic cascade mediated by a variety of cells & proteins
- Clinical evidence = absence of tenderness & motion at the fracture site
- Radiographic evidence = union–amount of bridging callus or obliteration of the fracture line
Risk Factors for Impaired Fracture Healing
Smoking Indolent infection Inadequate immobilization Malnutrition NSAID use Significant soft tissue injury
Phases of Fracture Healing
Three overlapping phases
1: inflammation
- hematoma forms
2: repair
- fibrocartilaginous callus forms
- bony callus forms
3: remodeling
- bone remodeling occurs
Fracture Healing: Phase 1
- begins w/ bleeding from fracture site & surrounding soft tissue
- peaks after several days
- formation of granulation tissue
Fracture Healing: Phase 2
- formation of new blood vessels
- removal of necrotic tissue & debris by phagocytes
- production of new collagen by fibroblasts
- soft cartilaginous callus produced -> mineralized -> converted to woven (immature) bone
Fracture Healing: Phase 3
- overlaps w/ repair phase (occurs at 6-10 wks)
- can continue for several months
- woven bone replaced w/ mature lamellar bone
Primary Fracture Healing Pattern
Direct re-establishment of bony cortex
- requires very small gaps
- occurs almost exclusively w/ surgical anatomic restoration w/ rigid internal fixation
- osteoclasts on 1 fragment show a tunneling resorptive response
- no intermediate callus forms
Secondary Fracture Healing Pattern
Indirect bone healing through a cartilaginous callus intermediate
- does not require absolute stability (allows for relative stability–controlled fracture motion)
- immobilized by splints, casts, or certain intramedullary fixation devices
- periosteum provides progenitor cells, which differentiate into healing cells
Malunion
= An inadequately aligned union of a fracture
- MCC’s-inadequate fx reduction, immobilization, or surgical error in alignment
- May result in loss of function or poor cosmesis
Delayed Union
= Prolongation time to union (beyond 16-20 weeks)
Non-Union
= Failure of normal fracture healing
(1) fx unhealed after 6 months of tx
(2) fx w/o healing process on x-rays for 3 consecutive months
Tx: bone grafting
Delayed Union & Non-Union Presentation
- Persistent pain
- Etiology: compromised biologic environment, infection, insufficient immobilization, inadequate reduction, or extensive surgical disruption of the surrounding vascular supply
Hypertrophic Nonunion
Cause: inadequate stability
Tx: revision to more stable fixation
Atrophic Nonunion
Cause: inadequate biologic conditions
Tx: bone grafting
Fibrous Nonunion
Cause: - inadequate reduction - inadequate biologic conditions - inadequate stability Tx: - debridement - bone grafting
Oligotrophic Nonunion
Cause: inadequate reduction
Tx: revision of reduction
Septic Nonunion
Cause: infection
Tx: debridement, antibiotics
Nonsurgical Tx of Fractures
Indicated w/ stable fracture patterns that can be immobilized w/ a splint or cast
- require follow-up radiographs
- loss of reduction or a lack of healing may require surgical interventions
- electrical & ultrasound stimulation may enhance healing in fractures prone to impaired healing
Surgical Tx of Fractures
Indicated for unstable fractures & fractures that fail to respond to nonsurgical tx
- open fx: debridement to reduce infection
- intraarticular fx: reduce articular cartilage & minimize future posttraumatic arthritis
- malunion: osteotomy, or bone cuts
- nonunion: debridement & bone grafting
