Bone Diseases Flashcards
Clinical Healing of bone healing
healing of pain and swelling
Radiographic healing of bone healing
healing of 3 of 4 cortices
What does Wolff’s law state
bone will adapt to a load/pressure
What are the stages of bone healing and their descriptions (5)
- Inflammatory stage: pain/hyperemia/edema. Induction of growth factors. Differentiation of MSC into osteoblasts and chondrocytes (immediately)
- Hematoma formation: fibriblast/platelet differentiation (immediately)
- Soft callus: Cartilage (4 days to 4 weeks)
- Hard Callus: calcification (4 weeks to 4 months)
- Remodeling: Wolff’s law (4 months- 2 years)
2 mechanisms of bone healing
-Primary bone healing, membranous, direct healing
Secondary bone healing, spontaneous, indirect, enchondral healing
Describe primary bone healing
1) Contact healing/Haversian remodeling: occurs when there is
Describe secondary bone healing
- formation of bone callus… followed by resorption of callus. Wide gaps are filled with cortical bone via Haversian remodeling
- Motion allowed at the fracture site
Description of woven bone
- unorganized collagen fibers
- mechanically weak
- produced when osteoid is produced rapidly
Description of Lamellar bone
- Parallel alignment of collagen
- Mechanically strong
- Replaces woven bone eventually
What are the zones of an epiphyseal growth plate(4)
- Zone of proliferation/growth
- Zone of maturation
- Zone of transformation
- Zone of provisional calcification
What is the description and location of the zone of proliferation/growth
- site of chondrocyte replication
- it is located closest to the epiphysis
What is the description of the zone of maturation
- chondrocyte hypertrophy
- Weak due to loss of intracellular matrix
What is the description of the zone of transformation
-chondrocytes become calcified
What is the description and location of the zone of provisional calcification
-Between growth plate and metaphysis. Closest to the shaft
Comorbidities that result in significant nonunion of bone
- Diabetes
- Osteoporosis
- Vitamin D deficiency
- Osteogenesis imperfecta
- Osteomyelitis
Social history that results in significant nonunion of bone
- smoking
- poor nutritional status
- poor bone quality
- infection
- ETOH consumption
Medications that result in significant nonunion of bone
-Chronic steroid use
–NSAIDS
- immunosuppressants
- Chemotherapy
Conservative treatments for nonunion of bone
- oral calcitonin
- Functional bracing
- Bone stimulator
What is the mechanism, duration and contraindication for bone simulator use
Mechanism: Electronegative charge used to stimulate bone growth at areas of growth and repair.
Duration: 3-6 months
Contraindication: not for use in synovial pseudoarthrosis, gaps >1cm or 50% of bone diameter
4 categories of bone grafts
- Bone grafts- for small defects
- Intercalary graft-from fresh frozen femoral head. For defects < 5 cm
- Trabecular cage
- Vascularized graft- for large defects 10-40cm
Description of cancellous graft healing (5)
- revascularization occurs in 2 weeks
- gain strength with growth pattern
- results in a complete remodeling
- Many osteocytes are present in this type of healing
Description of cortical graft healing
- revascularization occurs in 2 months
- lose strength in the first 6 months with this type of growth pattern
- Remodeling is incomplete with necrotic pockets with this type of remodeling.
- Not as many osteocytes present in this type of healing
What are the stages of bone graft healing (5)
- Vascular ingrowth
- osteogenesis: osteoblasts from the bone graft cause bone growth
- osteoinduction: regular bone growth with many growth factors
- osteoconduction: bone graft serves as scaffold/framework for osteoblasts to conduct and spread
- Graft remodeling: according to Wolff’s law
What osteobiologics help with osteoinduction phase
- BMP: stimulates osteoblast production
- MSC allograft
- PRP: provides growth factors
- BMA- provides MSC