Bone Repair

Question 1

Bone Fractures are Classified by…

Answer 1

1. Position of the bones end after fracture
   - nondisplaced
   - displaced
2. Completeness of the fracture
   - complete
   - incomplete
3. Whether or not the bone ends penetrate the skin
   - open/compound
   - closed/simple

Question 2

Nondisplaced fracture

Answer 2

bones retain their normal position

Question 3

Displaced fracture

Answer 3

bones ends are out of normal alignment

Question 4

Complete fracture

Answer 4

bone is broken through

Question 5

incomplete fracture

Answer 5

bone is not broken through

Question 6

Open/compound fracture

Answer 6

bone ends penetrate the skin

Question 7

Closed/simple fracture

Answer 7

bone ends remain within the skin

Question 8

Fracture Treatment

Answer 8

• begins with reduction - realignment of the broken bone ends
  
  • closed reduction
  • open reduction
• immobilization of the bone by cast/traction is needed for healing
• time needed for fracture repair depends on severity, which bone, and age of patient

Question 9

closed reduction

Answer 9

clinician manipulates bone ends back into position

Question 10

open reduction

Answer 10

surgeon utilizes pins and wires to resecure the bone ends

Question 11

4 major stages of fracture repair

Answer 11

• hematoma formation
• fibrocartilaginous callus formation
• bony callus formation
• bone remodeling

Question 12

Hematoma formation

Answer 12

• torn blood vessels hemorrhage
• a hematoma is formed (mass of clotted blood)
• site is swollen, painful, inflamed, and fed by nutrients and oxygen from blood

Question 13

Fibrocartilaginous callus formation

Answer 13

• capillaries grow into hematoma
• phagocytic cells (like white blood cells) clear debris
• fibroblasts secrete collagen fibers to span break and connect broken ends
• fibroblasts, cartilage, and osteogenic cells begin reconstruction of the bone
  
  • create a cartilage matrix of repair tissue
  • osteoblasts form spongy bone within matrix
• mass of repair tissue = fibrocartilaginous callus

Question 14

bony callus formation

Answer 14

• within a week, new trabeculae appear within the fibrocartilaginous callus
• fibrocartilaginous callus is converted into bony callus of spongy bone
• bony callys continues for about 2 months - until a firm union forms

Question 15

Bone Remodeling

Answer 15

• begins during bony callus formation and continues for several months
• excess material on the diaphysis exterior and within the medullary cavity is removed
• compact bone is laid down to reconstruct shaft walls
• final structure resembles original structure - it responds to the same mechanical stressors