Fracture Healing & Bone Remodeling & Healing Complications

Question 1

What are the three phases of fracture healing?

Answer 1

Inflammatory, reparative, and remodeling phases

Question 2

What happens during the inflammatory phase of fracture healing?

Answer 2

A hematoma forms, and inflammation begins to clear necrotic tissue

Question 3

What is the purpose of the hematoma in fracture healing?

Answer 3

It provides a temporary framework for new tissue formation

Question 4

What cells are responsible for forming soft callus?

Answer 4

Chondrocytes from the endosteum and periosteal osteoblasts

Question 5

How does soft callus become hard callus?

Answer 5

Osteoblasts replace fibrocartilage with woven bone

Question 6

What happens during the remodeling phase of fracture healing?

Answer 6

Woven bone is replaced by lamellar bone for strength

Question 7

What are the specialized cells in bone tissue?

Answer 7

Osteoblasts, osteoclasts, osteocytes, and osteogenic cells

Question 8

What type of bone cell is responsible for bone remodeling?

Answer 8

Both osteoblasts and osteoclasts

Question 9

What is the primary role of osteocytes?

Answer 9

Regulating bone metabolism and maintaining the bone matrix

Question 10

What is the difference between cortical and trabecular bone?

Answer 10

Cortical bone is dense and strong; trabecular bone is porous and flexible

Question 11

What is the main structural unit of cortical bone?

Answer 11

The osteon (Haversian system)

Question 12

What is the function of the Haversian canal?

Answer 12

It contains blood vessels and nerves for bone nutrition

Question 13

What are the two types of microscopic bone?

Answer 13

Woven bone and lamellar bone

Question 14

Why is woven bone weaker than lamellar bone?

Answer 14

Its collagen fibers are randomly arranged, making it less organized

Question 15

How is woven bone replaced by lamellar bone?

Answer 15

Through bone remodeling, where osteoclasts resorb woven bone and osteoblasts replace it

Question 16

What type of fracture is common in osteoporotic patients?

Answer 16

Pathologic fractures

Question 17

What causes stress fractures?

Answer 17

Repetitive mechanical loading that exceeds the bone’s ability to repair

Question 18

How do bones heal in primary fracture healing?

Answer 18

Through direct remodeling without callus formation

Question 19

How do bones heal in secondary fracture healing?

Answer 19

By forming a callus before remodeling

Question 20

What are the two main types of bone ossification?

Answer 20

Intramembranous and endochondral ossification

Question 21

What type of ossification is responsible for fracture healing?

Answer 21

Mostly endochondral ossification

Question 22

What type of ossification occurs in flat bones of the skull?

Answer 22

Intramembranous ossification

Question 23

What factors can delay bone healing?

Answer 23

Poor blood supply, inadequate immobilization, infection, and poor nutrition

Question 24

Why does poor blood supply delay bone healing?

Answer 24

Bone cells rely on blood flow for oxygen and nutrients

Question 25

What are the common causes of osteonecrosis?

Answer 25

Trauma, corticosteroid use, alcohol abuse, and vascular diseases

Question 26

Why is osteonecrosis often progressive?

Answer 26

The affected bone loses blood supply, leading to tissue death and joint destruction

Question 27

What is the histological appearance of osteonecrosis?

Answer 27

Empty lacunae with degenerating bone marrow

Question 28

What are the clinical symptoms of osteonecrosis?

Answer 28

Initially asymptomatic, progressing to pain with movement, then pain at rest

Question 29

Where does osteonecrosis commonly occur?

Answer 29

The femoral head, humeral head, knee, and talus

Question 30

What is a common long-term consequence of osteonecrosis?

Answer 30

Joint collapse and osteoarthritis

Question 31

What are the main complications of fracture healing?

Answer 31

Delayed union, non-union, malunion, infection, and osteonecrosis