Musculoskeletal Alterations

Question 1

Important cells

Answer 1

Osteocytes
– bone cells
Bone deposition
– bone formation
Bone resorption
– bone breakdown
Osteoblasts
– specialized cells that are involved in bone formation (deposition)
Osteoclasts
– specialized cells involved in bone breakdown (resporption)

Question 2

Fracture classification

Answer 2

Oblique
- shaft of bone broken on angle
Occult
- fracture that is hidden
Open
- skin broken over fracture
Pathologic
- break cause by illness
Segmented
- fracture with two or more pieces
Spiral
- fracture that curves around bone
Transverse
- horizontal break through bone
Greenstick
-break straight through
Impacted
- fracture with one end wedged into opposite end

Question 3

Inflammatory Phase of bone healing

Answer 3

• Lasts 3–4 days
• Bone tissue destruction triggers inflammatory response
• Hematoma formation

Question 4

Repair Phase of bone healing

Answer 4

• Lasts several days
• Capillary ingrowth,
  mononuclear cells, and fibroblasts transform hematoma into granulation tissue
• Osteoblasts within procallus synthesize collagen and matrix to form callus

Question 5

Remodeling Phase of bone healing

Answer 5

• Lasts months to years
• Unnecessary callus is resorbed, and trabeculae formed
• At the end, bone can withstand normal stresses

Question 6

Complications of fractures healing

Answer 6

Nonunion
* failure of bone ends to grow together
* gap between broken ends of bone fills with dense fibrous and fibrocartilaginous tissue instead of new bone
Delayed union
* union that does not occur until approximately 8 to 9 months after fracture
Malunion
* healing of bone in nonanatomic position

Question 7

What is Osteoporosis

Answer 7

• often progresses silently until fractures occur
• Low bone mineral density (BMD), impaired structural integrity of bone, decreased bone strength, risk
  of fracture
• Old bone reabsorbed faster than new bone being made
• bones lose density → become thinner and more porous
• may continue until skeleton no longer strong enough to support itself

Question 8

Primary or idiopathic osteoporosis (most common)

Answer 8

age-associated
* aging skeleton and calcium deficiency
postmenopausal
* estrogen deficiency

Question 9

Secondary osteoporosis

Answer 9

endocrine diseases
* hormone imbalances, diabetes, hyperparathyroidism,
hyperthyroidism drugs
* heparin, corticosteroids - glucocorticoids, phenytoin, barbiturates, lithium
other substances
* tobacco
* alcohol

Question 10

RANKL

Answer 10

RANKL
* cytokine that activates receptor RANK, which is expressed on osteoclasts
* suppresses apoptosis, which leads to activation and prolongation of osteoclast survival
* so…RANKL promotes antiapoptotic effects on osteoclasts → increases life span

Question 11

OPG

Answer 11

• OPG is a glycoprotein acting as an antagonist (decoy receptor) for RANKL
• prevents RANKL from binding and activating RANK receptor on osteoclasts and their precursors

Question 12

OPG/RANKL/RANK System Sumary

Answer 12

Rankl promotes survival of osteoclasts which allows them to eat away at bones
Opg prevents rankl from binding to osteoclasts and prevents rankl function

Question 13

What is Osteoarthritis

Answer 13

Degenerative, age-onset joint disease
- characterized by changes in cartilage and bone but also the ligaments, muscle and periarticular
fat
Age-related disorder of articular/synovial joints
- weight-bearing joints i.e. knee, spine, hip, hands

Question 14

Primary (idiopathic) Osteoarthritis

Answer 14

• most common type
• no known cause (but is associated with increasing age)
• Diagnosed in the absence of predisposing trauma or disease
• Related to risk factors of age, obesity, genetics, previous trauma

Question 15

Secondary Osteoarthritis

Answer 15

• pre-existing joint abnormality