Aging and MSK

Question 1

What causes an accelerated loss of bone density with age?

Answer 1

low reproductive hormones
poor calcium and or vitamin D status,
inactivity, endocrine or GI pathologies

Question 2

What often accompanies loss of bone mineral?

Answer 2

Changes in trabecular architechure –> makes bone less strong

Question 3

What is sarcopenia?

Answer 3

Loss of muscle mass due to loss of muscle fibres and reduced muscle cross-sectional area

Question 4

Describe the changes in muscle with age.

Answer 4

sarcopenia
loss of muscle contractility
loss of neuronal innervation

Question 5

Describe the changes in terms of percentages for body weight composition from adult to over 75.

Answer 5

adult: 30% of body weight is muscle and 20% adipose

age 75: 15% muscle, 40% adipose

Question 6

Name 3 clinical consequences of ageing.

Answer 6

osteoporosis
fractures
osteoarthritis

Question 7

What is osteoporosis?

Answer 7

A disease in which there is a reduction in bone mass in the presence of normal mineralisation

• low bone mass per unit volume
• deterioration of micro-architechture
• increased bone fragility
• increased susceptilbity to low trauma fractures

Question 8

How would you define osteoporosis clinically?

Answer 8

osteoporosis is a bone mineral density of more than 2.5SD below the mean (in young adults of the same sex)

Question 9

How would you define osteopenia clinically?

Answer 9

1-2.5 SD below mean bone mineral density (mean is in young adults)

Question 10

How would you diagnose osteoporosis?

Answer 10

Dual Energy Xray Absorptiometry (DEXA scan)

• assesses bone mineral density (BMD)
• X rays at 2 different energies
• aimed at femur and L-spine

Question 11

What does the T score from a BMD report indicate?

Answer 11

T score - number of SD below mean for sex and race matched healthy young adult pop (25-35y)

Question 12

What does the Z score of a BMD report indicate?

Answer 12

The number of SD below the mean for age, sex and race compared with their peirs

Question 13

Give some risk factors for osteoporosis

Answer 13

Age, low bone mass, Caucasian/asian, previous fragility fracture, positive family history, low BMI, early menopause

Question 14

Discuss the pathophysiology of osteoporosis.

Answer 14

osteoporosis caused by a loss of coupling in the bone remodelling process

• due to increased bone resorption, decreased bone formation or both
• loss of coupling –> net loss of bone volume

Question 15

Which type of bone is most affected in osteoporosis?

Answer 15

trabecular bone due to its greater metabolic activity

Question 16

What is type 1 osteoporosis?

Answer 16

post menopausal

loss of oestrogen - accelerated loss (2-3%) over 6-10 years

Question 17

What is type 2 osteoporosis?

Answer 17

senile

age related, hyperparathyroidism, Ca2+ deficiency

Question 18

What drugs are used to treat osteoporosis and what is their effect on bone?

Answer 18

Bisphosphonates -  anti-resorptive agents which effect osteoclasts (bone resorption)
effect on bone:
- decrease bone turnover
- increase bone mineralisation
- minimal effect on bone volume

Question 19

How do bisphosphonates work?

Answer 19

Inhibit osteoclastic bone resorption by reducing osteoclastic activity and promoting osteoclast apoptosis
bisphosphanates inhibit mevalonate pathway
osteoclasts lose their ruffled border –> inactivated

Question 20

Give an example of a bisphosphanate.

Answer 20

Risedronate

Question 21

How many hip fractures in the UK per year?

Answer 21

75,000

Question 22

Describe the blood supply to the hip joint

Answer 22

medial and lateral circumflex arteries and the artery to the head of the femur
circumflex arteries are branches of the profunda femoris artery –> anastamose at the base of the femoralneck to form a ring
Medial circumflex artery is responsible for majority of arterial supply

Question 23

What can happen in an intracapsular fracture of the hip joint?

Answer 23

damage to the medial circumflex femoral artery found around neck of femur –> avascular necrosis of the femoral head

Question 24

What are the main types of femoral neck fractures?

Answer 24

Intracapsular and extracapsular

Question 25

What type of femoral neck fractures are grouped under intracapsular fractures?

Answer 25

supcapital basicervical transcervical

Question 26

What type of femoral neck fractures are grouped under extracapsular fractures?

Answer 26

intertrochanteric | subtrochanteric

Question 27

What is the treatment for intracapsular neck of femur fracture?

Answer 27

operative - hemiarthroplasty (unipolar, bipolar, cemented, uncemented) total hip arthroplasty internal fixation non-operative - those who are too ill to undergo anaesthesia and people who were unable to walk before

Question 28

What is a hemiarthroplasty?

Answer 28

only the articular surface of the femoral head is replaced unipolar hemiarthroplasty - replacement of femoral head and neck bipolar - replacement of femoral neck, head and addition of an acetabular cup

Question 29

What is the treatment for an extracapsular neck of femur fracture?

Answer 29

dynamic hip screw | intramedullary hip screw

Question 30

What are possible consequences of hip fractures?

Answer 30

high mortality rate (up to 30% at 1 year) | high morbitity rate - PE, DVT, MI, pressure sores, chest infections, UTIs, reduced mobility, confusion

Question 31

What is osteoarthritis?

Answer 31

a disorder of the synovial joints that is characterised by: - focal areas of damage to the articular cartilage - remodelling of underlying bone and formation of osteophytes - new bone at joint margins - mild synovitis

Question 32

Who gets osteoarthritis?

Answer 32

eventually everyone | 80% of over 80 year olds

Question 33

What is the common type of pain associated with OA?

Answer 33

hip OA pain knee OA pain joints of cervical spine (cervical spondylosis)

Question 34

What are the clinical features of osteoarthritis?

Answer 34

pain, stiffness, deformity, joint swelling

Question 35

Discuss the pathogenesis of OA.

Answer 35

earliest changes - fragmentation and fibrillation of normally smooth surface of articular cartilage (these changes v. common with ageing and may not progress to symptomatic OA) with disease progression - increasing loss of articular cartilage accompanied by abortive attempts at regen. later changes: reactive proliferation at the subchondral bone plate articular surfaces become deformed

Question 36

What are some radiological features of OA?

Answer 36

decreased joint space (bone articulating against bone = eburnation) sclerosis - hardening of tissue osteophytes - bone spurs; most specific sign of OA but is only seen in advanced disease bone cysts

Question 37

What is the non-operative treatment for osteoarthritis?

Answer 37

weight loss, exercise, physiotherapy, analgesia/NSAIDs, joint injection

Question 38

What are the possible operative treatments for osteoarthritis?

Answer 38

- arthroscopy - key hole surgery - osteotomies - bone is cut to shorten, lengthen or change its alignments - arthrodesis - artificial induction of joint ossification between 2 bones - done to relieve intractable pain.e.g. using a bone graft - arthroplasty - articular surface of joint is replaced

Question 39

What is the point in replacing a hip?

Answer 39

in the past: relief of pain, improve function, return to life, better ROM in the future: relief of pain, back to work, improve function, better ROM

Question 40

What are the components of a total hip replacement?

Answer 40

acetabular component femoral head femoral stem

Question 41

what is the most common type of total hip replacement implant?

Answer 41

metal on polyethylene

Question 42

What are local complications of hip and knee replacements?

Answer 42

``` leg length inequality dislocation infection loosening neurovascular damage - sciatic/femoral ```

Question 43

What are some systemic complications of hip and knee replacement?

Answer 43

UTIs/chest infection DVT PE death

Question 44

From what age does bone mineral start to decline?

Answer 44

from age 30 rate of loss is 0.5-1% per year