Osteoporosis and Osteoarthritis

Question 1

Normal Bone Homeostasis

Answer 1

• Bone remodelling process
  1. Inside the sponge bone resides Osteoblasts (Builds the bone) and Osteoclasts (Consumes the bone)
  2. During childhood and teenage years, bone formation is faster than bone reabsorption (Bone becomes larger, heavier, and denser)
  3. Peak bone mass is reached at around age 30 (After 30, bone reabsorption slowly exceeds bone formation)

Question 2

Definition of Osteoporosis

Answer 2

• Described as decrease in mineral bone density and increased risk of fractures because of alterations in bone microarchitecture

(WHO’s Definition) A systemic skeletal disease characterised by low bone density and micro-architectural deterioration of bone tissue with a consequent increase in bone fragility

Question 3

Pathophysiology of Osteoporosis

Answer 3

1. Disruption of bone reabsorption and bone formation leads to an imbalance in the remodelling process
2. Osteoclasts start to outwork Osteoblast
3. Old bone is being absorbed faster than new bone is formed, causing the bone to lose density, becoming thinner and porous
4. Progressive loss of bone mass continues
5. The skeleton is no longer strong enough to support, and may cause the bone to fracture spontaneously

Question 4

Risk Factors of Osteoporosis (‘CALCIUM’)

Answer 4

• C: Low Calcium or Vitamin D in diet
• A: Age, bones become weaker and bone mass decreases after age 30; due to low testosterone and oestrogen levels
• L: Lifestyle, high alcohol consumption, tobacco use, physical inactivity
• C: Caucasian and Asian Women, women have less bone tissue than men
• I: Inherited; genetics
• U: Underweight, BMI <19, thin or small body frame has less bone mass and anorexia nervosa
• M: Medications that lower calcium in blood; Corticosteroids, Anticonvulsants, Immunosuppressants

Question 5

Clinical Features of Osteoporosis

Answer 5

1. Usually / Remains asymptomatic until skeletal fragility is well advanced
2. 30-40% of bone mass must be loss before X-ray shows radiolucency
3. Bone Pain
4. Deformity (Height Loss) - Kyphosis; Excessive forward rounding of the upper back
5. Fractures (Femoral head, Vertebra, Waist): e.g. Compression Fracture

Question 6

Signs & Symptoms of Osteoporosis (‘FRAIL’)

Answer 6

• F: Fractures (Hip, Waist, Spine)
• R: Rounding of the upper back (Spine deformity, Stooped posture) from spine fractures
• A: Asymptomatic until fracture
• I: Inches of height loss overtime since a young adult (2-3 Inches) due to spinal fracture
• L: Low back pain, neck, or hip pain (On palpation or with activity like bending or increase stress put on the bone)

Question 7

Investigations for Osteoporosis

Answer 7

1. Dual X-ray Absorptiometry (DXA)
   - To measure bone density
2. Biochemical Markers of Bone Turnover
   - Markers of Reabsorption (N-Telopeptide, C-Telopeptide, Deoxypyridinoline)
   - Markers of Bone Formation (Bone-specific Alkaline Phosphate, Osteocalcin)

Question 8

Hyaline Cartilage

Answer 8

• A rubbery, smooth tissue found within the joint and it covers the end of each bone
• Acts as a protective mechanism for movement by providing this slick surface for the bones to slide and glide movement

Question 9

Aetiology of Osteoarthritis

Answer 9

• Though to be due to excessive wear of weight bearing joints (Hip, Knee, Joint)
• Considered to be a normal part of aging

Question 10

Pathophysiology of Osteoarthritis

Answer 10

1. Top layer of Cartilage begins to breakdown and wear away
2. Leads to a loss of joint space within the joint, and the bones to rub upon each other
3. Inside the bone experiences abnormal hardening of the bones (Sclerosis)
4. Outside of the bone experiences osteophyte formation (Bone spurs)
5. Pieces of Cartilage and bone can break off and float around the joint space
6. All of this leads to extreme stiffness and pain

Question 11

Risk Factors of Osteoarthritis

Answer 11

1. Older age, 40+ yo
2. History of repeated Joint Injuries
3. Strenuous jobs
4. Overweight
5. Genetics

Question 12

Investigations for Osteoarthritis

Answer 12

• Clinical assessment and Radiological studies
• Newer imaging technologies such as compositional MRI are showing promise in identifying structural changes in Cartilages
• CT Scan, Arthroscopy, and MRI are rarely needed

Question 13

Characteristics of Osteoarthritis

Answer 13

1. > 80% of >75 years old have radiographic evidence of Osteoarthritis
2. Slight Female Preponderance
3. Characterised by
   - Progressive Cartilage damage and loss
   - Narrow Joint Space
   - Reactive bony hypertrophy resulting in formation of ‘Osteophyte’ (Bony lumps that grow on the bone)
   - Subchondral bone sclerosis
   - Bone Cyst Formation

Question 14

Clinical Features of Osteoarthritis

Answer 14

1. Slow stepwise deterioration in Symptoms
2. Most commonly occur in the hands, knees, hips, and spine (Majorly the weight-bearing joints which experiences a lot of stress)
3. Does NOT affect other symptoms in the body
4. Joint pain
   - Insidious onset
   - Aggravated by activity
   - Relieved by rest
   - Worst at the end of the day
5. Joint stiffness in the morning
6. Bony swelling in the hands
   - Herberden’s nodes at distal interphalangeal joints
   - Bouchard’s nodes at proximal interphalangeal joints
7. Asymmetry of Large Joint Involvement
8. Impairs gait and mobility

Question 15

Signs & Symptoms of Osteoarthritis (‘OSTEO’)

Answer 15

• O: Outgrowth that are bony, especially due to spur formation
• S: Sunrise Stiffness, usually lasts less than 30 minutes
• T: Tenderness when touching the joint site with bony overgrowths
• E: Experience grating (Crepitus) of the bones when moving / flexing the joint from bones rubbing together
• O: Only the joints: Asymmetric / Uneven, limited to joints (Joint Site will be hard and bony), along with limited mobility, not systemic features such as Fever, Anaemia, fatigue, Systemic Inflammation