Osteoarthritis and metabolic bone disease

Question 1

Risk factors for Osteoarthritis (OA)

Answer 1

Old age – begins in 40s and continues
Women>men
Obesity
Trauma (secondary OA)

Question 2

Epidemiology of OA

Answer 2

Most common form of arthritis - 6% of adults over 30 have frequent knee pain with radiographic OA
9m in the UK – 2nd biggest cause of severe disability
Slightly more females up to 45 then more males

Question 3

Progression of OA - phase I

Answer 3

Chondrocyte injury due to biological and mechanical mechanisms

Question 4

Progression of OA - phase II

Answer 4

Early OA – chondrocytes proliferate and secrete inflammatory mediators, collagen, proteoglycans & proteases –> remodel matrix and initiate secondary inflammatory changes

Question 5

Progression of OA - phase III

Answer 5

Late OA – repetitive injury and chronic inflammation lead to chondrocyte drop out and loss of cartilage – this leads to subchondral bone changes

Question 6

Subchondral bone cysts

Answer 6

A common feature of late OA where small fractures through the articular bone allow synovial fluid to be forced into the subchondral region in a one way valve fashion

Question 7

Radiological features of OA

Answer 7

Loss of joint space
Osteophytes
Sclerosis
Subchondral cyst formation

Question 8

Osteophytes

Answer 8

Bony spurs which form along joint margins – most commonly associated with OA
Cause pain and restrict movement

Question 9

Clincial features of OA in a joint

Answer 9

Pain (with activity)
Bony swelling & periarticular tenderness
Reduced movement
Stiffness (after rest)
Joint crepitus

Question 10

Treatment of OA

Answer 10

Lifestyle measures – weight loss, exercise/physiotherapy, orthotic footwear
Analgesia – NSAIDs/Opiates or local injection (hyaluronic acid). Topical capsaicin.
If joint is failing consider osteotomy or replacement

Question 11

Glucosamine for OA

Answer 11

Cheap, safe and ineffective

Evidence is mixed, showing short term benefit but not recommended as not cost effective

Question 12

Intra-articular injections

Answer 12

Hyaluronic acid – weakly effective at reducing pain
NSAIDs – Minimal benefit & only short term
Steroids – immediate relief but not long term benefit
Capsaicin

Question 13

Commonly used NSAIDs in OA

Answer 13

Ibuprofen, Diclofenac, Naproxen – GI side effects
Celecoxib (selective COX-2 inhibitor) - cardiac side effects
Paracetamol – Relieves 50% of pain but dangerous in overdose and pts dislike taking multiple tabs a day

Question 14

Metabolic bone diseases

Answer 14

Osteoporosis – weak bones at risk of fracture
Osteomalacia – pain and weakness due to bone softness
Pagets disease – pain and weakness due to deranged bone remodelling

Question 15

Osteoporosis

Answer 15

Bone thinning due to increased resorption and decreased production, most commonly due to low post menopausal estrogen or prolonged steroid use
This increases the risk of hip or spine fractures and is a major health problem

Question 16

Risk factors for Osteoporosis (5)

Answer 16

Age and women (menopause) and drugs (steroids)
Family history
Chronic inflammatory diseases (RA)

Question 17

Diagnosis of Osteoporosis

Answer 17

Often happens after a pathological fracture

X-rays demonstrating thinning of the bone and confirmed by DEXA scan

Question 18

DEXA scan

Answer 18

Using X rays it can establish the bone density in the neck of the femur and the lumbar spine.
Gives a general score (T) and score related to age and gender (Z) – Severe (established) osteoporos is T-score <-2.5 and 1+ osteoporotic fractures
Scores should be adjusted if the pt is taking strontium

Question 19

Established drugs for preventing osteoporosis

Answer 19

Calcium and vitamin D
Bisphosponates (Alendronate, Risedronate, Ibandronate)
HRT or Selective Oestrogen Recpetor Modulators (SERM) (Raloxifene)

Question 20

Newer drugs for preventing osteoporosis

Answer 20

Strontium ranelate

Teriparatide (recombinant PTH)

Question 21

Bisphosponates

Answer 21

Slow the loss of bone by blocking bone resorption and inducing osteoclasts to undergo apoptosis
SE: GI and oesophagus erosions and inflammation and possible risk of oesophageal cancer, possibly AF in women

Question 22

Osteomalacia

Answer 22

Pain and weakness due to softening of bone – due to inadequate Vitamin D & calcium –> low dietary intake, insufficient sun exposure, Vit D malabsorption, Metabolic disorders, Renal failure

Question 23

Symptoms of osteomalacia

Answer 23

Diffuse bone pain (hips particularly)
Muscle weakness
Symptoms of hypocalaemia (numbness around the mouth or fingers)
Hand or feet spasms

Question 24

X-rays of osteomalacia

Answer 24

Pseudofractures (looser’s zones) are bands of thinning which develop and induce periosteal thickening and callose formation giving the appearance of a fracture

Question 25

Treatment of Osteomalacia

Answer 25

Calcium and vit D to correct imbalance

Question 26

Paget’s disease

Answer 26

Increased rate of bone remodelling leading to pain, bone enlargement and thickening – increased risk of fracture and other complications

Question 27

Treatment of Paget’s disease

Answer 27

Bisphosphates to slow bone resorption

Question 28

Rickets

Answer 28

Osteomalacia in children

Question 29

Skeletal dysplasias

Answer 29

Ehlers-Danlos syndrome
Marfans syndrome
Osteogenesis imperfecta
Osteopetrosis
Achondroplasia

Question 30

Ehlers-Danlos syndrome

Answer 30

A heterogenous group of collagen disorders –> 10 types varying in degrees of skin fragility & hyperextensibility and joint hypermobility
Types I,II,III, IV, VII are autosomal dominant
Type VI is autosomal recessive
Types V,VIII, IX and X are rare and less is know

Question 31

Osteogenesis imperfecta

Answer 31

A heterogenous group of autosomally dominant disorders of type I collagen –> type II die perinatally, Type III leads to severe bony deformity and Types I and IV have normal life spans –> treat with bisphosphonates
Major feature is brittle bones but also general features of collagen dysfunction (hypermobility, valvular problems)

Question 32

Osteopetrosis (marble bone disease)

Answer 32

Can be autosomal recessive (severe) or dominant (mild)
Severe form invole Cl channel mutation and increased bone density but also increased fracture risk – leads to mental retardation and early death
Mild form may only have X-ray changes with increased risk of fracture and infection

Question 33

Achondroplasia

Answer 33

Dwarfism –> fibroblast growth factor receptor-3 defect

autosomal dominant inheritance leading to short limbs and abnormal endochondrial ossification

Question 34

Myxoid cysts (AKA mucous cysts)

Answer 34

benign ganglion cysts usually found on the distal, dorsal aspect of the finger. More common in middle aged women and there is usually osteoarthritis in the surrounding joint`

Question 35

Treatment progression of osteoarthritis

Answer 35

Advice about weight loss, exercise and muscle strengthening
1st - paracetamol with topical NSAIDs (if hand or knee OA)
2nd - Oral NSAIDs (+PPI), opioids, intraarticular steroids
3rd - supports, braces or TENS
4th- consider for joint replacement

Question 36

Cardinal signs of OA

Answer 36

Hebeden’s Nodes at the DIP and Carpometacarpal joint pain.