Bone + Joint Disorders PT2

Question 1

What is osteomalacia?

Answer 1

Defect of bone characterised by abnormal softening due to deficient mineralisation of osteoid, caused by inadequate calcium and phosphorus

Question 2

What is the pediatric equivalent of osteomalacia?

Answer 2

Rickets

Question 3

What are the principal causes of osteomalacia and rickets?

Answer 3

1. Vitamin D deficiency
2. Hypophosphatemia
3. Impaired calcium absorption
4. Phosphate deficiency

Question 4

What is the clinical presentation of osteomalacia?

Answer 4

Symptoms
(1) Bone pain (pelvis, spine, femora)
(2) Hypocalcemia symptoms
(eg) cramps, irritability

(3) Easy fractures.

Signs
(1) Proximal myopathy
(2) Dental defects

Question 5

What is the clinical presentation of rickets?

Answer 5

1. Delayed fontanel closure
2. Gen varum (bowing of the legs)

Question 6

What are the typical lab findings in osteomalacia?

Answer 6

(1) Low calcium
(2) Low serum phosphate
(3) Raised serum alkaline phosphatase (ALP)
(4) Raised PTH

Question 7

What is the first-line treatment for osteomalacia?

Answer 7

Vitamin D therapy + Calcium and phosphate supplementation.

D3 tablets (400-800 IU per day) after a loading dose of 3200 IU per day for 12 weeks are commonly used

Question 8

How would you manage severe osteomalacia?

Answer 8

A vitamin D level of less than 25 nmol/L reflects deficiency and requires high-dose treatment initially followed by maintenance treatment

Question 9

Vitamin D deficiency leads to inadequate stores of [Blank] and [Blank] in the bone matrix

Answer 9

Calcium and Phosphate

Question 10

In osteomalacia, bones have a greater proportion of [Blank] bone matrix

Answer 10

Unmineralised

Question 11

What are the symptoms and signs of rickets?

Answer 11

Bowed legs
Bone pain
Stunted growth

Question 12

Darker skin tones [Blank] your risk of rickets

Answer 12

Increase

Question 13

Rickets is a skeletal disorder caused by a prolonged lack of [Blank]

Answer 13

Vitamin D

Question 14

A 6-year-old patient presents with bone pain, weakness and constipation. A diagnosis of rickets is suspected

What findings would be seen on X-ray?

Answer 14

bowed femurs and widened epiphyseal plates

Question 15

A four-year-old boy presents to his GP with his mother after concerns he is not growing as he should. On examination, the boy has a patent anterior fontanelle, and a prominent forehead. He has enlarged wrists and ankles, and he is bow-legged. He does not yet have all his teeth. He was predominantly breastfed until he was two years old

What is the most likely cause of his condition?

Answer 15

Poor nutrition

Question 16

What is avascular necrosis (AVN)?

Answer 16

Failure of blood supply to a bone’s end, causing ischaemic necrosis

Question 17

Typical demographic for AVN?

Answer 17

Males, ages 35-50

Question 18

Most commonly affected bone in AVN?

Answer 18

The femoral head, but can also affect the wrist, humerus head

Question 19

What is the “hanging rope sign” in AVN?

Answer 19

Later MRI sign of femoral head AVN with patchy sclerosis and a lytic zone from granulation tissue

Question 20

Typical presentation of femoral head AVN?

Answer 20

(1) Insidious groin pain → worsened by stairs or impact; often bilateral

Question 21

First-line imaging for AVN diagnosis?

Answer 21

MRI

Question 22

Key management options if AVN is reversible?

Answer 22

1. Bisphosphonates,
2. Core decompression
3. Bone grafting
4. Vascularised fibular graft

Question 23

Which region of bone is usually affected by avascular necrosis?

Answer 23

The epiphysis of long bones

Question 23

What is typically required for irreversible AVN?

Answer 23

Joint replacement (e.g., total hip replacement)

Rotational osteotomy (rare)
Fusion (in wrist/foot)

Question 24

What is the Steinberg classification used for?

Answer 24

It categorises stages of AVN, aiding in treatment decisions based on progression

Question 25

What part of the scaphoid is most prone to avascular necrosis?

Answer 25

The proximal pole

Question 26

A 21-year-old falls onto his outstretched hand while playing rugby On examination, there is bruising around the wrist and pain in the anatomical snuffbox. Imaging shows no obvious fracture and he is sent home with pain relief. On a follow-up appointment three weeks later in the orthopaedic clinic, he complained of ongoing pain and stiffness in the wrist. What is the diagnosis?

Answer 26

Avascular necrosis

Question 26

What are risk factors for fat necrosis of the breast?

Answer 26

Trauma or surgery

Question 26

A 38-year-old female presents to her GP with a two-week history of increasing pain in both of her hips. She denies any recent falls and does not recall any trauma. She has a medical history of systemic lupus erythematosus for 15 years and is taking prednisolone and hydroxychloroquine for it. She can weight-bear with pain. She is apyrexic with normal observations. Hip examination shows tenderness and a restricted range of movement of the hip bilaterally What is the most likely diagnosis and why?

Answer 26

Avascular necrosis of the femoral heads = Steroid use is one of the common nontraumatic cause of avascular necrosis

Question 27

Long-term corticosteroid use is a risk factor for what disease?

Answer 27

Avascular necrosis

Question 28

Which organisms most commonly cause periprosthetic infections?

Answer 28

Staph. aureus and Staph. epidermidis

Question 29

What is Prosthetic Joint Infection?

Answer 29

Periprosthetic infection involving the joint prosthesis and adjacent tissue

Question 30

Describe the mechanism of periprosthetic joint infection

Answer 30

Infection can occur from direct inoculation during surgery, joint manipulation, or later through bacteraemia

Question 31

Differentiate between early, chronic, and haematogenous periprosthetic infections

Answer 31

Early: Within 2-3 weeks, from surgery; Chronic: After 3+ weeks Haematogenous: Abrupt onset, systemically unwell

Question 32

What causative organisms are found in chronic periprosthetic infections?

Answer 32

S. epidermis cutibacterium corynebacterium S. aureus

Question 33

What causative organisms are found in haematogenous periprosthetic infections?

Answer 33

S. aureus GNB

Question 34

What causative organisms are found in early periprosthetic infections?

Answer 34

(1) Staph. aureus (2) S. epidermis

Question 35

What are the common symptoms of periprosthetic infection?

Answer 35

(1) Fever (2) Joint pain (3) Minimal swelling (4) Sometimes sinuses

Question 36

What does Planktonic bacteria mean?

Answer 36

Is responsible for most symptoms, bacteraemia

Question 37

What does sessile bacteria mean?

Answer 37

phenotypic transformation of planktonic bacteria to form a biofilm encased in an extracellular matrix

Question 38

General advice for those with prosthetic Joint Infection

Answer 38

If there is pus, let it out!

Question 39

What is the primary treatment approach for early or haematogenous infection?

Answer 39

1. DAIR - Debridement = Antibiotics (for 12 weeks) 2. Implant retention

Question 40

Frail patients with chronic infection - Stage 1 exchange management

Answer 40

(1) Removal of joint and antibiotics

Question 41

Chronic infection - Stage 2 exchange management

Answer 41

(1) Removal of joint and 6 weeks of aggressive antibiotic therapy (2) Patient left without a joint for 6 weeks (3) Once the infection is under control a revision joint replacement is performed with more complex joint replacement components

Question 42

A 60-year-old man describes difficulty in standing from the seated position and diffuse joint and bone pain. Other than a recent fracture sustained from a mechanical fall he has no other past medical history and denies any systemic signs of illness. On examination, he has a waddling gait. What is the most likely diagnosis?

Answer 42

Osteomalacia

Question 43

What is a significant risk factor for avascular necrosis?

Answer 43

Previous chemotherapy Steroid use alcohol excess + trauma

Question 44

A 67-year-old woman who is taking long-term prednisolone for polymyalgia rheumatica presents with progressive pain in her right hip joint. On examination, movement is painful in all directions but there is no evidence of limb shortening or external rotation. An x-ray of the hip shows osteopenia and microfractures. What is the most likely diagnosis?

Answer 44

Avascular necrosis of the femoral head

Question 45

What are the plain X-ray findings seen in avascular necrosis of the hip?

Answer 45

1. osteopenia and microfractures may be seen early on 2. collapse of the articular surface may result in the crescent sign

Question 46

Bone pain, tenderness and proximal myopathy (→ waddling gait) = ?

Answer 46

osteomalacia