Orthopaedics

Question 1

What is Shenton’s line and what does it indicate?

Answer 1

An imaginary line drawn along the inferior border of the superior pubic ramus (superior border of the obturator foramen) and along the inferomedial border of the neck of femur. Line should be continuous and smooth. And interruption indicates DDH or fractured NOF.

Question 2

What are the three descriptors used in classifying fractures? Muller/AO system

Answer 2

Location - Bone and segment (proximal, diaphysis, distal)
Morphology
- Diaphysis (simple, wedge, complex)
- Articular (extra-articular, partial articular, articular)

Question 3

What is the difference between closed/simple and open/compound fractures?

Answer 3

Open means break in skin and soft tissue - has 3 different grades of soft tissue damage

Question 4

What are some examples of a pathological fracture?

Answer 4

Cancer
Osteoporosis
Cyst
Osteomyelitis
Osteogenesis imperfecta

Question 5

Describe the 4 main steps of bone healing

Answer 5

1. Fracture and inflammatory phase, haematoma formation, coagulatiom and fibrin fibres
2. Soft callus - fibroblasts collonise and produce collagen, granulation tissue –> loosely links bone fragments
3. Hard callus - endochondral ossification, stiffening the healing tissue, create woven bone
4. Callus stiffening - remodelling and lamellar bone creation

Question 6

What are some factors that can affect bone healing?

Answer 6

Nature and extent of the trauma
Nature of patients - age, nutrition, smoking, etc.
Drugs - steroids, ABx, cytotoxics (all inhibit)
Treatment factors - splinting, traction, osteosynthesis

Question 7

What is osteosynthesis?

Answer 7

Reduction and internal fixation of bone fracture with implanted devices

Question 8

Describe why the right amount of movement is critical for fracture healing

Answer 8

Movement stimulates arterial and venous flow, stimulates callus maturation (increased cytokine production)
Prevents muscle atrophy and callus malformation
Prevents DVT
Too much movement will compromise the fracture alignment

Question 9

What are some complications of fractures?

Answer 9

Neurovasculature injury
AVN
Misalignment
Compartment syndrome

Question 10

What is compartment syndrome and how does it present?

Answer 10

When the tissue pressure is greater than the perfusion pressure in a closed anatomical space due to the accumulation of necrotic debris and hemorrhage following trauma –> muscle and nerve ischaemia
Presents as excessive pain not proportional to injury, associated with paraesthesia and a tight feeling in the sin

Question 11

What are the operative and non-operative treatment options for fracture?

Answer 11

Non-surgical: plasters/casts following closed reduction, traction (tapes, moon boot)
Surgical: Reduction and internal fixation, osteosynthesis (plates and screws, intramedullary nails, external fixation)

Question 12

How does a fractured NOF present clinically?

Answer 12

Affected leg is shortened and external rotated with reduced ROM and mobility

Question 13

What are the classifications for fractured NOFs?

Answer 13

Intracapsular
- Subcapital, transcervical, basicervical
Extracapsular
- Intertrochanteric, subtrochanteric

Question 14

What investigations would you do if you suspect a fractured NOF and what do you expect to see?

Answer 14

Pelvic x-ray: disrupted Shenton’s line

Assess for pelvic symmetry - look for greater trochanter - is it rotated?

Question 15

What are the treatment options for a fractured NOF?

Answer 15

Subcapital fractures are a surgical emergency as the blood supply to the femoral head may be compromised. Displaced or non-displaced both require internal fixation, if 60-80 can consider hip replacement.

Question 16

What are the three most common kinds of forearm fractures?

Answer 16

Scaphoid fracture
Colle’s fracture: fracture of distal radius, extra-articular with DORSAL angulation
Smith’s fracture: fracture of distal radius with PALMAR angulation

Question 17

Compare and contrast colle’s and smith’s fractures of the forearm

Answer 17

http://images.slideplayer.com/14/4418223/slides/slide_13.jpg

Question 18

What are the signs of a subcapital fracture?

Answer 18

Leg is shortened and externally rotated
Unable to walk
Groin pain (pubic ramus) or referred pain to the knee

Question 19

Describe the Salter-Harris fractures

Answer 19

I Straight (across the physis)
II Above the physis into the metaphysis
III Low Below the physis into the epiphysis
IV Through extending to the metaphysis, physis, and epiphysis
V Rammed rammed together crushing the physis

Question 20

Explain the process you would use to describe a fracture (not the Muller/AO)

Answer 20

1. Demographics
2. Location - bone and segment, articular or non-articular
3. Type - transverse, oblique, spiral, avulsion, stellate, greenstick
4. Simple or communited (>1 fragment)
5. Displacement (translation, angulation, rotation, impaction)

Question 21

What is the Garden classification system and what is it used for?

Answer 21

For proximal femur fractures, predicts the development of AVN and determines the appropriate treatment
STABLE: internal fixation using screws etc.
1: non-displaced, incomplete #
2: non-displaced, complete #
UNSTABLE: requires arthroplasty (joint replacement)
3: incompletely displaced, complete #
4: completely displaced, complete #

Question 22

Avascular necrosis of the hip - definition and clinical features

Answer 22

Necrosis of bone due to disruption of vascular supply
- Usually affects superior articular surface following intracapsular #
Clinical features: Pain in the region of affected hip, thigh, groin, and buttock, some remain asymptomatic

Question 23

What types of burns require referral?

Answer 23

Burns > 10 % TBSA in an Adult
Burns > 5 % TBSA in a Child
Full thickness burns > 5% TBSA
Burns of face, hands, feet, perineum, genitalia, and major joints
Circumferential burns
Chemical or electrical burns
Burns in the presence of major trauma or significant co-morbidity
Burns in the very young patient, or the elderly patient
Burns in a pregnant patient
Suspicion of Non-Accidental Injury

Question 24

How do you estimate the extent of burns?

Answer 24

Rule of nines

Lund and Browder chart - more specific / accurate

Question 25

Describe the differences in appearance of superficial, partial thickness, full thickness burns

Answer 25

Superficial — involves the epithelium: burns appear pink, red, painful, and generally take 7-10 days to heal. Sunburn is the classic example.
Partial thickness — involves the epidermis and some dermis: appears mottled pink, painful, hairs intact, and generally take 2-3 weeks to heal. Scarring may occur, particularly if healing is delayed and skin grafts may be required.
Full thickness — extends through the skin to deeper structures: appears black or white (eschar), leathery, produces no response to pain, and hairs are absent. Skin grafts are required.

Question 26

How do you calculate the fluid requirements for a burns victim?

Answer 26

Parkland formula:
24 hour fluid requirement: 
3-4mL * %TBSA * weight 
- Replace 50% in first 8hours since burn
- Replace 50% in next 16hours since burn

Question 27

What first aid should be applied to a burn?

Answer 27

Initial first aid: Cool running water (2-15°C) for 20 mins, ASAP, effective up to 3 hours after the burn occurred
- reduces soft tissue damage, hastens wound re-epithelialisation and reduces scarring
Blisters: pros — they provides an barrier for the burn site against infection; cons — the underly damage to the epithelium cannot be visualised and the serous fluid in the blister may be impairing healing to the burn. The blister may impair joint functionality.
Many specialists now recommend de-roofing and debriding the blister, so the underlying wound bed can be assessed and managed accordingly, and so that any non-adherent de-vitalised tissue is debrided.

Question 28

Describe the pathophysiology of a local and systemic response to a burn injury

Answer 28

1. Zone of coagulative necrosis results from the direct thermal injury at time of exposure.
2. Zone of stasis borders the site of coagulation necrosis, there is a prominent inflammatory response and vascular reactivity that reduces blood flow. This reduction in flow occurs for the first 24-48 hours after the burn occurs.
3. Zone of hyperaemia is the outermost area of the burn injury and is characterised by intense yet reversible vasodilatation and increased blood flow.

Thermal injuries trigger an intense local and systemic inflammatory response, with increased capillary permeability causing fluids and proteins to leak from the vascular space. This leakage can lead to oedema and hypovolaemia in extensive burns.

Question 29

What are the appropriate dressings used for burns?

Answer 29

Partial thickness and full thickness burns require dressings to aid healing.
Types of dressing available are hydrocolloid, silicon nylon, antimicrobial, polyurethane film and biosynthetic dressings.
* SILVER: antimicrobial effects, starts killing bacteria within 30mins of application, last up to 3 days as long as the dressing is kept wet.

Question 30

What is your approach to interpreting a pelvic xray?

Answer 30

1. 3 rings (pelvic rim, both obturator foramina - superior and inferior pelvic brim)
2. Joint spaces (sacroiliac joints, symphisis pubis)
3. Acetabulum
4. Femur - head, neck, greater and lesser trochanter
5. Shenton’s line