MSK investigations

Question 1

In children with developmental hip dysplasia, How are they diagnosed?

Answer 1

1. Kids <6 months are diagnosed with an USS

2. Kids >6 months are diagnosed with an X-Ray

Question 2

What is the Anterior draw test examining?

Answer 2

An Anterior cruciate ligament (ACL) injury

Question 3

What is the Posterior draw test examining?

Answer 3

A posterior cruciate ligament (PCL) injury

Question 4

What mode of imaging is best for meniscal injuries?

Answer 4

MRI

Question 5

What is the difference between a cruciate and meniscal injury ?

Answer 5

Meniscal injury will predominantly cause pain whereas a cruciate injury will cause instability (A knee that gives way)

Question 6

What investigations would you do for gout?

Answer 6

1. GOLD STANDARD:
   - Joint aspiration and crystals analysis (Negatively birefringent)
2. Serum Uric acid levels (may be raised) – but usually during a flare this may be normal because the uric acid is now in the joint
3. FBC - Leukocytosis
4. ESR+CRP

Question 7

What is an arthroscope? and when would a arthroscopy be done?

Answer 7

A procedure done to look within the joints.

When may it be done:

1. Pre operative evaluation
2. Confirm a clinical diagnosis
3. Therapeutic (injuries, repairs, biopsies, fracture etc.)

Question 8

What would you find on (first line) joint aspiration in the following Monoarthropathies: 
septic arthritis (1 thing) and gout (2 things)?

Answer 8

Septic arthritis:
- Turbid, yellow fluid

Gout:

• Negatively birefringent crystals
• Raised urea (but note this will be low during an attack)

Question 9

On a synovial joint fluid culture for septic arthritis, what is the most common organism you will likely find?

Answer 9

Staphylococcus aureus

Question 10

What is the first line investigation for Vitamin D deficiency?

And what would be considered a deficiency and an insufficiency?

Answer 10

Note: only test for Vit D deficiency if theyre symptomatic!

1. Measure Serum 25-hydroxyvitamin D
2. <50 nanomoles/L (<20 nanograms/mL) = deficiency
   * Insufficiency: between 52-72 nanomoles/L (21-29 nanograms/mL)

Question 11

What fracture do you get from falling on an outstretched hand?

Answer 11

Colles fracture

Question 12

How do you get a smiths fracture?

Answer 12

Falling on a wrist that is flexed inwards or from direct trauma to the back of the wrist

Question 13

Gold standard investigation for Carpal tunnel ?

Answer 13

EMG **

Or Nerve conduction velocity study

Question 14

What is Oseomalacia and how is it characterised?

Answer 14

A marked softening of the bones. Most often caused by a vitamin D deficiency

Symptoms;

• Bone pain
• Muscle weakness
• Fatigue

Signs:

• Extremely low Vitamin D
• Low calcium
• Low phosphate levels

Question 15

When would you do a Fragility fracture risk score? (FRAX score)
(2 Things + 6 RF’s)

Answer 15

• If women aged >65 years and all men aged >75 years
• Women aged 50–64 years and men aged 50–74 years who have any of the following risk factors:

1. A previous osteoporotic fragility fracture.
2. Current use or frequent recent use of oral corticosteroids.
3. History of falls.
4. Low body mass index (less than 18.5 kg/m2).
5. Smoker.
6. Alcohol intake of more than 14 units per week.

Question 16

Explain the FRAX score

Answer 16

The patient’s risk of having an osteoporosis related fracture in the next 10 years.

Risk is expressed as a %.

Question 17

What does a DEXA scan tell you?

Answer 17

• How much higher or Lower your bone density is than that of a healthy 30 year old when the bones are at their strongest.
• 1.0 or above = normal bone density
  T score between= -1.0 and -2.5 is low bone density/ osteopenia