Musculoskeletal (MSK) Medicine 10 Single Best Answer (SBA)

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Orthopaedic Fracture SBA Quiz

1. A 65-year-old woman presents with pain and swelling in the mid-upper arm following a fall. Examination reveals tenderness over the midshaft of the humerus and wrist drop. What is the most likely associated nerve injury?

  • Median nerve
  • Axillary nerve
  • Ulnar nerve
  • Radial nerve

Answer: Radial nerve

Midshaft humerus fractures are classically associated with radial nerve injury, which presents with wrist drop.

2. A 7-year-old boy falls on his outstretched hand and complains of elbow pain. X-ray shows a posterior fat pad sign. What is the most likely diagnosis?

  • Olecranon fracture
  • Elbow dislocation
  • Supracondylar fracture
  • Radial head fracture

Answer: Supracondylar fracture

In children, a posterior fat pad sign on elbow X-ray commonly indicates a supracondylar fracture.

3. A 3-year-old girl refuses to use her right arm after being swung by her parents. Her arm is held slightly flexed and pronated. What is the most appropriate immediate management?

  • Reduction by supination and flexion
  • X-ray to confirm diagnosis
  • Immobilisation in a sling
  • Administer NSAIDs and observe

Answer: Reduction by supination and flexion

Radial head subluxation (“nursemaid’s elbow”) is usually reduced with a quick maneuver of supination and elbow flexion.

4. Which of the following best describes the mechanism of a nightstick fracture of the ulna?

  • Indirect trauma to the arm during a fall on an outstretched hand
  • Direct blow to the ulna, typically while defending oneself
  • Twisting injury causing simultaneous radial and ulnar fractures
  • High-impact trauma leading to comminuted fractures of both bones in the forearm

Answer: Direct blow to the ulna, typically while defending oneself

A “nightstick” fracture is an isolated fracture of the ulna from a direct blow to the forearm.

5. A 60-year-old woman falls on an outstretched hand and presents with a “dinner fork” deformity. X-ray shows a distal radius fracture with dorsal angulation. What is the most appropriate initial management?

  • Immediate referral for physiotherapy
  • Open reduction and internal fixation (ORIF)
  • Closed reduction and splinting
  • NSAIDs and observation

Answer: Closed reduction and splinting

A Colles’ fracture involves dorsal angulation. Initial management often involves closed reduction under anesthesia and splinting/casting.

6. A 25-year-old man presents with wrist pain after a fall. There is tenderness in the anatomical snuffbox. X-ray appears normal. What is the most appropriate next step?

  • Repeat X-ray in 2 weeks
  • Allow the patient to resume normal activity
  • MRI of the wrist
  • Immobilisation in a thumb spica splint

Answer: Immobilisation in a thumb spica splint

Because scaphoid fractures are prone to avascular necrosis, suspected fractures must be immobilised in a thumb spica even if initial X-rays are normal.

7. What is the most common complication of an untreated Boxer’s fracture?

  • Rotational deformity of the 5th finger
  • Chronic pain in the wrist
  • Avascular necrosis of the 5th metacarpal head
  • Non-union of the fracture site

Answer: Rotational deformity of the 5th finger

Boxer’s fractures involve the neck of the 5th metacarpal. If improperly treated, malunion can cause the 5th finger to rotate and overlap adjacent fingers.

8. A 30-year-old man presents with pain and swelling at the base of his thumb after a fall. X-ray reveals a fracture dislocation at the base of the first metacarpal. What is the most appropriate management?

  • Thumb spica splinting
  • Closed reduction and splinting
  • NSAIDs and activity modification
  • Open reduction and internal fixation (ORIF)

Answer: Open reduction and internal fixation (ORIF)

A Bennett fracture is an intra-articular fracture dislocation at the base of the first metacarpal. ORIF is typically necessary for stable fixation.

9. A 30-year-old man presents with ankle pain after twisting it during a football match. According to the Ottawa Ankle Rules, which of the following findings would indicate the need for an X-ray?

  • Mild swelling over the Achilles tendon
  • Pain on palpation of the medial malleolus
  • Inability to bear weight immediately and in the emergency department
  • Full range of motion with no tenderness

Answer: Inability to bear weight immediately and in the emergency department

Ottawa Ankle Rules indicate an X-ray if the patient cannot bear weight both right after the injury and in the emergency department, or if there is bone tenderness in specific areas.

10. A 40-year-old man falls on his outstretched hand and complains of elbow pain. According to the Ottawa Elbow Rule, which clinical feature warrants an X-ray?

  • Normal range of motion with mild swelling
  • Inability to fully extend the elbow
  • No pain but visible bruising over the elbow
  • Tenderness over the biceps tendon

Answer: Inability to fully extend the elbow

If a patient cannot fully extend the elbow after trauma, the Ottawa Elbow Rule recommends obtaining an X-ray to rule out fracture.

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