ABEM Orthopedic & Musculoskeletal Emergencies 1 — Questions and Answers
Question 1: A 28-year-old male twists his ankle and has tenderness over the lateral malleolus but can bear weight in the ED. According to the Ottawa Ankle Rules, which finding independently mandates an X-ray?
- Lateral malleolus tenderness alone
- Inability to bear weight both immediately after injury and in the ED (Correct answer)
- Mild swelling over the lateral ankle
- Pain with passive inversion of the foot
Correct answer: Inability to bear weight both immediately after injury and in the ED
Ottawa Ankle Rules require X-ray if there is bony tenderness at specific malleolar zones OR inability to bear weight (4 steps) both immediately after injury and in the ED.
Question 2: A 25-year-old develops severe forearm pain after a closed forearm fracture. The pain is disproportionate to injury and worsens with passive finger extension. Compartment pressure measures 35 mmHg with a diastolic BP of 60 mmHg. What is the next step?
- Elevate the extremity and reassess in 2 hours
- Ice, analgesics, and close monitoring
- Emergency fasciotomy (Correct answer)
- IV antibiotics and repeat pressure measurement
Correct answer: Emergency fasciotomy
Compartment syndrome is confirmed when pressures are within 30 mmHg of diastolic BP; emergency fasciotomy is the definitive and only treatment.
Question 3: An 80-year-old woman presents with groin pain and inability to bear weight after a fall. Her leg is slightly shortened and externally rotated but plain X-rays are negative. What is the best next imaging step?
- Discharge with analgesics and follow-up in 1 week
- MRI of the hip (Correct answer)
- CT scan of the pelvis
- Technetium bone scan
Correct answer: MRI of the hip
MRI is the preferred modality for occult hip fractures when plain radiographs are negative but clinical suspicion is high, offering high sensitivity and no radiation.
Question 4: A 3-year-old presents with refusal to use his right arm after being lifted by his hands. The arm hangs with the elbow slightly flexed and forearm pronated. X-rays are normal. What is the most appropriate management?
- Splint in posterior long-arm splint and obtain MRI
- Hyperpronation or supination-flexion reduction technique (Correct answer)
- IV sedation with closed reduction under fluoroscopy
- Orthopedic consultation for casting
Correct answer: Hyperpronation or supination-flexion reduction technique
Nursemaid's elbow (radial head subluxation) is successfully reduced at the bedside using hyperpronation or supination-flexion without anesthesia.
Question 5: A 22-year-old sustains an anterior shoulder dislocation during a tackle. Which neurovascular structure is most commonly injured in this dislocation?
- Radial nerve
- Axillary nerve (Correct answer)
- Musculocutaneous nerve
- Brachial artery
Correct answer: Axillary nerve
The axillary nerve wraps around the surgical neck of the humerus and is the most commonly injured nerve in anterior shoulder dislocations, causing deltoid weakness and lateral shoulder numbness.
Question 6: A patient falls on a flexed, pronated wrist and presents with dorsal wrist pain. X-ray shows a distal radius fracture with volar angulation and dorsal displacement of the carpus. This fracture pattern is called:
- Colles' fracture
- Smith's fracture (Correct answer)
- Barton's fracture
- Chauffeur's fracture
Correct answer: Smith's fracture
Smith's fracture (reverse Colles') involves volar angulation of the distal radius, occurring from a fall on a flexed wrist, in contrast to the dorsal angulation of a Colles' fracture.
Question 7: A 30-year-old female presents with acute knee injury after pivoting. To test anterior cruciate ligament integrity, which maneuver is performed with the knee at 20-30 degrees of flexion while translating the tibia anteriorly on the femur?
- McMurray test
- Lachman test (Correct answer)
- Valgus stress test
- Patellar apprehension test
Correct answer: Lachman test
The Lachman test is the most sensitive clinical test for ACL rupture, performed at 20-30 degrees of flexion to relax the posterior capsule and isolate ACL function.
ABEM Orthopedic & Musculoskeletal Emergencies 1
A 28-year-old male twists his ankle and has tenderness over the lateral malleolus but can bear weight in the ED.
According to the Ottawa Ankle Rules, which finding independently mandates an X-ray?