Musculoskeletal and Wound Emergencies practice questions

Answer: D) A thumb spica splint and follow-up imaging

• AIncorrect. Splinting and follow-up are typical.
• BIncorrect. A hidden fracture may be present.
• CIncorrect. A thumb spica is typical.
• DCorrect. Scaphoid fractures can be hidden early.

Answer: A) Necrotizing fasciitis

Severe pain out of proportion to skin findings, rapidly spreading purple discoloration, bullae and crepitus point to necrotizing fasciitis. It needs emergency surgical debridement and antibiotics.

• ACorrect. Pain out of proportion to skin findings, rapid red-to-purple discoloration, bullae and crepitus are classic signs. Treatment is early, aggressive surgical exploration and debridement plus IV antibiotics.
• BIncorrect. Cellulitis causes warm, red, tender skin, but pain matches the visible findings, and it does not cause crepitus or rapid dusky discoloration with bullae.
• CIncorrect. DVT can cause leg pain, swelling and discoloration, but it does not cause crepitus or bullae spreading from a wound.
• DIncorrect. Erysipelas is a superficial infection with raised, sharply outlined redness. It does not cause crepitus, severe disproportionate pain or rapid tissue death.

Answer: C) A tetanus toxoid-containing vaccine now, without TIG

For a dirty or major wound in a patient with 3 or more prior doses, a tetanus toxoid-containing vaccine is given if the last dose was 5 or more years ago (10 years for clean minor wounds). TIG is added only when the history is unknown, there were fewer than 3 doses, or the patient is immunocompromised.

• AIncorrect. For dirty wounds, TIG is indicated when the vaccination history is unknown or there were fewer than 3 prior doses, or if the patient is immunocompromised. None of these applies here.
• BIncorrect. The 10-year interval applies to clean, minor wounds. For dirty or major wounds, the threshold is 5 years.
• CCorrect. The patient has 3 or more prior doses and a dirty wound, and the last dose was 5 or more years ago. The patient should get a tetanus toxoid-containing vaccine (Tdap or Td). TIG is not needed.
• DIncorrect. TIG gives only temporary passive immunity and is not indicated for this fully vaccinated patient. What the patient needs is an active booster.

Answer: B) Pseudomonas aeruginosa

A nail puncture through a sneaker sole can carry Pseudomonas aeruginosa from the shoe's foam into bone or cartilage. Suspect osteomyelitis when foot pain, swelling, or trouble bearing weight develops or gets worse after the injury.

• AIncorrect. Pasteurella is the classic pathogen in cat and dog bite wounds, not in nail punctures through footwear.
• BCorrect. Pseudomonas lives in the moist foam inner sole of sneakers and is the classic cause of osteomyelitis or osteochondritis after a nail puncture through a sneaker. It often needs surgical debridement and IV antibiotics.
• CIncorrect. Eikenella is part of normal mouth flora and is linked to human bites and clenched-fist injuries.
• DIncorrect. Vibrio vulnificus infects wounds exposed to warm salt water or brackish water, or to raw shellfish, not puncture wounds through shoes.

Answer: A) Measure the ankle-brachial index on the injured leg and get vascular imaging if it is below 0.9

A knee dislocation that reduced on its own still carries a high risk of popliteal artery injury, and a palpable pulse does not exclude it. Measure the ABI and get duplex ultrasound or CT angiography if it is below 0.9.

• ACorrect. Up to 40% of knee dislocations cause vascular injury, most often to the popliteal artery. Many reduce before arrival. An ABI below 0.9 calls for arterial duplex ultrasound or CT angiography.
• BIncorrect. Ligament injury is expected, but grading instability does not come first. Ruling out popliteal artery injury is the priority because missing it can lead to amputation.
• CIncorrect. Collateral circulation can keep pedal pulses palpable even when popliteal artery injury is threatening the limb, so a pulse alone does not exclude arterial injury.
• DIncorrect. Capillary refill is not reliable for detecting popliteal artery injury. An objective measure such as the ABI, followed by imaging if abnormal, is needed.

Answer: A) Tenderness at the posterior edge or tip of either malleolus, or inability to take 4 steps both right after the injury and in the ED

With malleolar-zone pain, the Ottawa ankle rules call for radiographs if there is bone tenderness at the posterior edge or tip of either malleolus, or inability to take 4 steps both immediately after injury and in the ED. This gives near-100% sensitivity and cuts unnecessary films by about 30%.

• ACorrect. With malleolar-zone pain, the ankle rule calls for radiographs if there is bone tenderness at the posterior edge or tip of the lateral or medial malleolus, or if the patient can't bear weight for 4 steps both immediately after the injury and at evaluation.
• BIncorrect. Soft-tissue swelling and bruising are not Ottawa criteria. Without malleolar bone tenderness or inability to bear weight, the rule does not call for imaging.
• CIncorrect. The rule specifies tenderness at the posterior edge or tip of the malleoli, not the anterior distal tibia. Pain with passive inversion is not a criterion.
• DIncorrect. Ligament tenderness points to a sprain, and a patient who can take 4 steps (even with a limp) meets the weight-bearing standard. Neither finding triggers imaging.

Answer: B) Acute compartment syndrome of the lower leg

Escalating pain that opioids do not relieve, pain on passive stretch, and a tense compartment after a tibial fracture point to acute compartment syndrome even when pulses are present. It is a surgical emergency that may need fasciotomy.

• AIncorrect. Arterial occlusion causes absent or weak distal pulses, a cool pale limb, and slow capillary refill. This patient has a palpable pulse and normal refill.
• BCorrect. Pain much worse than expected that opioids do not relieve, pain on passive stretch, and a tense, swollen compartment are early signs. Distal pulses often stay present until late. The provider must be told right away because urgent fasciotomy may be needed.
• CIncorrect. DVT can cause calf pain and swelling, but it rarely appears within hours of injury. It does not cause severe pain on passive stretch that opioids fail to relieve.
• DIncorrect. Fat embolism usually appears 24 to 72 hours after injury with low oxygen, confusion, and petechiae. This patient has normal oxygen saturation and a normal mental status.

Answer: B) Copious saline irrigation using a large syringe fitted with a 19-gauge catheter

High-volume irrigation at adequate pressure, such as a 35–50 mL syringe with a 19-gauge catheter, is the single most important step for preventing wound infection. Antiseptic soaks are toxic to tissue, low-pressure pouring does not remove debris well, and antibiotics alone are not enough.

• AIncorrect. Povidone-iodine kills bacteria but is toxic to healthy cells. It should be used sparingly on the wound edges, not poured heavily into the wound.
• BCorrect. Irrigation is the single greatest wound-care intervention for reducing infection. A 35–50 mL syringe with a 19-gauge catheter generates enough pressure to remove debris and lower the bacterial load without injuring tissue. A commonly cited volume is about 50 mL per centimeter of wound.
• CIncorrect. Pouring saline over the wound gives volume but very little pressure. It does not reliably dislodge embedded soil and bacteria, so it is less effective than pressurized syringe irrigation.
• DIncorrect. Antibiotics do not replace mechanical cleansing. Skipping irrigation leaves contaminants in the wound and raises the risk of infection and abscess.

Answer: A) Wrap it in saline-moistened gauze, seal it in a plastic bag, and place the bag in a container of ice water

Avulsed or amputated tissue should be wrapped in saline-moistened gauze, sealed in a plastic bag, and cooled in ice water without touching the ice. Direct ice, direct soaking and dry storage all damage the tissue.

• ACorrect. StatPearls advises covering an amputated part with saline-soaked gauze, sealing it in a plastic bag, and submerging the bag in icy water without direct contact with ice. Cooling extends the time the tissue can survive without blood supply, which keeps reconstruction options open.
• BIncorrect. Direct contact with ice causes cold injury and can leave the tissue unusable.
• CIncorrect. Soaking the tissue directly makes it waterlogged and damaged, and room temperature gives none of the protection of cooling. The tissue should be wrapped in moist gauze and kept in a sealed bag.
• DIncorrect. Dry gauze lets the tissue dry out, and keeping it at room temperature shortens how long it stays viable.

Answer: A) Prolonged dislocation compromises femoral head blood supply and raises the risk of avascular necrosis

A traumatic hip dislocation is an orthopedic emergency. Delayed reduction, generally beyond about 6 hours, sharply increases the risk of avascular necrosis of the femoral head.

• ACorrect. Time to reduction is the most important modifiable factor for femoral head viability. Most authors recommend reduction within about 6 hours, and complication rates, especially avascular necrosis, rise sharply with delay.
• BIncorrect. Fat embolism is mainly linked to long-bone (for example, femoral shaft) fractures. It is not the reason for urgent hip reduction.
• CIncorrect. Thigh compartment syndrome is not the characteristic time-dependent complication of a hip dislocation. The urgency comes from the threat to femoral head perfusion.
• DIncorrect. A posterior dislocation threatens the sciatic nerve, not the femoral artery. The main time-sensitive concern is loss of blood supply to the femoral head, which leads to avascular necrosis.