Trauma Practice Questions

Q: What is the commonest site of fracture leading to fat embolism?

Femur. **Explanation:** **Fat Embolism Syndrome (FES)** occurs when fat globules from the bone marrow enter the systemic circulation following a fracture. The **Femur** is the correct answer because it is the largest long bone in the body with the most extensive medullary canal containing a high volume of fatty marrow. 1. **Why Femur is Correct:** The risk of fat embolism is directly proportional to the volume of marrow involved and the degree of intramedullary pressure elevation during trauma or surgery. Being the largest weight-bearing bone, fractures of the femur (especially the shaft) release the highest amount of fat emboli into the venous sinusoids. 2. **Why others are incorrect:** * **Tibia:** While the tibia is the second most common site for fat embolism, its medullary cavity is smaller than that of the femur. * **Humerus and Ulna:** These are smaller long bones with significantly less marrow volume, making the systemic "fat load" released during a fracture insufficient to typically cause clinical Fat Embolism Syndrome. **High-Yield Clinical Pearls for NEET-PG:** * **Gurd’s Criteria:** Used for diagnosis. Major features include **Petechial rashes** (typically over the chest, axilla, and conjunctiva), **Respiratory distress** (hypoxemia), and **Cerebral involvement** (confusion/altered sensorium). * **Classic Triad:** Dyspnea, Confusion, and Petechiae (appearing 24–72 hours post-injury). * **Snowstorm Appearance:** Characteristically seen on Chest X-ray. * **Management:** Primarily supportive (Oxygenation). Early stabilization/fixation of the fracture is the most effective way to **prevent** FES.

Q: A transverse fracture of the medial malleolus is most commonly caused by which of the following forces?

Abduction force. **Explanation:** The morphology of a medial malleolus fracture is determined by the mechanism of injury, specifically the direction of the talar movement within the mortise. 1. **Why Abduction is correct:** In an **abduction (eversion) injury**, the talus tilts laterally, putting the strong deltoid ligament under extreme tension. This results in an **avulsion fracture** of the medial malleolus. Because it is an avulsion injury, the fracture line is typically **transverse** (horizontal) and located at or below the level of the tibial plafond. This is a classic feature of Lauge-Hansen’s Pronation-Abduction injuries. 2. **Why other options are incorrect:** * **Adduction (Inversion) force:** This causes the talus to push against the medial malleolus. This "push-off" mechanism results in a **vertical or oblique fracture** line, often associated with impaction of the supramalleolar purlieu. * **Flexion force:** While plantar or dorsiflexion can occur during ankle trauma, they typically result in anterior or posterior lip fractures (Pott’s fracture variants) rather than a pure transverse medial malleolar fracture. **High-Yield Clinical Pearls for NEET-PG:** * **Lauge-Hansen Classification:** The most common mechanism of ankle fracture is **Supination-External Rotation (SER)**. * **Transverse = Avulsion:** Always remember that transverse fractures in the ankle are generally avulsion injuries (tension), while vertical/oblique fractures are due to impaction (compression). * **Mortise View:** The best X-ray view to assess the distal tibiofibular syndesmosis and the medial clear space. * **Danis-Weber Classification:** Based on the level of the **fibula** fracture relative to the syndesmosis (A: below, B: at, C: above).

Q: A 43-year-old man sustains a fracture of the tibia. Following application of an above-knee cast, and its removal after 6 weeks, he develops a foot drop and is unable to extend his ankle. This is due to a pressure injury to which of the following nerves?

Deep fibular (peroneal) nerve. **Explanation:** The clinical presentation of **foot drop** (inability to dorsiflex the ankle) following a tight cast or pressure near the knee is a classic sign of **Common Peroneal Nerve (CPN)** or its branch, the **Deep Peroneal Nerve**, injury. **Why the correct answer is right:** The Common Peroneal Nerve is highly vulnerable to compression as it winds around the **neck of the fibula**. In this case, a tight above-knee cast or improper padding at the proximal end of the cast exerts direct pressure on this superficial site. The **Deep Peroneal Nerve** specifically innervates the muscles of the anterior compartment of the leg (Tibialis anterior, EHL, EDL), which are responsible for **dorsiflexion** of the foot and extension of the toes. Damage leads to "foot drop." **Why the incorrect options are wrong:** * **Posterior Tibial Nerve:** It supplies the posterior compartment (plantarflexors). Injury would result in an inability to tip-toe and loss of sensation on the sole, not foot drop. * **Saphenous Nerve:** This is a purely sensory branch of the femoral nerve. Injury causes numbness along the medial aspect of the leg/foot but no motor deficit. * **Femoral Nerve:** This nerve supplies the quadriceps (knee extension) and hip flexors. It is located much higher in the femoral triangle and is not affected by pressure at the fibular neck. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of CPN injury:** Neck of the fibula. * **Clinical Triad of CPN Palsy:** Foot drop, loss of toe extension, and sensory loss over the first dorsal web space (Deep branch) or lateral leg/dorsum of foot (Superficial branch). * **Gait:** Patients with foot drop exhibit a **High Steppage Gait** to prevent the toes from dragging. * **Splinting:** A **Foot Drop Splint (AFO - Ankle Foot Orthosis)** is used to maintain the foot in neutral position.

Q: All of the following areas are commonly involved sites in pelvic fracture except:

Ischial tuberosities. **Explanation:** Pelvic fractures typically occur due to high-energy trauma (e.g., motor vehicle accidents or falls from heights) [1]. The pelvis is a rigid bony ring; therefore, fractures usually occur at its weakest points or areas subjected to direct impact. **Why Ischial Tuberosities are the correct answer:** The **ischial tuberosities** are thick, robust bony masses designed to bear the body's weight while sitting. They are heavily protected by the gluteus maximus and dense soft tissue. Isolated fractures of the ischial tuberosity are rare and usually occur as **avulsion fractures** (common in young athletes due to forceful contraction of the hamstrings) rather than as a standard component of major pelvic ring disruptions [2]. **Analysis of Incorrect Options:** * **Pubic Rami (A):** These are the **most common** sites of pelvic fractures. The superior and inferior rami are thin and structurally weak, making them highly susceptible to "crush" injuries or lateral compression [2]. * **Alae of Ileum (B):** The broad, relatively thin wings of the ilium are frequently fractured during direct lateral impacts or "open-book" injuries [2]. * **Acetabula (C):** Fractures of the acetabulum occur when the head of the femur is driven into the pelvis (e.g., dashboard injuries). These are common in high-velocity trauma and often require surgical intervention. **Clinical Pearls for NEET-PG:** * **Stable vs. Unstable:** A single break in the pelvic ring is usually stable, but breaks in two or more places (e.g., **Malgaigne fracture**) are unstable and life-threatening [2]. * **Associated Injury:** The most common complication of pelvic fractures is **hemorrhage** (usually from the internal iliac venous plexus) [1]. * **Urethral Injury:** In males, pelvic fractures (especially of the pubic symphysis/rami) are highly associated with **membranous urethral rupture**. Look for "high-riding prostate" on rectal exam.

Q: A geriatric patient presents with a history of a fall in the bathroom, after which she was unable to move. She was found in an externally rotated position of the lower limb. There was tenderness in Scarpa's triangle. X-ray did not reveal a hip fracture. What is the next best step in management?

MRI. **Explanation:** The clinical presentation of a geriatric patient with a fall, external rotation of the limb, and tenderness in Scarpa’s triangle is highly suggestive of a **hip fracture** (specifically a femoral neck fracture), even if the initial X-ray is negative. **Why MRI is the Correct Choice:** In the elderly, up to 10% of hip fractures are **occult** (not visible on initial radiographs) due to osteoporotic bone or non-displaced fracture lines. **MRI is the gold standard** and the investigation of choice for occult hip fractures. It has a sensitivity and specificity approaching 100%. It can detect bone marrow edema and fracture lines within 24 hours of injury, which other modalities might miss. **Analysis of Incorrect Options:** * **CT Scan:** While CT is excellent for evaluating complex fracture anatomy and cortical bone, it is less sensitive than MRI for detecting early trabecular stress or non-displaced occult fractures in osteoporotic bone. It is usually the second-line alternative if MRI is contraindicated. * **Ultrasound:** Useful for detecting joint effusions or soft tissue injuries, but it cannot reliably diagnose or rule out an intra-articular hip fracture. * **PET Scan:** This is a functional imaging modality used primarily in oncology and infectious workups; it has no role in the acute management of trauma or suspected fractures. **Clinical Pearls for NEET-PG:** * **Classic Triad of Hip Fracture:** History of fall, shortening of the limb, and **external rotation**. * **Imaging Protocol:** Always start with X-ray (AP view of pelvis with both hips and Lateral view). If X-ray is negative but clinical suspicion is high, proceed to **MRI**. * If MRI is unavailable or contraindicated (e.g., pacemaker), a **CT scan** or a **Bone Scan** (after 48–72 hours) are the next alternatives.

Q: What is the commonest complication of a Colles' fracture?

Malunion. **Explanation:** **Colles' fracture** is a distal radius fracture occurring within 2.5 cm of the wrist joint, characterized by dorsal displacement and angulation (Dinner Fork deformity). **1. Why Malunion is the Correct Answer:** Malunion is the **most common complication** of a Colles' fracture. It occurs due to the difficulty in maintaining anatomical reduction in a cast, especially in elderly patients with osteoporotic bone. This typically results in a "residual dinner fork deformity" and radial shortening, though it often remains functionally acceptable despite the cosmetic defect. **2. Why the Other Options are Incorrect:** * **Nonunion (A):** Extremely rare in Colles' fractures because the distal radius is made of cancellous bone, which has an excellent blood supply and high osteogenic potential. * **Vascular injury (C):** Rare in this fracture. Nerve injuries (specifically Median nerve compression) are more common than vascular ones. * **Sudeck's osteodystrophy (D):** Also known as Complex Regional Pain Syndrome (CRPS). While it is a well-known and debilitating complication of Colles' fracture, it is not the *most common*. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common late complication:** Malunion. * **Most common associated nerve injury:** Median nerve (Carpal Tunnel Syndrome). * **Most common tendon rupture:** Extensor Pollicis Longus (EPL) rupture (usually occurs 4–8 weeks post-injury due to ischemia or attrition at Lister’s tubercle). * **Stiffness:** Shoulder-hand syndrome is a frequent complication where the patient develops a stiff shoulder due to lack of mobilization while the wrist is in a cast. * **Deformities in Colles':** Dorsal tilt, Dorsal displacement, Radial tilt, Radial displacement, Supination, and Impaction.

Question 1

In fracture neck of femur, in which stage are all the trabeculae of the pelvis and femur in alignment?

Accepted Answer

Stage II

Answer

Stage I

Answer

Stage III

Answer

Stage IV

Question 2

What is the commonest site of fracture leading to fat embolism?

Accepted Answer

Femur

Answer

Tibia

Answer

Humerus

Answer

Ulna

Question 3

A transverse fracture of the medial malleolus is most commonly caused by which of the following forces?

Accepted Answer

Abduction force

Answer

Adduction force

Answer

Inversion force

Answer

Flexion force

Question 4

Which of the following are features of common peroneal nerve injury?

Accepted Answer

Foot drop, Loss of extension of great toe, Seen in fibular neck fracture

Answer

Inversion inability, Loss of sensation of sole, Foot drop

Answer

Loss of sensation of sole, Foot drop, Loss of extension of great toe

Answer

Inversion inability, Loss of sensation of sole, Foot drop, Loss of extension of great toe, Seen in fibular neck fracture

Question 5

A 43-year-old man sustains a fracture of the tibia. Following application of an above-knee cast, and its removal after 6 weeks, he develops a foot drop and is unable to extend his ankle. This is due to a pressure injury to which of the following nerves?

Accepted Answer

Deep fibular (peroneal) nerve

Answer

Posterior tibial nerve

Answer

Saphenous nerve

Answer

Femoral nerve

Question 6

All of the following areas are commonly involved sites in pelvic fracture except:

Accepted Answer

Ischial tuberosities

Answer

Pubic rami

Answer

Alae of ileum

Answer

Acetabula

Question 7

The Thompson and Epstein classification is used for which of the following conditions?

Accepted Answer

Posterior dislocation of the hip

Answer

Anterior dislocation of the hip

Answer

Central dislocation of the hip

Answer

Fracture of the neck of the femur

Question 8

A geriatric patient presents with a history of a fall in the bathroom, after which she was unable to move. She was found in an externally rotated position of the lower limb. There was tenderness in Scarpa's triangle. X-ray did not reveal a hip fracture. What is the next best step in management?

Accepted Answer

MRI

Answer

CT scan

Answer

Ultrasound

Answer

PET scan

Question 9

What is the commonest complication of a Colles' fracture?

Accepted Answer

Malunion

Answer

Nonunion

Answer

Vascular injury

Answer

Sudeck's osteodystrophy

Question 10

A young male, after sudden unconsciousness following an episode of seizure, on awakening, finds that both of his arms were adducted and internally rotated. What is the most probable diagnosis?

Accepted Answer

Posterior dislocation

Answer

Anterior dislocation

Answer

Greater tuberosity fracture

Answer

Rotator cuff injury

Trauma — MCQs

Trauma — MCQs

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