Trauma Practice Questions

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.

Q: A 32-year-old male with a history of seizures presents with pain in the left shoulder region. The left upper limb is addicted and internally rotated. What is the diagnosis?

Posterior dislocation of shoulder. ### Explanation **Correct Option: B. Posterior Dislocation of Shoulder** The diagnosis is based on the classic clinical presentation and history. Posterior shoulder dislocations are rare (2-5% of all dislocations) and are classically associated with **seizures** or **electric shocks**. During a seizure, the powerful internal rotators (Latissimus dorsi, Pectoralis major, and Subscapularis) overpower the weaker external rotators, forcing the humeral head posteriorly. The clinical hallmark is a limb fixed in **adduction and internal rotation**, with a pathognomonic **loss of external rotation**. On examination, there is often a palpable fullness in the posterior shoulder and a flattened anterior profile (loss of deltoid contour). **Analysis of Incorrect Options:** * **A. Anterior Dislocation:** This is the most common type. The limb is typically held in **abduction and external rotation**. It is usually caused by trauma (fall on an outstretched hand), not seizures. * **C. Inferior Dislocation (Luxatio Erecta):** A rare condition where the arm is held fixed in **full abduction** (pointing upwards) over the head. * **D. Impingement Syndrome:** A chronic overuse condition involving the rotator cuff; it does not present with an acute deformity or a fixed rotational deformity following a seizure. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Look for the **"Light Bulb Sign"** on AP view (the internally rotated humerus looks symmetrical like a bulb) and the **"Empty Glenoid Sign."** * **Best View:** The **Axillary view** is the gold standard to confirm posterior displacement. * **Associated Lesion:** **Reverse Hill-Sachs lesion** (impaction fracture of the anterior humeral head). * **Treatment:** Closed reduction (Modified Hippocratic method) followed by immobilization in **external rotation** (unlike anterior dislocation).

Q: Recurrent dislocation of the shoulder is most commonly associated with which type?

Anterior dislocation. **Explanation:** **1. Why Anterior Dislocation is Correct:** Anterior dislocation is the most common type of shoulder dislocation, accounting for approximately **95-97%** of all cases. Recurrence is a hallmark of anterior instability because the initial traumatic event often causes structural damage to the glenohumeral joint. The most significant factor is the **Bankart lesion** (avulsion of the anterior-inferior labrum), which fails to heal anatomically, leading to a permanent loss of the "chock-block" effect. Additionally, the presence of a **Hill-Sachs lesion** (compression fracture of the posterosuperior humeral head) further reduces joint stability, making recurrent episodes highly likely, especially in younger patients (age <20 years has a recurrence rate of up to 90%). **2. Why Other Options are Incorrect:** * **Posterior Dislocation:** These are rare (2-5%) and typically associated with seizures or electric shocks. While they can become chronic or "missed," they do not have the same high incidence of spontaneous recurrence as anterior dislocations. * **Inferior Dislocation (Luxatio Erecta):** This is the rarest form, characterized by the arm being locked in an overhead position. It is usually a high-energy trauma event associated with significant neurovascular injury rather than chronic recurrence. **3. Clinical Pearls for NEET-PG:** * **Most common cause of recurrence:** Patient age at the time of the first dislocation (younger = higher risk). * **Bankart Lesion:** Most common pathological finding in recurrent anterior dislocation. * **Putti-Platt/Magnuson-Stack:** Historical surgeries for recurrence (now largely replaced by Bankart repair). * **Latarjet Procedure:** Indicated when there is significant glenoid bone loss (>20-25%). * **Nerve Injury:** The **Axillary nerve** is the most commonly injured nerve in anterior dislocations (tested by sensation over the "Regimental Badge" area).

Q: What is the most common type of hip dislocation?

Posterior. **Explanation:** **1. Why Posterior Dislocation is Correct:** Posterior hip dislocation is the most common type, accounting for approximately **85-90%** of all traumatic hip dislocations. The underlying mechanism is typically a high-energy trauma, such as a "dashboard injury" in a motor vehicle accident. When the hip is flexed and adducted, a force applied to the knee drives the femoral head backward, rupturing the posterior capsule and dislodging it from the acetabulum. **2. Analysis of Incorrect Options:** * **Anterior Dislocation (Option B):** Much less common (approx. 10-15%). It occurs when the hip is in extreme extension, abduction, and external rotation (e.g., a fall from a height). * **Central Dislocation (Option C):** This is technically a fracture-dislocation where the femoral head is driven medially through a fractured acetabular floor into the pelvis. It is considered an acetabular fracture rather than a simple ligamentous dislocation. **3. High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** * **Posterior:** Limb is **Shortened, Adducted, and Internally Rotated** (Mnemonic: "S-A-I-R"). * **Anterior:** Limb is **Abducted and Externally Rotated**. * **Associated Nerve Injury:** The **Sciatic nerve** (specifically the peroneal division) is most commonly injured in posterior dislocations. * **Vascular Complication:** **Avascular Necrosis (AVN)** of the femoral head is the most serious late complication; the risk increases if reduction is delayed beyond 6 hours. * **X-ray Sign:** In posterior dislocation, the femoral head appears smaller than the contralateral side on AP view (due to being closer to the film). * **Management:** Emergency closed reduction (e.g., Allis or Bigelow maneuver) under sedation.

Question 1

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 2

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 3

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 4

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 5

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 6

What is the commonest complication of a Colles' fracture?

Accepted Answer

Malunion

Answer

Nonunion

Answer

Vascular injury

Answer

Sudeck's osteodystrophy

Question 7

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

Question 8

A 32-year-old male with a history of seizures presents with pain in the left shoulder region. The left upper limb is addicted and internally rotated. What is the diagnosis?

Accepted Answer

Posterior dislocation of shoulder

Answer

Anterior dislocation of shoulder

Answer

Inferior dislocation of shoulder

Answer

Impingement syndrome

Question 9

Recurrent dislocation of the shoulder is most commonly associated with which type?

Accepted Answer

Anterior dislocation

Answer

Posterior dislocation

Answer

Inferior dislocation

Answer

All of the above

Question 10

What is the most common type of hip dislocation?

Accepted Answer

Posterior

Answer

Answer

Central

Answer

None of the above

Trauma — MCQs

Trauma — MCQs

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