Trauma Practice Questions

Q: A 21-year-old man presents with shoulder pain after falling off his bike. What is your diagnosis?

Acromioclavicular dislocation. ***Acromioclavicular dislocation*** - **Fall on shoulder** mechanism commonly causes **AC joint injury** with **widened AC joint space** and **elevated distal clavicle** on X-ray - Clinical **piano key sign** (depressible distal clavicle) and **point tenderness** over AC joint are characteristic findings *Anterior glenohumeral joint dislocation* - Would show **humeral head displacement** anteriorly with loss of normal **glenohumeral joint relationship** on X-ray - Associated with **axillary nerve injury** and **Bankart lesions**, not consistent with AC joint pathology shown *Posterior glenohumeral dislocation* - Rare injury showing **lightbulb sign** on AP X-ray with **fixed internal rotation** of humerus - Often missed but would demonstrate **glenohumeral joint abnormality**, not isolated AC joint changes *All of the above* - Only **one specific diagnosis** can be made based on the radiographic evidence of AC joint pathology - **Multiple simultaneous dislocations** are extremely rare and not supported by typical imaging findings

Q: What is the pathognomic sign of a traumatic fracture?

Crepitus. ### Explanation In orthopaedics, clinical signs of a fracture are categorized into **Probable (Suggestive)** and **Definitive (Pathognomonic)** signs. **Why Crepitus is the Correct Answer:** Crepitus is the palpable or audible grating sensation produced by the friction of two broken bone ends rubbing against each other. It is considered a **pathognomonic (definitive) sign** because it can *only* occur if there is a breach in the continuity of the bone. Other definitive signs include abnormal mobility and visible deformity where no joint exists. **Analysis of Incorrect Options:** * **A. Tenderness:** This is a **suggestive sign**. While localized bone tenderness is a sensitive indicator of a fracture, it is non-specific as it also occurs in contusions, infections (osteomyelitis), or ligamentous injuries. * **B. Swelling:** This is a **general sign** of inflammation. It results from hematoma formation and soft tissue edema, which are common in sprains, strains, and various non-traumatic inflammatory conditions. * **C. Bruising (Ecchymosis):** This indicates subcutaneous bleeding. While common in fractures, it is also seen in simple soft tissue bruising or bleeding diathesis, making it non-diagnostic for a fracture. **High-Yield Clinical Pearls for NEET-PG:** * **Definitive Signs of Fracture:** 1. Abnormal mobility, 2. Crepitus, 3. Bony deformity. * **Clinical Caution:** One should **never** intentionally elicit crepitus or abnormal mobility to diagnose a fracture, as it causes extreme pain and risks further neurovascular injury. * **Exception:** Crepitus is absent in impacted fractures, as the bone ends are wedged together and do not move against each other. * **Differential Diagnosis:** Do not confuse "Bony Crepitus" with "Joint Crepitus" (seen in Osteoarthritis) or "Gas Crepitus" (seen in Gas Gangrene/Subcutaneous Emphysema).

Q: What is the absolute pressure threshold for indication of surgical compartment release in compartment syndrome?

30 mm Hg. **Explanation:** Acute Compartment Syndrome (ACS) is a surgical emergency where increased pressure within a fibro-osseous space compromises tissue perfusion. The diagnosis is primarily clinical, but intracompartmental pressure (ICP) measurement is the gold standard for objective assessment. **Why 30 mm Hg is the correct answer:** Traditionally, an **absolute ICP of 30 mm Hg** is considered the threshold for performing an emergency fasciotomy. This value is based on the physiological principle that when tissue pressure exceeds 30 mm Hg, it overcomes the capillary perfusion pressure, leading to muscle and nerve ischemia. **Analysis of Incorrect Options:** * **A & B (15 & 20 mm Hg):** These values represent elevated pressures but are generally considered "gray zones." While they require close monitoring, they do not meet the threshold for surgical intervention unless clinical symptoms are rapidly deteriorating. * **D (Varies from compartment to compartment):** While different compartments have different baseline pressures, the threshold for ischemia (30 mm Hg) is a standardized surgical guideline across all extremities. **Clinical Pearls for NEET-PG:** 1. **Delta Pressure ($\Delta P$):** Modern practice often favors the "Delta Pressure" over absolute pressure. $\Delta P = \text{Diastolic Blood Pressure} - \text{ICP}$. A **$\Delta P < 30$ mm Hg** is a more reliable indicator for fasciotomy, especially in hypotensive patients. 2. **Earliest Sign:** Pain out of proportion to the injury and pain on passive stretching of the muscles. 3. **Latest Sign:** Pulselessness (indicates irreversible damage; the "6 Ps" are often late findings). 4. **Whitesides’ Technique:** A common manometric method used to measure ICP. 5. **Volkmann’s Ischemic Contracture:** The permanent sequela of untreated compartment syndrome in the forearm.

Q: Tenderness in the anatomical snuff box is characteristic of which carpal bone fracture?

Scaphoid. **Explanation:** **Scaphoid fracture** is the most common carpal bone fracture, typically resulting from a fall on an outstretched hand (FOOSH). The scaphoid forms the floor of the **anatomical snuff box**. Therefore, localized tenderness in this area is considered pathognomonic for a scaphoid injury until proven otherwise. **Why the other options are incorrect:** * **Capitate:** This is the largest carpal bone, located centrally in the distal row. Fractures are rare and usually associated with complex perilunate injuries; tenderness would be deep and central, not in the snuff box. * **Lunate:** Located medial to the scaphoid, it is more prone to dislocation (leading to Median nerve compression) or avascular necrosis (Kienböck's disease) rather than isolated fractures. Tenderness is typically over the dorsum of the wrist, distal to Lister’s tubercle. * **Triquetrum:** This is the second most common carpal fracture (often a dorsal chip fracture). Tenderness is localized to the ulnar (medial) aspect of the wrist, distal to the ulnar styloid. **High-Yield Clinical Pearls for NEET-PG:** * **Blood Supply:** The scaphoid has a **retrograde blood supply** (from the distal pole to the proximal pole). This makes the proximal pole highly susceptible to **Avascular Necrosis (AVN)** and non-union. * **Radiology:** Fractures may not appear on initial X-rays. If clinical suspicion is high despite a normal X-ray, the wrist should be immobilized in a **Scaphoid cast** (thumb spica) and re-imaged after 10–14 days. * **Anatomical Snuff Box Boundaries:** Lateral (Abductor pollicis longus, Extensor pollicis brevis) and Medial (Extensor pollicis longus).

Q: What is the physiological interruption of nerve transmission?

Neuropraxia. The classification of nerve injuries is a high-yield topic for NEET-PG, primarily based on the **Seddon Classification**. ### **Explanation of the Correct Answer** **A. Neuropraxia** is the correct answer because it represents the mildest form of nerve injury. It is a **physiological interruption** of nerve conduction without any anatomical disruption of the axon or the connective tissue sheath. It is typically caused by local compression or ischemia (e.g., Saturday Night Palsy). Since the axon remains intact, there is no Wallerian degeneration, and recovery is complete and rapid (usually within days to weeks) once the pressure is relieved. ### **Analysis of Incorrect Options** * **B. Neurotmesis:** This is the most severe grade. It involves complete anatomical disruption of the entire nerve trunk (axon and all supporting connective tissue sheaths). Recovery is impossible without surgical intervention. * **C. Axonotmesis:** This involves anatomical disruption of the **axon** itself, but the supporting connective tissue frameworks (endoneurium, perineurium, and epineurium) remain intact. Wallerian degeneration occurs distal to the injury, and recovery is slow (1 mm/day) but possible because the intact sheaths guide regenerating sprouts. ### **Clinical Pearls for NEET-PG** * **Wallerian Degeneration:** Occurs in Axonotmesis and Neurotmesis, but **never** in Neuropraxia. * **Tinel’s Sign:** This is **absent** in Neuropraxia (as there is no axonal regeneration) but becomes **positive** in Axonotmesis as the nerve begins to heal. * **Sunderland Classification:** An expansion of Seddon’s; Neuropraxia corresponds to Grade I, Axonotmesis to Grades II-IV, and Neurotmesis to Grade V. * **Recovery Sequence:** In nerve injuries, **Motor** function is the first to go and last to return; **Pain** is the last to go and first to return.

Question 1

A 21-year-old man presents with shoulder pain after falling off his bike. What is your diagnosis?

Accepted Answer

Acromioclavicular dislocation

Answer

Anterior glenohumeral joint dislocation

Answer

Posterior glenohumeral dislocation

Answer

All of the above

Question 2

What is the pathognomic sign of a traumatic fracture?

Accepted Answer

Crepitus

Answer

Tenderness

Answer

Swelling

Answer

Bruising

Question 3

What is the absolute pressure threshold for indication of surgical compartment release in compartment syndrome?

Accepted Answer

30 mm Hg

Answer

15 mm Hg

Answer

20 mm Hg

Answer

Varies from compartment to compartment

Question 4

What is the treatment of choice in acute myositis ossificans?

Accepted Answer

Immobilization of the elbow

Answer

Shock wave diathermy

Answer

Passive movements of the arm

Answer

Active exercises

Question 5

Which of the following statements about eponymous fractures are true?

Accepted Answer

Pott's fracture is a trimalleolar ankle fracture.

Answer

Monteggia fracture is a fracture of the proximal third of the ulna with radial head dislocation.

Answer

Galeazzi fracture is a fracture of the distal third of the radius with dislocation of the distal radio-ulnar joint.

Answer

Colles fracture is a fracture at the cortico-cancellous junction of the distal end of the radius with dorsal tilt.

Question 6

In which of the following clinical scenarios is a prosthesis at the head of the femur typically applied?

Accepted Answer

A 65-year-old male with a non-united fracture of the femoral neck.

Answer

A 40-year-old male with a fracture of the femoral head.

Answer

A 40-year-old male with a fracture of the femoral neck.

Answer

A 40-year-old male with a posterior dislocation of the hip.

Question 7

A 50-year-old female presents with pain in the left hip and inability to walk following a fall. On examination, there is tenderness in the Scaepa's triangle. What is the most likely diagnosis?

Accepted Answer

Intracapsular neck of femur fracture

Answer

Intertrochanteric fracture femur

Answer

Transervical fracture neck of femur

Answer

Ischial tuberosity fracture

Question 8

Limb salvage can be done in all except?

Accepted Answer

Vascular injury

Answer

Nerve injury

Answer

Bone injury

Answer

Muscle injury

Question 9

Tenderness in the anatomical snuff box is characteristic of which carpal bone fracture?

Accepted Answer

Scaphoid

Answer

Capitate

Answer

Lunate

Answer

Triquetrum

Question 10

What is the physiological interruption of nerve transmission?

Accepted Answer

Neuropraxia

Answer

Neurotmesis

Answer

Axonotmesis

Answer

None of the above

Trauma — MCQs

Trauma — MCQs

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