Trauma — MCQs

A child develops severe forearm pain after a supracondylar fracture reduction and POP cast application. The child describes the pain as worse than the fracture pain and has limited finger movement. Volkmann's ischemic contracture is suspected. Which muscle is most commonly affected in Volkmann's ischemia?

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Whiplash injury is damage to?

Trauma Indian Medical PG Practice Questions and MCQs

Question 151: Prosthetic replacement of the femoral head is indicated for which of the following fracture sites of the femur?

A. Inter-trochanteric fracture
B. Subcapital fracture of the neck of femur (Correct Answer)
C. Transtrochanteric fracture
D. Basal fracture of the neck of femur

Explanation: **Explanation:** The primary indication for prosthetic replacement (Hemiarthroplasty) in femoral neck fractures is the high risk of **Avascular Necrosis (AVN)** and **Non-union**. **1. Why Subcapital Fracture is the Correct Answer:** The femoral head receives its blood supply mainly through the **retinacular vessels** (branches of the medial circumflex femoral artery) which run along the neck. A **subcapital fracture** occurs just below the femoral head, where the fracture line is intracapsular. This frequently disrupts the blood supply, leading to a high incidence of AVN. In elderly patients with low functional demands, primary prosthetic replacement is preferred over internal fixation to avoid the complications of re-operation. **2. Analysis of Incorrect Options:** * **Inter-trochanteric (A) and Transtrochanteric (C) Fractures:** These are **extracapsular** fractures. This region has a rich blood supply and a large surface area of cancellous bone, leading to excellent healing potential. The treatment of choice is internal fixation (e.g., DHS or Cephalomedullary nail), not replacement. * **Basal Fracture of the Neck (D):** This occurs at the junction of the neck and the trochanter. Being further away from the head, the blood supply is often preserved compared to subcapital fractures. These are usually treated with internal fixation. **Clinical Pearls for NEET-PG:** * **Garden’s Classification:** Used for intracapsular fractures. Stage III and IV (displaced) in elderly patients are the classic indications for Hemiarthroplasty. * **Pauwels’ Classification:** Based on the angle of the fracture line; higher angles (Type III) indicate greater shear forces and higher risk of non-union. * **Choice of Surgery:** In young patients, always attempt **Internal Fixation** (Head salvage) regardless of displacement. In active elderly patients, **Total Hip Arthroplasty (THA)** is superior to Hemiarthroplasty.

Question 152: A 40-year-old male with a history of road traffic accident (RTA) and multiple long bone fractures develops tachypnea, periumbilical rashes, and has urinary fat globules. What is the most likely diagnosis?

A. Proximal urethral injury
B. Bladder injury
C. Bacterial pneumonitis
D. Fat embolism syndrome (Correct Answer)

Explanation: ### **Explanation** The correct answer is **Fat Embolism Syndrome (FES)**. **1. Why Fat Embolism Syndrome is correct:** Fat Embolism Syndrome typically occurs 24–72 hours after a **long bone fracture** (most commonly the femur or tibia). The pathophysiology involves the release of marrow fat into the systemic circulation, leading to mechanical obstruction and a biochemical inflammatory response. The diagnosis is clinical, based on **Gurd’s Criteria**, which includes the classic triad seen in this patient: * **Respiratory Distress:** Tachypnea and hypoxia (most common early sign). * **Cerebral Involvement:** Confusion or altered sensorium. * **Petechial Rash:** Characteristically found in the conjunctiva, axilla, or **periumbilical** region (pathognomonic but present in only 20-50% of cases). * **Supporting evidence:** The presence of **urinary fat globules** (lipuria) is a minor criterion supporting the diagnosis. **2. Why the other options are incorrect:** * **A & B (Urethral/Bladder Injury):** While common in pelvic fractures, these present with hematuria, inability to void, or suprapubic pain. They do not cause respiratory distress or petechial rashes. * **C (Bacterial Pneumonitis):** While it causes tachypnea, it is usually associated with high-grade fever and purulent sputum, and it would not explain the periumbilical rashes or the specific association with recent long bone trauma. **3. High-Yield Clinical Pearls for NEET-PG:** * **Gurd’s Major Criteria:** Respiratory insufficiency, Cerebral symptoms, Petechial rash. * **Snowstorm Appearance:** Classic finding on Chest X-ray (diffuse bilateral pulmonary infiltrates). * **Early Fixation:** The most effective way to prevent FES is the early stabilization/fixation of long bone fractures. * **Treatment:** Primarily **supportive** (Oxygenation/Ventilation). Corticosteroids are controversial and not routinely recommended. * **Free Fatty Acids:** These are the toxic metabolites responsible for the chemical pneumonitis in FES.

Question 153: What is the preferred treatment for cubitus varus?

A. Medial closing wedge osteotomy
B. Lateral closing wedge osteotomy (Correct Answer)
C. Medial opening wedge osteotomy
D. Lateral opening wedge osteotomy

Explanation: **Explanation:** **Cubitus varus**, commonly known as "Gunstock deformity," is the most frequent late complication of malunited supracondylar fractures of the humerus. It is a three-dimensional deformity involving varus angulation, internal rotation, and hyperextension. **Why Lateral Closing Wedge Osteotomy (French Osteotomy) is the Correct Choice:** The **Lateral Closing Wedge Osteotomy** is the gold standard treatment for correcting cubitus varus. In this procedure, a wedge of bone is removed from the lateral aspect of the distal humerus. This allows the surgeon to tilt the distal fragment laterally, effectively correcting the varus angle. It is preferred because: 1. **Stability:** Closing a wedge provides better bone-on-bone contact, leading to faster healing and inherent stability. 2. **Simplicity:** It avoids the need for bone grafting and minimizes tension on the ulnar nerve. **Analysis of Incorrect Options:** * **Medial Closing Wedge Osteotomy:** This would worsen the varus deformity by further tilting the forearm toward the midline. * **Medial/Lateral Opening Wedge Osteotomies:** These require bone grafting to fill the gap, carry a higher risk of non-union, and can lead to increased tension on neurovascular structures (especially the ulnar nerve in medial opening procedures). **Clinical Pearls for NEET-PG:** * **Most common cause:** Malunited supracondylar fracture (specifically, failure to correct the medial tilt). * **Indication for surgery:** Primarily cosmetic; functional impairment is rare. * **French Osteotomy:** A specific type of lateral closing wedge osteotomy using two screws and a tension band wire. * **Ulnar Nerve:** While cubitus varus is usually asymptomatic, it can occasionally lead to **tardy ulnar nerve palsy** or posterolateral rotatory instability in adulthood.

Question 154: Which of the following is NOT a type of healthy bone healing?

A. Contact healing
B. Gap healing
C. Healing with callus formation
D. Fibrous healing (Correct Answer)

Explanation: **Explanation:** In orthopaedics, healthy bone healing is categorized into **Primary (Direct)** and **Secondary (Indirect)** healing. The goal of both is the restoration of bony continuity through mineralized tissue. **Why Fibrous Healing is the correct answer:** **Fibrous healing** (or fibrous union) is considered a form of **impaired healing** or non-union. Instead of forming a bony bridge, the fracture gap is filled with dense fibrous connective tissue. This results in a lack of structural stability and clinical "false motion" at the fracture site. It is not a healthy physiological end-point of bone repair. **Analysis of Incorrect Options:** * **A. Contact Healing:** A type of **Primary Healing**. It occurs when there is absolute stability (compression plating) and the gap is <0.01 mm. Osteoclasts create "cutting cones" that cross the fracture line, followed by osteoblasts laying down lamellar bone immediately. There is no callus formation. * **B. Gap Healing:** Also a type of **Primary Healing**. It occurs when the gap is small (<1 mm) and stable. The gap is first filled by woven bone, which is later remodeled into lamellar bone. Like contact healing, this occurs without external callus. * **C. Healing with Callus Formation:** This is **Secondary Healing**, the most common type of natural bone healing. It occurs in the presence of relative micromotion (e.g., casts, intramedullary nails). It involves a sequential process: Hematoma → Soft Callus (cartilage) → Hard Callus (woven bone) → Remodeling. **NEET-PG High-Yield Pearls:** * **Absolute Stability** (Plating) → Primary Healing → **No Callus.** * **Relative Stability** (Nailing/Casting) → Secondary Healing → **Callus present.** * **Cutting Cones** are the hallmark of primary bone healing. * **Strain Theory (Perren):** Bone formation requires low strain (<2%). If strain is too high, fibrous tissue forms instead of bone.

Question 155: Uncomplicated shoulder dislocation most commonly occurs in which direction?

A. Anterior (Correct Answer)
B. Posterior
C. Superior
D. Medially

Explanation: **Explanation:** The shoulder (glenohumeral) joint is the most commonly dislocated joint in the body due to the inherent instability provided by a shallow glenoid cavity and a large humeral head. **1. Why Anterior is Correct:** **Anterior dislocation** accounts for approximately **95-97%** of all shoulder dislocations. It typically occurs when the arm is in a position of **abduction and external rotation**. The anatomical weakness of the anterior capsule, specifically between the superior and middle glenohumeral ligaments (Foramen of Weitbrecht), makes the joint prone to displacement in this direction. **2. Why Other Options are Incorrect:** * **Posterior (B):** Accounts for only 2-5% of cases. It is classically associated with **seizures, electric shocks**, or direct trauma to the front of the shoulder. It is often missed on initial X-rays (look for the "Light bulb sign"). * **Superior (C):** Extremely rare. It usually involves a high-energy upward force and is typically associated with fractures of the acromion, clavicle, or coracoid process. * **Medially (D):** This is not a standard anatomical direction for shoulder dislocation. Displacement occurs relative to the glenoid fossa (Anterior, Posterior, or Inferior/Luxatio Erecta). **Clinical Pearls for NEET-PG:** * **Most common nerve injured:** Axillary nerve (tested via sensation over the "Regimental Badge" area). * **Hill-Sachs Lesion:** A compression fracture of the posterolateral humeral head. * **Bankart Lesion:** Avulsion of the anteroinferior glenoid labrum. * **Kocher’s Method:** A historical reduction technique (though no longer preferred due to high complication rates like humeral fractures). * **Hippocratic Method:** The oldest described reduction technique using foot-in-axilla traction.

Question 156: Fracture of the base of the first metacarpal joint without associated dislocation is called?

A. Bennett fracture
B. Rolando fracture (Correct Answer)
C. Jones fracture
D. Boxer's fracture

Explanation: **Explanation:** The correct answer is **Rolando fracture**. This is a **comminuted intra-articular fracture** at the base of the first metacarpal. Classically, it presents as a T-shaped or Y-shaped fracture pattern. Unlike a Bennett fracture, the fragments often remain relatively in place without a gross dislocation of the shaft, although the joint surface is severely disrupted. **Analysis of Options:** * **Bennett fracture:** This is an oblique, intra-articular fracture-dislocation at the base of the first metacarpal. The hallmark is the **dislocation** of the metacarpal shaft proximally and radially due to the pull of the Abductor Pollicis Longus (APL) muscle, while a small volar fragment remains attached to the trapezium. * **Jones fracture:** This occurs at the **base of the fifth metatarsal** (foot), specifically at the junction of the diaphysis and metaphysis (Zone 2). It is notorious for poor healing due to a watershed blood supply. * **Boxer's fracture:** This is a fracture of the **neck of the fifth metacarpal**, typically caused by striking a hard object with a closed fist. **High-Yield Pearls for NEET-PG:** * **Mechanism:** Both Bennett and Rolando fractures result from axial loading along the first metacarpal (e.g., a punch). * **Prognosis:** Rolando fractures have a **worse prognosis** than Bennett fractures because the comminution makes anatomical reduction difficult, leading to early-onset osteoarthritis. * **Treatment:** Bennett fractures usually require K-wire fixation (CRIF/ORIF), while Rolando fractures often require open reduction with a T-plate or external fixation if highly comminuted. * **Gamekeeper’s Thumb:** An injury to the Ulnar Collateral Ligament (UCL) of the first MCP joint, often associated with an avulsion fracture.

Question 157: Which of the following associations between clinical angles and their corresponding conditions is incorrect?

A. Kite's angle - club foot
B. Gissan's angle - calcaneus fracture
C. Baumann's angle - fracture of the lateral condyle of the femur (Correct Answer)
D. Cobb's angle - scoliosis

Explanation: **Explanation:** The correct answer is **C**, as Baumann’s angle is associated with the **humerus**, not the femur. **1. Why Option C is the correct (incorrect association) answer:** **Baumann’s Angle** (humeral-capitellar angle) is measured on an AP radiograph of the elbow. It is the angle between the long axis of the humeral shaft and the physeal line of the lateral condyle. It is clinically vital in evaluating **Supracondylar fractures of the humerus** in children to assess the adequacy of reduction and predict subsequent cubitus varus deformity. It has no relation to the lateral condyle of the femur. **2. Analysis of other options:** * **A. Kite’s Angle (Talocalcaneal angle):** Used to evaluate **Clubfoot (CTEV)**. In a normal foot, this angle is $20-40^\circ$; in clubfoot, the talus and calcaneus become more parallel, significantly decreasing the angle. * **B. Gissane’s Angle (Crucial Angle):** Formed by the downward and upward slopes of the calcaneal superior surface. It is a key landmark in **Calcaneal fractures**; an increase in this angle indicates a collapse of the posterior facet. * **D. Cobb’s Angle:** The gold standard for quantifying the magnitude of spinal curvature in **Scoliosis**. It is measured using the end-plates of the most tilted vertebrae. **High-Yield Clinical Pearls for NEET-PG:** * **Bohler’s Angle:** Also used for calcaneal fractures (normal: $25-40^\circ$); it **decreases** in displaced fractures. * **Southwick Angle:** Used for Slipped Capital Femoral Epiphysis (SCFE). * **Alpha Angle:** Used in the ultrasound diagnosis of Developmental Dysplasia of the Hip (DDH). * **Garden Index:** Used to assess the alignment of femoral neck fractures on AP and lateral views.

Question 158: A 56-year-old woman visits the emergency department after falling on wet pavement. Radiographic examination reveals osteoporosis and a Colles' fracture. Which of the following carpal bones are often fractured or dislocated with a Colles' fracture?

A. Triquetrum and scaphoid
B. Triquetrum and lunate
C. Scaphoid and lunate (Correct Answer)
D. Triquetrum, lunate, and scaphoid

Explanation: **Explanation:** **1. Why Scaphoid and Lunate are correct:** A Colles' fracture is a distal radius fracture (within 2.5 cm of the wrist joint) occurring due to a fall on an outstretched hand (FOOSH) with the wrist in dorsiflexion. The mechanism of injury involves the transmission of force from the ground through the carpal bones to the distal radius. The **Scaphoid** and **Lunate** are the two primary carpal bones that articulate directly with the distal radius (at the scaphoid and lunate fossae). During the impact, these bones act as a wedge against the radial articular surface, making them the most susceptible to concomitant fractures or ligamentous dislocations (such as scapholunate dissociation) alongside the radial fracture. **2. Analysis of Incorrect Options:** * **A & B (Triquetrum):** The triquetrum articulates with the TFCC (Triangular Fibrocartilage Complex) rather than the radius itself. While it can be injured in wrist trauma, it is not as frequently associated with the direct axial loading mechanism of a Colles' fracture compared to the scaphoid and lunate. * **D (Triquetrum, Lunate, and Scaphoid):** While multiple carpal injuries can occur in high-energy trauma, the standard clinical association for a typical Colles' fracture specifically highlights the two bones forming the primary radiocarpal joint. **3. NEET-PG High-Yield Pearls:** * **Colles' Fracture:** Characterized by **dorsal displacement**, dorsal tilt, and radial deviation ("Dinner Fork Deformity"). * **Smith’s Fracture:** The "Reverse Colles," involving volar displacement (Garden Spade Deformity). * **Associated Injury:** The most common associated fracture in a Colles' case is the **Ulnar Styloid process** (60% of cases). * **Complication:** The most common late complication is **Secondary Osteoarthritis**, while the most common tendon rupture is the **Extensor Pollicis Longus (EPL)**.

Question 159: A child develops severe forearm pain after a supracondylar fracture reduction and POP cast application. The child describes the pain as worse than the fracture pain and has limited finger movement. Volkmann's ischemic contracture is suspected. Which muscle is most commonly affected in Volkmann's ischemia?

A. Pronator teres
B. Flexor carpi radialis longus
C. Flexor digitorum profundus (Correct Answer)
D. Flexor digitorum superficialis

Explanation: **Explanation:** Volkmann’s Ischemic Contracture (VIC) is the sequela of untreated **Compartment Syndrome**, most commonly occurring after supracondylar fractures of the humerus. When tissue pressure within the deep fascia of the forearm exceeds capillary perfusion pressure, ischemia occurs. **Why Flexor Digitorum Profundus (FDP) is the correct answer:** The muscles located deepest in the compartment and closest to the bone are the most vulnerable to increased pressure and ischemia. The **Flexor Digitorum Profundus (FDP)** and the **Flexor Pollicis Longus (FPL)** are the deepest muscles in the volar compartment of the forearm. Among these, the FDP is considered the "watershed" area of perfusion and is the **most commonly and severely affected muscle** in Volkmann’s ischemia. **Analysis of Incorrect Options:** * **A. Pronator teres:** This is a superficial muscle. While it can be involved in severe cases, it is not the primary or most common site of ischemia. * **B. Flexor carpi radialis:** This is a superficial flexor. Ischemia typically progresses from the deep to the superficial layers. * **D. Flexor digitorum superficialis (FDS):** Although frequently involved as the condition progresses, it lies superficial to the FDP and is generally less affected than the deep layer in the early stages. **Clinical Pearls for NEET-PG:** * **Earliest Sign:** Pain out of proportion to the injury and **pain on passive extension** of fingers. * **Infarct Shape:** The ischemic zone is typically **ellipsoid-shaped**, with the center located at the FDP. * **Nerve Involvement:** The **Median nerve** is the most commonly affected nerve in the forearm compartment. * **Management:** Immediate removal of the cast/dressings. If no improvement within 30–60 minutes, urgent **fasciotomy** is indicated.

Question 160: Whiplash injury is damage to?

A. Skull
B. Spine (Correct Answer)
C. Rib cage
D. Long bones

Explanation: **Explanation:** **Whiplash injury** refers to a mechanism of acceleration-deceleration forces where energy is transferred to the **cervical spine**. It most commonly occurs during rear-end or side-impact motor vehicle collisions. 1. **Why the Spine is correct:** The term "whiplash" describes the rapid "whip-like" motion of the neck. When a vehicle is struck from behind, the torso is accelerated forward while the head lags behind, causing sudden **hyperextension** followed by rapid **rebound flexion**. This motion strains the soft tissues (ligaments, tendons, and muscles) of the cervical spine and can lead to facet joint injuries or disc herniation. 2. **Why other options are incorrect:** * **Skull:** While a head injury (concussion) can coexist with whiplash, the primary site of mechanical strain in whiplash is the neck, not the cranium. * **Rib cage:** Rib fractures typically require direct blunt trauma or compression, which is not the mechanism of a whiplash injury. * **Long bones:** These are injured in high-velocity impacts or direct falls, but they are not involved in the specific acceleration-deceleration mechanism defining whiplash. **Clinical Pearls for NEET-PG:** * **Quebec Classification:** Used to grade the severity of Whiplash-Associated Disorders (WAD), ranging from Grade 0 (no symptoms) to Grade 4 (fracture/dislocation). * **Common Symptom:** The most frequent symptom is neck pain/stiffness, often appearing **12–24 hours after** the injury (delayed onset). * **Radiology:** X-rays are often normal, but may show a "loss of cervical lordosis" due to muscle spasms. * **Treatment:** Early mobilization and NSAIDs are preferred over prolonged immobilization with a cervical collar.

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