INI-CET 2025 — Orthopaedics

Q: A 17-year-old boy presents with a progressively increasing swelling over the tibia along with fever. Radiological examination reveals a Codman triangle and sunburst appearance. What is the most likely diagnosis?

Osteosarcoma. ***Osteosarcoma*** - This is the most common primary malignant bone tumor in adolescents, often presenting with pain and swelling, typically affecting the **metaphysis** of long bones (like the tibia). - The presence of the **Codman triangle** (periosteal elevation) and the **sunburst appearance** (spicules of bone radiating outwards) are pathognomonic radiological signs due to aggressive bone formation. *Ewing sarcoma* - While also affecting adolescents and associated with systemic features like **fever** (mimicking infection), its classic radiological sign is the **'onion-peel' (laminated) periosteal reaction**. - It typically involves the **diaphysis** of long bones or flat bones, unlike the metaphyseal involvement seen here. *Giant cell tumour* - This tumor usually affects slightly older adults (20-40 years) and predominantly involves the **epiphysis** of long bones. - Radiographically, GCT exhibits a non-sclerotic, **'soap bubble' appearance** (multiloculated lytic lesion) but does not feature the aggressive Codman triangle or sunburst pattern. *Chondrosarcoma* - This diagnosis is unlikely in a 17-year-old, as it typically presents in older adults (40-70 years). - The radiologic hallmark of chondrosarcoma is the presence of **ring-and-arc** or **'popcorn' calcifications** within the cartilaginous matrix, not the ossifying reactions seen in this case. [Practice more Orthopaedics PYQs on OnCourse]

Q: A labourer falls on an outstretched hand and complains of pain in the anatomical snuff box. Which of the following is the most appropriate next step?

Thumb spica cast and follow-up after 10-14 days. ***Thumb spica cast and follow-up after 10-14 days*** - The combination of a **fall on an outstretched hand (FOOSH)** and pain in the **anatomical snuff box** is highly suggestive of a **scaphoid fracture**, even if initial X-rays are negative. - The most appropriate initial management is immobilization with a **thumb spica cast** (to prevent non-union) and re-evaluation with a repeat X-ray or advanced imaging in **10–14 days**, as the fracture line often becomes visible after bone resorption. ***NSAIDs and discharge*** - Discharging the patient with only NSAIDs is inappropriate as it risks missing a potentially serious injury like an occult scaphoid fracture, which can lead to complications such as **non-union** and **avascular necrosis (AVN)**. - Scaphoid fractures are the most common carpal fracture and require prompt immobilization due to their precarious blood supply. ***MRI of the wrist*** - While MRI is the **most sensitive and specific** imaging modality for diagnosing an occult scaphoid fracture, it is often not the first line of management in resource-limited or non-critical settings due to cost and availability. - Immobilization and delayed X-ray is the standard, cost-effective initial approach, reserving MRI for cases where early definitive diagnosis is surgically important or when repeat X-rays are inconclusive. ***CT scan of the wrist*** - CT scans are excellent for evaluating **complex fractures**, **comminution**, and defining fragment displacement, but they are less sensitive than MRI or bone scan for detecting acute, undisplaced, occult fractures. - CT is typically used pre-operatively to better plan fixation or distinguish between acute and chronic non-union, rather than as the immediate next step for presumed occult scaphoid injury. [Practice more Orthopaedics PYQs on OnCourse]

Q: What is the preferred treatment for an inter-trochanteric fracture in a 72-year-old female?

Hemiarthroplasty / Dynamic Hip Screw (DHS). ***Hemiarthroplasty / Dynamic Hip Screw (DHS)*** - **DHS** is the standard treatment for stable (Type I and II) inter-trochanteric fractures, providing controlled collapse and compression at the fracture site. - For unstable fractures (Type III and IV), especially in elderly patients with poor bone quality, **Intramedullary (IM) nailing** is often preferred over DHS due to superior biomechanical stability, though the combination option provided suggests the widely applicable stabilization principles for this age group. ***Intramedullary nailing*** - **IM nailing** is generally the preferred choice for unstable inter-trochanteric fractures (e.g., reverse oblique pattern or severe comminution) as it resists varus collapse more effectively than DHS. - While highly effective, it is not the *only* preferred treatment, and DHS remains primary for stable patterns, making the combined option more comprehensive for standard fracture care in the elderly. ***Open Reduction and Internal Fixation (ORIF) with plating*** - ORIF with plate fixation (other than DHS) is rarely used for inter-trochanteric fractures today, as it involves extensive soft tissue stripping and offers inferior biomechanical stability compared to compression screws (DHS) or nails. - This technique is typically reserved for highly unusual fracture patterns or as a salvage procedure, not as the primary 'preferred' method. ***Boot and bar*** - **Traction (boot and bar)** is historical and obsolete for treating hip fractures, including inter-trochanteric fractures. - Modern management mandates operative fixation as soon as the patient is medically optimized to allow early mobilization, reduce pain, and prevent complications like **deep vein thrombosis (DVT)** and pneumonia. [Practice more Orthopaedics PYQs on OnCourse]

Q: A teenager presents to the emergency department with wrist pain after falling off his skateboard. He has snuff-box tenderness. Which bone is likely fractured?

Scaphoid. ***Scaphoid*** - **Snuff-box tenderness** is the classic and most reliable clinical sign indicating a scaphoid fracture, usually sustained after a **fall onto an outstretched hand (FOOSH)**, common in young adults and teenagers. - The **scaphoid** is the most frequently fractured carpal bone (approx. 60%) and requires careful immobilization and follow-up due to the high risk of **avascular necrosis** from its retrograde blood supply. ***Trapezoid*** - Fractures of the trapezoid are extremely rare (less than 1% of carpal fractures) because of its stable position wedged between the **second metacarpal** and other carpals. - Tenderness for an isolated trapezoid fracture would be localized to the dorsal aspect of the wrist, more centrally, not specifically within the anatomical snuff box which is bounded by the **extensor tendons** of the thumb. ***Capitate*** - The capitate is the largest carpal bone, located in the center of the wrist, articulating with the **third metacarpal**; it is the second most commonly fractured carpal bone after the scaphoid. - Tenderness would be localized more centrally over the dorsal wrist, proximal to the third metacarpal base, and is not associated with classic **snuff-box tenderness**. ***Trapezium*** - The trapezium carpal bone articulates primarily with the **first metacarpal (thumb)**, forming the highly mobile carpometacarpal joint. - A fracture typically results in tenderness localized to the base of the thumb or the **thenar eminence**, rather than the radial dorsal wrist corresponding to the anatomical snuff box. [Practice more Orthopaedics PYQs on OnCourse]

4 Previous Year Questions with Answers & Explanations

Questions

A 17-year-old boy presents with a progressively increasing swelling over the tibia along with fever. Radiological examination reveals a Codman triangle and sunburst appearance. What is the most likely diagnosis?

A labourer falls on an outstretched hand and complains of pain in the anatomical snuff box. Which of the following is the most appropriate next step?

What is the preferred treatment for an inter-trochanteric fracture in a 72-year-old female?

A teenager presents to the emergency department with wrist pain after falling off his skateboard. He has snuff-box tenderness. Which bone is likely fractured?

INI-CET 2025 - Orthopaedics INI-CET Practice Questions and MCQs

Question 1: A 17-year-old boy presents with a progressively increasing swelling over the tibia along with fever. Radiological examination reveals a Codman triangle and sunburst appearance. What is the most likely diagnosis?

A. Ewing sarcoma
B. Giant cell tumour
C. Chondrosarcoma
D. Osteosarcoma (Correct Answer)

Explanation: ***Osteosarcoma*** - This is the most common primary malignant bone tumor in adolescents, often presenting with pain and swelling, typically affecting the **metaphysis** of long bones (like the tibia). - The presence of the **Codman triangle** (periosteal elevation) and the **sunburst appearance** (spicules of bone radiating outwards) are pathognomonic radiological signs due to aggressive bone formation. *Ewing sarcoma* - While also affecting adolescents and associated with systemic features like **fever** (mimicking infection), its classic radiological sign is the **'onion-peel' (laminated) periosteal reaction**. - It typically involves the **diaphysis** of long bones or flat bones, unlike the metaphyseal involvement seen here. *Giant cell tumour* - This tumor usually affects slightly older adults (20-40 years) and predominantly involves the **epiphysis** of long bones. - Radiographically, GCT exhibits a non-sclerotic, **'soap bubble' appearance** (multiloculated lytic lesion) but does not feature the aggressive Codman triangle or sunburst pattern. *Chondrosarcoma* - This diagnosis is unlikely in a 17-year-old, as it typically presents in older adults (40-70 years). - The radiologic hallmark of chondrosarcoma is the presence of **ring-and-arc** or **'popcorn' calcifications** within the cartilaginous matrix, not the ossifying reactions seen in this case.

Question 2: A labourer falls on an outstretched hand and complains of pain in the anatomical snuff box. Which of the following is the most appropriate next step?

A. NSAIDs and discharge
B. Thumb spica cast and follow-up after 10-14 days (Correct Answer)
C. CT scan of the wrist
D. MRI of the wrist

Explanation: ***Thumb spica cast and follow-up after 10-14 days*** - The combination of a **fall on an outstretched hand (FOOSH)** and pain in the **anatomical snuff box** is highly suggestive of a **scaphoid fracture**, even if initial X-rays are negative. - The most appropriate initial management is immobilization with a **thumb spica cast** (to prevent non-union) and re-evaluation with a repeat X-ray or advanced imaging in **10–14 days**, as the fracture line often becomes visible after bone resorption. ***NSAIDs and discharge*** - Discharging the patient with only NSAIDs is inappropriate as it risks missing a potentially serious injury like an occult scaphoid fracture, which can lead to complications such as **non-union** and **avascular necrosis (AVN)**. - Scaphoid fractures are the most common carpal fracture and require prompt immobilization due to their precarious blood supply. ***MRI of the wrist*** - While MRI is the **most sensitive and specific** imaging modality for diagnosing an occult scaphoid fracture, it is often not the first line of management in resource-limited or non-critical settings due to cost and availability. - Immobilization and delayed X-ray is the standard, cost-effective initial approach, reserving MRI for cases where early definitive diagnosis is surgically important or when repeat X-rays are inconclusive. ***CT scan of the wrist*** - CT scans are excellent for evaluating **complex fractures**, **comminution**, and defining fragment displacement, but they are less sensitive than MRI or bone scan for detecting acute, undisplaced, occult fractures. - CT is typically used pre-operatively to better plan fixation or distinguish between acute and chronic non-union, rather than as the immediate next step for presumed occult scaphoid injury.

Question 3: What is the preferred treatment for an inter-trochanteric fracture in a 72-year-old female?

A. Hemiarthroplasty / Dynamic Hip Screw (DHS) (Correct Answer)
B. Intramedullary nailing
C. Open Reduction and Internal Fixation (ORIF) with plating
D. Boot and bar

Explanation: ***Hemiarthroplasty / Dynamic Hip Screw (DHS)*** - **DHS** is the standard treatment for stable (Type I and II) inter-trochanteric fractures, providing controlled collapse and compression at the fracture site. - For unstable fractures (Type III and IV), especially in elderly patients with poor bone quality, **Intramedullary (IM) nailing** is often preferred over DHS due to superior biomechanical stability, though the combination option provided suggests the widely applicable stabilization principles for this age group. ***Intramedullary nailing*** - **IM nailing** is generally the preferred choice for unstable inter-trochanteric fractures (e.g., reverse oblique pattern or severe comminution) as it resists varus collapse more effectively than DHS. - While highly effective, it is not the *only* preferred treatment, and DHS remains primary for stable patterns, making the combined option more comprehensive for standard fracture care in the elderly. ***Open Reduction and Internal Fixation (ORIF) with plating*** - ORIF with plate fixation (other than DHS) is rarely used for inter-trochanteric fractures today, as it involves extensive soft tissue stripping and offers inferior biomechanical stability compared to compression screws (DHS) or nails. - This technique is typically reserved for highly unusual fracture patterns or as a salvage procedure, not as the primary 'preferred' method. ***Boot and bar*** - **Traction (boot and bar)** is historical and obsolete for treating hip fractures, including inter-trochanteric fractures. - Modern management mandates operative fixation as soon as the patient is medically optimized to allow early mobilization, reduce pain, and prevent complications like **deep vein thrombosis (DVT)** and pneumonia.

Question 4: A teenager presents to the emergency department with wrist pain after falling off his skateboard. He has snuff-box tenderness. Which bone is likely fractured?

A. Trapezoid
B. Trapezium
C. Scaphoid (Correct Answer)
D. Capitate

Explanation: ***Scaphoid*** - **Snuff-box tenderness** is the classic and most reliable clinical sign indicating a scaphoid fracture, usually sustained after a **fall onto an outstretched hand (FOOSH)**, common in young adults and teenagers. - The **scaphoid** is the most frequently fractured carpal bone (approx. 60%) and requires careful immobilization and follow-up due to the high risk of **avascular necrosis** from its retrograde blood supply. ***Trapezoid*** - Fractures of the trapezoid are extremely rare (less than 1% of carpal fractures) because of its stable position wedged between the **second metacarpal** and other carpals. - Tenderness for an isolated trapezoid fracture would be localized to the dorsal aspect of the wrist, more centrally, not specifically within the anatomical snuff box which is bounded by the **extensor tendons** of the thumb. ***Capitate*** - The capitate is the largest carpal bone, located in the center of the wrist, articulating with the **third metacarpal**; it is the second most commonly fractured carpal bone after the scaphoid. - Tenderness would be localized more centrally over the dorsal wrist, proximal to the third metacarpal base, and is not associated with classic **snuff-box tenderness**. ***Trapezium*** - The trapezium carpal bone articulates primarily with the **first metacarpal (thumb)**, forming the highly mobile carpometacarpal joint. - A fracture typically results in tenderness localized to the base of the thumb or the **thenar eminence**, rather than the radial dorsal wrist corresponding to the anatomical snuff box.