UPSC-CMS 2013 — Orthopaedics

Q: Which one of the following fractures is most often complicated by fat embolism ?

Shaft of femur. ***Shaft of femur*** - **Long bone fractures**, especially those involving the **femur**, are classic causes of **fat embolism syndrome (FES)** due to the large amount of fatty marrow released into the circulation. - The **intraosseous pressure** increases at the fracture site, pushing fat globules into the bloodstream, which then travel to the lungs and other organs. *Shaft of tibia* - While the tibia is also a long bone and can cause fat emboli, it contains less marrow than the femur, making **tibial shaft fractures** less frequently associated with severe **fat embolism syndrome** compared to femoral fractures. - The **mechanical disruption** is generally less extensive than in a femoral fracture, reducing the volume of fatty material released. *Supra condyler humerus* - This fracture involves the **distal humerus**, which is a long bone, but its **marrow content is significantly less** than that of the femur. - While any long bone fracture can theoretically cause a **fat embolism**, the risk is much lower for **supracondylar humerus fractures** due to the smaller amount of fatty marrow. *Lumbar vertebrae* - Vertebral fractures, particularly those in the lumbar region, are primarily associated with the release of **bone marrow cells** and potentially spinal cord injury, but not typically with significant **fat embolism syndrome**. - The **marrow in vertebrae** is predominantly hematopoietic and much less fatty compared to the large medullary cavities of long bones like the femur. [Practice more Orthopaedics PYQs on OnCourse]

Q: The nerve most likely to get injured in patients with fracture of upper end of radius is :

Posterior interosseous. ***Posterior interosseous*** - The **posterior interosseous nerve** (deep branch of radial nerve) winds around the **neck of radius** through the **radial tunnel** between the heads of the supinator muscle, making it most vulnerable to injury with upper radial fractures. - Injury results in weakness of **finger and thumb extensors** with no sensory loss, as it is a purely **motor nerve** branch. *Ulnar* - The **ulnar nerve** passes behind the **medial epicondyle** of the humerus, making it vulnerable to elbow injuries but not typically affected by upper radial fractures. - Injury leads to **claw hand deformity** and sensory loss in the **medial hand**, which is anatomically distant from the radius. *Median* - The **median nerve** travels through the **cubital fossa** and is anatomically protected from direct trauma by upper radial fractures. - More commonly injured by **distal radial fractures** (Colles' fracture) causing **carpal tunnel compression**, not upper end fractures. *Radial* - The **radial nerve trunk** courses around the **spiral groove** of the humerus, making it susceptible to **humeral shaft fractures**, not upper radial fractures. - Injury causes **wrist drop** and sensory loss over the **posterior forearm**, but the main trunk is anatomically distant from the upper radius. [Practice more Orthopaedics PYQs on OnCourse]

Q: The commonest complication of fracture of clavicle is :

malunion. ***malunion*** - **Malunion** is the most frequent complication following a clavicle fracture, meaning the bone heals in an anatomically incorrect or deformed position. - This often results in a palpable bump or cosmetic deformity, and can occasionally cause functional impairment. *non union* - **Non-union** occurs when the fracture fails to heal completely, leaving a persistent gap between the bone fragments. - While possible, it is less common than malunion in clavicle fractures, especially with appropriate management. *avascular necrosis* - **Avascular necrosis** is rare in clavicle fractures because the clavicle has a rich blood supply. - It typically affects bones with precarious blood supply, such as the femoral head or scaphoid. *Neurovascular injury* - **Neurovascular injury** involving the subclavian vessels or brachial plexus is a serious but relatively rare complication of clavicle fractures. - While possible, especially with displaced fractures, it is not the most common adverse outcome. [Practice more Orthopaedics PYQs on OnCourse]

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Which one of the following fractures is most often complicated by fat embolism ?

The nerve most likely to get injured in patients with fracture of upper end of radius is :

The commonest complication of fracture of clavicle is :

UPSC-CMS 2013 - Orthopaedics UPSC-CMS Practice Questions and MCQs

Question 1: Which one of the following fractures is most often complicated by fat embolism ?

A. Shaft of femur (Correct Answer)
B. Shaft of tibia
C. Supra condyler humerus
D. Lumbar vertebrae

Explanation: ***Shaft of femur*** - **Long bone fractures**, especially those involving the **femur**, are classic causes of **fat embolism syndrome (FES)** due to the large amount of fatty marrow released into the circulation. - The **intraosseous pressure** increases at the fracture site, pushing fat globules into the bloodstream, which then travel to the lungs and other organs. *Shaft of tibia* - While the tibia is also a long bone and can cause fat emboli, it contains less marrow than the femur, making **tibial shaft fractures** less frequently associated with severe **fat embolism syndrome** compared to femoral fractures. - The **mechanical disruption** is generally less extensive than in a femoral fracture, reducing the volume of fatty material released. *Supra condyler humerus* - This fracture involves the **distal humerus**, which is a long bone, but its **marrow content is significantly less** than that of the femur. - While any long bone fracture can theoretically cause a **fat embolism**, the risk is much lower for **supracondylar humerus fractures** due to the smaller amount of fatty marrow. *Lumbar vertebrae* - Vertebral fractures, particularly those in the lumbar region, are primarily associated with the release of **bone marrow cells** and potentially spinal cord injury, but not typically with significant **fat embolism syndrome**. - The **marrow in vertebrae** is predominantly hematopoietic and much less fatty compared to the large medullary cavities of long bones like the femur.

Question 2: The nerve most likely to get injured in patients with fracture of upper end of radius is :

A. Ulnar
B. Posterior interosseous (Correct Answer)
C. Median
D. Radial

Explanation: ***Posterior interosseous*** - The **posterior interosseous nerve** (deep branch of radial nerve) winds around the **neck of radius** through the **radial tunnel** between the heads of the supinator muscle, making it most vulnerable to injury with upper radial fractures. - Injury results in weakness of **finger and thumb extensors** with no sensory loss, as it is a purely **motor nerve** branch. *Ulnar* - The **ulnar nerve** passes behind the **medial epicondyle** of the humerus, making it vulnerable to elbow injuries but not typically affected by upper radial fractures. - Injury leads to **claw hand deformity** and sensory loss in the **medial hand**, which is anatomically distant from the radius. *Median* - The **median nerve** travels through the **cubital fossa** and is anatomically protected from direct trauma by upper radial fractures. - More commonly injured by **distal radial fractures** (Colles' fracture) causing **carpal tunnel compression**, not upper end fractures. *Radial* - The **radial nerve trunk** courses around the **spiral groove** of the humerus, making it susceptible to **humeral shaft fractures**, not upper radial fractures. - Injury causes **wrist drop** and sensory loss over the **posterior forearm**, but the main trunk is anatomically distant from the upper radius.

Question 3: The commonest complication of fracture of clavicle is :

A. non union
B. avascular necrosis
C. Neurovascular injury
D. malunion (Correct Answer)

Explanation: ***malunion*** - **Malunion** is the most frequent complication following a clavicle fracture, meaning the bone heals in an anatomically incorrect or deformed position. - This often results in a palpable bump or cosmetic deformity, and can occasionally cause functional impairment. *non union* - **Non-union** occurs when the fracture fails to heal completely, leaving a persistent gap between the bone fragments. - While possible, it is less common than malunion in clavicle fractures, especially with appropriate management. *avascular necrosis* - **Avascular necrosis** is rare in clavicle fractures because the clavicle has a rich blood supply. - It typically affects bones with precarious blood supply, such as the femoral head or scaphoid. *Neurovascular injury* - **Neurovascular injury** involving the subclavian vessels or brachial plexus is a serious but relatively rare complication of clavicle fractures. - While possible, especially with displaced fractures, it is not the most common adverse outcome.