UPSC-CMS 2012 — Orthopaedics

Question 1: Avascular necrosis may develop in the following fractures except

• A. Fracture of the talus
• B. Subcapital fracture of the femoral neck
• C. Fracture of the scaphoid
• D. Fracture of the calcaneum (Correct Answer)

Explanation: ***Fracture of the calcaneum*** - The **calcaneum** (heel bone) has a rich and robust blood supply from multiple arteries, making it highly resistant to avascular necrosis (AVN) even after significant fractures. - While calcaneal fractures can lead to other complications like **subtalar arthritis** or wound issues, AVN is exceedingly rare due to its excellent vascularity. *Fracture of the talus* - The **talus** has a precarious blood supply, primarily from branches off the dorsalis pedis artery, peroneal artery, and posterior tibial artery, which enter at specific non-articular areas. - Fractures, especially those involving the **talus neck**, can disrupt these vital vascular channels, frequently leading to **avascular necrosis** of the talar body. *Subcapital fracture of the femoral neck* - **Subcapital fractures** occur within the hip joint capsule and often disrupt the **retinacular arteries** (medial and lateral circumflex femoral arteries), which are the main blood supply to the femoral head. - This interruption of blood flow to the femoral head is a very common cause of **avascular necrosis**, particularly in displaced fractures. *Fracture of the scaphoid* - The **scaphoid bone** has a unique blood supply where arteries typically enter the distal pole and travel proximally. - A fracture, especially in the **waist** or **proximal pole**, can easily disrupt this retrograde blood flow, leading to a high incidence of **avascular necrosis** in the proximal fragment.