**Question:** The most common complication of supracondylar fracture is

A. compartment syndrome
B. neurovascular injury
C. non-union or malunion
D. avascular necrosis

**Core Concept:** Supracondylar fractures are a type of humerus fracture that occurs in children, typically involving the distal humerus. They are classified as either Gartland type I, II, or III based on the degree of displacement. Supracondylar fractures can lead to various complications depending on the severity and treatment.

**Why the Correct Answer is Right:** The most common complication of supracondylar fracture is **B. neurovascular injury**. This occurs when the fracture results in injury to the underlying neurovascular structures, such as the ulnar nerve, radial artery, and vein. The high-riding neurovascular structures in the child's forearm make them susceptible to injury during a supracondylar fracture.

**Why Each Wrong Option is Incorrect:**

**A. compartment syndrome:** This is a rare complication of supracondylar fracture, which typically develops due to extensive soft tissue swelling and compression within the forearm compartment. The correct answer (neurovascular injury) is specific to the injury of the neurovascular structures, whereas compartment syndrome involves extra-neurovascular factors.

**C. non-union or malunion:** These complications refer to the fracture's failure to heal properly or resulting in an abnormal bone alignment, respectively. They are consequences of inadequate reduction and fixation during fracture management, not direct complications of the fracture itself.

**D. avascular necrosis:** This refers to bone death due to reduced blood supply. While avascular necrosis can occur in certain fractures, it is not the primary complication of supracondylar fracture. The primary concern is neurovascular injury and subsequent complications like non-union or malunion.

**Clinical Pearl:** In managing supracondylar fractures, it is crucial to maintain the neurovascular structures to avoid devastating complications. Prompt reduction, fixation, and follow-up are essential for optimal outcomes. In cases of neurovascular injury, timely intervention can prevent long-term sequelae such as paralysis, deformity, and loss of function.