## **Core Concept**
Complications of Colles' fracture can be immediate or delayed and include issues related to the fracture itself, immobilization, or associated injuries. Understanding these complications helps in the proper management and prevention of long-term disability. Colles' fracture is a type of fracture that occurs at the distal end of the radius bone in the forearm.

## **Why the Correct Answer is Right**
The question asks for the exception among listed complications of Colles' fracture. Typically, complications include malunion, nonunion, nerve injury (especially median nerve), vascular injury, compartment syndrome, and post-traumatic osteoarthritis.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Malunion is a known complication where the fracture heals in an incorrect position, leading to deformity and functional impairment. This is indeed a complication of Colles' fracture.
- **Option B:** Nerve injury, particularly to the median nerve, can occur due to swelling, direct injury, or compartment syndrome. This is a recognized complication.
- **Option C:** Compartment syndrome is a serious complication that can arise due to increased pressure within the forearm compartments, threatening nerve and muscle function. This is also a complication.
- **Option D:** While certain complications are directly related to the fracture or its immediate aftermath, **Stiffness of the elbow** is less directly related as a specific complication of Colles' fracture compared to the others listed. However, without specific options provided, we infer based on common complications.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that **malunion** is one of the most common complications of Colles' fracture, often resulting in a "dinner fork" deformity. Early recognition and proper management of complications can significantly improve outcomes.

## **Correct Answer: D. Stiffness of the elbow.**
Given that stiffness of the elbow, while possible due to immobilization, is less specifically highlighted as a direct complication unique to Colles' fracture compared to the direct mechanical and anatomical complications listed, it stands out as the exception in the context of direct fracture-related complications.