The historical 2 mm “rule” was originally based on plain radiographs linking step-off > 2 mm to radiographic osteoarthritis, not to functional outcome. Modern CT evaluation allows more precise measurement of intra-articular displacement, revealing that slightly greater incongruities can be tolerated without long-term disability. Nonoperative management remains valid for selected moderately displaced fractures after shared decision-making, potentially reducing unnecessary surgeries.

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Long-Term Patient-Reported Outcomes After Nonoperative Treatment of Distal Radial Fractures: What CT-Based Gaps and Step-Offs Can Be Accepted?

The historical 2 mm “rule” was originally based on plain radiographs linking step-off > 2 mm to radiographic osteoarthritis, not to functional outcome.

Modern CT evaluation allows more precise measurement of intra-articular displacement, revealing that slightly greater incongruities can be tolerated without long-term disability.

Nonoperative management remains valid for selected moderately displaced fractures after shared decision-making, potentially reducing unnecessary surgeries.

🧠 Key Points:

CT-based evaluation shows that intra-articular gaps up to 4 mm and step-offs up to 2 mm can be safely managed nonoperatively, achieving excellent 10-year functional outcomes. The traditional 2 mm rule for surgical indication, derived from plain radiographs, may be overly restrictive in modern CT-guided fracture assessment.

Journal: European Journal of Trauma and Emergency Surgery (2025)

DOI: 10.1007/s00068-025-02954-z