The Copenhagen Classification System for Distal Humeral Fractures is useful to identify patients who may require treatment with hemi- or total elbow arthroplasty.

Background: Classification systems are only useful if there is agreement among observers. The purpose of this study is to introduce a simple and clinically applicable classification system - The Copenhagen Classification System for Distal Humeral Fractures (CCDHF) and to compare the interobserver and intraobserver agreement for this classification with the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma Association (AO/OTA), and the Sheffield classification systems. The primary objective of the new classification system is to distinguish fractures that may not be suitable for open reduction and internal fixation, necessitating treatment options such as elbow hemiarthroplasty or total elbow arthroplasty (TEA). Methods: Five consultant elbow surgeons assessed a consecutive series of 105 sets X-rays of distal humeral fractures on 2 occasions with at least 10 weeks interval. All X-rays were classified according to AO/OTA, Sheffield, and the CCDHF systems. The CCDHF system has been developed collaboratively by a panel of five experienced elbow surgeons. Based on consensus, the surgeons identified specific fracture characteristics where elbow hemiarthroplasty or TEA might be needed. Results: The mean interobserver agreement was fair for AO/OTA and moderate for Sheffield and the CCDHF. The mean intraobserver agreement was moderate for AO/OTA and substantial for Sheffield and the CCDHF. The observers were uncertain about the classification in 29% of the cases with the AO/OTA classification, 15% with the Sheffield classification, and 12% with CCDHF. Conclusion: The CCDHF demonstrated validity and clinical applicability and can assist surgeons in identifying fractures that may require hemiarthroplasty or TEA treatment.