Fractures of the proximal humerus.

Area of Science:

• Orthopaedic surgery
• Traumatology
• Radiology

Background:

• Proximal humerus fractures have been treated for millennia, with current classification systems like Neer and AO/OTA established.
• High intra- and inter-observer variation has been noted in these classification systems since the late 1980s.

Observation:

• Observer studies evaluated agreement on proximal humerus fracture classification across varying clinical experience and imaging modalities (radiographs, CT, 3D CT).
• Low agreement was consistently found for the Neer classification, regardless of observer experience or imaging quality.
• Inter-observer agreement on treatment recommendations was higher than on fracture classification itself.

Findings:

• No significant improvement in classification agreement was achieved by altering experience levels, reducing categories, or using advanced imaging.
• Training demonstrated a significant improvement in agreement, particularly among specialists.
• Despite classification challenges, treatment recommendation agreement was higher, and evidence for surgical interventions in complex fractures is limited.

Implications:

• Proximal humerus fracture classification remains a significant challenge for clinical trials and reporting.
• The weak evidence base for surgical management of complex fractures warrants caution.
• Conducting randomized controlled trials is recommended to establish evidence-based treatment guidelines for complex proximal humerus fractures.