Jakob et al. describe a distinct four-part proximal humerus fracture subtype defined by valgus impaction of the humeral head. The key question: does this pattern carry the same AVN risk and arthroplasty indication as classically displaced four-part fractures? They report outcomes in 19 surgically treated cases using closed or limited open reduction with minimal fixation.
The reflex in 1991 was to treat all displaced four-part proximal humerus fractures with primary hemiarthroplasty, based on Neer's teaching that AVN risk was prohibitively high. This paper showed that teaching did not apply uniformly — the valgus-impacted subtype is biomechanically different.
When you see a four-part fracture where the head is impacted into valgus rather than laterally or posteriorly translated, do not proceed straight to arthroplasty. Instead, attempt closed or limited open reduction with minimal fixation. 74% of patients do well, and you preserve the native joint in a patient who may be young.
The critical distinction on imaging: angulation without translation means soft-tissue attachments are intact and the head can stay viable. If the head is laterally or posteriorly displaced by more than 1 cm, that reasoning no longer applies and arthroplasty remains appropriate.
This paper is the foundation for recognizing valgus-impacted four-part fractures as a favorable subtype. A concept now embedded in modern proximal humerus fracture decision-making and the AO C2 classification.
Jakob et al. describe a distinct four-part proximal humerus fracture subtype defined by valgus impaction of the humeral head. The key question: does this pattern carry the same AVN risk and arthroplasty indication as classically displaced four-part fractures? They report outcomes in 19 surgically treated cases using closed or limited open reduction with minimal fixation.
The reflex in 1991 was to treat all displaced four-part proximal humerus fractures with primary hemiarthroplasty, based on Neer's teaching that AVN risk was prohibitively high. This paper showed that teaching did not apply uniformly — the valgus-impacted subtype is biomechanically different.
When you see a four-part fracture where the head is impacted into valgus rather than laterally or posteriorly translated, do not proceed straight to arthroplasty. Instead, attempt closed or limited open reduction with minimal fixation. 74% of patients do well, and you preserve the native joint in a patient who may be young.
The critical distinction on imaging: angulation without translation means soft-tissue attachments are intact and the head can stay viable. If the head is laterally or posteriorly displaced by more than 1 cm, that reasoning no longer applies and arthroplasty remains appropriate.
This paper is the foundation for recognizing valgus-impacted four-part fractures as a favorable subtype. A concept now embedded in modern proximal humerus fracture decision-making and the AO C2 classification.