This is Neer's own 30-year retrospective on the 4-segment classification of proximal humeral fractures. He restates the purpose, updates the criteria for each category, and defends the system against reliability studies. The core argument: the classification depicts pathoanatomy of bone and soft tissue, not just radiographic lines.
Anchor your reading of any proximal humeral fracture on two questions: how many segments are displaced beyond 1 cm or 45°, and is the head's blood supply intact? That second question drives treatment. A true 4-part fracture severs the head from its vascular supply, so prosthetic replacement is favored, whereas a valgus-impacted 4-part may retain medial periosteal blood supply and can be salvaged.
Neer's central teaching point is subtle but testable: reliability studies that produced disappointing kappa scores measured whether interpreters agreed on films, not whether the categories are biologically real. He argues validity was proven by decades of direct operative observation.
Practically, get a proper trauma series (scapular AP, scapular Y, Velpeau axillary) and never anchor on a single view. Rotation changes apparent valgus or varus, and the axillary view is what catches a posterior dislocation with an impression fracture. When radiographs are ambiguous in complex fractures, the final classification is legitimately made at surgery.
This is Neer's own 30-year retrospective on the 4-segment classification of proximal humeral fractures. He restates the purpose, updates the criteria for each category, and defends the system against reliability studies. The core argument: the classification depicts pathoanatomy of bone and soft tissue, not just radiographic lines.
Anchor your reading of any proximal humeral fracture on two questions: how many segments are displaced beyond 1 cm or 45°, and is the head's blood supply intact? That second question drives treatment. A true 4-part fracture severs the head from its vascular supply, so prosthetic replacement is favored, whereas a valgus-impacted 4-part may retain medial periosteal blood supply and can be salvaged.
Neer's central teaching point is subtle but testable: reliability studies that produced disappointing kappa scores measured whether interpreters agreed on films, not whether the categories are biologically real. He argues validity was proven by decades of direct operative observation.
Practically, get a proper trauma series (scapular AP, scapular Y, Velpeau axillary) and never anchor on a single view. Rotation changes apparent valgus or varus, and the axillary view is what catches a posterior dislocation with an impression fracture. When radiographs are ambiguous in complex fractures, the final classification is legitimately made at surgery.