Four-segment classification of proximal humeral fractures: Purpose and reliable use

Abstract

It is now more than 30 years since the first description of the 4-segment classification system for proximal humeral fractures was published. 46 Neer II., CS Displaced proximal humeral fractures. Part I. Classification and evaluation. J Bone Joint Surg Am. 1970; 52: 1077-1089 Crossref PubMed Google Scholar It is based on displacement of segments rather than fracture lines and depicts the pathoanatomy of the soft tissue as well as the bone (Figures 1 and 2). Fig. 2The 4-segment classification system and terminology for proximal humeral fractures and fracture-dislocations. In a 1-part fracture (minimal displacement) no segment is displaced more than 1.0 cm or angulated more than 45° regardless of the number of fracture lines. The terminology for displaced lesions relates a pattern of displacement (2-part, 3-part, or 4-part) and the key segment displaced. In the 2-part pattern, the segment named is the one displaced, including the 2-part articular segment (anatomic neck) fracture, the 2-part shaft (surgical neck) fracture of 3 types (A, impacted, B, unimpacted, and C, comminuted), the 2-part greater tuberosity fracture, the 2-part lesser tuberosity fracture, and the 2-part fracture-dislocations. In all 3-part displacements, one tuberosity is displaced and there is a displaced unimpacted surgical neck component that allows the head to be rotated by the tuberosity, which remains attached to it, including the 3-part greater tuberosity fracture, the 3-part lesser tuberosity fracture, and the 3-part fracture-dislocations. Of the 4-part fractures, the impacted valgus 4-part fracture (A) is less displaced and considered to be, in the continuum of lateral displacement, the precursor to B, the 4-part fracture (lateral fracture-dislocation) in which the head is dislocated laterally and detached from both tuberosities and from its blood supply. In fracture-dislocations, the fracture occurs with a true dislocation, which implies damage outside the joint so that neurovascular injuries and pericapsular bone occur more often. They are named according to the pattern of the fracture (2-part, 3-part, and 4-part) and the location of the head (anterior, posterior, inferior, etc). In 4-part fracture-dislocations, the head is detached from its blood supply. Displaced fractures of the articular surface, the impression and head-splitting fractures, are classified with fracture-dislocations because, while part of the articular cartilage is crushed or fragmented against the glenoid, other fragments are extruded from it. Large impression fractures usually occur with posterior dislocations, as drawn in the diagram, and head-splitting fractures usually extrude fragments both anteriorly and posteriorly. (Drawing A of the valgus-impacted 4-part fracture is used with permission from Jakob et al. Classification and aspects of the treatment of fractures of the proximal humerus. In: Bateman JE, Welsh RP, editors. Surgery of the shoulder. Toronto: Decker-Mosby; 1984. p. 330-43.) (Diagram modified and used with permission from Neer CS II. JBone Joint Surg Am 1970;52:1077-89 and from Neer CS II. Four-segment classification of displaced proximal humeral fractures. In: Chapter 9, Instructional Course Lectures of the American Academy of Orthopaedic Surgeons. Volume XXIV. St. Louis: Mosby; 1975. p. 160-8.) View Large Image Figure Viewer Download Hi-res image This system is widely used for preoperative and intraoperative decision making and for organizing material for outcome studies. 9 Bigliani LU Part I—fractures of the proximal humerus. in: 3rd ed. Fractures in adults. Volume 1. Lippincott, Philadelphia1991: 871-927 Google Scholar , 10 Bigliani LU Flatow EL Pollock RG Fracture classification systems. Do they work and are they useful? [correspondence]. 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J Am Acad Orthop Surg. 1994; 2: 54-66 Crossref PubMed Google Scholar In 1987 the original article had the honor of being selected as “The Classic” and republished in its entirety in one of the leading orthopaedic journals in the United States. 50 Neer II., CS The classic. Displaced proximal humeral fractures. Part I. Classification and evaluation. Clin Orthop. 1987; 223 (By Charles S. Neer I 1970): 3-10 PubMed Google Scholar Further thought and experience have been given to the definitions of the categories, and some improvements have been made in roentgen technique.