Gartland Type-IV Supracondylar Humeral Fractures: Preoperative Radiographic Features and a Hypothesis on Causation.

BACKGROUND:The diagnose of Gartland Type-IV (G-IV) supracondylar humeral fractures (SCHF) has been reported to only be possible via fluoroscopy intra-operatively. HYPOTHESIS:A preoperative radiographic fracture pattern can indicate a G-IV SCHF. PATIENTS AND METHODS:Retrospective qualitative analysis of radiographs and reduction techniques used in twenty-seven GIV SCHF. RESULTS:Anterior-posterior radiographs demonstrated lateral translation or angulation in 21 cases (valgus type) and medial translation or angulation in 6 cases (varus type). In spite of a complete cortical disruption, lateral radiographs showed that the distal fragment was vertically aligned with the proximal fragment. Reduction was achieved in semi-extension, via supination in valgus type fracture and pronation for varus type fractures. DISCUSSION:Our conjecture is that a trauma vector in the coronal plane would result in a near-circumferential periosteal disruption, with which either a medial or lateral periosteal hinge remains. The distal fragment would be vertically aligned in lateral radiographs. LEVEL OF EVIDENCE:IV; Diagnostic.